Title Page
 Table of Contents
 List of Tables and Figures
 Vascular Plants
 Amphibians and Reptiles
 Literature Cited - Database

Biological Criteria for Inland Freshwater Wetlands in Florida: A Review of Technical & Scientific Literature (1990-1999)
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Permanent Link: http://ufdc.ufl.edu/AA00004279/00001
 Material Information
Title: Biological Criteria for Inland Freshwater Wetlands in Florida: A Review of Technical & Scientific Literature (1990-1999)
Physical Description: Report
Language: English
Creator: Doherty, Steven
Cohen, Matt
Line, Laura
Surdick, Jim
Publisher: Center for Wetlands
Publication Date: 2000
Subjects / Keywords: wetlands
biological indicators
vascular plants
Spatial Coverage: United States -- Florida
General Note: 139 Pages
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Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: AA00004279:00001


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Table of Contents
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Full Text

Biological Criteria for Inland Freshwater Wetlands in Florida:
A Review of Technical & Scientific Literature (1990-1999)

Biological Criteria for Inland Freshwater Wetlands in Florida:

A Review of Technical & Scientific Literature (1990-1999)


Steven Doherty


Matt Cohen, Chuck Lane, Laura Line and Jim Surdick

A Report to:
United States Environmental Protection Agency
Biological Assessment of Wetlands Workgroup

Mark Brown, Principal Investigator
Steven Doherty, Co-Principal Investigator

Center for Wetlands
PO Box 116350
University of Florida
Gainesville, FL 32611

December 2000


Support for this project came from a USEPA Wetlands Division grant to the University of
Florida Center for Wetlands (project 4510363-12), Mark T. Brown and Steven J. Doherty,
Principal Investigators. This report is an outcome of author participation in the USEPA
Biological Assessment of Wetlands Workgroup (BAWWG). The authors wish to
acknowledge the supportive interests of the FDEP Non-Point Source Bioassessment Program
(Ellen McCarron and Russ Frydenborg), BAWWG (Tom Danielson), Florida Water
Management Districts and the ACOE Waterways Experiment Station Florida HGM Program.
Peer review by agency personnel expected to use and benefit from the document will insure
thoroughness and accuracy of information presented here.

This project and the preparation of this report were funded in part by a Section 104(b)(3)
Water Quality Improvement grant from the U.S. Environmental Protection Agency through a
contract with the Florida Department of Environmental Protection.


A ck n ow ledg em ents ................................................................................... .................. ii

List of Tables and Figures ................. ...... ................ ................................ ...... ........... vi

Chapter 1: Introduction .................. ................................................. .. ...... ..... 1
D escrip tio n o f R ep o rt......................................................... ..................................... 1
Background .................................................................. 3

Chapter 2: Procedures .................. .......................................... .. ...... .... 5
L iteratu re S each ........................................................................................................... 5
Database Development .. ............... ............................................ 6

C chapter 3: A lgae ........................................ .................... ........................ ......... 9
U se A s Indicators ................................... ........................... 9
Enrichment / Eutrophication / Reduced Dissolved Oxygen ...................... ............. 9
Contam inant Toxicity ...................................... .. ... ....... .... .... ........... 21
Acidification ............... ................ ...... ....... ...................... 23
S a lin iz atio n .................................................................................................................. 2 5
Sedim entation / Burial .................. ...... ........ ............ .... .. ................. 25
Turbidity / Shading ............................................................... ............... 25
V vegetation R em oval ...................... .. .......................................... .......... 26
Thermal Alteration.............. ...................... ..................... ........ 26
D ehy duration / Inundation ........... ................. ................. ..................................... 26
Habitat Fragmentation / Disturbance...... ................... .................27

C h apter 4 : V ascu lar P lants............................................................................... .. ...... 2 8
U se A s Indicators ................................... ... .. ................................. 28
Enrichment / Eutrophication / Reduced Dissolved Oxygen ............... ................. 32
Contam inant Toxicity .............................. ..... ......... .... .. .... .. ............ 37
A c id ific atio n ..................................................................................................3 8
S alin iz atio n .................................................................3 9
Sedim entation / B urial ............................................. 39
Turbidity / Shading ............... ....... ... .. ........... ....... ....... .............40
Vegetation Removal ................ ............. ............................... 40
Thermal Alteration ................ ...............................................42
Dehydration / Inundation ............. .............................. ...............42
Habitat Fragmentation / Disturbance .......... ................... ........ 46


C chapter 5: M acroinvertebrates................................................................................. 49
U se A s Indicators ................................... ............................49
Enrichment / Eutrophication / Reduced Dissolved Oxygen ............... ................. 53
Contam inant Toxicity ........................................ ........ ..... ............ .......... .. 54
A c id ifi c atio n ...................... .. ............. .. .................................................... 5 5
S alin iz atio n ................................................................. 5 5
Sedim entation / B urial .............. .......................................................... ........ ..... 56
Turbidity / Shading .............. ............. ........... ...... ..... ......... 56
Vegetation Removal ................ ............. ............. .................. 56
Therm al A lteration............................................ 56
D dehydration / Inundation ......... ............... .......................................... ............. 57
Habitat Fragmentation / Disturbance .......................................... .... ............ 58

Chapter 6: Fish ..................... ........ .. ...... .... 60
Use As Indicators ..................................................... ... ...... ..... ......... ....60
Enrichment / Eutrophication / Reduced Dissolved Oxygen ................................... 62
Contam inant Toxicity ........... .... ... ..... ................ .......... ........ ...63
A cid ifi catio n ......... ................................. ........................ ......................................... 6 4
S a lin iz atio n .................................................................................................................. 6 4
Sedim entation / B urial ......... ..... .................................................. ...................65
Turbidity / Shading ............... ....... ... .. ........... ....... ....... .............65
Vegetation Removal ................ ...........................6..................65
Thermal Alteration ................ ...........................6..................65
Dehydration / Inundation ......... ......................................................... ..............66
Habitat Fragmentation / Disturbance ..................... ....................... 67

Chapter 7: Am phibians and Reptiles ......... ......... ...... ............................ 68
Use As Indicators ................. ........................ .......................68
Enrichment / Eutrophication / Reduced Dissolved Oxygen ............... .................70
Contam inant Toxicity .............................. ..... ......... .... .. .... .. ............ 70
A c id ifi c atio n ..................................................................................................7 1
S alin iz atio n .................................................................7 1
Sedim entation / B urial .................. ...... ........ ............ .... ................ ......71
Turbidity / Shading .................................................. .. ........ .. .......... 72
V vegetation R em oval ...................... .. ....................................................... 72
Therm al Alteration.............. ........ ............. ................. ............ 73
D dehydration / Inundation ......... .................... ................. ....................... .............. 73
Habitat Fragmentation / Disturbance.................................... ..................... 74

C chapter 8 : B irds ........................................................... ... ..... . ............75
Use As Indicators ................. .......... ............. .......................75
Enrichment / Eutrophication / Reduced Dissolved Oxygen ............... .................76
Contaminant Toxicity .............................. ...... .................. ............... 77
Acidification ............ .. ....... .. ...... ..................... ........ 78
Salinization .............................................................. ............... 78
Sedim entation / B urial ......... ..... .................................................. ...................78


Turbidity / Shading .............. ................................. .. ... ........ ............ .. 78
Vegetation Removal ................ ............. ............................... ........ 79
T herm al A lteration ............................. ...................... .. .... ...... . ............ 80
D dehydration / Inundation ......... .................... ................. ....................... .............. 80
Habitat Fragmentation / Disturbance................. ....... .............. ... .............. 82

C chapter 9: M am m als................... ................... ...................... .. ........ ...... .............. 84
Use As Indicators ..... ........... .... ................ ........ 84
R response to Stessors ........... .......... .......... .......... .. ............. .. 84

Chapter 10: Wetland Classification and Distribution.............................................. 87
Proposed Wetland Classification ............... ............ ................... 87
Proposed Wetland Regions .......... ........ ................. .............. 89
Wetland Distribution in Florida ............... ............... ................... 93

Chapter 11: Sum m ary ........ ........... ................. .. .... ............. .. 95
Literature B ase ......... .. ....... ..................................................................... 95
Candidate Indicators ............ ... ....... ...... ............ .. ..............99

L literature C ited D atab ase ............................................................................................. 103



Table 2.1. Categorical terms and secondary keywords used in library database
searches........................................................ ......... ...... ............ 7
Table 2.2. Stressors in inland freshwater wetlands. .......... ............... .............. 8
Table 3.1. Summary of potential algal species indicators for freshwater biological
assessm ents. ................... ................. ............................... 10
Table 3.2. Algae typically found in low and high CaCO3 concentrations in reference
w waters of the Everglades. .................................................................... .... 17
Table 3.3. Expected algal trophic states for Florida lakes.......................................... 19
Table 3.4. Algal species typical of eutrophic conditions in the Everglades. ...............22
Table 3.5. Benthic algae found in acidic lakes and streams. ............. .... ................24
Table 4.1. Wetland plant species that typically increase and decrease with
disturbance.................................................................... ... .......... . 29
Table 4.2. Florida wetland plants found in lakes with high and low levels of
phosphorus, salinity, nitrogen, and pH. ............. ...........................30
Table 4.3. Plant species indicators of disturbance in inland freshwater wetlands
o f F lo rid a ............................... ................. ............. ..................3 3
Table 5.1. Macroinvertebrate taxon and weighted index scores for the FDEP
preliminary W wetlands Bio-Recon. ........................................ ................. 51
Table 10.1. Classifications of Florida's inland freshwater wetlands............................ 88
Table 10.2. Proposed classification for biological assessment of Florida inland
fresh ater w wetlands. .......................................................... .............. 90
Table 10.3. Classification cross-reference of proposed classes for biological
assessment of inland freshwater wetlands in Florida. ................................91
Table 11.1. Summary of literature on Florida inland freshwater wetlands. ................... 96
Table 11.2. Summary of literature between 1990-1999 on taxonomic assemblages
and stressors in inland freshwater wetlands of Florida. ........................... 98

Table 11.3. General characteristics of candidate indicator assemblages. .................... 100
Table 11.4. Summary evaluation of taxonomic assemblages as possible indicators
for Florida inland freshwater wetlands. ........................................ ........... 101

Figure 10.1. Proposed regions for biological assessment of Florida inland freshwater
wetlands. .................. ...... ........................ .......... 94



This review document is a compilation of existing and current knowledge regarding
responses of organisms and species assemblages to stressors in Florida inland freshwater
wetlands. It is an outcome of an extensive search of technical and scientific literature
between 1990 and 1999 in libraries and local, state and federal agencies. The document and
database are intended to assist agencies in the development of biological assessment
programs for Florida wetlands to better protect this resource. It is designed to aid in the
identification of appropriate biological assemblages and to provide a basis for an initial
selection of potential metrics and possible methods and field sites for biosurveys. Efforts by
Florida Department of Environmental Protection and others will benefit by drawing upon
past and current wetlands research and biomonitoring programs in the State.

Development of regionally appropriate multimetric indices of biological integrity for
wetlands is requisite of an effective bioassessment program. A first and critical step is
identifying, assembling and reviewing current, on-going, and relevant literature. This review,
specific to inland freshwater wetlands in Florida and the Southeastern Coastal Plain, may
carry more utility for organizations starting biomonitoring programs in Florida that may not
be possible in broader literature reviews. As such, this report compliments other reviews,
including Adamus and Brandt (1990), Impacts on Quality ofInland Wetlands of the United
States: A Survey ofIndicators, Techniques, and Applications of community-level
biomonitoring Data, and Danielson (1998), Indicators for Monitoring and Assessing
Biological Integrity ofInland, Freshwater Wetlands: A Survey of Technical Literature (1989-

The report is organized into chapters of 7 assemblage profiles with research and information
on the biological response of organisms and species assemblages to 10 stressors reviewed
under subheadings within each chapter:

Taxonomic assemblages:
algae, vascular plants, macroinvertebrates, fish, amphibians and reptiles, birds,
and mammals.

Biological response to stressors:
physical/chemical (including nutrient enrichment, contaminant toxicity,
acidification, salinization, sedimentation, turbidity, thermal alteration);
biological (including vegetation removal, species introductions);
hydrological (including ground and surface water withdrawals, stormwater runoff,
drainage, ditching, and other alterations in frequency, duration, and timing of
inundation); and
regional (including habitat fragmentation, connectivity, landscape heterogeneity)

An introduction (Use as Indicators) to each chapter (3-9) outlines advantages and
disadvantages of using a taxonomic assemblage to indicate health in Florida wetlands. If
available, and to a lesser extent, information on sampling designs is reviewed, including
spatial and temporal variability, appropriate and cost-effective field collection methods, data
assembly and analysis. The report includes descriptions of proposed wetland regions and
classifications (Chapter 10) and closes with a summary chapter (11) identifying candidate
indicator assemblages for biological assessment of Florida's inland freshwater wetlands.

Although the primary aim of this report is to identify possible and appropriate taxonomic
assemblages for use in wetland biological assessments in Florida, other relevant information,
if present in the collected literature, is also reviewed. This includes documentation of spatial
and temporal variability of regionally specific biological groups, indicator tolerances, life
histories, habitat preferences, environmental gradients, potentially applicable sampling
methods, and reference conditions for wetland types. If possible, depending upon suitability
of available data and descriptions in the literature, the location of the research is identified
within proposed wetland (eco)regions of Florida (using Lane et al. 1999 and Griffith et al.
1994) and for specific wetland types (using Doherty 1999 et al. and FNAI and HGM

The majority of literature retrieved and reviewed herein pertains to inland freshwater
wetlands in Florida or the Southeastern Coastal Plain and is published or printed between
1990 and 1999. Literature pertaining to other freshwater ecosystems (i.e., streams and lakes),
from other regions, or published prior to 1990, is also included if the available literature is
limited, if the information is transferable to Florida wetlands, or if the publications are
integral to the advancement of wetland biological assessments in general, such as
multivariate statistics applications. Success criteria for wetland creation and restoration
efforts in Florida are also reported if literature is available, including constructed wetlands
for stormwater and wastewater treatment, as mitigation of losses, and for reclamation on
phosphate mined lands. Finally, documents shared by members of the USEPA Biological
Assessment of Wetlands Workgroup are included if relevant to Florida wetland conditions.

Because available research is descriptive and experimental, qualitative and quantitative,
variable in its reporting and general application, and because statistical verification was not
always reported, an effort was made to temper adjectives describing results. Instead, research
outcomes are reported here in unbiased and general terms, indicating positive and negative
correspondence between organisms and stressors, but without qualifiers. This conservative
approach requires that the reader take the necessary step of reading relevant referenced
literature for better understanding.

Thus, this review is a first step and introduction to the literature and documents the relative
extent of knowledge about different taxonomic assemblages and stressors in inland
freshwater wetlands of Florida. Interested persons are encouraged to further process the
information overviewed here based on directives and their own interests.

There are 2 outcomes of this literature retrieval and review project. The report reviews the
literature, and a database allows users to search the collected literature for information

relevant to their inquiry. Because the report is cursory in its review, the reader is encouraged
to access the database (described in Procedures, Chapter 2) to locate literature pertinent to
their needs and specific to wetland type and regions within the State.


Assessments of wetland condition and the degree of impairment due to human actions are
essential to effectively manage Florida's surface and ground water resources and to meet the
objectives of the Clean Water Act, namely to "maintain and restore the chemical, physical,
and biological integrity of the Nation's waters." Under the Clean Water Act, wetlands are
considered "waters of the State," requiring that States set water quality standards and
develop criteria for monitoring and protecting wetlands (USEPA 1987, 1989). Appropriate
criteria include physical/chemical as well as biological conditions.

Assessment methods and indicators are needed that integrate a range of cumulative impacts
on [wetland] ecosystem condition (McCarron et al. {no date}). Biological assessments can
provide effective information about ecological condition (Karr 1991). Numerous studies have
documented the responses of biological attributes across diverse taxa and regions to human
disturbance. Biological indicators are species, species assemblages, or communities whose
presence, abundance, and condition are indicative of a particular set of environmental
conditions (Adamus 1996). Measurement of empirical change in biological indicators can
identify appropriate metrics (biocriteria) sensitive to a range of human activities. The
aggregation of metrics into multi-metric indexes of biological integrity (i.e., IBIs) can assess
stressor gradients and communicate biological condition, both in numeric and narrative form
(Karr and Chu 1999).

The Florida Department of Environmental Protection (FDEP) has developed indices of
biological integrity (IBIs) for assessing the ecological health of streams (Stream Condition
Index, SCI; Barbour et al. 1996) and lakes (Lake Condition Index, LCI; Gerritsen and White
1997). FDEP has conducted limited biosurveys on created wetlands (Division of Technical
Services 1994) and to measure mitigation success (Division of Technical Services 1992,
1996) relating physical and chemical parameters to macroinvertebrate assemblages and algal
community structure. However, prominent assessment protocols for freshwater inland
wetlands in Florida, including the Wetland Rapid Assessment Procedure WRAP (Miller
and Gunsalus 1998) and hydrogeomorphic models HGM (Brinson 1995, 1996; Trott et al.
1997), do not fully utilize biological information to measure disturbance or assess condition,
and there is currently limited coordination between efforts.

A statewide committee of water management district and FDEP representatives
(Subcommittee on Impacts to Natural Systems) issued a report on methods and criteria for
assessing water resources and concluded that a coordination of water management and
monitoring efforts was necessary to develop a set of criteria suitable for determining
unacceptable harm to natural systems (Lowe et al. 1995). A comprehensive evaluation of
constructed wetlands on phosphate mined lands in Florida (Erwin et al. 1997) indicated the

overall adequacy of monitoring data is poor and lacking in standardization due to conflicting
and disparate evaluation techniques.

Development of an index of biological integrity (IBI) for Florida wetlands can help assess
the degree of impairment, identify the source and type of disturbance, monitor the
effectiveness of management programs (e.g., pollution abatement), and evaluate restoration,
creation, and mitigation projects. FDEP in coordination with the University of Florida Center
for Wetlands is developing a biological approach for assessing the health of inland
freshwater wetlands in Florida. In addition to development of wetland classes and ecoregions
for bioassessments, the identification of appropriate biological criteria is needed.

A review of scientific and technical literature is a first step by identifying information
relevant to wetland biological assessment in Florida in order to benefit from past and current
research and to pre-select possible species assemblages that have been noted in the literature
to be sensitive to stressors. Information on regional biological variability, wetland
association, and possible sampling methods is also highlighted in a survey of the literature.
Compiled information on the response of organisms and species assemblages to stressors can
then be tested in field studies to determine its utility in the development of biological
assessments for Florida wetlands.



Technical and scientific literature on inland freshwater wetlands in Florida was located
through library searches of electronic databases, abstracts and indexes, and collected from
participating local, state and federal agencies. Several articles were supplied from members
of the EPA Biological Assessment of Wetlands Workgroup (BAWWG). EPA documents
served as prototypes for this effort, including Indicators for Monitoring and Assessing
Biological Integrity ofInland Freshwater Wetlands (Danielson 1998) and Bioindicators for
Assessing Ecological Integrity ofPrairie Potilihe (Adamus 1996).

Geographic extent of the literature search included Peninsula and Panhandle Florida and,
where applicable studies were located for wetland types also found in Florida, the Outer
Coastal Plain Ecoregion Province of the United States (Omernick and Griffithl987) (i.e., the
Southeastern Coastal Plain). This project surveyed literature published between 1990 and
1999 covering the period following a 1990 review document by Adamus and Brandt
(Impacts on Quality of Inland Wetlands of the United States: A Survey of Indicators,
Techniques, and Applications of Community-level Biomonitoring Data). Relevant
publications and biomonitoring programs conducted prior to 1990 that have been integral to
the advancement of biological assessments of wetlands in Florida were also reviewed. Some
literature published in year 2000, located during the review and writing components of this
project are also included here.

Library databases and online providers were used in keyword searches, and included:
Web of Science
(University of Florida Web LUIS, Library User Information Service)
AFSA (Internet)
AbSearch (Internet)
ZoolRecord (CD ROM)
NISC (Internet)
o Biblioline
Cambridge Scientific
o Aquatic: AFSA, NTIS, Water Resources Abstracts
o Environ: Environmental Sciences and Pollution Management, TOXLINE

Series of keywords were used in each search, combined using Boolean operators and limited
by geographic area and publication date. Three primary keyword (associations) were
repeated in each search to narrow the range of possible matches:

o Wetland
o Florida
o Years, 1990-present

Categories were defined for keyword associations, including: general, wetland type,
taxonomic assemblage, impact/stressor, methodology, agency, and classification/type. Series
of keywords were then assembled for each category and combined with primary keywords to
broaden the search (Table 2.1). Each primary keyword was combined using the Boolean
operand AND, narrowing the search references to include all three primary keyword
associations. Each array of secondary keywords was separated by an OR which broadened
the search within a category. Primary and secondary keywords were combined with the
operand AND. All keywords are truncated using an asterisk (*) that defines the word as a
wildcard and broadening the search by allowing word variants.


The database searches produced compendiums of literature selections, complete with
references and often including article abstracts. Identified references were queried for each
search and a subsample of each database was selected for library retrieval based on the
perceived relevance of each article to the development of bioassessments for Florida inland
freshwater wetlands. Unrelated articles identified by each search were culled from the
selection. Each selected article (from journal publications, book chapters, agency reports,
university theses and dissertations) was copied, indexed and organized into a local database.
Some additional references were located in the literature cited for collected articles, retrieved
and added to the local library. Material collected from other sources was also catalogued.

Reference information for selected literature is recorded into a searchable computer file using
ProCite bibliographic software. Xerox copies of the articles are placed into file cabinets
according to a unique tag identifying the corresponding record in the electronic database. A
local library was developed (filename: WBA CFW library) that can be searched by author,
journal source, publication date, or keywords (from the abstract or other text within the
record). This database is organized and maintained by the University of Florida Center for
Wetlands and will continue to archive literature related to inland freshwater wetlands in

An intention is for this literature database to be available for research and education toward
the development of bioassessment approaches and biological criteria for Florida wetlands.
The searchable electronic database is available to be placed on websites, possibly linked to
the University of Florida Libraries, Florida Department of Environmental Protection, and the
homepage of USEPA's Biological Assessment of Wetlands Workgroup (BAWWG). The
database can be made available to District Biologists, Park Managers, researchers,
consultants, university faculty and students, and citizens interested wetland health and
biological assessments in Florida.

Report chapters (3-9) are organized by taxonomic assemblage (algae, vascular plants,
macroinvertebrates, fish, birds, herpetofauna, and mammals; microbes were not reviewed)
and stressor effects following the descriptions of Adamus and Brandt (1990) (Table 2.2).

Table 2.1. Categorical terms and secondary keywords used in library database searches.

(bio)indicator, (bio)assessment, (bio)monitor, (bio)criteria, integrity, function, health

Wetland type:
palustrine, marsh, emergent, depression, swamp, slough, strand, dome, bog, floodplain,
bottomland, cypress, gum, titi, baygall, hydric hammock, seepage slope, wet prairie, wet

Taxonomic assemblages:
Macroinvertebrate; Ephemeroptera, Plecoptera, Trichoptera, Odonata, Diptera, Gastropoda,
Pelecypoda, Coleoptera, Trombidiformes, Oligochaeta, Hemiptera, Decapoda, Amphipoda,

Fish; Heterandria, Gambusia, Lucania, Fundulus, Lepomis, Ennecanthus, Poecilia

Algae; diatom, periphyton, plankton, lichen, aquatic moss, aufwuch, adventitious root

enrichment, chemical, nutrient loading, eutrophication, organic loading, contaminant, toxin,
acidification, salinization, agriculture, sedimentation, turbidity, shade, clear cut, thermal,
hydrologic drawdown, inundation, hydroperiod, land-use, fragmentation, visitor use, noise,
groundwater withdrawal

IBI (Index of biological integrity), HGM (Hydrogeomorphic model), WRAP (Wetland rapid
assessment procedure), Minimum Flows and Levels, WET (Wetland evaluation technique),
EMAP (Environmental monitoring and assessment procedure)

FDEP (Florida Department of Environmental Protection), WMD (State Water Management
Districts; NWF-, SR-, SJR-, SWF-, SF- WMD), Florida Department of Transportation
(FDOT), ACOE (Army Corps of Engineers), DOA (Department of Agriculture, Forest
Service), USGS (US Geologic Survey), FFWCC (Florida Fish and Wildlife Conservation
Commission), USFWS (US Fish and Wildlife Service), TNC (The Nature Conservancy)

FLUCCS (Florida Land Use, Cover and Forms Classification System), NWI (National
Wetlands Inventory), HGM (Hydrogeomorphic Wetlands Classification), FNAI (Florida
Natural Areas Inventory), FFWCC (Florida Fish and Wildlife Conservation Commission),
SCS (Soil Conservation Service)

Table 2.2. Stressors in inland freshwater wetlands addressed in this report.

concentration or availability of nitrogen and phosphorus. Typically associated with fertilizer
application, cattle, ineffective wastewater treatment, fossil fuel combustion, urban runoff, and
other sources. DO reduction refers to increases in carbon, to a point where increased biological
oxygen demand (BOD) reduces dissolved oxygen in the water column and sediments and can
increase toxic gases (e.g., hydrogen sulfide, ammonia).
CONTAMINANT TOXICITY. Increases in concentration, availability, and/or toxicity of metals
and synthetic organic substances. Typically associated with agriculture (pesticide applications),
aquatic weed control, mining, urban runoff, landfills, hazardous waste sites, fossil fuel
combustion, wastewater treatment systems, and other sources.
ACIDIFICATION. Increases in acidity (decreases in pH). Typically associated with mining and
fossil fuel combustion.
SALINIZATION. Increases in dissolved salts, particularly chloride, and related parameters such as
conductivity and alkalinity. Typically associated with road salt used for winter ice control,
irrigation return waters, seawater intrusion (e.g., due to land loss or aquifer exploitation), and
domestic / industrial wastes.
SEDIMENTATION / BURIAL. Increases in deposited sediments, resulting in partial or complete
burial of organisms and alteration of substrate. Typically associated with agriculture, disturbance
of stream flow regimes, urban runoff, ineffective wastewater treatment, dredge and fill activities,
and erosion from mining and construction sites.
TURBIDITY / SHADING. Reductions in solar penetration of waters as a result of blockage by
suspended sediments and/or overstory vegetation or other physical obstructions. Typically
associated with agriculture, disturbance of stream flow regimes, urban runoff, ineffective
wastewater treatment, and erosion from mining and construction sites, as well as from natural
succession, placement of bridges and other structures, and re-suspension by organisms and wind.
VEGETATION REMOVAL. Defoliation or reduction of vegetation through physical removal,
with concomitant increases in solar radiation. Typically associated with aquatic weed control,
agricultural and silvicultural activities, channelization, bank stabilization, urban development,
defoliation from airborne contaminants, grazing / herbivory, disease, and fire.
THERMAL ALTERATION. Long-term changes (especially increases) in temperature of water or
sediment. Typically associated with power plants, other industry, and climate change.
DEHYDRATION / INUNDATION. 1) Reductions in water levels and/or increased frequency,
duration, or extent of desiccation of sediments. Typically associated with ditching, channelization
of nearby streams, colonization by highly transpirative plant species, outlet widening, subsurface
drainage, climate change, and ground / surface water w ithdra\ anl for agriculture, industry, or
residential use. 2) Increases in water levels and/or increase in the frequency, duration, or extent of
saturation of sediments. Typically associated with impoundment (e.g., for cultivation, flood
control, water supply, or waterfowl management) or changes in watershed land-use that result in
more runoff entering wetlands.
distance between, and reduction in sizes and connectivity of suitable habitat and increases in
noise, predation from pets, disturbance from visitation, and invasion by noxious species capable
of out-competing species that normally characterize wetlands.

Chapter 3: ALGAE


The term "algae" broadly includes benthic algae (epipelon), algae growing attached to
vascular and nonvascular plants (epiphyton), mat algae typically found on the water surface
or within the water column (metaphyton), unattached algae in the water column
(phytoplankton), and other alga growing on substrata (periphyton). Potential algal species
indicators for freshwater biological assessment summarizing the following review are given
in Table 3.1.

Algae provide important functions in Florida inland freshwater wetlands (McCormick et al.
1997) including: (1) as a food source for higher trophic level organisms, (2) in
biogeochemical cycling, (3) by oxygenating the water column, (4) in nitrogen fixation, (5) by
water chemistry regulation, notably pH and major ionic concentrations (Rader and
Richardson 1992), (6) as refugia for other organisms, and (7) as physical barriers to erosion.
Algae are the primary autotrophs in many freshwater wetlands (Goldsborough and Robinson

Algae have many features well suited for use as indicators of wetland health. Changes in
algal assemblages may have far-reaching effects throughout wetland trophic states. Algae are
essentially sessile and cannot avoid loading of deleterious inputs; thus the presence or
absence of a species or its relative abundance may provide information on wetland condition.
Because of relatively rapid lifecycles, algae are among the first organisms to respond to
wetland stressors and often the first to recover (Lewis et al. 1998). Algae are relatively easy
to identify, and certain algal structures resist decay and can be used to establish a history of
water quality (Browder et al.. 1994). Algal sensitivity to nutrient and toxic inputs is fairly
well known (van Dam et al.. 1994, Swift and Nicholas 1987), and due to small size and rapid
turnover, algae are well suited for mesocosm and in situ dose-response experiments.

Disadvantages of using algae as wetland health indicators are noted. While taxonomic keys
exist for algae, most species must be identified using high-powered microscopes. Although
most algae are non-motile, winds and currents can translocate individuals and local
populations from areas of impact to reference areas and vice versa. Algae generally exhibit
seasonal variation in abundance and morphological features that can complicate single
season sampling (Vymazal and Richardson 1995).


The majority of scientific and technical literature on algae in Florida inland freshwater
wetlands deals with response to nutrient enrichment and eutrophication in the Everglades and
associated Water Conservation Areas. The State of Florida Legislature has mandated that by
year 2001 total phosphorous (P) standards be set to protect aquatic resources. In the

Table 3.1. Summary of potential algal species indicators for freshwater biological assessments.
Species Type Healthy Impacted Indications, tendencies Reference
Achnanthes hungarica Diatom X Eutrophy Slate and Stevenson (2000)
Achnanthes sublaevis Diatom X Increase with P loading Pan and Stevenson (1996)
Amphipleura pellucida Diatom X Decrease with P loading Pan and Stevenson (1996)
Amphora lineolata Diatom X Oligotrophy McCormick et al.. (1996)
Amphora veneta Diatom X Eutrophy Slate and Stevenson (2000)
Anabaena sp. Blue-Green X Eutrophy Grimshaw et al.. (1993)
Anheteromeyenia ryderi sponge X Acidic Slate and Stevenson (2000)
Swift and Nicholas (1987)
McCormick et al.. (1996),
Anomoeneis serians Diatom X Low mineral concentrations McCormick and O'Dell (1996)
Anomoeneis serians var.
brachysira Diatom X Low mineral concentrations Swift and Nicholas (1987)
Swift and Nicholas (1987),
Raschke 1993,
Anomoeneis vitrea Diatom X Oligotrophy McCormick et al.. (1996)
Bulbochaete sp. Green X Eutrophy Browder et al.. (1994)
Caloneis bacillum Diatom X Eutrophy Slate and Stevenson (2000)
Chara sp. Macro-alga X Intermediate Craft et al. (1995)
Chroococcus turgidus Blue-Green X Oligotrophy McCormick et al. (1998)
Cocconeis placentula var. lineata Diatom X Eutrophy Slate and Stevenson (2000)
Cosmarium sp. Desmids X High mineral concentrations Gleason and Spackman (1974)
Cyclotella meneghiniana Diatom X Eutrophy Slate and Stevenson (2000)

Table 3.1 (Continued). Summary of potential algal species indicators for freshwater biological assessments.
Species Type Healthy Impacted Indications, tendencies Reference
Cymbella amphioxys Diatom X Low mineral concentrations Swift and Nicholas (1987)
Decrease in proportional McCormick and O'Dell (1996),
Cymbella lunata Diatom X abundance with P loading McCormick et al. (1996)
Cymbella microcephala Diatom X Oligotrophy Raschke 1993
Cymbella minute var.
pseudogracillis Diatom X Increase with P loading Pan and Stevenson (1996)
Cymbella munuta var. silesiaca Diatom X Low mineral concentrations Swift and Nicholas (1987)
Cymbella pusilla Diatom X Raschke 1993
Cymbella ruttneri Diatom X High mineral concentrations Swift and Nicholas (1987)
Cymbella sp. Diatom X Low mineral concentrations Gleason and Spackman (1974)
Epithemia adnata var.
proboscidea Blue-Green X Eutrophy Slate and Stevenson (2000)
Eunotia naegelii Diatom X Low mineral concentrations Swift and Nicholas (1987)
Fragilaria vaucheriae var.
capitellata Diatom X Raschke 1993
Frustulia rhomboids var. ,, i, i , Diatom X Low mineral concentrations Swift and Nicholas (1987)
Frustulia rhomboids var. 'l, ,t ,, Diatom X Low mineral concentrations Swift and Nicholas (1987)
Gomphonema angustatum Diatom X Increase with P loading Pan and Stevenson (1996)
Grimshaw et al. (1993),
McCormick and O'Dell (1996),
Slate and Stevenson (2000),
Gomphonema parvulum Diatom X Eutrophy Swift and Nicholas (1987)
Gomphonema truncatum Diatom X Increase with P loading Pan and Stevenson (1996)

Table 3.1 (Continued). Summary of potential algal species indicators for freshwater biological assessments.
Species Type Healthy Impacted Indications, tendencies Reference
Leptobasis sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)
Lyngbya sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)
Decrease in proportional McCormick and O'Dell (1996),
Mastogloia smithii Diatom X abundance with P loading McCormick et al. (1996)
Gleason and Spackman (1974),
Mastogloia smithii var. lacustris Diatom X Oligotrophy Swift and Nicholas (1987)
Microchaete sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)
Browder et al. (1994),
Grimshaw et al. (1993),
Microcoleus lyngbyaceus Blue-Green X Nutrient Tolerant Swift and Nicholas (1987)
Filamentous Gleason and Spackman (1974),
Mougeotia sp. Green X Low mineral concentrations Swift and Nicholas (1987)
Navicila acicularis Diatom X Increase with P loading Pan and Stevenson (1996)
Slate and Stevenson (2000),
Navicula confervacea Diatom X Eutrophy Swift and Nicholas (1987)
Navicula cryptocephala var. exilis Diatom X Eutrophy Slate and Stevenson (2000)
Slate and Stevenson (2000),
Navicula cuspidata Diatom X Eutrophy Swift and Nicholas (1987)

Navicula disputans Diatom X Eutrophy (but not dominant) Swift and Nicholas (1987)
Navicula minima Diatom X Eutrophy Slate and Stevenson (2000)
Navicula pupula var.
rectangularis Diatom X Eutrophy Slate and Stevenson (2000)
Navicula seminulum Diatom X Eutrophy Slate and Stevenson (2000)

Table 3.1 (Continued). Summary of potential algal species indicators for freshwater biological assessments.
Species Type Healthy Impacted Indications, tendencies Reference
Navicula sp. Diatom X Low mineral concentrations Gleason and Spackman (1974)
Navicula subtilissima Diatom X Low mineral concentrations Swift and Nicholas (1987)
Nitzschia acicularis Diatom X Increase with P loading Pan and Stevenson (1996)
Grimshaw et al. (1993),
McCormick and O'Dell (1996),
McCormick and Stevenson (1998),
Nitzschia amphibia Diatom X Eutrophy Swift and Nicholas (1987)
Nitzschia amphibia f frauenfeldii Diatom X Eutrophy Slate and Stevenson (2000)
Nitzschia brevissima Diatom X? Decrease with P loading Pan and Stevenson (1996)
McCormick and O'Dell (1996),
McCormich and Stevenson (1998),
Nitzschia fliformis Diatom X Eutrophy Pan and Stevenson (1996)
Nitzschia fonticola Diatom X Eutrophy McCormick and Stevenson (1998)
Nitzschia frustulum Diatom X Eutrophy Slate and Stevenson (2000)
McCormick and Stevenson (1998),
Raschke (1993),
Nitzschia palea Diatom X Eutrophy Swift and Nicholas (1987)

Nitzschia sigmoidea Diatom X Eutrophy (but not dominant) Swift and Nicholas (1987)
Nitzschia sp. Diatom X Low mineral concentrations Gleason and Spackman (1974)

Nitzschia sp. 7 Diatom X Eutrophy (but not dominant) Swift and Nicholas (1987)

Table 3.1 (Continued). Summary of potential algal species indicators for freshwater biological assessments.

Species Type Healthy Impacted Indications, tendencies Reference

Nitzschia tarda Diatom X Eutrophy (but not dominant) Swift and Nicholas (1987)
Browder et al. (1994),
Filamentous Grimshaw et al. (1993),
Oedogonium sp. Green X Nutrient Tolerant Swift and Nicholas (1987)
Oscillatoria sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)
Decrease in proportional
Oscillatoria limnetica Blue-Green X? abundance with P loading McCormick and O'Dell (1996)
Oscillatoria princeps Blue-Green X Eutrophy McCormick and Stevenson (1998)
Phormidium sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)
Pinnularia biceps Diatom X Low mineral concentrations Swift and Nicholas (1987)
Plectonema sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)
McCormick and O'Dell (1996),
Vaithiyanathan and Richardson (1997),
Rhopalodia gibba Diatom X Eutrophy Slate and Stevenson (2000)
Schizothrix sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)
Schizothrix calcicola Green X High mineral concentrations Swift and Nicholas (1987)
Scytonema sp. Blue-Green X High mineral concentrations Gleason and Spackman (1974)

Table 3.1 (Continued). Summary of potential algal species indicators for freshwater biological assessments.

Species Type Healthy Impacted Indications, tendencies Reference
Filamentous Swift and Nicholas (1987),
Blue- McCormmick and O'Dell (1996),
Scytonema hofmannii Green X High mineral concentrations McCormick et al. (1998)
Blue- Decrease in proportional
Shizothrix calcicola Green X? abundance with P loading McCormick and O'Dell (1996)
Filamentous Browder et al. (1994),
Spirogyra sp. Green X Nutrient Tolerant McCormick and Stevenson (1998)
Stenopterobia intermedia Diatom X Low mineral concentrations Swift and Nicholas (1987)
;I.... l /1 0iii sp. Green X Nutrient Tolerant Browder et al. (1994)
ST../.. hi /1 iii sp. Green X Eutrophy Swift and Nicholas (1987)
/;4 /1 i ,,1, tenus Green X Eutrophy Grimshaw et al. (1993)
Synedra pahokeensis sp. nov. Diatom X High mineral concentrations Swift and Nicholas (1987)
Synedra rumpens var. familiaris Diatom X Oligotrophy McCormick et al. (1996)
Synedra rumpens var. scotia Diatom X? Decrease with P loading Pan and Stevenson (1996)
Synedra tenera Diatom X Low mineral concentrations Swift and Nicholas (1987)
Synedra ulna Diatom X Eutrophy Slate and Stevenson (2000)

Everglades, extensive research on algae has been and is currently being undertaken in an
effort to acquire baseline data on the effects of nutrient enrichment.

Typically, high nutrient levels favor phytoplankton over macrophytes, especially submerged
species that are adversely affected by increased shading (Adamus and Brandt 1990, Adamus
et al.. 1991). High nitrogen concentrations relative to phosphorus favor green algae, whereas
high P:N ratios favor blue-green algae.

Oligotrophic freshwater marshes, including the Everglades and Savannas State Preserve in
South Florida, are generally phosphorus limited. Algal assemblages along a north-south
nutrient gradient in Everglades sloughs were correlated with nutrient concentrations
emanating from canals in the north that drain the Everglades Agricultural Area (Vymazal and
Richardson 1995, McCormick and Stevenson 1998). High and low concentrations of calcium
carbonate (CaCO3) and nutrients (mainly P) have been found to variously affect algal species
composition in the Everglades.

CaCO3 saturation in the water column is important to Everglades algae (Browder et al..
1994). Gleason and Spackman (1974) provide an early list of algal species indicative of high
and low CaCO3 concentrations in the Everglades. Surface water in the northern reaches
generally contains higher concentrations of CaCO3 (from groundwater) than in the south
reaches (Browder et al. 1994). In oligotrophic reference areas of the northern Everglades
(Water Conservation Areas 1, 2 and 3), both low and high CaCO3 concentrations affect
expected algal assemblages (Swift and Nicholas 1987). Gleason and Spackman (1974) found
calcareous periphyton populations did not flourish where nutrient and CaCO3 concentrations
were low. For example, desmids (Mesotaeniaceae and Desmidiaceae green algae) were
present in high numbers only if the reference areas were undersaturated with CaCO3 and low
nutrients. Browder et al. (1994) report that desmids are likely to occur not only in low
nutrient conditions and undersaturation of CaCO3 but also low pH. Table 3.2 lists algal
species typically found in high and low CaCO3 concentrations in low nutrient waters of the
Everglades. Reference algae in the Everglades indicative of oligotrophic conditions as
reported by McCormick et al. (1996) include: Amphora lineolata, Anomoeneis serians,
Anomoeneis vitrea, Cymbella lunata, Mastogloia smithii, and Synedra rumpens var.

Whereas in some lakes and streams algal mats indicate eutrophication, in the Everglades
algal mats with Utricularia spp. are viewed as indicators of health (McCormick and
Stevenson 1998, Craft et al. 1995, Rader and Richardson 1992). With increasing nutrient
loading, however, the polysaccharides that hold algal mats together disintegrate (McCormick
et al. 1997, McCormick and Stevenson 1998, Craft et al. 1995, Rader and Richardson 1992).
While the mats themselves dissipate the species responsible for the polysaccharides typically
remain, unless affected by other variables (Rader and Richardson 1992). In some cases where
nutrient loading continues, desmid species that construct the mats are replaced by more
nutrient tolerant species. Craft et al. (1995) found that as algae mats dissipated, Chara spp.
became dominant. Browder et al. (1994) reported that in areas of high nutrients, Utricularia -
algae mats were not present and a shift to pollution-tolerant species occurred, including:
Microcoleus lyngbyaceus, Stigeoclonium spp., Spirogyra spp., and Oedogonium spp. Rader

Table 3.2. Algae typically found in low and high CaCO3 concentrations in reference
(oligotrophic) waters of the Everglades.

Indicative of low CaC03

Gleason and Spackman (1974):
Desmids: 78 species
Filamentous green algae
Bulbochaete spp.
Mougeotia spp.
Oedogonium spp.
Spirogyra spp.
Cymbella spp.
Nitzschia spp.
Navicula spp.
Mastogloia smithii var. lacustris

Swift and Nicholas (1987):
Desmids (Order Zygnematales)
Filamentous green algae
Mougeotia spp.
Diatoms (present, generally not dominant):
Cymbella amphioxys
Cymbella. minute var. silesiaca
Anomoeneis serians
A. serians var. brachysira
Frustulia rhomboids var. saxonica
F. rhomboids var. silesiaca
Nitzschia spp.7
Eunotia naegelii
Synedra tenera
Pinnularia biceps
Navicula subtilissima
Stenopterobia intermedia

McCormick et al. (1998):

Indicative of high CaC03


Blue-green algae
Scytonema spp.
Lyngbya spp.
Microchaete spp.
Phormidium spp.
Oscillatoria spp.
Plectonema spp.
Leptobasis spp.
Schizothrix spp.
Cosmarium spp.


Filamentous blue-green algae:
Schizothrix calcicola
Scytonema hoffmannii
Mastogloia smithii var. lacustris
Cymbella ruttneri
Anomoeneis vitrea
Synedra pahokeensis spp. nov.

Scytonema hofmannii
Chroococcus turgidus

and Richardson (1992) report that phosphorus enrichment can cause disintegration of
cyanobacteria polysaccharide sheaths, resulting in a shift from cyanobacteria to filamentous
green algae and diatoms and a corresponding increase in algal biomass.

Enriched runoff (mainly P) has been identified in the Everglades and elsewhere as a principal
factor affecting species composition of algal assemblages. Gleason and Spackman (1974)
found that enriched runoff affected desmid species diversity, the number of blue green algae
species, blue-green algae abundance, the calcareous nature of blue-green algae, periphyton
biomass, and ash content. Browder et al. (1994) list phosphorus along with water chemistry,
nutrient concentration, hydrologic conditions, and soil type as determinants of algal
community composition. Calcite encrustation, occurring in low nutrient areas of the
Everglades, is also affected by phosphorus concentrations (Browder et al. 1994).

With increased P-loading, oligotrophic algal species are replaced by filamentous
chlorophytes like Spirogyra in moderately enriched areas (McCormick and Stevenson 1998,
McCormick and O'Dell 1996). FDEP's Division of Technical Services (1994) found that
moderate nutrient enrichment resulted in a mixed assemblage with no dominant taxa. Highly
enriched areas of the Everglades were dominated by Nitzschia amphibia, N. fliformis, N.
fonticola, N. palea (McCormick and Stevenson 1998). Deleterious affects of P-loading
typically occur at values > 10ug*L-1, and a complete shift away from oligotrophic (reference)
species occurs at values > 20ug*L-1 (McCormick and Stevenson 1998, McCormick et al.
1996, McCormick and O'Dell 1996).

McCormick et al. (1998) found that enriched Everglades areas contained distinct periphyton
assemblages dominated by Oscillatoriaprinceps and a higher percentage of filamentous
green algae taxa (e.g., Sp.liin' ,I). Algal species indicative of eutrophic conditions include
Gomphonema parvulum, Nitzschia amphibia, N. filiformis, and Rhopalodia gibba
(McCormick and O'Dell 1996). Browder et al. (1994) report Spirogyra, Bulbochaetae, and
Oedogonium genera tolerate high nutrients. Grimshaw et al. (1993), based on an extensive
literature review, identify Anabaena spp., Gomphonemaparvulum, Microcoleus
lyngbyaceus, Nitzschia amphibia, Oedogonium spp., and Stigeoclonium tenus as indicators of
eutrophication in the Everglades. Whitmore (1989) presents an extensive list of algae taxa
and expected trophic states from hypereutrophic to dystrophic for Florida lakes (Table 3.3
provides a modified list, potentially applicable to Florida wetlands).

In a study of forested and emergent marshes in Kentucky, Pan and Stevenson (1996) found
algal response to P-loading, but their model had difficulty predicting species assemblages at
low and high loading rates. Nevertheless, from the ordination of their data one could infer
species that respond positively to P-loading (Cymbella minute var. pseudogracilis,
Gomphonema angustatum, G. truncatum, Navicula acicularis, Nitzschiafiliformis, Nitzschia
acicularis, and A, hiuihe,'\ sublaevis) and those with the strongest negative response
(Amphipleurapellucida, Nitzschia brevissima, and Synedra rumpens var. scotica). The
authors conclude that diatoms were good indicators of P-loading and recommended the use
of planktonic and epiphytic diatoms. Studies in Michigan (Stevenson et al. 1999) and
Montana (Apfelbeck in preparation, Charles et al. 1996) also found positive correspondence
between diatom assemblages and phosphorus loading.

Table 3.3. Expected algal trophic states for Florida lakes (modified from Whitmore 1989).

Eu- Oligo- Eu- Oligo-
Species trophic trophic Species trophic trophic

dchnanthes linearis var. linearis X
dctinella punctata var. punctata X
dnomoeneis serians var. serians X
dnomoeneis serians var. acuta X
dnomoeneis serians var. apiculata X
Capartogramma crucicula var. crucicula X
Chaetoceros spp. X
Cocconeis placentula var. placentula X
Cocconeis placentula var. lineata X
Cyclotella meneghiniana var. meneghiniana X
Desmogonium rabenhostianum var. elongatum X
Eunotia bidentula var. bidentula X
Eunotia flexousa var. flexuosa X
Eunotia maior var. maior X
Eunotia microcephala var. microcephala X
Eunotia monodon var. monodon X
Eunotia vanheurckii var. vanheurckii X
Fragilaria construens var. construens X
Fragilaria construens var. pumila X

Fragilaria crotonensis var. crotonensis X
Fragilaria pinnata var. lancetulla X
Fragilaria vaucheriae var. vaucheriae X
Frustulia rhomboides var. rhomboides X
Frustulia rhomboides var. capitata X
Gomphonema acuminatum var. acuminatum X
Gomphonema parvulum var. parvulum X
Gomphonema parvulum var. lanceolata X
Gomphonema parvulum var. micropus X
Melosira ambigua var. ambigua X
Melosira granulata var. muzzanensis X
Melosira varians var. varians X
Navicula bacillum var. bacillum X
Navicula cryptocephala var. crytocephala X
Navicula cuspidata var. cuspidata X
Navicula cuspidata var. ambigua X
Navicula cuspidata var. major X
Navicula gastrum var. gastrum X
Navicula gottlandica var. gottlandica X

Table 3.3. (Continued) Expected algal trophic states for Florida lakes (modified from Whitmore 1989).
Eu- Oligo- Eu- Oligo-
Species trophic trophic Species trophic trophic
Navicula halophila var. halophila X Pinnularia braunii var. amphicephala X
Navicula minima var. minima X Pinnularia legumen var. legumen X
Navicula pupula var. capitata X Pinnularia maior var. maior X
Navicula pupula var. elliptica X Pinnularia subcaptitata var. paucistriata X
Navicula radiosa var. radiosa X Stenopterobia intermedia var. intermedia X
Navicula radiosa var. tenella X Stephanodiscus ui ..'i/i)t i' X
Navicula rhyncocephala var. rhyncocephala X Surirella biseriata var. biseriata X
Navicula subtilissima var. subtilissima X Surirella delicatissima X
Navicula tripunctata var. tripunctata X Surirella linearis var. linearis X
Neidium apiculatum var. apiculatum X Surirella linearis var. constricta X
Neidium floridanum var. floridanum X Surirella robusta var. robusta X
Neidium ladogense var. densestriatum X Surirella robusta var. splendid X
Nitzschia capitellata var. capitellata X Surirella tenera var. tenera X
Nitzschia frustulum X Synedra acus var. acus X
Nitzschia ignorata X Synedra delicatissima var. delicatissima X
Nitzschia paleaceae X Synedra radicans var. radicans X
Pinnularia abaujensis var. abaujensis X Synedra ulna var. ulna X
Pinnularia biceps var. petersenii X Tabellaria fenestrata var. fenestrata X
Pinnularia borealis var. borealis X

Nutrient loading can also affect morphological features of algae (Browder et al. 1994).
Browder et al. (1981) found a significant negative relationship between inorganic P
orthophosphatee) and the percent cell volume in desmids. McCormick and Stevenson (1998)
found P-loading increased algal growth rate and biomass volume. Several species are
identified by McCormick and O'Dell (1996) that decrease in proportional abundance with
increasing phosphorus (Cymbella lunata, Scytonema hofmanii, .\hl/n:,ti i\ calcicola,
Oscillatoria limnetica, Mastogloia smithii, and Anomoeneis serians).

Nutrients other than phosphorus have negative and cumulative impacts algal biota. Scheidt
et al. (1987) found that nitrate significantly decreased algal biomass and eliminated
periphyton within months. McCormick and O'Dell (1996) rank phosphorus as the nutrient
with the largest impact on algal assemblages, followed by nitrogen (N) and iron (Fe).
McCormick et al. (1998) report that phosphorus concentration limits algal growth in
oligotrophic areas of the Everglades. In enriched areas, nitrogen, other nutrients or light
limits growth (Vaithiyanathan and Richardson 1997, McCormick and Stevenson 1998). In
nitrogen limited areas, Vaithiyanathan and Richardson (1997) found increases in Rhopalodia
gibba and blue-green algae with heterocyst (Nostoc). Seasonal algal assemblages typically
found with eutrophication in the Everglades (high N and P concentrations) are listed in Table


Few studies were found in a search of the literature between 1990 and 1999 on the effects of
toxic contamination on algae in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Additional literature on toxic contaminants and wetland algae in other states is
surveyed by Adamus and Brandt (1990) and Danielson (1998), though both reviews conclude
that most research is focused on individual species in laboratory conditions and not on algal
community structure in the field. The reader is also referred to Stevenson et al. (1996),
especially chapters by Genter and Hoagland.

Toxic stress on algal assemblages can come in many forms from many sources. Toxicity
affects algae at biochemical, cellular, population, and community levels (Genter 1996), and
may potentially have chronic exposure effects (Hoagland et al. 1996). Lewis et al. (1998)
examined the response of Selenastrum capricornutum (a freshwater green algae) to in vitro
additions of different effluent (from two cities, one naval air station, three forest product
plants, two agro-chemical industries, one synthetic fibers industry and one steam power
generation plant). Water chemistry parameters were measured (pesticides, polynuclear
aromatic hydrocarbons, polycyclic biphenyls (PCB's), metals (silver, chromium, cadmium,
nickel, lead, aluminum, copper, mercury) and residual chlorine and nutrients). Cumulative,
synergistic toxic impacts from constituent combinations were not studied. Several of the
metals present in the samples were below detection levels. The authors conclude the most
sensitive indicator was algal biomass (which was stimulated in all but one forest product
effluent and one city effluent) and that biomass response was primarily a reflection of phyto-
stimulatory nutrients present in the effluent.

Table 3.4. Algal species typical of eutrophic conditions in the
Everglades (from Swift and Nicholas 1987).

Early Summer Filamentous Greens
Oedogonium spp.
1 11 / ii i,,,, spp.

Late Summer and Fall Filamentous Blue-Greens
Microcoleus lyngbyaceus (previously Oscillatoria tenius)

Winter Diatoms
Gomphonema parvulum
Nitzschia amphibia
Nitzschia palea
Navicula disputans
Navicula confervacea

Other diatoms characteristics of high nutrients
(present but not dominant)
Nitzschia tarda
Nitzschia sigmoidea
Nitzschia sp. 7
Navicula confervacea
Navicula disputans
Navicula cuspidata


No studies were found in a search of the literature between 1990 and 1999 on the effects of
acidification on algae in inland freshwater wetlands in Florida or the Southeastern Coastal
Plain. Literature reviews by Adamus and Brandt (1990) and Danielson (1998) both cite
studies that found filamentous and green algae, especially Mougeotia spp., increase in
abundance with acidification. Typically though, algal species richness declines with
acidification in lakes, but algal production can be relatively high in some naturally acidic

Florida ecosystems typically underlain by limestone are less at risk from point source
acidification than ecosystems in other regions. Also a paucity of geologic ores (phosphate
being the exception) also precludes damage from mining acidification in Florida wetlands.
However, non-point source acidification can occur from atmospheric deposition, and natural
differences in pH and alkalinity may be important determinants of algal assemblages (Rosen
and Mortellaro 1998).

Recent studies in Kentucky, Michigan, and Montana may prove relevant to algal research in
Florida wetlands. Pan and Stevenson (1996) identified conductivity, not pH, as a determinant
of diatom assemblages wetlands receiving acid mine drainage in western Kentucky. The
authors conclude that conductivity inference models based on phytoplankton had better
predictability than those based on epiphyton. In a study of wetland ponds, emergent marshes,
forested systems, bogs, and shrub scrub wetlands in Michigan, Stevenson et al. (1999) found
that variance in diatom assemblages could be partially explained by conductivity and pH.
Weighted average models based on environmental variables identify that relative abundance
of surface sediment diatom assemblages indicates conductivity and pH levels in wetlands.
Periphyton assemblages corresponded to conductivity and pH in a study of wetlands, lakes,
and reservoirs in Montana (Charles et al. 1996). Here inference models were also used with
relative accuracy as predictors of algal species assemblages based on environmental

Numerous studies have documented the impacts of acidification on algal assemblages in
freshwater lakes and streams. In a paleolimnological study of the Everglades, Slate and
Stevenson (2000), classify species indicative of low pH conditions in South Florida (Eunotia
spp.; Eunotiaflexuosa, Eunotia formica, Eunotia glacialis, Eunotia quaternary; and
Amheteromeyenia ryderi). Whitmore (1989) presents over 200 species of Florida lake algae
and a classification for acid tolerance (pH < 5.5, acidobiontic; pH 5.5-6.5, acidophilous; pH
6.5-7.5, circumneutral; pH 7.5-8.5, alkaliphilous; and pH > 8.5, alkalibiontic). Some trends
warrant research in Florida wetlands, especially the response of filamentous green algae,
diatoms, and Cyanophyceae (blue-green algae). Several genera of filamentous green algae
(Zygnemataceae) respond positively to acidification, most notably Zygogonium, Mougeotia,
Spirogyra, and Zygnema, as well as Ulothrix and Oedogoniium (Planas 1996). Among the
most sensitive algae to acidification are species of Cyanophyceae. Planas (1996) reports
tolerance levels (pH 4.8) for blue green algae. Benthic filamentous green algae, diatoms and
blue green algae that indicate acid conditions in surface water are summarized in Table 3.5.

Table 3.5. Benthic algae found in acidic lakes and streams (from Planas 1996).

Achnanthes marginulata
Anomoeneis spp.
Anomoeneis serians
Anomoeneis serians brachysira
Diatoma spp.
Eunotia bactriana
Eunotia curvata
Eunotia exigua
Eunotia incisa
Eunotia pectunalis
Eunotiapectunalis var. minor
Eunotia tenella
Eunotia vanheurkii
Eunotia veneta
Fragilaria acidobiontica
Fragilaria virescens
Fragilaria virescens var.
Frustulia spp.
Frustulia rhomboides
Frustulia rhomboides var. crassinervia
Navicula cumbriensis
Navicula hoeflen

Navicula subtilissima
Navicula tennicephala
Neidium affine
Neidium iridis amphigomphius
Neidium ladogense desentiatum
Pinnularia abaujensis
Stauroneis gracillima
Tabellaria binalis
Tabellaria quadriseptata
Bulbochaete spp.
Microspora spp.
Mougeotia spp.
Mougeotia quadragulata
Spirogyra spp.
Oedogonium spp.
Ulothrix spp.
Temmogametum tirupatiensis
Zygnema spp.
Zygogonium spp.
Zygogonium tunetanum


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of salinization on algae in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Adamus and Brandt (1990) did not find wetland salinization literature in their
review, but state that based on algal responses in other surface waters, it appears likely that
suitable assemblages of salt-sensitive algae species could be identified. Danielson's review
(1998) found lake algal assemblages, especially diatoms, have been correlated with salinity,
with diatom richness highest at specific conductance levels less than 45 mS and declining as
specific conductance increased.

Stevenson et al. (1999) report specific conductivity (a surrogate for salinity) strongly affects
algal assemblages by altering osmotic pressure within the cell and cell membrane. Apfelbeck
(in preparation) reports that diatom abundance was correlated with salinity in freshwater
wetlands in Montana, though the preliminary study does not identify species.


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of sedimentation on algae in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Reviews by Adamus and Brandt (1990) and Danielson (1998) also report a
paucity of literature on wetland algal response to sedimentation. Presumably benthic algae
(epipelon) and periphyton associated with benthic substrates would be adversely affected
from sedimentation and burial. Epiphytic species may be indirectly affected depending on the
response of host plants to sedimentation. Studies in the Everglades and other regions have
documented shifts in plant community assemblages associated with sedimentation and
subsidence (Reddy et al. 1993, Wardrop and Brooks 1998).


No explicit studies were found in a search of the literature between 1990 and 1999 on the
effects of turbidity or shading on algae in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Adamus and Brandt (1990) report a paucity of literature prior to
1990 on wetland algal response to turbidity and shading. Danielson's review (1998)
summarizes a limited literature on lake algae from other states, concluding generally that
turbidity, shading and tannins likely impact benthic algae more than phytoplankton.

In the Everglades, effects of turbidity and shading on algae appear as ancillary data from
phosphorus loading studies. P-loading promotes rapid growth and expansion of Typha
domingensis (cattail), which then shade out algae or fill open spaces formally occupied by
algal mats (Reddy et al. 1993, Browder et al. 1994). In oligotrophic water, P is a limiting
factor; in nutrient enriched water, sunlight for photosynthesis is often a limiting factor due to
shading by macrophytes (McCormick et al. 1998).


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of vegetation disturbance on algae in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Reviews by Adamus and Brandt (1990) and Danielson (1998)
also report a paucity of literature on wetland algal response to vegetation removal. Epiphyton
and periphyton, having lost host substrate, will likely decrease in abundance with the
removal of wetland vegetation, with possible increases in the abundance of other types of


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of thermal alteration on algae in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Browder et al. (1994) documented algae in the Everglades
present in natural water temperatures as high as 36C.

Danielson's review (1998) did not find recent literature on wetland algal response to thermal
alteration, but Adamus and Brandt (1990) state that based on algal responses in other surface
waters it is likely that suitable assemblages of temperature sensitive algal species could be
identified. In general, algal biomass increases with warming to an optimal temperature after
which there is a decrease (DeNicola 1996). Lake studies generally conclude there is an
overall decrease in algal diversity with increasing water temperature with only a few
dominant species of green algae, cyanobacteria (blue-greens), and diatoms.


In their literature review, Adamus and Brandt (1990) state that draw-down of wetland water
levels may concentrate available nutrients and mobilize unavailable nutrients which can
cause algal blooms, while inundation may dilute nutrients and reduce nutrient mobility which
can cause reductions in some algal taxa. Danielson (1998) reviews literature on the response
oflotic periphyton and filamentous algae to flood events, finding both positive (increased
nutrient availability) and negative (increased turbidity, respectively) correspondence.
Increased salinity (higher specific conductance) may result from low water conditions,
negatively affecting wetland algal assemblages.

Episodic dehydration and inundation describes many Florida wetland hydroperiods. For
several months of a year, typically winter in Peninsular Florida, rainfall is low and wetlands
are dry exposing wetland organisms. Adaptations to drying stress include thick cell walls,
mucilage and spore production (Rosen and Mortellaro 1998). During summer rains wetland
algae acclimate to inundation. Thus many algal species are variously tolerant of pulsed
hydroperiods confounding their use as water stress indicators.

Rosen and Mortellaro (1998) found Microsporapachyderma in South Florida was tolerant of
desiccation and thus a good indicator of wetland draw-down, and that Microspora species
had unique growth forms (such as thicker cell walls and akinetes) depending on water
regime. Van Meter-Kasanof (1973) found that larger algae species were better suited for
environmental extremes in the Everglades, and that green periphyton (including some
desmids) required year-round inundation. Swift and Nicholas (1987) report a significant
negative relationship between water depth and percent cell volume in Scytonema spp. and
. hi/_,rthi i\ spp., and a positive relationship between water depth and percent cell volume of
Microcoleus spp.

Browder et al. (1981) found that diatoms and blue-green algae were dominant components of
Everglade wetlands with long hydroperiods. Hydroperiod and water depth are identified by
Browder et al. (1994) as determinants of algal composition in the Everglades: sites with
frequent draw-downs were predominantly comprised of benthic cyanobacteria; diatoms and
green algae were found at frequently inundated sites; and desmids were present only at sites
that were continuously flooded.

McCormick et al. (1998) found algal assemblages in oligotrophic areas of the Everglades
were seasonally different. In the wet period (May October), the predominant algae were
cyanobacteria with high biomass; in the dry period (November April) diatom biomass was
high. Although biomass varied, presence (or absence) of oligotrophic species remained
relatively constant with seasonal changes. Seasonal effects were muted in eutrophic areas of
the Everglades, possibly due to year-round nutrient availability (McCormick et al. 1998). In
eutrophied wetlands, metaphyton and epiphyton biomass varied across seasons and
inundation regimes, while epipelon biomass remained constant (McCormick et al. 1998).
This may indicate that water depth and marsh drying are not strong determinants of algal
species assemblages in the Everglades.

In a paleolimnological study of intermittent bay wetlands in South Carolina and Georgia,
Gaiser et al. (1998) found that Eunotia spp., Luticola saxophila, and Pinnularia borealis var.
scalaris were indicators of sustained drying or draw-down; and other Pinnularia spp. and
Stenopterobia densestriata responded positively to persistent ponding.


No studies were found in a search of the literature between 1990 and 1999 on direct effects
of habitat fragmentation or landscape scale disturbance on algae in inland freshwater
wetlands in Florida or the Southeastern Coastal Plain. Adamus and Brandt (1990) report a
paucity of literature prior to 1990 on wetland algal response to habitat fragmentation and
disturbance, and Danielson's review (1998) similarly finds no recent literature in other states.
Effects of habitat alteration on wetland algae would likely be manifested through changes in
nutrient loading and hydrology and possibly through removal of planktivorous fish.



Wetland plants have many characteristics suited to biological assessments of condition
including: their ubiquitous presence in wetland communities, their relative immobility, the
well developed protocols for sampling, and their moderate sensitivity to disturbances (for
herbaceous species). Disadvantages of using wetland plant assemblages as biological
indicators are that plant species presence and distribution closely reflects wetland
hydroperiodicity and that plant response to anthropogenic disturbances and natural wetland
variability is difficult to distinguish, especially due to changes in hydropattern (Adamus and
Brandt 1990, Danielson 1998).

Sampling procedures for plants are well defined, and several studies have discussed ways of
refining sampling protocols to reduce environmental impact (Hsieh 1996), simplify and
better quantify statistical analysis (Almendinger {no date} and TerBraak 1986), and fully and
effectively characterize the community (Peet et al.. 1996, Division of Environmental
Services 1998, Brown 1991, HDR 1992, Brooks and Hughes 1988). Plant community
development is often monitored in wetland restoration and construction in Florida as a
surrogate to ecosystem remediation and health (Brown et al.. 1997) and the literature is
replete with information on constructed wetlands for stormwater and wastewater treatment,
as mitigation of losses, and for reclamation on phosphate mined lands (Erwin et al. 1997).

Possible plant metrics include: total species richness, abundance of graminoids (Cyperaceae,
Poaceae and Juncaceae), abundance of Carex spp., presence/absence of Utricularia spp., a
floating leaved guild metric, a decomposition metric (i.e., abundance of taxa with persistent
litter), annual vs. perennial, and exotics vs. native (BAWWG Plant Focus Group 1997,
Danielson 1998). Wetland plant species that are generally tolerant (i.e., increases) and
intolerant (i.e., decreasers) of disturbance (Table 4.1) are used by Southwest Florida Water
Management District in a simple index of wetland health [Decreaser Species / (Decreaser +
Increaser Species)].

Hoyer et al. (1996) as part of a statewide lake survey, sampled macrophyte communities in
lake littoral zones. A range of physical-chemical measurements for each lake was also
recorded. The book, titled Florida Freshwater Plants, summarizes a useful database of levels
and ranges of physical and chemical parameters associated with aquatic plant species in
Florida lakes. Because many freshwater plants common in Florida lakes are also component
species in inland freshwater wetlands, this database provides information important to
identification of stressor response signals in wetland plants. The reader is encouraged to use
this compendium as a baseline to identify tolerance ranges of freshwater plants common in
Florida wetlands in the development of biotic indicators. Table 4.2 lists Florida wetland
plants found in lakes with high and low levels (i.e., levels significantly different than the
study average) of selected physical and chemical parameters (phosphorus, nitrogen, pH, and
salinity). The reader is also referred to other literature reviews on wetland plant response to
stressors from other states and regions (Adamus and Brandt 1990, Danielson 1998). Table

Table 4.1. Wetland plant species that typically increase and decrease with
disturbance (adapted from Rochow (1994) and SWFWMD).

Eriocaulon spp.
Sphagnum spp.
Pondeteria cordata
Nymphaea spp.
Nymphoides aquatica
Utricularia inflata, purpurea
Hypericum fasciculatum
Sagittaria spp.
Bacopa caroliniana
Polygala nana, lutea, rugeli, cymosa
Rhynchospora tracyii, corniculata,
Eleocharis spp. (except baldwinii)
Drosera spp.
Juncus repens

Eupatorium spp.
Andropogon spp.
Amphicarpum spp.
Euthamia minor
Rubus spp.
Erianthus spp.
Axonopus spp.
Lycopus spp.
Pinus spp.
Paederia spp.
Paspalum notatum
Blechnum spp.
Woodwardia spp.
Smilax spp. + glauca

Table 4.2. Florida wetland plants found in lakes with high and low levels of phosphorus,
salinity, nitrogen, and pH (i.e., parameter levels significantly different than the study
average, p< 0.05). Adapted from Hoyer et al. (1996).
Species typically found in high range Species typically found in low range

Alternanthera philoxeroides Eleocharis baldwinii
Azolla caroliniana Eriocaulon spp.
Brachiaria mutica Fontinalis spp.
Ceratophyllum demersum Fuirena scirpoidea
Cicuta mexicana Hypericum spp.
Cyperus articulatus Lachnanthes caroliniana
Echinochloa spp. Leersia hexandra
Lemna minor Mayacafluviatilis
Limnobium spongia Myriophyllum heterophyllum
Ludwigia octovalvis Nymphoides aquatica
Myriophyllum aquaticum Rhyncospora tracyi
Paspaldium geminatum Utriculariafloridana
Paspalum repens Utricularia purpurea
Phragmites australis Utricularia resupinata
Pistia stratiotes Xyris spp.
Sagitaria latifolia
Salix spp.
Salvinia minima
Spirodela polyrhiza
Thalia geniculata
Chloride (salinity)
Vallisneria americana Xyris spp.
Thalia geniculata Utriculariafloridana
Spartina bakeri Hypericum spp.
Salvinia spp. Eriocaulon spp.
Pistia stratiotes Brasenia schreberi
Phragmites australis
Paspalum repens
Paspaldium geminatum
Ludwigia octovalvis
Lemna minor
Cyperus articulatis
Crinum americanum
Ceratopteris thalictroides

Table 4.2 (Continued). Florida wetland plants found in lakes with high and low levels of
phosphorus, salinity, nitrogen, and pH.
Species typically found in high range Species typically found in low range

Echinochloa spp. Eriocaulon spp.
Lemna minor Fontinalis spp.
Paspaldium geminatum Fuirena scirpoidea
Hypericum spp.
Leersia hexandra
Xyris spp.


Alternanthera philoxeroides
Bacopa monnieri
Brachiaria mutica
Canna spp.
Ceratophyllum demersum
Ceratopteris thalictroides
Cicuta mexicana
Colacasia esculenta
Cyperus articulatus
Echinochloa spp.
Lemna minor
Limnobium spongia
Ludwigia octovalvis
Mikania scandens
Myriophyllum aquaticum
Najas guadalupensis
Nymphaea mexicana
Panicum repens
Paspaldium geminatum
Paspalum repens
Phragmites australis
Pistia stratiotes
Potamogeton illinoensis
Sagitaria lancifolia
Sagitaria latifolia
Salix spp.
Salvinia minima
Sambucus candensis
Scirpus californicus
Spirodela polyrhiza
Thalia geniculata
Typha spp.
Vallisneria americana

Brasenia schreberi
Eleocharis baldwinii
Eriocaulon spp.
Fontinalis spp.
Fuirena scirpoidea
Hypericum spp.
Lachnanthes caroliniana
Leersia hexandra
Myriophyllum heterophyllum
Nymphoides aquatica
Rhyncospora tracyi
Utricularia purpurea
Websteria confervoides
Xyris spp.

4.3 lists potential plant species indicators of disturbance in inland freshwater wetlands of
Florida, summarizing the following review.

Several reservations about the use of plants as indicators are noted. Jordan et al. (1997) found
that variation in species composition was high between adjacent sites and within micro-
habitats, but that at larger scales variability was reduced. This suggests caution in the use of
sampling protocols and in subsequent analysis of sampled data to ensure that broad scale
metrics are extracted and not indicators of local variability. Harris et al. (1983) argue that
because plants integrate highly localized regions, plant assemblages are better used as
surrogate indicators for birds, which can be used to assess landscape health. Tiner (1991)
argues that wetland plants are unreliable as sole indicators of change in hydrologic regime or
nutrient status. Rather, soil biogeochemistry and physical characteristics need to be used in
concert with vegetation to avoid lag times in plant response to hydrologic alteration.

Other issues concern plant identifications and the use of presence/absence metrics,
particularly for annual wetland vegetation (BAWWG Plant Focus Group 1997). Briggs et al.
(1996) propose that pre- and post-development plant inventories and long-term monitoring
are necessary to adequately characterize effects. Crisman et al. (1997) and Bridges (1996)
suggest that the high spatial and temporal variability in marsh plants preclude the selection of
indicators, but that temporal trends at specific sites may provide more reliable information.
Also a large number of rare and threatened plant species occur in wetlands, and although
they may be inappropriate for use as robust indicators, their presence is important in wetland
valuation (Ward {no date}).

Conclusions from theoretical ecology and modeling are important considerations for wetland
plant indicator development. In a study of plant diversity and grassland stability (Tilman
1996) observed that biomass variability at the plant community level decreased with
increasing richness but populations of specific taxa fluctuate more widely. This suggests that
interspecific competition selects species adapted for current conditions, and phases others
out, illustrating the need to distinguish between community measures and population
dynamics. Another consideration is the distinction between disturbance regimes, and the
possibility that a species may be an indicator of pristine conditions for one disturbance and
an indicator of stress for another. From a grassland model of diversity and disturbance,
Moloney and Levin (1996) conclude that plant species response was a function of
disturbance architecture, implying that spatial and temporal autocorrelation of effects
(contingency) was necessary to simulate ecosystem dynamics.


Nutrient enrichment affects wetland plant community characteristics, particularly annual,
herbaceous and short-lived assemblages such as emergent, submerged and floating species
(Adamus and Brandt 1990, Ewel 1990). Invasions in the Everglades sawgrass (Cladium
jamaicense) communities by Typha domingensis and T latifolia have inspired a plethora of
studies on nutrient enrichment gradients that appear responsible. Doren et al. (1997) studied
community shifts along a phosphorous enrichment gradient in the northern Everglades and

Table 4.3. Plant species indicators of disturbance in inland freshwater wetlands of Florida, based on a review of the literature.
Stressor Tolerant or increasing species Intolerant or decreasing species Reference
Phosphorus Enrichment Typha domingensis Cladium jamaicense Doren et al. (1996)
Amanthus australis Utricularia spp.
Rumex crispa Eleocharis spp.
Nymphaea odorata
Rhycospora spp.
Phosphorus Enrichment Chara sp. Utricularia spp. Craft et al. (1995)
Phosphorus Enrichment Hymenocallis palmeri Peltandra virginica Daoust and Childers (1999)
Typha spp. Pontedaria cordata
Sagitaria lancifolia
Panicum hemitomon
Cladium jamaicense
Phosphorus Enrichment Lemna spp. Ewel (1990)
Eichhornia crassipes
TNT & RBX (Explosives) Potamogeton nodosus Best et al. (1997)
Toxicity Ceratophyllum demersum
Phalaris arundinacea
Lead Toxicity Eleocharis baldwinii Ton et al. (1993)
Salinization Juniperus silicicola Vince et al. (1989)
Baccharis ,i Ai \t /'l, I
B. halimnifolia
B. glomerulifolia
Iva frutescens
Sedimentation and Burial Typha latifolia Carr (1994)
Ludwigia peruviana
Mikania scandens
Agricultural activities Eleocharis spp. Hypericum fasiculatum Broth (1998)
Cattle grazing Digitaria serotina Winchester et al. (1995)
Paspalum paspalodes
Polygonum punctatum
Hydrocotyle spp.
Juncus effusus

Table 4.3. (Continued). Plant species indicators of disturbance in inland freshwater wetlands of Florida.
Stressor Tolerant or increasing species Intolerant or decreasing species Reference

Silviculture Persea borbonia Taxodium distichum Conde et al. (1987)
Magnolia virginiana Taxodium ascendens
Gordonia lasianthus
Fire suppression and subsequent Pinus elliottii Sabalpalmetto Vince et al. (1989)
hotter fires Pinus taeda
Fire suppression Cephalanthus occidentalis Hypericumfasiculatum Winchester et al. (1995)
Salix carolinana
Subsequent hotter fires Rhyncospora spp. Pontedaria cordata Winchester et al. (1995)
Panicum hemitomon
Fire suppression Shrubs Emergent macrophytes Kushlan (1990)
Off-Road-Vehicle Tracks Bacopa caroliniana Cladium jamaicense Duever et al. (1981)
Utricularia spp. Muhlenbergia sp.
Dichromena colorata
Physical disturbance due to Micranthemum umbrosum Shem et al. (1994) &
Right-of-Way Installation Paspalum notatum Van Dyke et al. (1993)
Justicia ovata
Juncus marginatus
Dicanthelium dichotomum
Turbidity/Shading Vallisneria americana Davis and Brinson (1981)
Myriophyllum spicatum
Ceratophyllum demersum
Desiccation UPL and FACU species OBL and FACW species FWS (1990)
Excessive inundation Typha latifolia Salix caroliniana David (1994)
Eleocharis spp.
Rhycospora spp.
Increased hydroperiod Sagitaria lancifolia Rhycospora tracyii David (1996)
Nympaea odorata Baccharis spp.
Utricularia spp.
Increased hydroperiod Utricularia spp. Cladium jamaicense Busch et al. (1998)
Stabilized high water Typha spp. Cladium jamaicense Kludze and Delaune (1996)

Table 4.3. (Continued). Plant species indicators of disturbance in inland freshwater wetlands of Florida.
Stressor Tolerant or increasing species Intolerant or decreasing species Reference

Increased inundation Quercus spp. Titus (1990)
Carpinus caroliniana
Morus rubra
Decreased inundation depth Cladium jamaicense Typha latifolia Koch and Rawlik (1993)
Increased hydroperiod Utricularia spp. Oxypolisfiliformix Wood and Tanner (1990)
Nympaea odorata Dichromena colorata
Bacopa caroliniana Ludwigia repens
Eleocharis elongata Sacciolepis striata
Panicum hemitomon Rhycospora tracyii
Andropogon spp.
Aster spp.
Erianthus giganteus
Pluchea odorata
Increased inundation stress Mikania scandens Sarcostemma clausum Moon et al. (1993)
Decreased hydroperiod Toxicodendron redicans Titus (1996)
Smilax spp.
Quercus spp.
Liquidambar ,,i i o, il,,
Sabal palmetto
Desiccation Eupatorium cappillifolium Rochow (1994)
Amphicarpum muhlenbergianum
Rubus betulifolius
Panicum hemitomon
Desiccation species listed in Rochow (1994) Ormiston et al. (1995)
Myrica cerifera
Phytolacca americana
Passiflora incarnata
Desiccation Andropogon glomeratus Edward and Denton (1994)
Diospyros virginiana

Table 4.3. (Continued). Plant species indicators of disturbance in inland freshwater wetlands of Florida.
Stressor Tolerant or increasing species Intolerant or decreasing species Reference
Decreased Hydroperiod Panicum hemitomon Pontedaria cordata Kushlan (1990)
Rhyncospora spp.
Serenoa repens
Sagitaria lancifolia
Desiccation Melaleuca quinquenervia Typha spp. Hofstetter (1990)
Myrica cerifera Crinum americanum
Eleocharis spp.
Desiccation Dicanthelium ensifolium Bacopa caroliniana SFWMD (1996)
Hypericum tetrapeletum Gratiola racemosa
Lyoniafruticosa Eriocaulon compressum
Xyris caroliniana
Shortened hydroperiod Melaleuca quinquenervia Ewel (1990),
Kushlan (1990)
General urbanization Boehmaria cylindrica Small (1996)
Pilea pumila
Impatiens capensis
Hypericum mutilatum
Juncus effusus
Polygonum sagitatum
Galium obtusum
Habitat fragmentation Typha spp. Brown and Tighe (1991),
Salix carolinana Gunderson (1994),
Eupatorium cappillifolium Schmitz and Simberloff (2000)
Biden alba
Schinus terebinthefolius
Melaleuca quinquenervia
Urena lobata
Paspalum notatum
Phosphate mining effects Wolfiella spp. Crisman et al. (1997)
Wofia spp.
Azolla spp.

documented the reduction of nutrient sensitive species such as Utricularia spp., Eleocharis
spp., Nymphaea odorata, and Rhyncospora spp. In addition to Typha spp., non-native species
such as Amaranthus australis and Rumex crispa increase in response to elevated nutrients.
Biogeochemical studies identify phosphorus as a primary agent driving nutrient enrichment
in the Everglades (Craft and Richardson 1997, Craft et al. 1995, Reddy et al.1993).

Bladderwort (Utricularia spp.) has attracted attention as a potential early-warning indicator
of nutrient enrichment. Moderate levels of P-enrichment in the water column encouraged
growth of Chara spp., a macroalga, which replaced bladderwort several years before other
measurable shifts in wetland plant community composition or dominance were apparent
(Craft et al. 1995). Utricularia spp. is particularly sensitive to enrichment because the
periphytic communities upon which it depends are highly nutrient sensitive, decreasing in
dominance with subtle changes in water quality (Kushlan 1990).

Daoust and Childers (1999) examined the N:P ratios at which nutrient limitation occurs in
the Everglades. Wet prairies were highly P-limited at N:P ratios above 36:1 and Cladium
jamaincense remained dominant, with sub-dominants including Peltandra virginica,
Pontedaria cordata, S.,,ii t ia lancifolia and Panicum hemitomon. When N:P ratios
dropped below this threshold, Typha spp. became increasingly dominant. Hymenocallis
palmer was shown to be N-limited and may signal a change in nutrient regime.

Several studies caution using Typha spp. as a direct indicator of P-enrichment. Maceina
(1994) suggests that water levels have synergistically interacted with elevated nutrient levels
to favor cattail growth, and that removal of the enrichment source may be insufficient to
inhibit the pattern. Similarly, Kludze and DeLaune (1996) show that Typha spp. responds
favorably to increased redox intensity, suggesting that hydropattern (depth and duration of
flooding) plays an essential role in cattail colonization. David (1996) reports that Typha spp.
invaded marsh communities in Lake Okeechobee in response to increased hydroperiod.

Few recent papers were found on wetland plant community response to nutrient enrichment
in regions other than the Everglades. Palis (1997) documented the effects of vegetation shifts
due to silvicultural based enrichment in depression marshes on the flatwoods salamander.
Ewel (1990) reports that a general response to nutrient enrichment in forested wetlands of
Florida is an increase in understory and floating vegetation such as Lemna spp. and
Eichhornia crassipes. Hoyer et al. (1996) surveyed macrophyte communities in lake littoral
zones throughout Florida listing species typical of eutrophic and oligotrophic conditions.


Effects of toxic substances are generally not manifested in wetland plant community
assemblages (Adamus and Brandt 1990), though plants may concentrate contaminants at
levels harmful to higher trophic organisms. Cooke and Azous (1993) found metal
accumulation in plant tissues rose as a function of urban proximity. Tsuji and Karagatzides
(1998) examined lead accumulation in northern marshes from spent gunshot and found no
correlation between increased lead in soil and lead in plant tissue, which remained at

background concentrations. Emergent or floating species with soft-tissue may be promising
indicators of metal toxicity. Several studies document wetland plants propensity for toxic
contaminant attenuation. Best et al. (1997) studied the use of emergent and submerged
plants to remove TNT and RBX (explosive materials) from contaminated groundwater in
Iowa and concluded that Potamogeton nodosus, Ceratophyllum demersum and Phalaris
arundinacea were most effective.

In Florida, several studies have examined accumulation of metals in wetlands. Ton (1990)
and Ton et al. (1993) studied the fate of lead from battery manufacturing in a North Florida
swamp. A compendium volume of Ton's research and others, edited by Odum et al. (2000),
titled Heavy Metals in the Environment Using Wetlands for Their Removal, provides
description and analysis of the ecology, energetic and distribution of lead in swamps. The
authors report slow lead accumulation rates in woody and shrub vegetation but effectively
higher rates in fast growing species such as Eleocharis baldwinii and in components of
woody plants with high turnover such as leaves and shallow roots. A conclusion is that marsh
systems may be more effective sinks for lead due to shallow rooting of emergent

Miles and Fink (1998) examined the ability of constructed marshes to remove mercury and
methyl-mercury from Everglades water. Mercury accumulated primarily in the soil, while
methyl-mercury had large fractions in the soil, plants and animals. Marsh attenuation
measured 70% and mercury bioaccumulation in large-mouth bass within the marsh was
lower than in surrounding areas. McLeod and Ciravalo (1998) studied Boron removal by
bottomland tree species, identifying Betula nigra, Nyssa aquatica, Platanus occidentalis and
Taxodium distichum as tree species with the highest uptake, though no significant changes in
growth parameters were observed. The authors conclude that at low concentrations, Boron is
not toxic to bottomland hardwoods.


No studies were found in a search of the literature between 1990 and 1999 on the direct
effects of acidification on inland freshwater wetland plants in Florida or the Southeastern
Coastal Plain. In general, pH tends to be an important factor in northern depression and
lacustrine wetlands (Adamus and Brandt 1990), and less so in southern swamps and marshes.
In Florida, depression wetlands dominated by Taxodium ascendens tend to have naturally
occurring pH levels less than 5.5 (Ewel and Odum 1984). Hoyer et al. (1996) document
freshwater plant species typically found in low pH lake fringe wetlands of Central Florida
(Table 4.2), though the minimum pH documented in their lake study was 5.2, corresponding
to pH levels of Florida freshwater wetlands receiving rain as the primary water source. Low
pH associated with acid mine drainage is not common in Florida.

Wetland plants found in phosphorus enriched sites are also common in sites with elevated
pH. Acidification effects in Florida may be important by increasing solubility of underlying
carbonate geology. Many of the carbonates contain phosphorus, and dissolution may enrich
surrounding surface water (Reddy et al. 1993).


Gradients between saline and freshwater communities in Florida are generally delineable.
Latham et al. (1994) used detrended correspondence analysis (DCA) to distinguish plant
community composition of marshes in the Southeastern Coastal Plain along a salinity
gradient. With increasing salinity (from oligo- to meso-haline) plant community composition
shifted from typical freshwater emergent plants (Pontedaria cordata, S.0,,,iii i, lancifolia)
to typical salt-marsh plants (Spartina alterniflora, Juncus roemarianus), with Scirpus validus
found across the salinity gradient. In hydric hammocks, a measurable species shift occurs
with higher salinity with increased dominance by Juniperus silicicola and an understory of
Baccharis angustifolia, B. halimnifolia, B. glomerulifolia and Ivafrustescens (Vince et al.
1989). Cephalanthus occidentalis and Nyssa sylvatica var. biflora are both sensitive to
salinity in excess of 2 ppt, with responses most evident in gross photosynthesis, stomatal
conductance, water pressure potential, and stem and root biomass (McCarron et al. 1998).
Under prolonged lower salinity, and in response to short term pulses of high salinity, Nyssa
was more sensitive than Cephalanthus, though the authors conclude that neither species
would survive long-term salinity exposure to 10 ppt.

In general, however, despite an increasing potential of saltwater intrusion into ground and
surface waters in Florida, particularly in the Lower Peninsula, the literature is limited. Hoyer
et al. (1996) document freshwater plant species typical of above and below average lake pH
in Florida lakes (Table 4.2). In their survey, salinity peaks at 90 ppm, which is lower than
what might be expected in surface waters receiving saline inflows, but the results indicate a
marked compositional shift.


Effects of sedimentation on freshwater inland wetland vegetation in Florida have not been
widely studied, though sedimentation rates may be high in wetlands that are impacted by
urban or agricultural runoff, and a considerable literature exists on the ability of wetlands to
facilitate the settling of suspended sediments. In a study of storm water impacts on wetland
vegetation Carr (1994) report a rapid compositional shift in vegetation under high
sedimentation rates, with selection for Typha latifolia, Ludwigiaperuviana and Mikania
scandens, all registered nuisance species in Florida. Changes in plant composition dropped as
sedimentation declined with distance from storm water source.

In a study of the effects of sedimentation in central Pennsylvania wetlands, Wardrop and
Brooks (1998) found specific species respond positively to increased sedimentation, but
community indices such as richness and diversity were uncorrelated. In a related seed
germination study, the authors recorded a reduction in seed viability even under low rates of
sedimentation. Dittmar and Neely (1999) found seed bank response to sediments was
significantly dependent on sedimentation rates but a non-significant function of sediment

texture, with a marked decrease in seed germination with coarser sediments. The authors also
documented reduced plant species richness and diversity under high sedimentation.


Few studies were found in a search of the literature between 1990 and 1999 on the effects of
turbidity and shading on plants in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Adamus and Brandt (1990) state that effects of turbidity and shading on
wetland plants are most pronounced in submerged aquatic vegetation with excess turbidity
resulting in shifts from rooted plants to floating plants or microphytes. Davis and Brinson
(1981) introduced a 'turbidity tolerance index' for submerged aquatic plants as the ratio of
depth maxima of a species to recorded Secchi transparency depth. Adamus and Brandt
(1990) provide a list of turbidity-tolerant aquatic plants with several Florida examples
(Valliseneria americana, Myriophyllum spicatum, Ceratophyllum demersum, Eichhornia
crassipes, Elodea spp., Hydrilla verticillata and Lemna minor)

Grimshaw et al. (1997), studying macrophyte shading of periphytic communities in the
Everglades, found that light transmittance by Typha spp. is 15% compared with 65% by
Cladiumjamaicense. Reduced light available for periphytic photosynthesis is predicted to
influence the replacement of sawgrass by cattail. Reduced capacity to absorb enriched
phosphorus due to loss of the periphyton community may further exacerbate the invasion.


Physical disturbance here includes direct vegetation removal, cultivation, cattle grazing, fire
and fire suppression, rooting by feral hogs, and off-road vehicle use.

Typical plant responses to grazing and cultivation in Florida wetlands are outline in
Winshester et al. (1995). Winshester et al. (1995) describe the displacement of Hypericum
fasiculatum by grasses Digitaria serotina and Paspalum paspalodes and forbs Polygonum
punctatum and Hydrocotyle spp. under high cattle stocking densities. Grazing may result in a
selection of unpalatable species such as Juncus effusus. Arrington (1999) found that feral hog
rooting significantly reduced plant cover and biomass in a broadleaf floodplain marsh, but
increased plant species diversity and richness.

Conde et al. (1987) used Sorensen's coefficient of similarity to compare effects of logging in
adjacent flatwoods on wetland plant community composition and found herbaceous plant
similarity corresponded to silvicultural extent. While woody vegetation similarity was not a
robust indicator, the authors predict a greater dominance of bay species (Persea borbonia,
Magnolia virginiana, Gordonia lasianthus) in cypress wetlands influenced by silviculture. A
hydrologic model of flatwoods interspersed with cypress depressions (Sun et al. 1998)
predicts increased runoff, sedimentation, and longer hydroperiods resulting from adjacent
clearcuts, while selective harvests generate lower impacts.

Fire is an important feature of Florida ecosystems and is often suppressed (Kushlan 1990,
Ewel 1990, Gunderson 1994). Fire in hydric hammocks promotes a dominance of Sabal
palmetto (Vince et al. 1989), and excessively hot fires due to litter accumulation may result
in a compositional shift towards Pinus elliottii and P. taeda. Fire exclusion in marsh
depressions changes location and extent of vegetation zones (Winchester et al. 1985) with a
Hypericumfasiculatum fringe typically invaded by shrubs Cephalanthus occidentalis and
Salix caroliniana. H. fasiculatum seeds may be serrotinous, requiring fire for germination.
Peat fires can arise if exposed to air for prolonged periods and where fire has been
suppressed long enough to allow hotter fires to ignite the organic matter. Peat fires typically
result in a shift from mixed emergent communities dominated by Pontedaria cordata to
communities dominated by Rhyncospora spp. and Panicum hemitomon (Winchester et al.

Effects of fire suppression and dehydration are closely linked (Ewel 1990). Drought induced
shrub invasions into forested wetlands can promote greater fire frequency and burn intensity.
Kushlan (1990) suggests that rapid shrub and tree recruitment in marshes is a direct result of
fire suppression, and that most of the plant species that invade are non-native. A study of
wetlands in Osceola National Forest (Best et al. 1990) however, found that a composite index
of wetland plant status (from 1 = obligate to 5 = upland) was unrelated to fire management.
While hydrologic alterations and fire suppression together influence wetland plant
community composition and zonation, metrics based on plant assemblages may not be robust
enough to separate the stressors. Certainly though plant community characteristics are
suitable indicators of cumulative impacts.

Duever et al. (1981) document vegetative shifts due to off-road vehicles in Big Cypress
Preserve in South Florida and found that off-road vehicle (ORV) impacts were most
pronounced in regions with elevated water tables. Cladiumjamaicense and Muhlenbergia
spp. were most sensitive to ORV impact and were generally replaced by Bacopa carolinana,
Utricularia spp. andDichromena colorata. The response of Utricularia spp. is notable due
to the genera's known sensitivity to nutrient enrichment. Shem et al. (1994) and Van Dyke et
al. (1993) studied vegetation shifts from placement of gas pipelines in North Florida and
report that plant species diversity and richness were elevated in the right-of-ways (i.e.,
disturbed) areas and plant community similarity indices were significantly different.
Dominant cover species in the ROW areas were primarily opportunistic non-natives
(Micrantemum umbrosum and Paspalum notatum), and sub-dominants included Justicia
ovata, Juncus marginatus and Panicum dichotomum.

Broth (1998) found a shift from annual to perennial plant species in Montana wetlands was a
robust indicator of cultivation stress: species ofEleocharis increased, while mosses and other
non-vascular plants were highly sensitive and declined. Cultivation and grazing also resulted
in an increased occurrence of dominant species compared with reference sites. The study also
found that wetland edges were more affected than aquatic beds and that plant species
generally migrate toward deeper water in the presence of grazing. This suggests that a
comparison of plant rooting depths in reference and impacted wetlands might be an indicator
of grazing stress.

Wetland plant responses to natural disturbance are difficult to separate from responses to
human induced stress but responses may be amplified from coupled influences (Loope et al.
1994. Gunderson 1994). For example, the effects of Hurricane Andrew in 1990 on forest
wetlands of the southern peninsula directly resulted in tree-falls, epiphyte removal and
extreme hydrologic conditions. Long-term impacts, however, are related to the diffusion of
non-native propagules into new regions and the proliferation of vines and ruderal species due
in part to loss of canopy cover.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of thermal alteration on plants in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Plant physiology is generally affected at extreme high (> 450 C)
and low (< 0 C) ambient water temperatures. Adamus and Brandt (1990) state that changes
in thermal regime can cause changes in production and shifts in herbaceous species
composition of wetland plant communities. Danielson (1998) also located few studies on
wetland plant response to temperature. Both reviews conclude that vascular plants are likely
poor indicators of thermal alteration in freshwater wetlands.


Hydrology is considered the principal variable directing wetland plant community structure
and function (Mitsch and Gosselink 1993, Kushlan 1990, Ewel 1990). Wetland hydrology is
determined by landscape position, hydraulics and primary water sources (Brinson 1993,
1995, 1996). Changes in the pattern (duration, frequency and timing) and magnitude of
inundation affect plant growth rates and morphology, seed production, germination and
diversity. Ewel (1990) notes that lengthening hydroperiod may have fewer effects on plant
community composition than shortening it. Longer hydroperiods are generally more
conducive to herbaceous plant communities (Sharitz and Gresham 1998). Reviews by
Adamus and Brandt (1990) and Danielson (1998) document a vast literature on wetland plant
response to hydrologic alteration in other states and from Florida studies prior to 1990.
Several recent Florida studies characterize the plant effects of wetland drying and others
have examined wetland plant response to water stage stabilization at abnormally high levels.

Wetland plant communities are commonly described using composite indices of state and
federally assigned designations of typical hydric affinity for plant species. Wetland plant
status is scaled from obligate (OBL) to upland (UPL) with intermediate designations
(facultative -FAC and facultative wet FACW). A test of wetland delineation techniques in
Osceola National Forest found a high degree of correlation between wetland status metrics
and hydric soil characters (Best et al. 1990). The strongest relationship was recorded for
herbaceous plant species and no correspondence was measured for woody species and trees.
A study of depression wetland ecotones in longleaf pine-wiregrass communities in southwest
Georgia used wetland plant status designations to discern plant communities along a
hydrologic gradient (Kirkman et al. 1998). The authors document consistent discontinuities

in plant community composition and a delineated boundary identified by plants designated
'facultative', and suggest that frequent fire in part determined co-dominance of hydrophytes
and non-hydrophytic plants and a high species diversity in the ecotone. Ormiston et al.
(1995) studied floodplain swamps above a wellfield near Tampa and found that average
wetland plant status was significantly higher (more 'facultative' and 'upland' species and
fewer 'fac-wet' and 'obligate' species) in sites within the 3-ft and 1-ft draw-down contours
than outside the cone of depression.

Individual plant species response can be observed from hydrologic change. North of Tampa
Bay, where groundwater pumping has significantly lowered aquifer levels, several indicators
are observed including: more tree falls, increasing rates of limb loss, greater root exposure
from higher soil oxidation and a higher occurrence of peat fires (ESE 1995, Ormiston et al.
1995, Rochow 1994). Wetland tree mortality increased at depths greater than 20 cm in the
Ocklawaha River floodplain from elevated water levels after construction of the Rodman
Reservoir (Harms et al. 1980). The regeneration of Taxodium spp. requires a specific
sequence of hydrologic events (prolonged flooding followed by draw-down followed rapidly
by moderate inundation) that is not likely to occur under an altered hydrologic regime (Ewel
1990). Wood and Tanner (1990) report that tussock height (i.e., height of the meristem) of
Cladiumjamaicense was greater in sawgrass marshes with elevated water levels, rendering
them more susceptible to mechanical disturbance such as airboats.

Keeland and Sharitz (1997) studied the tree growth rates in forest depressions (Nyssa
sylvatica and Taxodium distichum) under two hydrologic regimes: permanently flooded and
periodically flooded. Growth rates were correlated with inundation depth for periodically
flooded trees but not for permanently flooded ones, but no significant difference was
measured between tree growth rates.

Morphological changes in plants may also indicate restructured hydrologic regimes. A study
in South Carolina of root response in Taxodium spp. to inundation (Megonigal and Day
1992) found that cypress trees that were permanently inundated had shallower roots, less
overall below-ground biomass and greater leaf biomass than trees that were not continuously
inundated. The presence of adventitious roots, intercellular air-spaces and distinctly different
root colors and textures were also noted. The authors observed that periodically flooded
cypress trees were more effective at resisting drought stress. These results corroborate Hook
and Brown (1973) who identified root morphology response to hydrologic gradients in
several tree species (Liquidambar styraciflua, Nyssa aquatica, Fraxinas pennsylvanica and
Platanus occidentalis). Only Liriodendron tuliperfera displayed no resistance to flooding

Miller et al. (1993) using chromatography analysis identified a flavinoid in the tissue of
cypress trees under excessive flooding that was absent in unstressed trees and 3 additional
compounds were identified only in the unstressed cypress. As such, biomarkers or the use of
chemical indicators in plant tissue, may provide early warning of hydrologic alterations.

Shifts in plant community structure and zonation can occur due to changes in hydropattern.
On Lake Okeechobee in Southern Florida, David (1994) documented a 35% loss of Salix

carolinana communities due to artificially high water levels, a concurrent decline in cover of
Eleocharis spp. and Rhyncospora spp., and an increase in Typha domingensis. Wading bird
nesting in the region declined from 10000 to 3 nesting sites over 15 years. David (1996)
observed an increase in dominance of Sagitaria lancifolia, Nymphaea odorata and
Utricularia spp. due to longer hydroperiods and a concurrent decline in Rhyncospora tracyii
and Baccharis spp. Cattail increased in importance, but this change could not be
distinguished from the response to enrichment. Busch et al. (1998) corroborated the positive
response of Utricularia spp. to longer inundation and deeper water levels, but found that
Cladiumjamaicense dominance was negatively correlated with water depth.

Stabilized water levels in the Water Conservation Areas of South Florida are implicated as a
primary factor in the displacement of Cladiumjamaicense to Typha spp. (Kludze and
DeLaune 1996). This is primarily due to adaptations in cattail for tolerating highly reduced
soil conditions, which the authors directly correlated with water depth. Titus (1990) studied
microtopographic relief in floodplain forests and concluded that dry micro-sites were
essential for retaining Taxodium distichum, Ulnus americana and Fraxinus caroliniana in
wetlands where water levels were stabilized, whose seedling distribution were best correlated
with micro-site elevation. In hydric hammocks, it is predicted that increased inundation stress
will result in a loss of Quercus spp., Carpinus caroliniana and Morus rubra. Management of
higher water levels from 1992 to 1995 in wet prairie habitats of Southwest Florida caused a
change from the favored muhly grass (Muhlenbergiafilipes) dominated habitat to a habitat
dominated by sawgrass (Cladiumjamaicense) (54% muhly in 1992 to 25% in 1995) (Nott et
al. 1998).

In the Everglades, Koch and Rawlik (1993) report generally higher transpiration and
conductance rates for Typha domingensis (11 mmmol/m2/sec) than for Cladiumjamaicense
(min 7 mmmol/ m2/sec), measured in the winter and spring months. Annual transpiration
rates for both species were 1 to 2 mmmol/ m2/sec greater at a eutrophic site than at
oligotrophic sites. These results at the leaf scale suggest that nutrient enrichment and
vegetation shifts have the potential to alter water balances in the Everglades and may amplify
the dehydration processes.

Newman et al. (1998) concluded that multiple and interacting factors influenced cattail
invasions in the northern Everglades. While nutrient enrichment was a primary variable,
vegetation shifts also occurred in areas that were not P-enriched. Rather, a synergistic
interaction between increased depth of inundation, P-enrichment, and episodic fires set
conditions suitable for sawgrass displacement and cattail invasion. Historically Typha spp.
was restricted to deep water areas and around alligator holes, and increased inundation
depths may favor cattail over sawgrass. Peat fires may increase availability of mineral
nutrients and lower substrate elevation, conditions favorable to cattail.

Wood and Tanner (1990) used ordination techniques to classify Everglades graminoid
communities into functional groups with hydropattern as the primary descriptive variable.
Plant community associations followed a hydrologic gradient: wet prairies occupied the
deepest zones; communities dominated by the medium growth form of C. jamaicense
occurred in areas with less standing water; and tall sawgrass stands in the shallowest areas.

Increased hydroperiod caused vegetation shifts in all communities. In wet prairies,
Utricularia spp. and Nymphaea odorata increased in extent with elevated water levels, along
with Bacopa carolinana, Eleocharis elongata and Panicum hemitomon. Wet prairie species
that required annual draw-down for seed germination were not found with increasing
hydroperiod, including Oxypolisfiliformis, Dichromena colorata, Ludwigia repens,
Sacciolepis striata and Rhyncospora tracyii. In sawgrass communities elevated water levels
resulted in a loss of Andropogon spp., Aster spp., Erianthus giganteus, Pluchea odorata and
Sarcostemma clausum.

Climbing hempweed, Mikania scandens, a noxious plant in Florida, also responds favorably
to inundation stress during early life stages is (Moon et al. 1993). The vine has adapted stem
stomata for gas exchange, which is unique, and can readily produce aerenchymous tissue to
transport oxygen to the root zone. Climbing hempweed is a noxious plant with strong
presence in wetland edges and disturbances in central and South Florida. Normal
hydropatterns in riparian wetlands appear to favor the selection of Panicum rigidulum,
Panicum dichotomum and Chasmanthium laxum, while sites with lower flood frequency tend
to be dominated by Toxicodendron radicans and Smilax spp. Titus (1996) predicts that
reductions in inundation magnitude and duration in forest floodplains would result in an
increase in dominance of Quercus spp., Liquidambar styraciflua and Sabalplametto.

Draw-down effects on wetland plant community composition are well documented. Rochow
(1994) monitored wetlands overlying cones of depression from groundwater withdrawal in
West Florida and found rapid invasions by Eupatorium capillifolium, Amphicarpum
muhlenbergianum, Rubus betulifoilus and Panicum hemitomon. In addition to the species
listed above, Ormiston et al. (1995) documented the recruitment ofMyrica cerifera,
Paederiafoetida, Phytolacca americana and Passiflora incarnata in response to
groundwater draw-downs. Edwards and Denton (1993) monitored a wellfield site in Pinellas
County and found that common invaders include Andropogon glomeratus and Diospyros
virginiana. Kushlan (1990) suggests that common plant indicators of prolonged dry
conditions in marshes are Panicum hemitomon, Rhyncospora spp., Serenoa repens. Though
both are obligate wetland plants, Pontedaria cordata may replace Sagitaria lancifolia during
periods of drought. In the Everglades, however, David (1996) found the distribution of
Sagittaria lancifolia increased significantly with longer flooding duration.

Sonenshein and Hofstetter (1990) document marsh vegetation changes within a regional
wellfield in the Southern Florida peninsula. In the site most impacted by the cone of
depression, Melaleuca quinquenervia was highly invasive, along with Myrica cerifera.
Wetter sites outside the cone of depression, supported Typha spp, Crinum americanum,
Sagitaria lancifolia and Eleocharis spp., but there was a clear trend of increased dominance
by shrubs and trees.

In an effort by South Florida Water Management District to develop metrics of hydrologic
alteration in depression wetlands, Bridges (1996) discusses the difficulty of extracting
metrics from wetlands for which normal variability is extreme. Certain species, such as
Andropogon spp., Aristida rhizomorpha and Amphicarmpum muhlenbergianum may be poor
indicators because they have adapted to a wide variety of hydrologic conditions in ephemeral

marshes. Trees, long-lived shrubs and some graminoids (Panicum hemitomon, Cladium
jamaicense) may also be poor indicators because they can withstand intense periodic
hydrologic stress. Bridges (1996) recommends some general indicators for the South Florida
region including Bacopa caroliniana, Gratiola racemosa and Eriocaulon compressum, as
they are all sensitive to desiccation. More specific indicators of a trend towards drier
conditions include Dicanthelium ensifolium, Hypericum tetrapetalum, Lyonia fruticosa and
Xyris carolinana.

Ewel (1990) and Kushlan (1990) articulate several plant responses to draw-down typical in
the Everglades. Melaleuca quinquenervia invasion in the Everglades is strongly facilitated
by hydropattern changes with drier periods than were normal under historical conditions.
Marsh succession to a shrub/scrub community can be attributed to drier conditions.
Taxodium distichum, though appearing healthy in abnormally dry substrates, will not be able
to regenerate. Cooke and Azous (1993) argue that non-native plant species presence and
distribution increase with drastic changes in hydropattern.

The Kissimmee River restoration effort has focused on re-hydrating emergent marshes that
were characteristic of the region prior to channelization (Toth 1993). A demonstration
project showed a marked shift in species composition after rehydration. Former (pre-
channelization) dominants that returned were Eleocharis vivipara, Panicum hemitomon,
Polutgonum punctatum and Salix caroliniana in addition to the invasive hydrophyte
Alternantheraphiloxeroides. The importance of meso- and xero-phytic species that
colonized when the wetlands dried decreased after re-flooding, including Ambrosia
artemisiifolia, Axonopus affinis, Axonopus compressus, Boltonia diffusa, Centella asiatica,
Eupatorium capillifolium, Hydrocotyle spp., Paspalum conjugatum, Sambucus canadensis
and Urena lobata.


Despite new research in GIS, few studies were found in a search of the literature between
1990 and 1999 on direct effects of habitat fragmentation and disturbance on plants in inland
freshwater wetlands in Florida or the Southeastern Coastal Plain. In general, fragmentation
will favor those species that can disperse seeds widely (e.g. Typha spp., Salix caroliniana,
Eupatorium capillifolium and Bidens alba) and those that are opportunistic invaders after a
disturbance (e.g. Schinus terebinthefolius, Melaleuca quinquenervia, Urena lobata Paspalum
notatum) (Doherty 1991, Brown and Tighe 1991, Gunderson 1994, Schmitz and Simberloff

There is a large body of research on wetland restoration and construction on phosphate
mined lands in Florida (Brown and Tighe 1991, Crisman et al. 1997, Richardson et al. 1998).
Erwin et al. (1997) summarize the literature and analyzed the available data base on created
wetlands to determine current technical, operational, and ecological success of wetland
construction. One of seven research components, a section on ecosystem and landscape
organization addresses 3 subject areas: ecological connectedness, hydrological
connectedness, and community fitness. An upland to wetland ratio was higher in reclamation

projects than in the regional landscape with agriculture the dominant land cover. These
landscape parameters likely influence successional trajectories and restoration successes,
explaining in part a documented trend of declining obligate wetland species and no
concurrent decline in plant species richness in herbaceous wetlands on reclaimed lands.

Doherty (1991) used principle component analysis and general linear models to investigate
the role of landscape organization on ecological restoration in phosphate mined and
abandoned agricultural lands in Central Florida. Tree species composition on sites 40 years
and older were 70% similar to one another and on average 30% similar to natural
communities displaced as a result of the land-use. Swamps and sandhills, which have been
displaced at the greatest rate in the region, were not returning. Age since abandonment was
the most predictive variable in determining structural factors such as tree density, basal area
and ground cover, though 'interaction potential' of and mean distance to forest areas were
better predictors of overall species richness and herbaceous and tree diversity than age alone.

Crisman et al. (1997) compare reclaimed marshes in the phosphate mining district of Central
Florida and nearby reference marshes, and conclude that, while plant species similarity
indices are low, chemical function and landscape function are comparable. In general,
invasive species tend to concentrate in the reclaimed sites, but non-native cover drops to
background levels within 7 years. Higher densities of floating plants were found in the
reclaimed sites, with an abundance of Wolfiella spp., Wolfia spp. and Azolla spp.

Schmalzer and Hinckle (1990) state that of the 1045 plant species found at John F. Kennedy
Space Center, 195 were non-native, and 76 were listed as endangered, threatened or of
special concern. They suggest a qualitative relationship between proximity to disturbed
regions and the density of non-native (positive) and endangered (negative) species.

Research in other states on plant response to landscape fragmentation and disturbance is
available. Miller et al. (1997) measured landscape pattern in central Pennsylvania and
conclude that general landscape descriptors (diversity, contagion, mean forest-wetland patch
size, proportion of forest cover, forest edge) were most effective at predicting disturbance
levels and changes manifested in bird and plant communities. Azous et al. (1998) studied 19
wetlands in Washington, finding significant correlation between disturbance gradient and
community attributes, including canopy closure, nesting cavities, vegetation distribution and
dominance, woody debris, presence of thin-stemmed emergent vegetation, plant species
richness and non-native species cover. Azous and Horner (1997) found direct
correspondence between plant species richness and impervious surface in a Washington
watershed, but a less significant relationship was found between weedy native and exotic
plant species and disturbance.

Fennessey et al. (1998) developed a Floristic Quality Assessment Index (FQAI) to indicate
landscape disturbance effects on wetlands. The FQAI is a scoring technique that assigns a
quality rating to each plant species present in a wetland based on general disturbance

0 Opportunistic native invaders and non-native taxa.
1-3 Widespread ubiquitous taxa that do not indicate a specific community with a wide
range of tolerances.
4-6 Taxa that typify some successional phase of a native community, tolerant of some
7-8 Taxa associated w/ advanced succession, community specific, tolerant of minor
9-10 Taxa that exhibit high degrees of habitat fidelity to ecological condition,
endemism, and a narrow range of environmental parameters.

Average index scores [Species Tolerance Score / (No. Native Species)1/2] for wetlands
correlated with a qualitative disturbance gradient. The FQAI score was also correlated with
site biomass, total-P in the water column, buffer zone presence and distance to the nearest
propagule source.

Small (1996) quantified macrophyte response to watershed development in the Chesapeake
Bay region and found that most (75%) of the riparian wetlands could be categorized along a
disturbance gradient using only plant species richness as an indicator. Ten species drop out
as landscape disturbance increased: Boehmaria cylindrica, Pileapumila, Impatiens capensis,
Hypericum mutilum, Juncus effusus, Polygonum sagitatum and Galium obtusum.



Macroinvertebrate assemblages are particularly appropriate for use in multi-metric indices of
biotic integrity in streams (Karr 1997) and may also be robust indicators for wetland
biological assessment. Invertebrates are abundant and easily sampled, and the species living
in virtually any water body represent a diversity of morphological, ecological, and behavioral
adaptations to their natural habitat. A diverse component of wetland habitats,
macroinvertebrates respond quickly to changes in physical, chemical or biological
parameters (Stansly et al.. 1997). Structure and function of macroinvertebrate communities
reflect biological conditions, and change in predictable ways with increased human

Macroinvertebrates are also an important link in wetland food webs as most vertebrate and
higher trophic organisms are dependent upon invertebrate populations (Hart and Newman
1995). Removal of aquatic arthropods would likely cause a local collapse of fish, amphibian,
reptile, and wading bird populations (Trott et al.. 1997). However, evaluation of impacts of
environmental perturbations to wetland macroinvertebrate assemblages is a daunting task,
given poor taxonomic knowledge of groups such as Chironomids (midges) that may
represent more than 50% of total secondary production in depression wetlands of South
Florida (Stansly et al. 1997).

Macroinvertebrate assemblages are used as biological indicators in streams in several states
including Florida (Kerans and Karr 1994; Barbour et al. 1996). Florida Department of
Environmental Protection (FDEP) developed the Stream Condition Index (SCI) and the
recently employed Rapid BioRecon Method using macroinvertebrate assemblages to evaluate
biotic integrity. Samples are collected using dip net sweeps in representative substrate.
Biological condition is determined using a multi-metric approach comparing test stream
results with regional reference conditions, assumed to be the best attainable condition of the
water resource. For Florida streams the best macroinvertebrate metrics are: Florida Index
species, EPT taxa (Ephemeroptera, Plecoptera, Trichoptera), percent dominant taxon, and
percent gatherers. All indices decrease with increased pollution or disturbance except for the
% dominant taxon (Barbour et al. 1996).

FDEP has recently been developing a method of assessing biotic integrity of lakes (Gerritsen
and White 1997). This method employs grab samples of macroinvertebrates from lake
sediments just beyond the littoral zone, with either a Petit Ponar or Eckman dredge, in 60-
100 cm deep water (aquatic bed-littoral zone). Results are compared with reference
conditions using multi-metric indices suitable for lakes. Metrics under consideration are: taxa
richness, Shannon-Weiner diversity, Hulbert index, ETO taxa (Ephemeroptera, Trichoptera,
Odonata), percent dominance, percent filterers, percent ETO, and percent gatherers. Use of
two trophic state indicators (Secchi depth and Chlorophyll-a concentration) in conjunction
with a lake IBI may best determine the biological condition of a lake (Gerritsen and White

FDEP uses a preliminary wetland Bio-ReCon field sheet that scores macroinvertebrate taxa
present in dip sweeps using a weighted index for sampled taxa (Table 5.1). Three metrics are
currently computed (total taxa richness, total lake index, and total ETO taxa). Wetland health
or impairment is determined based on deviation from target values. The scoring and selection
of metrics is developed from Bio-ReCon protocols for Florida streams and lakes, the SCI and
LCI, and best professional judgment of District Biologists.

The Department of Environmental Resources Management is developing a biomonitoring
program for the fresh surface waters in Southern Florida canal systems using the SCI as
protocol (Snyder et al. 1998) and adapted for the special conditions facing the canal systems
as data are collected and analyzed. Benthic macroinvertebrates are also being used to
evaluate the success of restoration projects. Merritt et al. (1996) report on the restoration of
the Kissimmee River Basin and identify regional species pools of aquatic insects that
potentially occur in the basin. The authors also evaluate the assignation of functional groups
based on feeding, habit, and voltinism and the use of calculated ratios to make assessments of
ecosystem attributes. Toth (1993) documents invertebrate responses to water level
manipulation in a Kissimmee River demonstration project.

Macroinvertebrate communities appear to colonize newly constructed wetlands with
reasonable success (Erwin et al. 1997). In a study of the biological success of created
marshes in Central Florida, FDEP used components of the SCI and the LCI to assess the
benthic macroinvertebrates for the wetlands and compared them to a reference marsh
(Division of Technical Services 1994). Results indicate that structural and functional groups
of created marshes were moderately close to those of the reference wetland.
Macroinvertebrate populations in a natural/created wetland system for advanced secondary
treated wastewater in Central Florida were similar to a control wetland (Best 1993). Crisman
et al. (1997) reviewed research on aquatic fauna in constructed wetlands on phosphate mined
lands in Florida and found that within three years invertebrate communities stabilized in
numbers and feeding guilds were generally comparable to those of natural wetlands. Erwin et
al. (1997) caution the reader that inferences made from this review may not be accurate due
to different monitoring programs, constructed wetland design and substrate conditions.

Dip net sweeps are an effective sampling method for wetland macroinvertebrates (Cheal et
al. 1993, Rader and Richardson 1994). However, Turner and Trexler (1997) found that use of
three complimentary methods a funnel trap, a D-frame sweep net and a 1-m2 throw trap -
give a complete representation of a wetland invertebrate assemblage. Turner and Trexler
(1997) and Fennessy et al. (1998) found Hester Dendy samplers to be ineffective in wetlands.
Stansly et al. (1997) and Gore et al. (1998) used bottle-brush samplers to represent
macrophyte substrate, as well as dip nets and Hester-Dendy samplers in their surveys of
isolated wetlands in South Florida with satisfactory results. In wetlands, as in other aquatic
habitats, it is important to sample all types of substrate and plant communities as
macroinvertebrate abundance and distribution vary between habitat types. Streever et al.
(1995) sampled Chironomidae in vegetated and non-vegetated areas and found the
communities different in each habitat type.

Table 5.1. Taxon and weighted index scores for the FDEP preliminary Wetlands Bio-Recon.
Total scores are used in combination with 3 metrics (Total Taxa Richness, Total
Lake Index, ETO) to indicate wetland health or impairment.

WI Taxa

WI Taxa

Other Chironomidae
Clinotanypus spp.
Ablabesmyia spp.
Procladius spp.

Ferrissia spp.
Littoridinops spp.
Physella spp.
Planorbella spp.
Pomacea paludosa
Viviparus spp.


Dineutes spp.
Haliplus spp.
Peltodytes spp.


Neohermes spp.

1 Hemiptera
1 Belostoma spp.
1 Corixidae
Hydrometra spp.
Pelocoris spp.
1 Pleidae
Ranatra spp.

Other groups

Palaemonetes spp.
Procambarus spp.

Gammarus sp.
Hyalella azteca
Crangonyx spp.

Caecidotea spp.

Callibaetis spp.
Caenis spp.

Argia spp.
Enallagma spp.
Ischnura spp.
2 Lestes spp.
Nehalennia spp.
Telebasis byersi

Anax spp.
Coryphaeschna ingens
Gomphaeschna spp.

Aphylla williamsoni
Argomphus pallidus

Epitheca spp.
Somatochlora spp.

Celithemis spp.
Erythrodiplax spp.
Erythemis spp.
1 Libellula spp.
Pachydiplax longipennis
1 Tramea spp.


Nectopysche spp.
Orthotrichia spp.
Oecetis spp.
Oxyethira spp.
Triaenodes spp.
Leptocercus spp.
Ceraclea spp.

Total score:


Total score:

Total score:

Wetland macroinvertebrate ecology in Florida and the Southeastern Coastal Plain is well
researched. Wharton et al. (1982) describe macroinvertebrate fauna of bottomland hardwood
swamps by vegetative zone. Batzer and Wissinger (1996) reviewed literature on insect
community ecology in non-tidal wetlands, including some found in the Southeastern Coastal
Plain. Kushlan (1990) documented invertebrate populations of Florida marshes, including
amphipods, dragonflies, damselflies, mosquitoes, gnats, deerflies, horseflies, waterbugs,
water beetles and ostracods. Freshwater prawns, crayfish and snails are also found in large
numbers and are conspicuously important in food chains.

Haag et al. (1987) found that on floating islands in Orange Lake in North Central Florida, the
following macroinvertebrates are a major source of food for Boat-tailed Grackles and
Redwing Blackbirds: water bugs (Belostoma spp.), plant hoppers (Fulgoridae), diving beetles
(Dytiscidae), crayfish (Procambarusfallax), shell snails (Planorbella spp.), dragonflies and
damselflies (Odonata, genus Libellulidae), leaf beetles (Chrysomelidae, genus Donacia),
noctuid caterpillars, rat-tailed maggots (Eristalis spp.), water beetles (Hydrophilidae), scarab
beetles (Scarabaeidae), soldierfly larvae (Stratomyidae), water hyacinth weevils (Neochetina
eichhorniae and N. bruchi), grasshoppers, arachnids and ants.

Pickard and Benke (1996) studied the amphipod Hyalella azteca in southeastern wetlands, on
3 habitats (benthos, Nymphaea odorata leaves, and submerged wood) and found that H.
azteca was most abundant in benthic habitat. Birth and death rates were highest in summer,
with predation and/or environmental stress were mortality factors. Hyalella azteca does not
appear to be a dominant primary consumer. This study is a part of a more comprehensive
analysis of invertebrate production in southeastern wetlands. Rader (1994) found one
hundred forty-eight macroinvertebrate taxa in sloughs in the northern Everglades.
Chironomidae, Gastropoda, and Coleoptera, were the most diverse groups with the greatest
densities, and the amphipod Hyallella azteca was the most abundant species. Planorbella
duryi was the most abundant snail, and Callibaetisfloridanus the most abundant mayfly.
Stansly et al. (1997) catalogued 225 macroinvertebrate species in 159 general, 49 families
and 13 orders of crustaceans, mollusks and insects in isolated wetlands within the South
Florida Water Management District. Oligochaetes and acarines were not included.
Chironomids dominated, with odonates, hemipterans, and coleopterans all well represented.

In South Florida's hydric pine flatwoods, Gore et al. (1998) catalogued 292 taxa, of which 60
were various species of chironomids. Fishing spiders (Dolomedes triton) are found in the
Everglades among dense stands of cattails and sawgrass, but density estimates suggest that
they are unlikely to play important roles in the marsh food web (Jordan et al. 1994). Jordan et
al. (1996) studied the crayfish Procambarus alleni in wet prairies. Mean density and biomass
of crayfish increases with increased plant biomass found in densely vegetated wet prairies
compared with less dense, deep-water sloughs.

Literature available on macroinvertebrate ecology and responses to stressors in Florida
wetlands, combined with the SCI, Rapid BioRecon, the LCI, information on wetland types
and locations, and successful sampling methods are a basis to develop a macroinvertebrate
index of biotic integrity for Florida wetlands.


Benthic macroinvertebrate species composition responds to trophic state (Cairns and Pratt
1993). For example, tubificid oligochaetes increase with organic enrichment (Barbour et al.
1996). High nutrient wastewater added to a cypress swamp changes the invertebrate
community (Ewel 1990), and the addition of stormwater or wastewater to cypress ponds is
shown to cause the community to shift to a simpler trophic structure (Harris and Vickers
1984). Duckweed (Lemna spp.) mats over the water surface in Florida cypress domes blocks
sunlight from the water column creating anoxic conditions (Dierberg and Brezonik 1984),
reducing the diversity and biomass of benthic invertebrates, and leaving only a few pollution-
tolerant organisms (Brightman 1984). Gerritsen and White (1997) found that sublittoral
macroinvertebrate communities in Florida lakes also appear to respond to lake trophic status.

Rader and Richardson (1992, 1994) studied macroinvertebrate response to nutrient
enrichment in the northern Everglades. A greater number of coleopteran species (especially
in the Hydrophilidae and Dytiscidae families) was recorded in enriched and intermediate
areas than in unimpacted sites (total mean annual density of macroinvertebrates at enriched
and intermediate sites was 6.1 and 3.5 times greater, respectively, than in the unenriched
area). Except for decapods, especially Palaemonetespaludosus, the density of each order or
class was higher within enriched and intermediate areas. Percent composition measured 2.6
times higher and density of dipterans as 16.2 times greater at enriched and intermediate sites
than at the unenriched site. Dominant dipterans at enriched sites were Dasyhelia spp.,
Goelkichironomus holoprasinus, Larsia decolorata, Polypedilum trigonus,
Pseudochironomus spp., and Tanytarsus sp. J. The number of taxa (primarily Chironomidae)
did not increase, and was very similar for all sites.

Schwartz et al. (1994) studied impacts of reclaimed water from an advanced wastewater
treatment facility on wetland communities in Orange County, Florida. Reclaimed water flows
through a distribution created wetland to a natural pond cypress swamp. It then flows into a
redistribution created wetland, to a natural hardwood swamp and then exits through a final
pond cypress swamp. Aquatic and benthic macroinvertebrates were sampled in the water
column and substrate with a modified stovepipe sampler. Shannon-Weaver diversity indices
increased overall in all the wetlands during the third year of the study, with the hardwood
swamp displaying the highest diversity in each sampling event. Numbers of pollution-
sensitive species were highest in the control and exit wetlands. However, all pollution
tolerant assemblages were represented in each treatment wetland for every sampling event,
indicating good water quality in all wetlands.

Stormwater input to the freshwater marsh in Savannas State Preserve increased phosphorus
levels, lowered oxygen levels and raised pH and hardness, resulting in macroinvertebrate
population shifts toward pollution tolerant species and those intolerant of typical acidic and
oligotrophic conditions of the preserve (Graves et al. 1998).


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of contaminant toxicity on macroinvertebrate communities in inland freshwater
wetlands in Florida or the Southeastern Coastal Plain. The reader is referred to Danielson
(1998) for a review of recent wetland invertebrate toxicity studies from other regions. Here,
select studies from other regions that may have relevance to Florida wetlands are reviewed.
Lenat (1993) reports that toxic conditions caused increases in the number and types of
deformities in Chironomus larvae in streams in North Carolina.

Eisemann et al. (1997) found mercury concentration in apple snails (Pomaceapaludosa) as
high as (0.091ppm) at the Panther National Wildlife Refuge in Florida. Apple snails are an
important component of food webs in South Florida wetlands and can serve as indicators of
bioavailable mercury. From results of stream studies, Barbour et al. (1996) state that some
chironomids of the family Orthocladiinae, genus Cricotopus, are tolerant of metal pollution.
Other Orthocladinae (Rheocricotopus spp. and Corynoneura spp.) are thought to be sensitive
to metal pollution.

Selenium has become an important environmental contaminant in agricultural arid and semi-
arid regions of the western U.S. and in areas where fossil hydrocarbons are mined, processed,
and used for combustion. Selenium is a trace element present in coal, crude oil, shale, coal
conversion materials and their waste by-products. It is highly concentrated in the mineral
fraction (fly ash and bottom ash) remaining after coal is burned. A slight increase in selenium
concentration in water can quickly bioaccumulate in aquatic organisms and become toxic to
the higher trophic levels (Lemly 1996). While no Florida studies on selenium in wetlands
were found in this review, it may be an overlooked toxic contaminant in areas where fossil
fuels are stored and burned.

Batzer and Wissinger (1996) found the primary influence of herbicides on wetland insects is
indirect, killing the macrophyte and algae food base. Buhl and Faerber (1989) performed
toxicity tests of selected herbicides and surfactants on the midge Chironomus riparius. The
relative order of toxicity to this midge is similar of those for other macroinvertebrates and
fish, so results may be applicable to wetland chironomids of southeastern wetlands.

Henry et al. (1994) studied macroinvertebrate survival in Prairie Pothole wetlands of South
Dakota treated with a mixture of a glyphosate-based herbicide, a surfactant and a drift
retardant used for cattail control. Populations of Chironomus spp. (midge), Hyalella azteca
(amphipod), Stagnicola elodes (pond snail) and Nephelopsis obscura (leech) were monitored.
After 21 days, there was no difference in the survival of the study organisms and those of the
control. In laboratory tests, based on nominal formulations of the concentrations, the
surfactant was approximately 100 times more toxic than the herbicide, which was about 24
times more toxic than the drift retardant. The authors conclude that these formulations pose
no threat to aquatic life, when applied according to the directions, but could be hazardous if
used improperly.

Various chemical pest applications are used in agriculture, silviculture and lawn care in
Florida, and pesticides in water and sediment can adversely affect wetland macroinvertebrate
communities, though no recent studies were found. Broad-spectrum pesticides such as
organophosphate mosquito larvicide may unintentionally or indirectly impact other wetland
insect populations. The microbial mosquito larvicide Bacillus thuringiensis israelensis is
much more target-specific and has minimal impact on nontarget insects (Batzer and
Wissinger 1996) though mortality has been observed in several taxonomic orders (see
Danielson 1998 for review).


No studies were found in a search of the literature between 1990 and 1999 on the effects of
acidification on macroinvertebrate assemblages in inland freshwater wetlands in Florida or
the Southeastern Coastal Plain. Calcium carbonate common in Florida soils buffers acidity,
and activities associated with acidification are not common in Florida. Still, natural
differences in pH and alkalinity may be important determinants of macroinvertebrate
communities. Highly acidic water generally results in impoverishment of fauna, and low
acidities generally reflect better buffering and higher productivity (Adamus and Brandt
1990). Stribling et al. (1995) found that in Montana wetlands, low acidities are positively
correlated with metrics of percent dominant taxon, percent amphipoda and Hilsenhoff Biotic
Index. Circumneutral pH, but on the acidic end of the range, is positively correlated with the
metrics of total taxa, Chironomidae taxa, and percent filterer-collectors.

Experimental acidification of wetland habitats often has shown little impact on insects unless
the pH becomes very low. In contrast, low pH may benefit insects in some cases where
insectivorous fish cannot tolerate the acidic conditions. Apparently, many wetland insects
tolerate broad ranges of environmental pH (Batzer and Wissinger 1996) and may be poor
indicators of acid pollution stress.

Metals and acidity interact variously affecting toxicity. Short et al. (1990) found lower
macroinvertebrate abundance and diversity in wetlands with low pH and high concentrations
of dissolved minerals (Al, Cu, Fe, Mn, Zn). Albers and Camardese (1993) studied the effects
of acidification on metal accumulation by aquatic plants and invertebrates in constructed
wetlands in Laurel, Maryland. The pH of the acidified wetlands was 5.0, not low enough to
cause a difference in amount of the twelve metals released into the water column except for
zinc, but calcium was lower in the acidified wetland. The low pH could cause adverse effects
on the occurrence of crustaceans and mollusks by threatening egg production and
development of young.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of salinization on macroinvertebrate assemblages in inland freshwater wetlands in
Florida or the Southeastern Coastal Plain. However, Stribling et al. (1995) found that

salinization is positively correlated with percent dominant taxon while all other metrics
decreased as salinity increased in Montana wetlands.


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of sedimentation on macroinvertebrates in inland freshwater wetlands in Florida or
the Southeastern Coastal Plain. Generally, benthic species composition is determined by
substrate (Gerritsen and White 1997) and invertebrate communities change with erosion and
sedimentation. Evans (1996) studied sedimentation in constructed wetlands on Florida
phosphate-mined lands and found that gently sloping banks were lower in silt content than
steeper slopes, and silt content in sediments decreased with age since construction and bank
colonization by freshwater plants.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of turbidity and shading on algae in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Shading from dense stands of emergent vegetation can limit the
productivity of benthic algae (Adamus and Brandt 1990) favoring detritivores over grazers.
In a study of California wetlands, De Szalay and Resh (1996) found that fine particulate
organic matter settles out with increased shading, providing a rich detritus that supports high
numbers of benthic detritivores.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of vegetation disturbance on macroinvertebrates in inland freshwater wetlands in
Florida or the Southeastern Coastal Plain. Reviews by Adamus and Brandt (1990) and
Danielson (1998) also report a paucity of literature on wetland invertebrate response to
vegetation removal. Canopy opening and the loss of vegetative structure will likely shift the
macroinvertebrate community to more open water, less sedentary, and predatory species.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of thermal alteration on macroinvertebrates in inland freshwater wetlands in Florida
or the Southeastern Coastal Plain. Adamus and Brandt (1990) in their review conclude that in
general, heated effluents reduce the richness of invertebrate communities in wetlands and
may either increase or decrease their density and productivity. The former may be true in
Florida where ambient temperature increases do not necessarily expand ranges or provide
over-wintering conditions.


Hydropattern (depth, duration and periodicity of flooding) entrain wetland community
organisms and influence composition, including associated macroinvertebrate assemblages,
which either temporarily relocate or cope using behavioral and biological adaptations.
Hydroperiod affects the movement of crayfish Procambarus alleni, which has been identified
as a critical species in the food webs of freshwater marshes of Southern Florida (Frederick
and Spalding 1994). The crayfish prefer shallow waters of wet prairies to deeper areas, and
disperse during times of inundation (Jordan et al. 1996). Apple snails (Pomaceapaludosa)
are not as adaptable, however, and water level increases threaten their eggs, which are
intolerant of submergence (Turner 1998).

During draw-down or dewatering in lakes, benthic macroinvertebrate populations can
experience reduced densities or elimination. After refill however, macrophyte densities may
increase due to colonization of the increased littoral zone habitat (Greening and Doyon
1990). A draw-down and sediment removal project in Lake Tohopekaliga, Florida (Butler et
al. 1992), resulted in lower densities and numbers of invertebrate taxa associated with
macrophytes, and bottom-dwelling macroinvertebrates increased in the restored area. The
difference was attributed to fish predation on invertebrates associated with macrophytes.
Predatory sport fish in the restored lake area increased to three times the number in the
control site.

Rader and Richardson (1994) compare 2 wetlands in the northern Everglades; a nutrient
enriched area with a shorter hydroperiod and a control site that remained inundated
throughout the study. Invertebrate and small fish diversity and abundance was higher in the
enriched site with less standing water and 3-6 weeks of no surface water, though the higher
measures may be due to the proximity of permanent water to the site that may act as a source
for colonizers. Loftus et al. (1986) found that invertebrate and small fish abundances in
Everglades National Park declined in marshes with short hydroperiods.

Small pond cypress swamps can remain flooded all year or dry completely four times or
more in a single year. Leslie et al. (1997) sampled benthic macroinvertebrates using a
stainless steel coring device in three pondcypress swamps in North Central Florida and
documented 85 taxa. This is a higher richness count than some other southern wetlands
(though other studies typically do not sample sediments). Ninety percent of the samples were
found surviving in sediments of dry ponds. 70% of overall density was accounted for by 3
generalist feeders, Crangonyx (Amphipoda) and chironomids Polypedilum spp. and
Chironomus spp. Densities of benthic invertebrates in depressions that had been dry for over
one month were similar to those with wet months, suggesting that density and distribution
metrics may not be robust indicators.

Wetland macroinvertebrates exhibit both behavioral and physiological adaptations to cope
with draw-down. Crangonyx spp. and several insects including beetles and odonate nymphs
can burrow into moist sediments, and some chironomid larvae can withstand draw-down in a

cryptobiotic state, as reported by Gore et al. (1998) for wetland depressions in hydric
flatwoods of South Florida. Other insects complete their life cycle or have emerged as adults
before drought, and other insects lay eggs that withstand desiccation (Stansly et al. 1997,
Gore et al. 1998, Batzer and Wissinger 1996).

Aquatic macroinvertebrates that are predatory or have a long life cycle may be indicators of
hydroperiod stability in isolated wetlands of South Florida (Stansly et al. 1997). Indicators of
persistent water include mayflies, Caenis, and odonates Anax spp., Libellula spp. and
Pantala spp. The chironomids Beardius spp., some members of Chironomus and Tanytarsus,
and Zavreliella marmorata also apparently need permanent standing water. Some common
species in isolated wetlands, including Polypedilum trigonus and Tanytarsus sp. B., rarely if
ever were found in intermittently exposed wetland (Gore et al. 1998). Other species were
typical of intermittently exposed and ephemeral wetlands, including Ablabesmyia rhamphe
grp., Krenopelopia spp., and Tanytarsus sp. G.


No studies were found in a search of the literature between 1990 and 1999 on direct effects
of habitat fragmentation and disturbance on macroinvertebrates in inland freshwater wetlands
in Florida or the Southeastern Coastal Plain. Reviews by Danielson (1998) and Adamus and
Brandt (1990) also report a paucity of literature related to wetland macroinvertebrate
response to habitat fragmentation and disturbance prior to 1990 and from other regions.
Adamus and Brandt (1990) surmise that as the distance between wetlands with colonizers
becomes greater, species with narrow environmental tolerances and which do not disperse
easily might be most affected.

An example of an insect that may be at risk from landscape scale wetland fragmentation is a
distinctive endemic phenotype ofEuphyes dukesi, a Lepidopteran that was first discovered in
Florida in 1971. E. dukesi has been found on wetland sedges, Rhyncospora and Carex
(Calhoun 1995). Harris (1988) proposes that surface water pollution probably reduced the
production of macroinvertebrates, in turn affecting swallow-tailed kite (Elanidesforficatus)
populations in the Everglades. Destruction of the Citronelle Ponds, wetlands of the Gulf
Coastal Plain of Florida, is pervasive due to agriculture and forestry (Folkerts 1997).
Presumably invertebrates and other species associated with this wetland type are imperiled
with the loss of their habitat.

Colonization of nonnative and noxious species is common in disturbed wetlands. Local
invertebrate populations may be affected by introduction and spread of other exotics, such as
fish and plants that change the community composition and food webs of wetlands. Rader
(1994) found some macroinvertebrate colonists from Central and South America in the
northern Everglades. The snail Marisa cornuarietis (Ampulariidae) has been introduced in
the canals of Dade County and is likely to invade the Everglades (Robins 1971).

Water hyacinth weevils, Neochetina eichhorniae and N. bruchi, have been introduced in
Central Florida as a biological control agent (Haag et al. 1987) but to date have not colonized
in numbers sufficient to impair the productivity of water hyacinth and are not known to
disrupt community structure.

In a pilot study for the development of a biomonitoring program for the South Florida canal
system, Snyder et al. (1998) found that macroinvertebrate taxa with (relatively) long life
cycles were reduced in numbers in urban, industrial and suburban canal sites and higher in
canals surrounded by wetlands and relatively protected from human impact. Pioneering taxa
with comparatively short life cycles and capable of rapid re-colonization were typical of
impacted canal sites with early successional communities. Rader (1994) reports an
abundance of amphipods and freshwater shrimp (Palaemonetes paludosus) abundance in
South Florida canals compared with proximate wetlands.

Chapter 6: FISH


Fish community characteristics have been used to assess relative ecosystem health since the
beginning of the 20th century. Within the past 20 years, scientists have developed integrative
ecological indices that directly relate fish communities to other biotic and abiotic components
of ecosystems. Research and development in this area have focused on streams, although fish
communities may also be useful indicators of wetland health.

Fish are an important food source for wildlife in wetlands and their health and population
status is reflected in the wildlife feeding upon them (Hart and Newman 1995). Benefits of
using fish as indicators include: the taxonomy of fishes is well established reducing
laboratory time by identification of many specimens in the field; the distribution, life
histories and tolerances to environmental stresses of most North American fish species are
well documented in the literature; and fish are a highly visible component of the aquatic
community to the public (Simon 1999). Multiple factors are believed to be responsible for
declining populations and extinctions of North American fishes (Williams et al. 1989, Miller
et al. 1989), including habitat destruction and modification, introduced species and
hybridization, pollution, chemical alteration, overfishing, acidification, and disease.

Jordan et al. (1998) recommend monitoring small-sized fishes of Florida marshes. Several
benefits of using small fish include their short life cycle, their quick response to
environmental perturbations, their ability to indicate habitat alteration and ecosystem
function, and fish are reliably and effectively quantified (Jordan et al. 1997).

As humans alter watersheds and water bodies, shifts occur in taxa richness, species
composition, individual health, and feeding and reproductive relationships of fish (Karr
1997). Key biological features to detect changes in species include: identity and number of
species present in standard samples; ecological processes such as nutrient dynamics and
energy flow through food webs; and the health of individuals, which influences survival and
reproduction. These features provide a comprehensive picture of water resource condition -
one that goes beyond the toxicity or extent of chemical pollutants (Karr 1997).

Schultz et al. (1999) released an index of biotic integrity based on fish and limnological data
for Florida lakes. Eight metrics were used: total fish, native fish, Lepomis, piscivores,
generalists, insectivores, and intolerant and tolerant species. A total IBI score was calculated
for each of sixty lakes. Other data collected for the lakes included: trophic category of lake,
surface area, mean depth, total phosphorus, total nitrogen, total chlorophyll, secchi depth,
percent volume infested with macrophytes (PVI), and mean adjusted chlorophyll.
Anthropogenic impact was estimated by amount of chloride and road density correlated with
lake surface area, adjusted total chlorophyll and PVI. The authors state that numerous
environmental factors significantly influence the distribution and abundance of fish species
and assemblages found in Florida lakes. Lake trophic status and lake surface area had
significant and positive influences on the fish-IBI scores. The study concludes that dominant

environmental and ecological factors of a watershed should be clearly understood before an
IBI approach is used to indicate watershed disturbance and biological integrity.

Fish are not commonly used as success indicators in wetland restoration; in a comprehensive
evaluation of constructed wetlands on phosphate mined lands in Central Florida, Erwin et al.
(1997) do not include fish along with other assemblages. Weller (1995) describes the
restoration of a South Florida forested wetland in which the natural return of eight fish
species occurred, among other groups of flora and fauna. In East Central Florida, an isolated
constructed wetland quickly recruited a rich and abundant fish community (Langston and
Kent 1997) with fish likely introduced through irrigation or transport on terrestrial or volant
fauna. A few differences in fish community assemblages in constructed and unimpacted
wetlands are noted by Streever and Crisman (1993) and Streever et al. (1997). The sailfin
molly (Poecilia latipinna) was represented in five of seven samples collected from a
Pontederia cordata community in a constructed wetland in Central Florida, though no
mollies were found in any of seven samples collected from an adjacent Hydrocotyl
community. Lucania goodei were collected in constructed marshes on phosphate mined
lands but not in proximate natural marshes. Elassoma evergladei was found in higher
percentages in natural marshes than in constructed marshes and never attained the numbers
found in natural marshes. Fish species collected in constructed marshes include the
mosquitofish (Gambusia holbrooki), Least killifish (Heterandriaformosa), Golden
topminnow (Fundulus chrysotus), Flagfish (Jordanellafloridae), Sailfin molly (Poecilia
latipinna), Bluefin killifish (Lucania goodei), Everglades pygmy sunfish (Elassoma
evergladei), Fundulus rubifrons and small fish of the Centrarchidae family.

Fish communities in wetlands of Florida and the Southeastern United States are described in
several studies. Wharton et al. (1982) describe fish communities in bottomland hardwoods of
the southeast and their relationship to specific plant communities. Kushlan (1990) describe
fish populations in Florida marshes as depauperate, especially toward the southern end of the
peninsula. Marsh species are typically small and minnow-sized such as the live-bearing
mosquitofish (Gambusia affinis) and least killifish (Heterandriaformosa). Marsh
cyprinodonts are typically flagfish (Jordanellafloridae), golden topminnow (Fundulus
chrysotus), Seminole killifish (F. seminolis), and bluefin killifish (Lucania goodei). Small
sunfishes are also abundant such as the pygmy sunfish (Elasoma spp.), bluespotted sunfish
(Enneacanthus gloriouss, and dollar sunfish (Lepomis marginatus). Occasionally warmouth
(L. gulosus) and redear sunfish (L. microlophus) may be found in fluctuating marshes
receiving overland flow.

The South Florida Water Management District Isolated Wetland Monitoring Program
sponsored a bioinventory of freshwater fish in 20 isolated wetlands (Main et al. 1997).
Wetland sites included mature cypress stands, marshes, cypress swamps, savanna marshes
and one riverine site. Fish were classified into three functional groups: 1) small omnivorous
fishes, 2) small predatory fishes, and 3) large predatory and open-water fishes. The study lists
seven small omnivorous fishes common in shallow, ephemeral wetlands of which mosquito
fish, least killifish and flagfish were most prevalent. Marsh killifish, redfaced topminnow,
pygmy killifish and sailfin mollies were also present. Ten small predatory fish were common
in wetlands with deep-water refugia including golden and lined topminnows, sunfishes,

Seminole and bluefin killifish, and tadpole madtoms. The large predatory and open-water
fish were found in semi-permanent wetlands with deep-water refugia, including gar, pickerel,
catfish, bluegill, redear sunfish, largemouth bass, golden shiners and brook silversides.
Summary tables from the study list common, scientific and family names of the fish, physical
descriptions, reproductive biology, feeding biology, distribution in South Florida, capture
techniques, and key references.

Hoyer and Canfield (1994) sampled fish communities and a range of physical-chemical
measurements as part of a statewide lake survey. The Handbook of Common Freshwater Fish
in Florida Lakes presents descriptions, distribution, biology and biologist comments on each
fish species, as well as statistics for lake morphology and limnological measurements from
the study. The database is also used by Schulz et al. (1999) to develop and test a fish-IBI for
Florida lakes.

The U.S. Geological Survey released a publication on methods of sampling fish communities
as part of the national water quality assessment program (Meador et al. 1993). Methods for
sampling wetland fish depend on habitat. Throw traps of heavy aluminum or sheet metal,
generally one meter by one meter-square and 0.5 m to 0.75 m tall can be used in thick, dense
vegetation (Chick et al. 1992, Jordan 1996). For most other wetland types, a lighter trap
made with a copper pipe frame and 1.5-mm mesh to cover the sides can be used to obtain
data which corresponds well with the actual density, size structure, and relative abundance of
fish populations sampled (Jordan et al. 1997). Lorenz et al. (1997) describe a nine meter
square drop net and removable walkways designed to quantify densities of small fishes in
wetland habitats with low to moderate vegetation density. Main et al. (1997) used three
methods of collecting fish in a bioinventory of freshwater fish in isolated wetlands of South
Florida: 1) rectangular, Plexiglas funnel 'Breder' traps; 2) seines; and 3) D-frame dip nets
with a 1.0 mm mesh size. Funnel traps and dip nets work well in heavily vegetated areas.
Seines, needed to catch larger and more evasive fish, are useful in deeper marshes and
cypress ponds but tend to have the lead line roll up and over rooted plants and get tangled in
submerged twigs and branches.

Information on deformities, ectoparasites, lesions, and tumors (i.e., DELTs) found on fish are
used as indicators of stream health in other regions and may be a component of a multi-
metric approach for freshwater wetlands in Florida.


Wetlands used as receptors for treated wastewater likely have elevated nutrient loads
affecting resident fish assemblages. The fish community in an isolated, created wetland
receiving water from an advanced wastewater treatment facility in Orange County was
limited relative to other proximate natural wetlands (Schwartz et al. 1994). Although
immigration was limited, fish tended to move out of the forested portion of the treatment
wetland to an adjacent marsh where there was more food, oxygen and water. Fish density and
biomass in the created wetland approached natural levels by the third year of use. Fish
diversity in the jurisdictional and exit wetlands changed little over the three-year study. In

general, wetlands supported higher fish populations after receiving reclaimed water above
than before discharge began.

Rader and Richardson (1994) found greater fish densities in nutrient enriched areas of the
northern Everglades compared with an unenriched area, although percent composition of fish
(primarily Gambusia affinis and Heterandriaformosa) remained the same. Smith (1992) also
reports similar trends stemming from nutrient enrichment in forested wetlands in Central
Florida, but documented a shift in the relative composition of the dominant assemblages as
the abundance of Heterandria spp. increased relative to Gambusia. In another wetland
receiving advanced secondary treated wastewater in Central Florida, fish populations
maintained similar characteristics to fish populations in the control (Best 1993). Rader and
Richardson (1992) found that fish kills from anaerobiosis occurred with equal frequency in
enriched and control sites.

The Florida lake study by Hoyer and Canfield (1994) identified correspondence between fish
species presence and median total nitrogen (TN), total phosphorus (TP) and chlorophyll-a.
Typical fish found in lakes with the lowest TP (median value of 6-11 ug/L) were lined
topminnow, pygmy killifish, chain pickerel and redfin pickerel. The median value for all 60
lakes was 20 ug/L. Many fish species were found in lakes with TP levels as high as1043
ug/L. Fish typically found in lakes with the lowest TN (median values of 353-522 ug/L)
included the lined topminnow, pygmy killifish and redfin pickerel. The median value for all
60 lakes was 694 ug/L. Many fish species were found in lakes with TN levels as high as 3789
ug/L. Typical fish found in lakes with low chlorophyll-a corresponded with fish found in low
TN and low TP lakes. The reader is encouraged to use this study as a baseline to identify
tolerance ranges of freshwater fish common in Florida wetlands in the development of biotic


Stormwater runoff contains heavy metals from roofs, roads, parking areas, service stations
and other nonpoint sources. Wetlands and stormwater ponds used to treat stormwater runoff
may experience metal bioaccumulation in component organisms.

In stormwater treatment ponds in Orlando, Campbell (1995) found silver, cadmium, nickel,
copper, lead and zinc in red ear sunfish, largemouth bass, and bluegills. The red ear sunfish
that dive into sediments in search of food contained significantly higher metal concentrations
other fish. The largemouth bass, a predator, accumulated significant amounts of cadmium
and zinc. Bluegills accumulated significant amounts of copper, and high (but not statistically
significant) amounts of cadmium, nickel, lead and zinc compared to bluegills in control

Mercury was found in Everglades largemouth bass at concentrations of 0.13 to 3.64 ppm
(Eisemann et al. 1997). Miles and Fink (1998) monitored total mercury and methyl mercury
at a nutrient removal wetland in the Everglades and found total mercury concentration in bass
was about 0. lug/g. In the adjacent water conservation area (WCA) mercury levels exceeded

the standard of 0.5 ug/g. Total mercury found in mosquitofish was lower than in bass and
was lower in the wetland interior than in the inflow and outflow sites.

Selenium, which is an increasingly important environmental contaminant, is concentrated in
the mineral fraction (fly ash and bottom ash) of combusted coal. Disposal by dumping a wet-
slurry into dry-ash basins can overflow into aquatic systems (Lemly 1996). Selenium
concentrations can rapidly increase in fish and aquatic organisms in the receiving water,
ultimately resulting in tissue damage, reproductive failure, and possible elimination of local
fish populations.

Lemly (1996) describe selenium effects in fish living in contaminated power plant reservoirs.
Bluegill (Lepomis macrochirus) with selenium concentrations of 12-16 ug/g in skeletal
muscles and 40-60 ug/g in ovaries were associated with reproductive failure and mortality.
Females with selenium levels in tissues of 8-36 ug/g and 12-55 ug/g in ovaries did not
produce viable offspring. Mosquitofish (Gambusia affinis) and other forage fishes can
accumulate 20-370 ug/g of selenium and still maintain stable, reproducing populations.
Lemly (1996) concludes, that because selenium bioaccumulates, direct exposure to
organisms is not the problem but rather the dietary source of selenium contaminated
organisms provide to predatory fish and other wildlife that can be toxic.

Gaines (1994) found dilute landfill leachate had limited short-term impacts on fish
populations in a Central Florida wetland. Fish tended to avoid the leachate entry area, and
sampled fish assemblages most represented the original fish community structure in areas
farthest from the leachate.


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of acidification on fish in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Hoyer and Canfield (1994) recorded pH levels in 60 Florida lakes and the fish
associated with those lakes. Fish typically found in low pH waters include the lined
topminnow, Everglades pygmy sunfish, pygmy killifish and redfin pickerel. Acidification of
a wetland below 5.0 may be detrimental to the fish populations. Eleven species of fish were
found in lakes with a minimum measured pH of 4.3. In Florida acidification is not a common
problem due to buffering capacities from substrates and the nature of effluent added to
wetlands that tends to raise pH.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of acidification on fish in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of sedimentation on algae in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Reviews by Adamus and Brandt (1990) and Danielson (1998) also report a
paucity of literature on wetland fish response to sedimentation. Presumably sedimentation
can affect fish by altering substrate, submerged vegetation, and invertebrate prey base.
Sediment feeders, such as the red ear sunfish (Lepomis microlophus) may be directly


Few studies were found in a search of the literature between 1990 and 1999 on the effects of
turbidity or shading on fish in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Adamus and Brandt (1990) and Danielson (1998) also report a paucity of
literature prior to 1990 and in other regions on wetland fish response to turbidity and shading.

The addition of wastewater to a blackwater wetland in Central Florida increased the density
and cover of Lemna causing shading underwater (Smith 1992). Gambusia and Heterandria
populations were affected, with Gambusia most negatively affected. Total suspended solids
also increased with Heterandria responding positively.

Hoyer and Canfield (1994) recorded Secchi depth in their study of 60 Florida lakes. The
median value for all lakes was 1.5 m. The fish typically found in lakes with a median Secchi
depth >2.0 m included the chain and redfin pickerel, Everglades pygmy sunfish, lined
topminnow and pygmy killifish. Fish typically found in lakes with small Secchi depths
include inland silverside, redbreast sunfish, taillight shiner and sunshine bass.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of vegetation removal on fish in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Reviews by Adamus and Brandt (1990) and Danielson (1998)
also report a paucity of literature on wetland fish response to vegetation removal. In general,
increased macrophyte growth and (re)colonization of bare sediments result in higher fish
densities, by providing habitat and cover for prey species, and removal of submerged and
emergent vegetation may decrease fish density and alter community composition.


No studies were found in a search of the literature between 1990 and 1999 on the effects of
thermal alteration on fish communities in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain.


Drawdowns and prolonged inundation are common in Florida wetlands. Marsh fish are
influenced by water level fluctuations, and hydroperiod differences may lead to differences
in fish communities (Streever and Crisman 1993). Fish populations are frequently absent
from isolated marshes subject to seasonal drying. Moler and Franz (1987) note that fish are
variably present in oligotrophic marshes of the Ordway Preserve of North Central Florida.
Fish tend to follow the water during dry spells and congregate in pools that may or may not
dry up entirely. Competition and predation are intensified during drawdowns. Some fish
move upstream when overland flow occurs, recolonizing depauperate wetland depressions.

Jordan et al. (1996) observed insect predation on small fish might be significant in semi-
isolated ephemeral marshes that lack predatory fish. In aquariums, larval Odonate Anax
junius predation on small fish (<40mm standard length) can approach 40%. Under natural
conditions, habitat complexity likely decreases foraging ability of predatory insects.
Sustained drawdowns may also eliminate or reduce invertebrate predators such as dragonfly

Dominance of small fishes in Everglades wetlands arises from hydropattern, as smaller
species can survive in small pools during dry spells (Loftus and Eklund 1994). Flooding in
the Okefenokee swamp releases nutrients in peat substrates, increasing algal and invertebrate
productivity and may result in short-term increases in abundance of some fish species
(Freeman 1989).

Some groups of fish are especially adapted to fluctuating water levels. Jordan et al. (1998)
report that mosquitofish and flagfish were aggressive pioneers during flooding in wet prairies
and sloughs of the St. Johns River headwaters. Repopulating dried wetlands when inundation
reoccurs requires a pathway of recruitment to an adjacent water body or replacement of
individuals through reproduction (Streever and Crisman 1993).

When rivers flood bottomland hardwood forests in the Southeastern Coastal Plain, inundation
greatly increases the surface area available for fish migration and spawning (Brinson et al.
1981). Leitman et al. (1991) describe fishes in forest floodplains of the Ochlockonee River
during flood and drought conditions. Thirty-seven species were collected during flood
conditions and only thirteen were found during drought.

Large fluctuations in water level expose spawning areas, denude shoreline vegetative cover,
and may reduce aquatic macroinvertebrate populations (Adamus 1983, Adamus et al. 1991).
However, Greening and Doyon (1990) state that draw-down of Lake Apopka would
potentially result in an improved littoral zone habitat, increasing gamefish species abundance
by increasing macroinvertebrate production, fish spawning and refuge areas for game- and
forage-fish species. A demonstration project for the Kissimmee River restoration plan
documented fish responses to water level manipulation (Toth 1993).

DeAngelis et al. (1997) modeled fish dynamics and effects of stress in a hydrologically
pulsed marsh typical of the Everglades-Big Cypress area of South Florida. The model
predicts that: 1) there is an effective threshold in the length of the hydroperiod that must be
exceeded for high fish population densities to be produced, 2) large, piscivorous fish do not
appear to have a major impact on smaller fishes in the marsh habitat, and 3) the recovery of
small fish populations in the marsh following a major drought may require up to a year.

Hydric pine flatwoods have the shortest hydroperiods, have small drainage areas, are those
most influenced by rainwater, and have the lowest conductivities, among wetlands in the
Myakka River basin of Southwest Florida (Dunson et al. 1997). Some fish species are
typically found within a certain ranges of dissolved Na, Ca and Mg.


No studies were found in a search of the literature between 1990 and 1999 on direct effects
of habitat fragmentation and disturbance on fish in inland freshwater wetlands in Florida or
the Southeastern Coastal Plain. Adamus and Brandt (1990) report a paucity of literature prior
to 1990 on wetland fish response to habitat fragmentation and disturbance, and Danielson's
review (1998) similarly finds a limited recent literature in other states. Habitat destruction or
modification is estimated to be 73% responsible for North American freshwater fish
extinctions and 98% responsible for fish population decline (Williams et al. 1989, Miller et
al. 1989).

Fish movement, recolonization rates and survival likely are decreased with increasing
distance between wetland depressions in the landscape or as hydrologic connections become
severed by dewatering, channelization and diversion. Fish species dependent on floodplain
habitats and those that do not disperse easily might be most affected. The magnitude of the
effect may depend on the size and intrinsic habitat heterogeneity of the wetlands within the
fragmented landscape (Adamus and Brandt 1990). Presumably fish populations are most
affected in the South Florida region where emergent marshes comprise 61% of the wetlands
and 21% of the landscape and where water diversion projects have been most extensive.



Herpetofauna (reptiles and amphibians) are unique as indicators of wetland health in that
they are not only obligate users of wetlands, but also the surrounding uplands for part of their
life cycle. Many herpetile species depend on suitable corridors of habitat between their
breeding and non-breeding areas, and more than any other taxonomic assemblage, may
reflect the health of wetland buffers and corridors. Furthermore, reptiles and amphibians can
play a substantial role in nutrient and energy transfer between wetlands and uplands. For
example, Deutschman and Peterka (1988) estimated maximum density of larval salamanders
in three prairie lakes in North Dakota to be 5000/ha. Similarly, Burton and Likens (1975)
found that salamander biomass in New Hampshire equaled that of small mammals and was
twice that of birds.

The use of amphibians and some reptiles as indicators of wetland health may be
advantageous because their distribution, behaviors, and life cycles are dependent on water
depth, hydroperiod, water quality (Ohio EPA 1987) and the availability of suitable corridors
(Azous et al. 1998). Amphibians absorb water through their skin and may be particularly
susceptible to contaminants (Harfenist et al. 1989) and their aquatic life stages may be
sensitive to sedimentation and eutrophication (Adamus 1996).

Herpetofauna are not commonly used as indicators of restoration and constructed wetland
success in Florida. Kale and Pritchard (1997) provide inventories of reptiles and amphibians
known to occur in constructed and restored wetland habitats on phosphate mined lands in
Central Florida and list several herpetile species that serve as indicators of suitable habitat.
Reptiles include American Alligator, Snapping Turtle, Common Musk Turtle, Florida Mud
Turtle, Striped Mud Turtle, Peninsula Cooter, Florida Softshell, Florida Green Watersnake,
Brown Watersnake, Florida Watersnake, Striped Crayfish Snake, South Florida Swamp
Snake, Eastern Mud Snake, and Florida Cottonmouth. Amphibians include Amphiumas,
sirens, newts, salamanders, toads and frogs.

Possible amphibian indicator metrics include, species richness, distribution, abundance
(Adamus 1996), quantity of successful metamorphosed larvae, bioaccumulation, proportion
of deformities, population structure, and guild or trophic structure (Wetlands Division 1999).
Amphibians breed at different times of the year and many breed only in ephemeral or
permanent water bodies. Thus, alterations in hydroperiod can cause shifts in species
composition and possibly extirpations (Mazzotti et al. 1992). In Ohio, the number of
salamander species collected was correlated to increasing Rapid Assessment Methodology
(RAM) scores in forested wetlands. However, there did not appear to be a relationship
between the numbers of anuran or salamander species in emergent wetlands and RAM scores
or Floristic Quality Assessment Index (FQAI) scores (Fennessy et al. 1998).

There are several caveats of using herpetiles as indicators of biological condition (Adamus
1996). First, to gain an accurate representation of amphibian abundance and species richness,

repeated visits to the habitat are necessary. Many amphibian species are primarily found after
heavy rains following a drought, making the appropriate sampling time annually variable.
Similarly, many species are prevalent only at night, during mid-day basking hours or
immediately after the first thaw. Some species are fossorial and are rarely encountered.
Sampling techniques for amphibians can be cumbersome and relatively expensive (Fennessy
et al. 1998, Adamus 1996). Finally, field identification of some larval amphibians may not be
possible (Fennessy et al. 1998, Palis and Fischer 1997).

The USEPA Environmental Monitoring and Assessment Program (EMAP) chose not to
explore the use herpetofauna as a potential metric of wetland health, because sampling
techniques are often cumbersome and amphibian distribution and abundance are inherently
variable (Brown {no date}). It may be difficult to account for natural temporal and spatial
variation of amphibian species richness, abundance, and distribution. For example, similar
habitats were sampled at two sites in Taylor County, Florida, but capture rates were
significantly different between the two sites (Enge and Wood 1998) with the difference
attributed to substantially higher rainfall (21.2cm) at one of the sites.

At this time, Minnesota, Ohio and the USGS Biological Resource Division are testing
amphibian metrics of wetland health (Danielson 1998). In Florida, amphibians have been
used as indicators to monitor potential impacts of groundwater withdrawal (Orinston et al.
1995, Division of Environmental Sciences 1998), to aid in the prioritization of lands for
habitat conservation (Cox et al. 1994), and to measure restoration success (Weller 1995).
Kale and Pritchard 1997 considered several reptiles and most amphibians useful for
evaluating constructed wetlands on phosphate mined lands, because they are wetland
dependent, wide spread, and abundant.

The Ohio Environmental Protection Agency (1987) determined funnel traps were more
effective than several other herpetile sampling techniques (Fennessy et al. 1998). Funnel
traps generated relative abundance data and collected more taxa than other sampling
techniques tested. Call surveys only sample frogs, are weather dependent, and there is often
only a short, annually variable, period of time when anurans are calling. Drift fence sampling
was determined to be more labor intensive and setup materials can be relatively expensive.
Enclosure sampling devices were more labor intensive, active organisms avoided the traps, it
was difficult to separate organisms from plant material and debris, and at times, it was
difficult sealing the enclosure bottom substrate. When using seines it was also difficult to
separate organisms from the large amounts of debris and plant material, and sampling
consistency between individuals and wetlands was difficult. Dipnets were not as effective
because it was difficult to separate organisms from debris and because of sampling
inconsistencies (sites and samplers). Adamus (1996) suggests the use of pitfall traps and
funnel traps is preferable to direct sampling methods (e.g., binocular scans, search transects,
anuran calls, egg mass counts) that do not supply quantitative data on abundance. However,
direct sampling methods may compliment pit fall trap and funnel trap sampling.


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of nutrient enrichment on herpetofauna in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Danielson (1998) also reports a paucity of literature on the
subject in other regions. The review by Adamus and Brandt (1990) concludes that indicator
assemblages of the most sensitive herpetiles remain speculative for eutrophication.

In southern England, Beebee (1987) found the bullfrog, Bufo calamita, consistently selects
more eutrophic wetlands. Amphibians may play an important role in transferring nutrients
from eutrophic wetlands into the uplands (Wassersug 1975). Tadpoles reduce blue-green
algae biomass, and may contain double the amount of residual nitrogen found in some
wetlands (Beebee 1996).

Palis (1996) observed that Flatwoods Salamanders (Ambystoma cingulatum) are not found in
wetlands of the Southeastern Coastal Plain with excessive amounts of algae. In cypress
depression wetlands receiving wastewater, Jetter and Harris (1976) initially noted high
proportions of frogs present, but low oxygen levels nearly stopped amphibian production.


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of heavy metals, pesticides and other toxins on herpetofauna in inland freshwater
wetlands in Florida or the Southeastern Coastal Plain. Danielson (1998) reviews research on
this subject in other regions. Biomarkers in amphibians can sometimes be used to detect
exposure to pesticides and heavy metal contaminants (Adamus 1996). Moser et al. (1993)
describes the methodology and assessment of contaminant bioaccumulation in amphibians.

Several authors have found correspondence between the distribution and fecundity of some
amphibian species and ambient water quality measures, primarily pH, Al, total cations, NO2,
chemical oxygen demand and dissolved organic carbon (Strijbosch 1979, Beattie and Tyler-
Jones 1992, Rowe et al. 1992, Sadinski and Dunson 1992, Rowe and Dunson 1993, 1995).
Red-legged Frog (Rana aurora) embryo mortality corresponded to Ca, Mg, and pH and
negatively correlated to total P, total suspended solids, Pb, Zn, Al, total organic content and
dissolved oxygen. At the same time, Northwestern Salamander (Ambystoma gracile) egg
mortality was not correlated with any of the above measures, but did correspond with total
petroleum hydrocarbons and fecal coliforms (Platin 1994, Platin and Richter 1995). Rowe et
al. (1996) report that bullfrog (Rana catesbeiana) tadpoles collected from coal ash deposition
basins contaminated with As, Cd, Cr, Cu, Se and other elements had reduced number of
labial teeth and deformed labial papillae. Deformed tadpoles were less able to graze algae,
which resulted in lower growth rates.

Alligators (Alligator mississippiensis) have a high trophic level status in many wetlands and
tend to bioaccumulate contaminants. Alligators may be particularly good indicators of
methyl mercury contamination. High rates of Hg methylation occur in anoxic wetland

environments (St. Louis et al. 1994, Rudd 1995) and methyl mercury is the form most readily
taken up by wildlife. The highest concentrations of methyl mercury in alligators sampled
throughout the southeast coastal plain were located in the Everglades (Yanochko et al. 1997
and Jagoe et al. 1998). The authors also report that methyl mercury concentrations sampled
by non-lethal means (e.g., scutes, blood, claws) do not correspond with concentrations found
in muscle tissue and organs but that Hg-concentration in specific tissues varies with alligator
location, size, and age.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of acidification or the combined effects of acidity and metals on herpetofauna in
inland freshwater wetlands in Florida or the Southeastern Coastal Plain. Danielson (1998)
reviews literature on the subject in other regions, including the combined effects of acidity
and metals on herpetile communities. From their review of literature prior to 1990, Adamus
and Brandt (1990) conclude that most amphibians require a pH higher than 4.5 to 5.0 for
embryo survival and metamorphosis. Dunson (1989) reports the LD50 level of nine species
of North Florida anurans was reached at pH levels between 3.3 and 4.2.

Sadinski and Dunson (1992) identified direct and indirect effects of acidification on
amphibian communities in Central Pennsylvania wetlands. For example the predatory
Jefferson's Salamander (Ambystomajeffersonianum) experiences reduced foraging rates and
increased mortality rates at pH levels below 4.5, while the more pH tolerant Rana sylvatica
experiences increased survival rates due to the reduced predation by A. jeffersonianum. Low
pH levels not only affect survival and predation rates. With low pH levels (- 4.2)
Notophthalmus viridescens reproductive success decreases and emigration rates increase
while fewer Ambystoma maculatum metamorphose and metamorphosis is delayed.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of salinity on herpetofauna in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Danielson (1998) also reports a paucity of literature on the
subject in other regions. The review by Adamus and Brandt (1990) concludes that indicator
assemblages of the most sensitive herpetofauna remain undefined for monitoring salinity


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of sediments on herpetofauna in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Reviews by Adamus and Brandt (1990) and Danielson (1998)
also report a paucity of literature on the subject. In the Pacific Northwest, Richter (1997)
found sedimentation was detrimental to the aquatic egg stage of many wetland amphibians.


No recent studies were found in a search of the literature between 1990 and 1999 on the
effects of turbidity on herpetofauna in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Reviews by Adamus and Brandt (1990) and Danielson (1998)
also report a paucity of literature on the subject. Turbidity, especially from suspended
particulate material, possibly affects amphibians through respiratory complications and egg
vitality. Herpetile response to understory shading from silvicultural practices is reviewed in
the vegetation removal section.


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of direct vegetation removal on herpetofauna in inland freshwater wetlands in Florida
or the Southeastern Coastal Plain. Cattle grazing, logging, herbicide application can act to
remove wetland vegetation and potentially affect reptiles and amphibians primarily by
exposure and subsequent changes to microclimates.

Several authors studied effects of habitat changes from silviculture on amphibians. Raymond
and Hardy (1991) reported higher soil temps and more evaporative water loss from the soil
and understory after clearcuts in bottomland hardwood forests, and hypothesized that the
habitat changes negatively impacted salamanders. Demaynadier and Hunter (1999) found
wood frogs (Rana sylvatica) use forest areas significantly more than clearcuts when
dispersing from ephemeral breeding ponds. In South Carolina, Phelps and Lancia (1995)
document salamanders, gray tree frogs (Hyla chrysoscelis) and box turtles (Terrapene
carolina) were more common in a mature bottomland swamp than in clearcut areas while
many lizards and snakes preferred the clearcuts.

In Florida, Enge and Marion (1986) found amphibian species richness did not differ between
clearcuts and naturally regenerated 40 years old slash pine stands, though reproductive
success was lower in clearcut areas, reducing amphibian abundance. Reptile species richness
was lowest in the maximum treatment clearcut, primarily due to the absence of arboreal
lizards and snakes. Logging related declines in herpetofauna were primarily due to decreases
in the relative humidity, increased insolation and altered hydropattern. Generally, amphibians
do not differentiate between open and forested habitats when dispersing under wet conditions
(Richter 1997), but moist microclimates, often afforded by forest cover, are selected by some
amphibians during drier periods (Gittens et al. 1980, Semlitsch 1981, Kleeberger and Werner

Fire suppression leads to the shading of understory habitat and may ultimately reduce
understory structure, which may impact flatwoods salamanders because their eggs and larvae
depend on the herbaceous zone surrounding wetland depressions (Palis 1997b). Understory
shading due to fire suppression compromises preferred upland habitat of both the gopher frog

(Rana capitol) and flatwoods salamander (Palis 1997b, Palis and Fischer 1997). Other
silvicultural practices (e.g., densely stocked plantations, mechanical site preparation,
herbicides) may also negatively affect the understory habitat. Logging equipment can
compact soil used by many fossorial amphibian species. Similarly, military vehicle activity
in and around marsh depressions has also been cited as potentially impacting amphibians by
reducing the understory vegetation and disrupting the soil (Palis 1997b, Hipes and Jackson
1996, Palis and Fischer 1997).


No recent studies were found in a search of the literature between 1990 and 1999 on ambient
water temperature changes on herpetofauna in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Reviews by Adamus and Brandt (1990) and Danielson (1998)
also report a paucity of literature on the subject. Amphibians are ectotherms, physiology and
egg development are dependent on water temperature, and thermal alteration may affect
breeding success.


Most amphibians and many reptiles are dependent on wetlands for at least one life stage and
are likely affected by hydrologic manipulations. For instance, prior to water management
actions in the Everglades during the last 30 years, alligators built their nest mounds and
placed their eggs within the mounds based on existing water levels, though now water level
manipulations have been implicated in an increase in egg mortality from 5% to 20%
(Kushlan and Jacobsen 1990). Richter and Azous (1995) document a decrease in amphibian
species richness due to larger water level fluctuations from increased impervious surface area
in urbanized watersheds of the Pacific Northwest. Azous and Homer (1997) add that the
number of amphibians captured in wetlands is reduced when water level fluctuation exceeds
20 cm.

Cypress ponds in Florida that are ditched experience a shift in the herpetile community from
mostly aquatic to more terrestrial species. Ditched cypress ponds can have almost 4 times as
many lizards, terrestrial snakes, and toads and unditched ponds have 1.4 times as many frogs
and salamanders (Hart and Newman 1995). Rewatering of a drained forest wetland
depression in Broward County was followed by a return of 15 species of herpetiles (six
turtles, 6 snakes, 2 frogs, and alligators) that were extirpated because of hydrologic
manipulations. Ditching connects some wetlands to sources of predatory fishes (Babbitt and
Tanner 2000) and affects the herbaceous component of marsh margins (Palis 1997b), which
may influence amphibian species richness and abundance. Ditching that decreases the
hydroperiod can cause a shift from cypress to broadleaf trees, promoting more shading of the
understory (Marois and Ewel 1983). Water filled ditches can invoke unsuccessful breeding
attempts by amphibians, and eggs laid in ditches with shorter hydroperiods than nearby
wetlands can be lost to desiccation (TNC 1995).

Based on their widespread distribution in Florida and their preferred habitat, Meshaka (1997)
expected to find Eastern spadefoot (Scaphiopus holbrookii) on a ranch in Highlands County.
Their absence was thought to be attributable to hydrologic manipulations of the improved
pasture that were incompatible with primarily fossorial habits of the species (water levels are
maintained higher in the dry season and lower in the wet season).


Because many amphibians travel through and live in terrestrial habitats separate from their
wetland breeding habitats, amphibians may be particularly susceptible to habitat
fragmentation. Two anuran species found in Florida have been known two disperse more
than 2 km from the wetland in which they metamorphosed (Breden 1987, Franz et al. 1988).
Wetland turtles also use uplands, for hibernation and nesting (Burke and Gibbons 1995).
Stenhouse (1985) and Verrell (1987) suggest amphibians use corridors (habitats conducive to
dispersal) to gain access to their breeding habitats. Movement to breeding areas can be
hindered by development. For example, roads fragment habitat and contribute to amphibian
population declines (Fehring et al. 1995). Maintenance of movement corridors will dampen
the affect of stochastic events (e.g., drought) (Richter 1997) and help prevent inbreeding
depression (Pechman and Wilbur 1994).

In the Pacific Northwest, Richter and Azous (1995) found amphibian species richness
highest in wetlands that retain at least 60% of the adjacent area in forest up to 500 m from
the wetland. In Florida, Folkerts (1997) hypothesized the reason Citronelle ponds have
unexpectedly low amphibian species richness in most cases is because the adjacent landscape
was converted to agriculture or was urbanized. Lehtinen et al. (1999) found amphibian
species richness decreased with increasing road density and proportion of urbanized land.
Based on a literature review and using the known dispersal distances of six salamander
species, Semlitsch (1998) recommends a general buffer distance of 164m from the edge of
wetlands to protect 95% of the salamander populations. Palis (1997a, 1997b) and Palis and
Fischer (1997) note fragmentation may not only affect amphibian dispersal but may reduce
the quality of remaining habitat. Fragmented landscapes do not carry fire well, and overtime
succession into another habitat type may occur.

Chapter 8: BIRDS


There is general agreement that wetland birds may be better indicators of regional or
landscape conditions than of the health of a particular wetland type or site (Cowardin et al.
1979, Harris 1988, Adamus et al. 1991, Adamus 1996, USEPA 1997, Danielson 1998). This
is due in part because of their mobility (Bennetts and Kitchens 1997, Myers and Ewel 1990)
and tendency to use a variety of upland, wetland and aquatic habitats based on resource
availability (e.g., prey and nest site availability) (Fleming et al. 1994, Gosselink et al. 1994,
Bessinger 1995, Hart and Newman 1995, DeAngelis et al. 1997). Changes in utilization (e.g.,
presence, timing and duration) of a wetland by birds, regional reductions in population size,
and local extirpations may indicate: alterations in the prey base (Gosselink et al. 1994, Hart
and Newman 1995), vegetation species composition and structure (Harris et al. 1983, David
1994, Schulz 1999) or other factors important to birds on a regional level. For example,
wading birds in wet prairies of the Everglades have declined by 93% in the last 70 years
primarily due to habitat loss and reduced prey availability (Ogden 1994), and in the Lake
Okeechobee fringe marsh communities, willow (Salix caroliniana) died due to artificially
maintained high water levels, causing a nesting colony of wading birds to decline from
10,000 to 3 within a 14 year period (Smith et al. 1995).

There are several advantages of using birds as health indicators in wetland bioassessments.
First, they are relatively easy to monitor and many species can be surveyed remotely (e.g.,
aerial surveys). Second, long-term, nationwide databases are available (e.g., waterfowl
hunting returns, Breeding Bird Surveys BBS, and Christmas Bird Counts CBC) supplying
information on trends, habitat needs and distribution (e.g., McCrimmon et al. 1997). Other
advantages include: temporal and spatial integration of birds (Adamus 1996, USEPA 1997),
standardized and established survey methodologies are available, avian response guilds show
a continuum of sensitivity (Croonquist and Brooks 1991), and wetland birds represent a wide
array of feeding strategies (Adamus et al. 1991). Also, many bird species are good indicators
of bioaccumulation of toxic substances because they tend to have long life spans and are
often top predators (Adamus 1996).

There are several cited disadvantages of using birds as indicators of wetland health. First is
their low wetland fidelity. Additionally, bird presence in a wetland does not necessarily
reflect wetland health or its ability to support the observed bird or other organisms. Sandhill
cranes (Grus canadensis), for example, will rest or roost in open inundated areas for
protection from predators (Bishop 1992) but this behavior indicates little about the status of
the prey base or wetland productivity. Another disadvantage is discerning cumulative affects
bird populations. For example, at this time, it is impossible to distinguish the relative impact
of lead shot toxicity, hunting pressure and loss of breeding habitat on the decline of
waterfowl in the prairie pothole region (Harris 1988). Perhaps another caveat in using birds
as indicators is the necessity to make multiple visits throughout the year to gain an accurate
representation of wetland bird use (USEPA 1997). Adamus et al. (1991) recommends that

wetlands be visited during the breeding, wintering and migration periods to assess bird use.
Finally, the ability to detect wetland bird species is variable (USEPA 1997) (e.g., rails and
bitterns are cryptic).

In Florida, wetland birds have been used as indicators in the evaluation of constructed
wetlands on mined lands (Erwin et al. 1997), to monitor impacts of groundwater withdrawal
(Orinston et al. 1995, Division of Environmental Sciences 1998), to aid in prioritization of
lands for habitat conservation (Cox et al. 1994), to evaluate wildlife habitat suitability of
depression wetlands used for wastewater treatment (Mcallister 1993), and in comparison of
hydrologically impacted and unimpacted wet prairie associations in South Florida (Gawlik
and Rocque 1998). Birds have been used to assess the restoration of a river marsh (Toth
1993), a South Florida cypress dome (Weller 1995), and mined lands in Central Florida
(Mushinsky and McCoy 1996, Doherty 1991). Kale and Pritchard (1997) provide inventories
of birds known to occur in wetland habitats on phosphate mined lands.

Nationally, there has been an attempt to place species within a bird community into guilds
and monitor the response of each guild to perturbations. Miller et al. (1997) found
Neotropical migrants and species dependent on large undisturbed areas of habitat (gamma
species) declined with increasing residential and agricultural land-use in Pennsylvania.
Croonquist and Brooks (1991) applied guild scores to bird species based on documented
information in two Pennsylvania watersheds. A high guild score corresponded to a low
tolerance to habitat disturbance. As intensity of habitat alteration increased the percentage of
bird species with high-response guild scores decreased. Species in 'edge' and 'exotic' guild
categories were more prevalent in disturbed watersheds. Changes in the bird community
were greater than changes in bird species richness as a result of land alteration. O'Connell et
al. (1998) developed a Bird Community Index (BCI) in the Mid-Atlantic Highlands and
inferred increased biological integrity as the insectivore guild increased and the omnivore
guild decreased.


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of nutrient enrichment on birds in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. Several studies address potential indirect affects of enrichment
on wetland birds. Increased amounts of nitrogen and phosphorus can cause increases in the
prey base (fish, macroinvertebrates, and herpetofauna) and forage for many wetland birds. In
the Everglades, Rader and Richardson (1994) found that enriched sloughs experienced
increases in macroinvertebrate and fish metrics, including species richness, Shannon
diversity index, number of unique species, and population density.

Hoyer and Canfield (1990) attributed an increase in bird density estimates in a North Florida
cypress dome to an increase in prey density due to enrichment. However, increased nutrient
inputs have the potential to cause the vegetation structure and composition to change in
manner that adversely affects prey availability. In the Everglades, plant community
composition in phosphorous enriched wet prairies frequently shift to dense cattail stands

(Typha spp.) and several studies have shown that most wading bird species avoid dense
stands of vegetation (Bancroft et al. 1994, Hoffman et al. 1994, Smith et al. 1995). There
appears to be a threshold where nutrient inputs increase prey density until the vegetation
increases to the point of obstructing or shading (e.g., Lemna spp.) the prey from wetland

Another potential negative impact on wetland birds due to enrichment is the increased
potential for parasite transmission. The parasitic nematode, Eustrongylides ignotus, which
has only been found in disturbed and enriched wetlands (Spaulding and Forester 1993),
negatively affects the health of adult wading birds and the survival of nestlings (Spaulding et
al. 1993).

Prolonged reduced dissolved oxygen levels in a wetland can negatively impact the prey base
of wetland birds. Prey species not adapted to low oxygen levels will be at a selective
disadvantage if low dissolved oxygen levels persist. At the same time, low dissolved oxygen
levels may temporarily increase prey availability for many wading bird species. Several
species of fish adapted to low dissolved oxygen levels take advantage of the oxygenated
water surface, performing aquatic surface respiration (ASR) (Lewis 1970). Prolonged ASR
has been found to increase the susceptibility of fish to avian predators (Kramer et al. 1983,
Cech et al. 1985).


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of contaminant toxicity on birds in inland freshwater wetlands in Florida or the
Southeastern Coastal Plain. While the effects of bioaccumulation of contaminants in wetland
bird tissues have been widely measured, the effects of pesticides, heavy metals, and other
contaminants on overall structure of wetland bird communities are poorly documented in
wetlands (Adamus and Brandt 1990), though it is likely that wetlands free of toxic
substances are more likely to have higher wetland bird species density and diversity
(Adamus et al. 1991).

Wading birds have been used to document elevated levels of mercury found in Southern
Florida. Mercury concentrations in wading bird feathers collected in Southern Florida on
average were much higher than similar studies conducted in Costa Rica, Hong Kong and
China (Beyer et al. 1997). Within Southern Florida concentrations of mercury in wading
birds appears to vary geographically. Birds in the Central Everglades and Eastern Florida
Bay had significantly higher levels of mercury than birds sampled in other areas of Southern
Florida (Sundlof et al. 1994). Mercury concentrations vary with geographic locations but also
with diet and age of the bird (Sundlof et al. 1994, Beyer et al. 1997). Species that eat larger
fish, and older birds, tend to have the highest Hg concentrations. Mercury concentrations of
many wading bird species in Southern Florida are near or above levels that may cause
reproductive impairment, and it has been suggested that mercury poisoning may play a part
in the population declines of wading birds in the Everglades (Sundlof et al. 1994, Beyer et al.
1997). However, more controlled studies are needed.


No studies were found in a search of the literature between 1990 and 1999 on the effects of
acidification on birds in inland freshwater wetlands in Florida or the Southeastern Coastal
Plain. Danielson (1998) reviews several studies in other states. Adamus and Brandt (1990)
also report a paucity of literature on the subject. Changes in the prey base and vegetation
structure in wetlands due to anthropogenic acidification will likely impact the bird
community. Birds feeding in acidified waters may have greater potential for calcium
deficiency and as a result will lay thinner eggs (Albers and Camardese 1993, Nybo et al.
1997). Parker et al. (1992) found more broods of piscivorous waterfowl in prairie pothole
wetlands with a pH greater than 5.5, while at the same time, insectivorous waterfowl seemed
to be unaffected by pH levels.


No studies were found in a search of the literature between 1990 and 1999 on the effects of
salinity changes on birds in inland freshwater wetlands in Florida or the Southeastern Coastal
Plain. Danielson (1998) documents a few studies in other states, and the Adamus and Brandt
review (1990) cite studies outside Florida that indicate breeding birds in coastal wetlands
generally select fresher portions, and inland wetlands that are naturally saline generally have
fewer nesting waterfowl. Changes in the prey base and vegetation structure in wetlands due
to salinization would likely alter the bird community. Thus, bird assemblages used as
indicators of salinization are speculative, especially in Florida where little is known about
bird response to salinity changes.


No studies were found in a search of the literature between 1990 and 1999 on the effects of
salinity changes on birds in inland freshwater wetlands in Florida or the Southeastern Coastal
Plain. Searches by Adamus and Brandt (1990) and Danielson (1998) also found the literature
limited on bird response to wetland sedimentation in other states. Sedimentation likely will
affect wetland birds by impacting growth and survival of aquatic prey and submerged forage


No studies were found in a search of the literature between 1990 and 1999 on the effects of
turbidity and shading on birds in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Effects of turbidity on the community structure of wetland birds in other states
are also poorly documented (Adamus and Brandt 1990, Danielson 1998). Shading may affect
the wading bird community differentially. Many of the herons and egrets are visual predators

while the wood stork (Mycteria americana), roseate spoonbill (Ajaia ajaja) and the ibises are
primarily tactile foragers (Kushlan 1978, Bancroft 1994). Tactile foragers may have a
selective advantage in wetlands that are turbid or shaded.


Bird communities are influenced by vegetation structure, density and composition.
Determining expected wetland bird communities for each wetland type within a region may
be possible, and changes to vegetation structure within a wetland type or site may alter the
bird community. Bird community composition is a more reliant indicator of vegetation
alteration than bird species richness. As vegetation changes are made to a wetland, new
wetland bird species may find the altered habitat favorable while other species find the
disturbance unfavorable. For instance, while dense stands of wetland vegetation are often
utilized by rails and bitterns (Dinsmore et al. 1993), complete removal of the vegetation may
make the area more attractive to shorebirds and some species of waterfowl that select areas
free of vegetation (McMurl et al. 1993). Thus, wetland bird species diversity or richness may
be a poor metric of wetland vegetation removal.

Silviculture and grazing are two common forms of vegetation disturbance in wetlands. High
cattle stocking rates can have profound effects on wetland habitat. Cattle compact soil,
trample vegetation and reduce ground cover (Vince et al. 1989, Hart and Newman 1995).
Hart and Newman (1995) report that cows favor wetland grasses (e.g., Panicum hemitomum)
present in depression wetlands to the grasses (e.g., Andropogon spp. and Aristida strict)
commonly found in uplands and pastures of Florida. In forested wetlands, structural diversity
is decreased by cows browsing on shrubs and tree seedlings (Hart and Newman 1995). Feral
pigs can cause severe soil disturbance and depletion of oak mast in hydric hammocks (Vince
et al. 1989).

Wetland vegetation impacts may affect wetland bird community composition and
reproductive success. Reduced waterfowl reproductive success has been documented because
of the loss of cover either due to grazing, herbicides, cultivation or other land-use action.
Dobkin et al. (1998) reported greater avian species richness and relative abundance in
riparian areas where cows were excluded. Exclosures had higher wetland avifaunal species
richness while grazed plots contained more upland bird species. Johnson et al. (1991) report
that grazing by cows and feral pigs in herbaceous marshes of South Florida may affect
mottled duck (Anasfulvigula) populations through habitat alteration.

A common silvicultural practice entails the removal of some or all of the overstory around
and or within a wetland. Complete removal of the trees (i.e. clearcut) not only changes the
habitat structure, but can also change the hydroperiod, water depth and water quality of a
wetland (Hart and Newman 1995). Changes to the wetland bird prey base and understory
vegetation due to clearcutting may impact wetland bird communities. The age of a timber
stand will also affect the bird community. Mitchell (1989) found 11 bird species were more
common in a 127-year-old cypress-tupelo stand (Taxodium spp. and Nyssa aquatic) than in
younger stands.


No studies were found in a search of the literature between 1990 and 1999 on the effects of
thermal alteration on birds in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. Temperature changes in ambient water can alter the plant community and the
type and availability of the prey base thus indirectly affecting the bird community (Adamus
and Brandt 1990 and Danielson 1998). Impoundments, bays, and wetlands receiving thermal
effluent discharged from cooling towers at nuclear power stations are favored sites for
migratory waterfowl and wading birds in winter.


As with the other stressors, hydrological impacts most often affect wetland birds indirectly
by altering the habitat on which they depend. Hydrological manipulations may be partly
responsible for a decreased bird prey base in the Everglades (DeAngelis et al. 1997) and
modifications to nest and roost sites in lake fringe wetlands in South Florida (David 1994).
Wetland birds may respond through a reduction in local populations, changes in the timing of
breeding or foraging, reduced breeding success, or reductions in species diversity and species

Most wading birds in South Florida wetlands depend on aquatic prey that is captured in 10-
30 cm of water (Powell 1987). Too much water will limit access to prey. Conversely, a
decreased hydroperiod will increase the frequency of drought, which negatively impacts fish
populations and subsequently the wading birds that depend on them (DeAngelis et al. 1997).
The density, distribution, demographics and availability of wetland bird food sources are
influenced by present and past water conditions (Gosselink et al. 1994). Sustained high water
levels over a 10 year period on Lake Okeechobee, converted much of the foraging habitat
(Eleocharis spp., Rhynchospora spp., mixed grasses) to dense cattail stands (Typha spp.)
which are not used by most wading birds (Smith et al. 1995).

Toth (1993) estimated that a constant source of 5 billion forage fish and 6 billion shrimp
were unavailable to wetland birds due to the channelization of the Kissimmee River. In a
dechannelization experiment, wading bird use of the river's wetlands nearly doubled. Other
birds were also affected by the drying of Kissimmee River wetlands. Bald eagle territories
declined by 74% (Shapiro et al. 1982) and waterfowl use of the area declined by 92% (Perrin
et al. 1982). A rehydration project in Central Florida precipitated the return of 16 wetland
bird species to a cypress dome (Weller 1995).

Changes in spatial and temporal availability of foraging habitat can affect the reproductive
success of wetland birds (Gosselink et al. 1994). Canals in the Everglades have altered the
seasonal drying trend, and the rate and degree of water recession is partly responsible for
making areas within the region suitable for foraging. As a result of the hydrological impacts
in the Everglades, wood storks begin breeding later in the season, and in most years a late

start is followed by nest failures (Ogden 1994). Anthropogenic and natural reversals in
wetland drying have also resulted in failed nesting attempts in wood stork colonies in the
South Florida (Bancroft et al. 1994) and Central America (Ramo and Busto 1992).

Nesting colonies of wading birds in the Everglades require a minimum of 5-10 cm of water
underneath nesting trees to deter predators (Frederick and Collopy 1989). Conditions that
cause the loss of these depths could result in nest site abandonment. Conversely, artificially
maintained hydroperiods were responsible for the death of willows (Salix spp.) along Lake
Okeechobee and at least one stand formerly supported a large colony of wading birds (David

The reproductive success of the endangered Cape Seaside Sparrow (Ammodramus maritimus
mirabilis) has been directly and indirectly affected by uncommonly high water levels in the
Everglades. High water levels flood nests or enable the nests to be preyed upon, and cause
changes in vegetation composition and structure. Management of higher water levels from
1992 to 1995 caused a change from the favored muhly grass (Muhlenbergiafilipes)
dominated habitat to a habitat dominated by sawgrass (Cladiumjamaicense) (54% muhly in
1992 to 25% in 1995) (Nott et al. 1998). Within this same time period Cape Seaside Sparrow
populations plummeted.

Many species are adapted to the natural fluctuating water levels found in wetlands.
Bessinger's (1995) model of snail kite population response to hydrology predicted that
greater than one drought every three to four years would be detrimental to the population.
Bennetts and Kitchens (1997), however, report that snail kites in South Florida disperse to
other wetland locations with the onslaught of regional droughts and that periodic droughts
are necessary to maintain stands of willow vital for snail kite nesting. Wetland birds are
adapted to and often dependent on fluctuating water levels. Smith et al. (1995) suggest that
high water years succeeded by drought in South Florida may build prey concentrations that
then can be exploited by wading birds. However, successive low water years may deplete the
prey base. Prolonged hydroperiods may be necessary for the development of populations of
large fish (Fleming et al. 1994) that are selected for by wood storks, great egrets (Ardea
albus) and great blue herons (Ardea herodias).

Weller (1995) argues that waterfowl and wading bird guilds as indicators of the Kissimmee
River restoration are useful because these guilds allow for comparison of use prior to and
after channelization, and of use in restored and channelized portions of the river. Waterfowl
and wading bird guilds, because of their high-trophic level status, integrate other components
of the ecosystem. Gawlik and Rocque (1998) document lower avian species richness in
hydrologically impacted sites than in reference sites of the Everglades.


Bird communities are suited as indicators of landscape change. Birds are highly mobile and
use a variety of habitat types and ecosystems. These characteristics confound their use as
indicators of wetland fragmentation and habitat disturbance as they can relocate as long as
other habitats are locally available. Some bird species, however, require not just a particular
density of wetlands, but a particular combination of wetland types and other land cover types
(Adamus and Brandt 1990). Thus bird communities and selection preferences of birds may
be better indicators of changes across landscapes than of disturbance or loss of specific
wetland types or sites.

Danielson (1998) reviews recent literature on bird response to fragmentation and landscape
disturbance in other states. Brown and Dinsmore (1986) documented low bird species
richness in isolated and small marshes in Iowa. Ten of 25 wetland bird species were absent
from marshes less than 5 ha and many species were only observed in smaller wetlands when
the wetland sampled was within a complex of wetlands. Large blocks of lowland forest
commonly contain forest interior Neotropical migrants (Hamel 1989, Mitchell et al. 1989)
and reduced numbers and local extirpation has been correlated with fragmentation (Finch
1991). In Pennsylvania, an increase in the number of Neotropical migrants and gamma
species (species dependent on large undisturbed areas of habitat) was recorded as residential
and agricultural land-uses decreased within the studied watershed (Croonquist and Brooks
1991). Generalists and bird species most adapted to edge and disturbed habitats, however,
increased with residential and agricultural land-uses (Miller et al. 1997). Ogden et al. (1987)
surmised the decline in many wood stork colonies throughout Florida was partly attributable
to increased urbanization and agricultural development.

In Central Florida uplands Mushinsky and McCoy (1996) used birds as indicators of mined
land restoration success, with surveys in reference and impacted sites. Bird species missing
from or found in lower numbers at impacted sites were selected as focal species. The authors
conclude that habitat requirements of focal species should be prioritized in ecosystem
reclamation. From a review of the literature, Doherty (1991) compared avian species
common to 5 forest communities in Central Florida (Sandhill, Scrub, Flatwoods, Hammocks
and Swamps) with bird use in mined lands, concluding that 97 bird species which have been
documented in the natural forest communities have not been observed using any feature of
the post-mined landscape. This represented 46% of avian species that occur or have occurred
in Central Florida prior to mining. Of the bird species common to swamps (132 species),
53% were not documented using mined lands, representing the largest percent shift in bird
composition among the forest communities displaced by mining. Because surface mining
creates open water, fringe wetland habitats and marsh communities on clay settling ponds, an
increase in wading birds, shore birds and migratory waterfowl is common in the mined
landscape (Schnoes and Humphrey 1987, Doherty 1991).

Agricultural land use is at least partly compatible with the habitat requirements of many
wetland bird species. For instance, 93% of Florida Sandhill Crane (Grus canadensis
pratensis) daytime locations were within cropland, plowed pasture, improved pasture and

emergent wetlands (Bishop 1992). In a similar study, the relative abundance of Florida
Sandhill Cranes was higher in pastures and wetland-pasture associations than in the
surrounding landscape (Nesbitt and Williams 1990).

Finally, Adamus et al. (1991) state that wetland birds are also suited as indicators of low
level disturbance generated from recreation in or near wetlands (e.g., jet skis, ATV off-road
riding, cycling, and hiking). Birds are activity-sensitive and very often show an immediate
response in comparison with the other indicators.

Chapter 9 MAMMALS


Mammals may be better indicators of regional or landscape condition than of individual
ecosystems or wetlands. Mammals are highly mobile, spend only a portion of their life in
wetlands, lack habitat specificity (Ewel 1990) and tend to have low species richness. Brooks
and Croonquist (1990) categorized some mammal species according to wetland dependency,
but generally it is difficult to define what constitutes 'wetland dependence' for mammals.
Also, wetlands are typically permanently inhabited by fewer mammal species than are
uplands (Adamus and Brandt 1990). Finally, human induced mortality (hunting/roadkills)
may cause population fluctuations unrelated to wetland status (Brown {no date)). Because of
these factors, the Environmental Monitoring and Assessment Program (EMAP) chose to
exclude mammals from a list of potential bioindicators.

Croonquist and Brooks (1991) developed mammalian response guilds using existing
literature to determine their sensitivity to disturbance, and then surveyed mammals within
disturbed and undisturbed watersheds in Pennsylvania. The mammal guilds did not
correspond with habitat disturbance, low sample sizes were collected, and little community
variability between watersheds was detected. Furthermore, six trapping methods necessary
for unbiased sampling of the mammalian community were considered cost ineffective.
Brooks and Hughes (1988) in a set of proposed guidelines for wetland biological assessment
in Pennsylvania recommended sampling mammals six times during the year to accommodate
for seasonal variability. Snap and live traps are recommended for small mammals, and
searches for signs of presence or use along 200meter transects are recommended for large

When compared with other taxa, the number of mammal species that inhabit and use Florida
wetlands is low, and most mammals are facultative users of wetlands. Only the round-tailed
muskrat (Neofiber alleni), rice rat (Orizymespalustris) and marsh rabbit (Syvilaguspalustris)
were considered obligate users of wetlands in Florida (Hart and Newman 1995). It is more
likely for small mammals to be robust wetland health indicators in the Pacific Northwest
where species richness is relatively high. For example, Richter and Azous (1995) captured 22
species of small mammals from 19 wetlands in the Pacific Northwest (though reported that
species richness only weakly corresponded with development intensity but positively
corresponded with the amount of large woody debris within the wetland buffer).


Few recent studies were found in a search of the literature between 1990 and 1999 on the
effects of stressors on mammals in inland freshwater wetlands in Florida or the Southeastern
Coastal Plain. A review of recent national literature on the subject is not included in
Danielson (1998) and Adamus and Brandt (1990) report a paucity of information on the
subject in literature prior to 1990, but offer a few general characterizations.

For most stressors the response of wetland mammals is unknown, difficult to assess and
nested in cumulative impacts, rendering speculative indicator assemblages of "most
sensitive" species. Hart and Newman (1995) call for more research on small mammals to
determine how they use wetlands and how they (especially) respond to hydrological
variability. Gosselink and Lee (1987) suggest that the presence of a healthy population of
native top carnivores is an indicator of regional biological integrity.

Local stressor effects on wetland mammals are likely to be manifested in changes in their
food base. For example, stressors such as organic wastes generating anoxic conditions or
severe acidification can eliminate mammal food species, and therefore may influence a shift
in community composition from piscivorous species to herbivores or invertebrate consumers.
Research on mammal response to toxicity in Florida wetlands is limited. Three panther
deaths in the Everglades have been attributed to mercury poisoning (Sundlof et al. 1994).

Changes in wetland hydropattern and soil moisture alter the suitability of mammal habitat
and may trigger migrations. For example, in North Florida cypress ponds Harris and Vickers
(1984) found an increase in relative abundance of rice rats (Oryzomyspalustris) and a
decrease in cotton rats (Sigmodon hispidus) with increases in water levels. During floods
many mammals are forced from wetlands into uplands, and while dispersing can experience
increased mortality rates primarily due to predation and encounters with automobiles (Hart
and Newman 1995), but also possibly due to poor reproductive success during prolonged

Research on mammal response to vegetation removal in Florida wetlands is limited In
general, species richness of small mammals corresponds with complexity of vegetation
structure, and many small herbivorous mammals are more common in denser herbaceous
ground cover that results from removal of overstory vegetation. In post-phosphate mined
land in Central Florida, Schnoes and Humphrey (1987) attributed higher species diversity
and abundance of small mammals in young and middle-aged successional spoils and pits to a
greater primary production of consumable forage in dense understory vegetation. Rice rats
and cotton rats may be forced to nest in uplands when wetland vegetation is too sparse
resulting in higher mortality rates (Hart and Newman 1995). Azous and Homer (1997) found
wetlands in the Pacific Northwest were more likely to have diverse mammal communities if
a substantial part of the adjacent land was not cleared but retained in forest.

Response to other stressors (salinization, sedimentation, burial, turbidity, shading, and
thermal alteration) is not documented for Florida wetland mammals in the recent literature.
Indicator assemblages of mammal species "most sensitive" to these stressors remain
speculative (Adamus and Brandt 1990). Mazotti et al. (1981) discuss the implications of
exotics on higher organisms in Florida wetlands and suggest that while small mammal
activity in Casuarina sp. swamps is extremely low, there is still extensive use of Melaleuca
quinquenervia forests, though densities are lower than pristine native communities.

Wetland mammal response to habitat fragmentation in Florida is poorly documented.
Doherty (1991), in a review of existing literature on wildlife inventories of Central Florida,

documented 27 of 47 mammal species present in forest communities in the region occurring
in the post phosphate mined landscape. Of 29 mammal species documented using mixed
hardwood swamps in the region, 10 species were not documented using communities
developing on the mined landscape, including one endangered, three threatened, and one rare
species. Kale and Pritchard (1997) provide additional inventories of mammals known to
occur in wetland habitats on phosphate mined lands.

Gosselink and Lee (1987) state that fragmentation has excluded many large carnivores from
bottomland hardwood forests. It is likely that wetland dependent mammals respond to
changes in hydrologic connectivity, vegetated corridors, and distance between isolated
wetlands. Water diversion projects, bank clearing, roads and proximate land-use act to
fragment and disturb wetland habitat. Mammals generally, because they are highly mobile
can ameliorate effects by dispersing to other areas, but they do so at a probable risk of greater
predation and energy expenditure.

Brown et al. (1987, 1989) used home range sizes of wetland mammals to define wildlife
guilds and as part of a variable buffer zone determination for the Wekiva River and East
Central Florida. Brandt et al. (1993) evaluate regional effects of citrus development on
wildlife habitat in South Florida using land cover maps in combination with species models
for wildlife, including the Florida panther, and identify areas most susceptible to citrus
development and habitat that should be high priorities for protection in order to protect the
species. The Florida Fish and Wildlife Conservation Commission (Cox et al. 1994) identifies
critical areas for wildlife habitat conservation in Florida, including 6 wetland community
types covering 18% of the State.


Appropriate consideration of the factors necessary to create homogenous sets for comparing
biological condition requires the identification of wetland classes within ecological regions.
A goal of classification for biological assessment is to group wetlands with similar biological
attributes and biological response to human disturbance. Because biological assessments
measure wetland health relative to reference conditions, classification must distinguish local
environments and address regional variability. Karr and Chu (1999) advocate judicious
classification, arguing that selection of too few classes [or few too regions] may overlook
important characteristics and that too many may unnecessarily complicate development of

Geography, landscape position, geomorphology, hydropattern, climate, physical/chemical
variables, and biogeographic processes determine the structure and function of local
wetlands. Aspects of these driving forces are incorporated in most hierarchical classification
and regionalization efforts, while others are based on plant community structure and species
composition. Regardless of the number or resolution of classes and regions, at all levels there
is overlap because of common species distributions and intergrading physical environmental

In conjunction with research in the development of a biological approach to wetland health
assessment in Florida, the University of Florida Center for Wetlands proposed wetland
classes and regions to test as homogenous sets for comparing biological condition. This
chapter is excerpted from Florida Department of Environmental Protection reports: Doherty
et al. (1999), Proposed Classification for Biological Assessment ofFlorida Inland
Freshwater Wetlands; and Lane et al. (1999), Proposed Regionsfor Biological Assessment of
Florida Inland Freshwater Wetlands. Proposed regions and classes for inland freshwater
wetlands of Florida are presented here to provide context for assemblage profiles and stressor
response reported in the literature reviewed. The reader is encouraged to obtain these reports
and contact authors and FDEP personnel with questions and requests for updated material.


Several classification schemes have been developed to describe Florida's inland freshwater
wetlands (Table 10.1). Each system is overviewed and cross-referenced by Doherty et al.
(1999), with summary provided here. FNAI provides the most comprehensive descriptions
for its communities, using species lists and typical hydroperiods (and other information) to
classify biologically distinct wetlands organized by landscape position. SCS also provides
ecosystem attributes but does not include hydrology or geomorphology as keying characters,
resulting in less distinct community types. FLUCCS is not organized by landscape features,
rather by dominant vegetation readily identifiable through remote sensing, resulting in
nomenclature that is not descriptive for biological assessment. NWI first divides wetlands by
landscape features followed by dominant vegetative form, but classification, while

Table 10.1. Classifications of Florida's inland freshwater wetlands.

Florida Land Use, Cover and Forms Classification System (Florida Department
of Transportation 1976/1985)
National Wetlands Inventory (U.S. Fish and Wildlife Service; Cowardin et al.
Guide to the Natural Communities of Florida (Florida Natural Areas Inventory
and Florida Department of Natural Resources 1990)
Florida Land Cover Classification (Florida Fish and Wildlife Conservation
Commission; Kautz et al. 1993, Cox et al. 1994)
Hydrogeomorphic Wetlands Classification (Army Corps of Engineers
Waterways Experimental Station; Trott et al. 1997/2000, Brinson 1993)
26 Ecological Communities of Florida (Soil Conservation Service 1981)
Ecosystems of Florida (Myers and Ewel, eds. 1990)
Wetlands Classification Key (Lake County Water Authority / SJRWMD)

hierarchical, often lacks resolution for assessing biological condition and the nomenclature is
not conducive to localities. FWC habitats were chosen based on imaging criteria and with
only 7 wetland habitats is too aggregated for biological description. The coarse resolution of
HGM functional classes may not distinguish all wetland types within a region, and
geomorphic settings may not be distinct, or it may not be possible to identify dominant
hydrologic characteristics (e.g., in Peninsula Florida, Flats is not readily discriminated from
Depression or Slope classes, and several water sources may exist for a wetland type).

A classification for biological assessment of Florida inland freshwater wetlands is described
here as proposed by Doherty et al. (1999). The approach is a preliminary effort to group
similar wetlands together for purposes of detecting biological condition. Considerations were
made to keep the system simple, user-friendly, related to other classifications, but robust
enough to generate a consistent wetland typology. It is a tiered approach using broad
landscape categories (River, Depression, Lake, Strand, Seepage and Flatland) subdivided
into forested and non-forested classes, generating 13 wetland types (Table 10.2). Additional
resolution is provided through (subclass) descriptors: Hydroperiod (depth, duration and
frequency of inundation); Primary Water Source (rainfall, surface or groundwater); and Soil
Type (organic or mineral).

The proposed classification builds on commonalities between and key elements from
prominent classifications (principally HGM, FNAI, and NWI). Other wetland classifications
used in Florida are cross-referenced with the proposed approach to generate a framework for
common nomenclature and to utilize the best components of existing systems (Table 10.3).


Regionalization is important to wetland bioassessment to account for natural variation in
species assemblages due to spatial location (Hughes et al.. 1990). Ecoregions are defined as
homogenous landscape patterns deduced from various climatic and geographic inputs
(Griffith et al.. 1994). The Environmental Protection Agency (EPA) more specifically
defines ecoregions as areas with apparent homogeneity in a combination of geographic
characteristics that are likely to be associated with resource quality, quantity, and types of
stresses (Gibson et al.. 1994). Several ecoregions are developed for Florida. Physiographic
regions proposed by Griffith (1994) are used as a basis for the State's lake regions (Griffith
et al.. 1997) and stream regions (Barbour et al.. 1996).

Regions for biological assessment of Florida inland freshwater wetlands are described here
as proposed by Lane et al. (1999) and Lane (2000). The approach is a preliminary effort to
identify distinct wetland regions within Florida for the purposes of detecting biological
condition. Spatial hydrological models and landscape level geostatistical algorithms were
used to generate proposed regions and to test correspondence between wetland type (using
NWI and FWCC data) and combinations of environmental variables including: precipitation,
groundwater inflow, evapotranspiration, surface water runoff, infiltration, pedogenic
characteristics, transmissivity, conductivity, imperviousness, and hydrologic gradients. Four

Table 10.2. Proposed classification for biological assessment of Florida inland freshwater
wetlands (from Doherty et al. 1999).

1. wetland is primarily forest
wetland is primarily herbaceous
wetland is shrub dominated


2 wetland is within stream channel or floodplain River Swamp
wetland is an isolated depression Depression Swamp
wetland is along a lake edge (permanent water >2 meters deep) Lake Swamp
wetland located on sloped topography Strand / Seepage Swamp
wetland associated with flat landscape; water source primarily precipitation Flatland Swamp

3 wetland is within a stream channel or floodplain
wetland is an isolated depression
wetland is along a lake edge (permanent water >2 meters deep)
wetland located on sloped topography with groundwater source
wetland associated with flat landscape; water source primarily precipitation

River Marsh
Depression marsh
Lake marsh
Seepage Marsh
Wet Prairie

Hydroperiod: Depth, duration, and frequency of inundation
Primary water source: rainfall, surface water, groundwater
Soil type: organic, mineral
Plant community association

Table 10.3. Classification cross-reference of proposed classes for biological assessment of
inland freshwater wetlands in Florida (from Doherty et al. 1999).

Forested wetlands:
River Swamp
FNAI: Bottomland Forest, Floodplain Forest, Floodplain Swamp, Freshwater Tidal Swamp, River
Floodplain Swamp
FLUCCS: 613-Gum Swamp, 615-Stream and Lake Swamp (Bottomland), 617-Mixed Wetland
Hardwood, 621-Cypress, 623-Atlantic White Cedar, 624-Cypress-Pine-Cabbage Palm
FWC: 12-Cypress, 13-Hardwood Swamp, 17-Bottomland Hardwood
NWI: PFO 1-Palustrine Forested Broad-leaved Deciduous, PFO2-Palustrine Forested Needle-leaved
Deciduous, PFO6-Palustrine Forested Deciduous mixed, PFO7-Palustrine Forested Evergreen
SCS: 17-Cypress Swamp, 20-Bottomland Hardwood, 21-Swamp Hardwood
Depression Swamp
FNAI: Basin Swamp, Bog, Dome Swamp, Baygall
FLUCCS: 611-Bay Swamp, 613-Gum Swamp, 617-Mixed Wetland Hardwood, 621-Cypress
FWC: 12-Cypress, 13-Hardwood Swamp, 14-Bay Swamp
NWI: PFO2-Palustrine Forested Needle-leaved Deciduous, PFO3-Palustrine Forested Broad-leaved
Evergreen, PFO6-Palustrine Forested Deciduous mixed
SCS: 17-Cypress Swamp, 22-Shrub Bog/Bay Swamp
Lake Swamp
FNAI: Swamp Lake, Basin Swamp, Bottomland Forest
FLUCCS: 613-Gum Swamp, 615-Lake Swamp (Bottomland), Mixed Wetland Hardwood, 621-
Cypress, 624-Cypress-Pine-Cabbage Palm
FWC: 12-Cypress Swamp, 13-Hardwood Swamp, 17-Bottomland Hardwood
NWI: PFO2-Palustrine Forested Needle-leaved Deciduous, PFO6-Palustrine Forested Deciduous
SCS: 17-Cypress Swamp, 21-Swamp Hardwoods
Strand Swamp
FNAI: Strand Swamp
FLUCCS: 614-Titi Swamp, 617-Mixed Wetland Hardwood, 618-Willow and Elderberry, 619-Exotic
Wetland Hardwood, 621-Cypress, 631-Wetland Scrub
FWC: 12-Cypress Swamp, 13-Hardwood Swamp, 15-Shrub Swamp
NWI: PFO2-Palustrine Forested Needle-leaved Deciduous, PFO6-Palustrine Forested Deciduous
SCS: 12-Wetland Hardwood Hammock, 16-Scrub Cypress, 17-Cypress Swamp
Seepage Swamp
FNAI: Baygall
FLUCCS: 611-Bay Swamp
FWC: 14-Bay Swamp
NWI: PFO3-Palustrine Forested Broad-leaved Evergreen, PFO7-Palustrine Forested Evergreen mixed
SCS: 10-Cutthroat Seep, 22-Shrub Bog/Bay Swamp
Flatland Swamp
FNAI: Hydric Hammock, Wet Flatwoods
FLUCCS: 614-Titi Swamp, 616-Inland Ponds and Sloughs, 618-Willow and Elderberry, 619-Exotic
Wetland Hardwood, 622-Pond Pine, 624-Cypress-Pine-Cabbage Palm, 625-Hydric Pine
Flatwoods, 626-Hydric Pine Savanna, 627-Slash Pine Swamp Forest
FWC: 13-Hardwood Swamp, 3-Pinelands
NWI: PFO4-Palustrine Forested Needle-leaved Evergreen, PFO7-Palustrine Forested Evergreen mixed
SCS: 6/7-Flatwoods

Table 10.3 (Continued.) Cross-reference of wetland types with proposed bioassessment

Non-forested wetlands:
River Marsh
FNAI: Floodplain Marsh
FLUCCS: 641-Freshwater Marsh, 644-Emergent Aquatic Vegetation
FWC: 11-Freshwater Marsh and Wet Prairie
NWI: R2AB-Riverine Lower Perennial Aquatic Bed, R2EM-Riverine Lower Perennial Emergent
Non-persistent, R3AB-Riverine Upper Perennial Aquatic Bed, R4SB-Riverine Intermittent
Streambed, PAB3-Palustrine Aquatic Bed Rooted Vascular, PAB4-Palustrine Aquatic Bed
Floating Vascular, PEM-Palustrine Emergent
SCS: 25-Freshwater Marsh
Depression Marsh
FNAI: Basin Marsh, Bog, Depression Marsh
FLUCCS: 641-Freshwater Marsh, 644-Emergent Aquatic Vegetation, 653-Intermittent Pond
FWC: 11-Freshwater Marsh and Wet Prairie
NWI: PAB3-Palustrine Aquatic Bed Rooted Vascular, PAB4-Palustrine Aquatic Bed Floating
Vascular, PEM-Palustrine Emergent
SCS: 25-Freshwater Marsh, 24-Sawgrass Marsh
Lake Marsh
FNAI: Flatwoods/Prairie/Marsh Lake, Basin Marsh
FLUCCS: 641-Freshwater Marsh, 644-Emergent Aquatic Vegetation, 645-Submergent Aquatic
FWC: 11-Freshwater Marsh and Wet Prairie
NWI: L1AB-Lacustrine Limnetic Aquatic Bed, L2AB-Lacustrine Littoral Aquatic Bed, L2EM-
Lacustrine Littoral Emergent non-persistent, PAB3- Palustrine Aquatic Bed Rooted Vascular,
PAB4- Palustrine Aquatic Bed Floating Vascular, PEM-Palustrine Emergent
SCS: 25-Freshwater Marsh
Seepage Bog
FNAI: Swale, Slough, Seepage Slope
FLUCCS: 641-Freshwater Marsh, 643-Wet Prairie
FWC: 11-Freshwater Marsh and Wet Prairie
NWI: PEM-Palustrine Emergent
SCS: 10-Cutthroat Seep, 23-Pitcher Plant Bog
Wetland Prairie
FNAI: Wet Prairie, Marl Prairie
FLUCCS: 643-Wet Prairie, 646-Treeles Hydric Savanna
FWC: 11-Freshwater Marsh and Wet Prairie
NWI: PEM-Palustrine Emergent
SCS: 25-Freshwater Marsh, 26-Slough, 24-Sawgrass Marsh
Shrub Scrub
FNAI: Seepage Slope, Bog, Slough
FLUCCS: 631-Wetland Scrub, 614-Titi Swamp, 616-Inland Pond and Slough, 618-Willow and
Elderberry, 619-Exotic Wetland Hardwood
FWC: 15-Shrub Swamp
NWI: PSS-Palustrine Scrub Shrub
SCS: Shrub Bog/Bay Swamp

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