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Title: Synthesis of the EMAP - inland wetlands approach : executive summary
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Title: Synthesis of the EMAP - inland wetlands approach : executive summary
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Creator: Brown, Mark T.
Publisher: University of Florida
Publication Date: 1989
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Table of Contents
    Title Page
        Page 1
    Introduction
        Page 2
    Synthesis
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
    EMAP - inland wetlands indicator strategy
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
Full Text











A SYNTHESIS OF THE EMAP INLAND WETLANDS APPROACH


EXECUTIVE SUMMARY





By




Mark T. Brown
Center for Wetlands
University of Florida
Gainesville, Fl 32611






for


Office of Research and Development
U.S. Environmental Protection Agency





October 1989


(CFW-89-10)














A SYNTHESIS OF THE EMAP INLAND WETLANDS APPROACH


By

Mark T. Brown
Center for Wetlands
University of Florida
Gainesville, Fl 32611




Introduction


The purposes of this synthesis report are to:

1. Summarize core and developmental indicators that have been selected for immediate use and
pilot testing by EMAP Inland Wetlands

2. explain the choices of indicators of ecological status by enumerating valued ecological qualities
and perceptions of ecological status by the public

3. explain the causal pathways of potential stressors to develop a clear picture of nominal and
subnominal ecological status, probable causes of subnominal status, and conflicting evidence of ecological
status;

4. establish critical research needs for EMAP Inland Wetlands over the next several years to
first test the suite of indicators of ecological status and then to further refine the indicator suite and
sampling protocols to meet overall EMAP goals and objectives.



Synthesis


EMAP Inland Wetlands Indicators

The overall goals and objectives of EMAP are designed to answer the following four questions:

1. What is the current extent of terrestrial and aquatic resources at risk from loss, alteration,
or damage from anthropogenic stresses at the regional and national scale?
2. What is the current status of these ecological resources?
3. What is the most probable diagnosis for resources in subnominal condition?
4. Are there regional or national trends in the condition of ecological resources?

The near term goals of the EMAP -Inland Wetlands effort are to: (1) identify indicators that are

appropriate for determining status and trends of ecological condition of the nation's wetlands, (2) field














A SYNTHESIS OF THE EMAP INLAND WETLANDS APPROACH


By

Mark T. Brown
Center for Wetlands
University of Florida
Gainesville, Fl 32611




Introduction


The purposes of this synthesis report are to:

1. Summarize core and developmental indicators that have been selected for immediate use and
pilot testing by EMAP Inland Wetlands

2. explain the choices of indicators of ecological status by enumerating valued ecological qualities
and perceptions of ecological status by the public

3. explain the causal pathways of potential stressors to develop a clear picture of nominal and
subnominal ecological status, probable causes of subnominal status, and conflicting evidence of ecological
status;

4. establish critical research needs for EMAP Inland Wetlands over the next several years to
first test the suite of indicators of ecological status and then to further refine the indicator suite and
sampling protocols to meet overall EMAP goals and objectives.



Synthesis


EMAP Inland Wetlands Indicators

The overall goals and objectives of EMAP are designed to answer the following four questions:

1. What is the current extent of terrestrial and aquatic resources at risk from loss, alteration,
or damage from anthropogenic stresses at the regional and national scale?
2. What is the current status of these ecological resources?
3. What is the most probable diagnosis for resources in subnominal condition?
4. Are there regional or national trends in the condition of ecological resources?

The near term goals of the EMAP -Inland Wetlands effort are to: (1) identify indicators that are

appropriate for determining status and trends of ecological condition of the nation's wetlands, (2) field










test measurement techniques of indicators and develop protocols, and (3) test a suitable suite of indicators

to determine their applicability to a national EMAP Design.

While the program goals of EMAP Inland Wetlands are obviously identical to the overall EMAP

goals, the near term goals and objectives are more related to developing and testing indicators and suites

of indicators to assure that the meet the overall program goals. To this end we have developed a

methodology and systematic review process to select a suite of potential indicators that seem to be

appropriate to begin testing immediately. We have also identified a set of indicators that may be added

to the indicator suite at a later time (from one to several years) once sufficient confidence related to their

application and appropriateness to EMAP has been demonstrated. The lack of confidence stems from

either one or both of the following two issues:

measurement techniques have not been thoroughly standardized or tested, or

their is some question whether they are sensitive enough or applicable to all wetland
types and conditions.

Field testing in a pilot program will provide needed information on methodologies and

standardized protocols for those indicators where techniques are weak, and analysis of data and

comparison with other indicators and known stressors will reveal whether indicators are appropriate

and sensitive for determining status and trends of end points of concern.

In addition, we have identified a third set of potential indicators that are further from

implementation (3-5 years), but that deserve testing and development because they may have great

potential in providing essential information not covered by other indicators.

The following list of proposed EMAP Inland Wetland indicators by class is ordered in a rough

confidence ranking that is based on (1) their ability to provide meaningful information, and (2)

developmental status.

Core Indicators

1. Regional changes in acreage, type diversity and spatial patterns
2. Hydroperiod
3. Direct measurement of nutrients
4. Direct measurement of pollutants
5. Vegetation patterns, abundance, biomass, and species composition
6. Sedimentation and Organic Matter accretion
7. Waterbird abundance and species composition.










Developmental indicators (well developed)

1. Bioaccumulation
2. Macroinvertebrate abundance, biomass, and species composition
3. Leaf area, greenness, and per cent light transmittance

Developmental Indicators (poorly Developed)

1. Microbial community structure
2. Bioassays
3. Biomarkers


Wetland Indicators Not Selected

In the literature concerning the state of the art of indicators of ecological status (sometimes

termed "bioindicators") there are numerous suggestions of extensive lists of components or pathways of

energy exchange that might be candidates for indicators. The lists were seriously considered, and

narrowed to those mentioned above as the most promising. Several proposed indicators that were not

chosen deserve mentioning to explain, in light of their public viability, why they have been discarded.

The three most common are fish, herpetofauna, and mammals.

In most cases, the public sees wetlands as wildlife habitat, and thus the use of visible wildlife

species as indicators of ecological status would seem to make good sense. They are widely known, the

public recognizes the connections between wildlife and habitat to some extent, and they are an important

"endpoint." Yet they present special difficulties in sampling that resultfrom the pulsing hydrology of most

wetland systems that effect spatial and temporal distributions and life habits which, in turn, cause

fluctuations in populations that may not be related to changes in wetland ecological status.

Variation in normal seasonal distributions of wildlife and fish within wetlands are compounded

by other pulsing events like wet and dry seasons or periods of extreme rainfall and drought. For instance,

many herpetofauna key reproduction to dry seasons or rainfall events that may vary considerably from

one year to the next. Fish populations within wetland ecosystems are extremely variablefrom year toyear,

and wetland to wetland. Viable populations within isolated wetlands depend on standing surface water

throughout the year; a condition that may vary from one year to the next. Fish populations in flowing

water wetland systems depend on conditions in contributing streams and rivers that have little or no










relation to the status of the associated wetland. Sampling schemes in the simplest of programs that are

designed to sample fish and herpetofauna quickly become cumbersome as a result accounting for these

factors; a national or regional program would be unwieldy.

Mammals are mobile species, the larger the animal, the more mobile. Many spend only portions

of yearly life cycles within wetland systems since they integrate over broad landscapes of uplands and

wetlands. Some species are affected by hunting pressure, or because of their mobility, are subject to

accidental death on roadways. These anthropogenic pressures result in fluctuations in populations that

are unrelated to ecological status. In addition, temporal variability in mammal populations is

compounded by wetland hydrologic pulses that can drive some species to higher ground during the wet

season or unusual rainfall events, or drive them to other wetlands where drought has not adversely

affected food supplies.

In all, the use of fish, herpetofauna, and mammals as indicators of ecological status of wetlands

was judged to present significant difficulties when proposed within the regional character of the sampling

scheme for EMAP Inland Wetlands. Required sampling frequency, and spatial resolution that would

be necessary to account for within region, temporal, and within wetland variability precludes their use in

the program. The use of mammals and to some extent herpetofauna as indicators of ecological status on

a larger scale (i.e. the landscape scale) may be a fruitful approach and probably should be pursued as a

means of accounting for status and trends in regional biodiversity.



Endpoints of Wetland Ecological Status

Ecological qualities or endpointss" valued by the public are related to four broad categories of

ecological functions: (1) water quality functions, (2) Water quantity hydrologicc) functions, (3) Wildlife

support, and (4) socio-cultural values. Each of these functions has one or more facets that are often

considered separately as endpoints depending on type of wetland, regional characteristics, and other

public perceptions as follows:

Water Quality Functions:










Two primary sources: (1) wetlands provide quality improvement through


sedimentation and immobilization, and limited uptake of various pollutants/ nutrients

carried in flowing waters, and (2) organic substrate acts as filter to immobilize substances

as they pass from surface waters through wetland soils to ground waters.



Hydrologic Functions

Water storage and flood abatement.
Wetland water storage acts as buffer against flooding by storing storm
water and releasing slowly to minimize flood peaks and maintain base flow.

Ground Water Recharge and Discharge
Wetlands are areas where ground waters either discharge or infiltrate.
Often, in individual wetlands bi-directional flow is characteristic during different
portions of the year.

Life Support

Primary Production and Food Chain Support
Wetland productivity is often greater than surrounding ecological
communities by virtue of their role as areas of landscape concentration. Internal
food chains and those where production is often exported are sustained by the
higher production.

Wildlife habitat.
As a result of higher production, and structural characteristics wetlands
offer habitat features not found in other community types.

Socio-Cultural values

Uniqueness and scarcity
Wetlands represent only about 20% of the total landscape, in some areas
they represent a very small percentage. Often wetlands are the last vestiges of a
wild landscape.

Cultural values.
Research,and educationalvalues,aestheticvalues,waste and stormwater
recycle, wood and wood products, sustained yield agricultural production.


Public Perceptions of Ecological Status


Public perceptions of ecological status are less complex than are the qualities for which wetlands

are valued. While there are over half a dozen qualities judged important and valuable, most are not easily

perceived. As a result there are three main indicators of wetland ecological status that are easily










understood and have often been shown to garner public concern. They include (in order of perceived

public importance): (1) loss of wetland area, (2) decline in viable populations of wildlife, and (3)

noticeable (rapid) changes in species composition.

The loss of acreage has been elevated in the minds of the public in recent years to an extent that

acreage in and of itself has become synonymous with wetland ecological status. While trends in the loss

of acreage are often blamed for decreases in wildlife populations, the actual loss is of great public

concern. As a result, the foremost important indicator of EMAP Inland Wetlands is measurement of

changes in acreage, type diversity and spatial patterns of wetlands across regions and among wetland

types.

Loss of wetland area, and to a lessor extent, declines in the quality of wetland habitat have been

suggested as the causes of decline in viable populations of wildlife. Many species of threatened birds and

mammals have been shown to be wetland dependent species; terminology that has become increasingly

important to the public. Public perceptions regarding losses of birds, mammals and fish (probably in that

order) as they relate to the spatial extent of inland wetlands is relatively high.

Rapid changes in species composition 'r in the condition of plant species present in wetland

ecosystems is often attributed to exogenous impacts by the public. Invasions of exotic species and species

considered noxious, as well as noticeable shifts in species composition are often quite apparent and

garner public attention. However, much of the public does not associate the changes in species

composition with functional impacts like loss of wildlife habitat and food chain support. The change in

species composition, in and of itself, is sufficient evidence for most of the public to suggest changes in

ecological status have occurred.


I










EMAP -Inland Wetlands Indicator Strategy


Determining Ecological Status

EMAP is being designed to provide information on a region by region basis concerning the

ecological status of the Nation's ecosystems. The chosen suite of indicators for each class of ecosystems

(inlandwetlands, agro-ecosystems,forests,near coastal systems, etc.) need provide information regarding

the percent of the target population that is nominal or subnominal, distinguish between contradictory

indications of status among the various indicators, and provide probable cause of the subnominal

condition. The suite then, must contain indicators of stress origins, exposure, and response.

Stressor Indicators Stressor indicators are economic, social,and environmental engineering data that

can be used to confirm diagnoses and determine most probable sources of exposure or as ancillary data

that may help in interpretation of diagnoses. Indicators that are of interest to EMAP Inland Wetlands

include: population, land use, changes in land use, drainage density of canals and ditches, ground water

and surface water withdrawals, sewage treatment methods and quantities, etc. Some of these data are best

complied from aerial photography, some from recent census information, and some from regional or local

engineering sources. While an important component of the EMAP Inland Wetlands program, these data

are required by each of the ecosystem teams and will be provided and maintained by the EMAP

characterization group as part of the Geographic Information Base for each sample location.

Response Indicators Response indicators are biological measurements that quantify the overall

condition of the ecosystem. Examples include gross pathology of species present, presence or absence

of "sentinel" species, and community structure. Response indicators can be used to separate the population

of wetlands into nominal and subnominal classes of condition. They tend to integrate the effects of all

stressors acting on a wetland system over time, but provide ambiguous diagnostic evidence.

Core indicators that are classed as response indicators include: (1) vegetation patterns,

abundance, biomass, and species composition; (2) waterbird abundance and species composition, and (3)

organic matter accretion.










Measurements of leaf area, percent light transmittance, and greenness, as well as

macroinvertebrate abundance, biomass, and species composition, once further developed may offer

advantages in increasing resolution of determination in nominal and subnominal classes and contribute

to resolving conflicting indicators.

Exposure Indicators Exposure indicatorsare physical,chemical, and biological measurements that can

be related to habitat degradation, pollutant exposure, or other causes of poor condition. Examples include

direct measurement of pollutant concentrations, bioaccumulation of toxins in tissue, bioassays using test

organisms, and measurement of habitat condition. Exposure indicators are used to partition the

subnominal fraction of the population into sources of exposure.

Core indicators that are classed as exposure indicators include: (1) regional changes in acreage,

type diversity, and spatial patterns; (2) hydroperiod; (3) direct measurement of pollutant; (4) direct

measurement of nutrients; and (5) sedimentation. Measurements of bioaccumulation is a developmental

indicator that may offer significant advantages for indicating exposure.



Setting the Nominal/Subnominal Boundaries '

Determination of the ecological status of wetlands within regions of the Nation requires

that someyardstick be developed thatindicateswhat is normalforvarious measured parameters, andwhat

is abnormal. For the purposes of EMAP, these two classes have been termed nominal and subnominal.

Separating the entire population of wetlands into nominal and subnominal may be accomplished by

deriving criteria values from reference sites, or by statistically classifying the population of sampled

wetlands where outlier or certain categories of measured parameters are considered subnominal.

The approach to setting the nominal/subnominal boundary that promises to be most fruitful in

the short run (considering the wide variation in parameters of wetland ecosystems) and that may provide

needed baseline data for statistical classification is the use of reference wetlands. Wetlands selected as

part of the overall sampling frame will be further subclassified based on surrounding landscape attributes

into a continuum of landscape development intensities from "relatively pristine" to highly developed.

Those wetlands in the relatively pristine classes will be used to determine nominal characteristics for










measured parameters, and subnominal characteristics established as some statistic (percent confidence

interval, for instance) of the nominal classes. Obviously, the entire population of wetlands must first be

classified by type and region to account for the extreme variability in measured parameters between

wetland types and regions.



Stressors and Wetland Ecological Status

Exogenous stressors on wetland ecological status can be ordered into two broad groups: a) those

resulting from changes in driving forces and b) and those associated with inputs of pollutants and toxins.

Changes in driving forces of wetland ecological systems include:


alterationsofhydroperiods resultingfrom manipulations of groundwater, surface
water, and stormwater that will lead to changes in biota and potential loss of
wetland dependent wildlife species.

loss of habitat and wetland conversion resulting from increased demands for wood,
peat, and other wetland "products".

Global climate changes causing increases or decreases in rainfall, and surface
water elevations resulting in changes in biota

Invasion by exotic and nuisance species that shift species richness, losses of
indigenous species, and declines in wildlife habitat suitability.

Changes associated with exogenous inputs of pollutants and toxins include:

Changes in salinity resultingfrom increased surface runoff from agricultural and
urbanized landscapes resulting in loss of wetland integrity and changes in species
composition.

Increased concentrations of nutrientsfrom agricultural and urbanized landscapes
resulting in changes in floral species composition and concurrent faunal
composition.

Increased concentrations of organic, metals, and pesticides etc. resulting in
declines or loss of faunal components and negative impacts of bio-accumulation.

Chosen response indicators (Vegetation, waterbirds, and organic matter accretion, as well as

future use of macroinvertebrates, measures of canopy closure and photosynthetic potential) cover the

most important community responses that result from exogenous stressors. However, it is quite obvious

that characteristic responses, like changes in species composition, or percent cover, can be caused by an


__










one of several of the stressors acting independently or in concert. The chosen exposure indicators will

help to determine most probable cause of subnominal behavior in one of the response indicators.

The suite of indicators has been chosen to illuminate the differences between these stressors and

identify probable causes for subnominal categorization. The single most important exposure indicator

that will have the greatest influence on separating causal influences is hydroperiod. Hydroperiod is by

far the most significant driving force that shapes wetland structural and functional organization, and is

the driving force most often manipulated by humans. Changes in hydroperiod have significant effects on

species composition, nutrient pathways and rates of cycling, habitat quality, and gross production.

Without simultaneous measurement of hydroperiod alongwith the response indicators, separation of the

subnominal population of wetlands by stressor will be hindered.

Other important exposure indicators that must be measured to interpreted the subnominal

population are direct measurement of pollutants, nutrients, and sedimentation. Once hydroperiod is

accounted for and subnominal responses are indicated by one or more of the indicators, the most probable

stressor can be identified using systems diagrams of pathways of energy and matter (see next section) and

then direct measurements of the appropriate exposure indicator can be made.



Resolving Conflicting Indications of Status

It is quite reasonable to assume that different response indicators can and will give conflicting

indications of ecological status. There are two things that contribute to this situation. First, stressors act

differentially in hierarchically organized systems affecting some compartments more than others,

depending on the quality and quantity of the stressor. Second, as a result of time lags, responses in some

compartments (those with rapid turnover times for instance) will be quicker than in other compartments.

Thus measurements in response in different hierarchical levels within an ecosystem can easily

demonstrate conflicting evidence. With time however, the conflicting evidence may resolve itself as

internal pathways of energy and mater exchange reorganize under the new influences. Annual or biennial

measurements on a population of wetlands in a dynamic landscape should exhibit significant conflicting

evidence of ecological status, but where change is not so rapid, conflicts should be minor.










The possibility of conflicting indicator situations where one of more measurements of response

indicators suggest that a portion of a regional population of wetlands is subnominal while one or more

suggest it is nominal, is difficult to resolve without a larger scale understanding of ecosystem structural

properties and stress action and response pathways. Systems diagrams like that given in Figure 1 showing

pathways of energy and matter exchange can be used to trace stressor actions and illuminate community

level responses. In this way, systems diagrams with sufficient detail can not only be used to resolve

conflicting response indications, but can be used to identify probable stressors, since not all stressors, act

along the same pathways to cause the same response. For example stressors that act at the "top end" of

an ecological community, like pesticides, will show responses in waterbird abundance first before lower

organisms and vegetation show significant responses; or on the other hand, "bottom end" stressors, like

nutrient enrichment will cause responses relatively quickly in vegetation compartments with delays in

cascading responses in higher order compartments.

Conflicting responses provide important information that can be used to determine probable

stressors, and while the situation may suggest difficulties in measurement techniques or interpretation

of data, it can easily be used to benefit the overall objectives of the program. With adequate analysis of

data and an overall system level perspective, conflicts can be resolved through tracing backwards from

the response indicator in the diagram to probable causal agents. Direct measurement of the agent can

then be done to confirm or deny the qualitative assessment using the systems diagram.



Research Needs for EMAP Inland Wetlands

There are three critical areas of research needed to help meet the objectives of EMAP and to

increase the efficiency and reliability of the suite of indicators in identifying sub classes of wetland

ecological resources that have experienced more damage than others. First, in the near term, a pilot

program that will test whether the suite of indicators can give unambiguous information will be conducted.

At this time measurement techniques and field protocols, and data analysis techniques and protocols will

be tested. Also developmental indicators will be further developed with preliminary testing conducted

to help move them toward implementation within 1 to 3 years.










Second, in the near term, analysis of landscape scale indicators measured from remotely sensed

data need development and testing. A proposed index called the Landscape Development Intensity (LDI)

index that is a measure of the level of developmental impact and therefore a possible indicator of potential

ecological impacts may provide a quick and cost effective method of identifying populations of wetlands

that are most likely to be subnominal. Further, the LDI may allow for landscape scale classification that

will quickly and economically allow for the targeting of resources within regions. The LDI has been

applied in some preliminary work in Florida and has showed some promise in stratifying populations of

wetlands in urbanizing landscapes. Further testing is needed to expand its applicability through

incorporating additional variables in the index.

Third, in the long term, much system level research on the structural organization of wetland

ecological resources is needed to better understand stress action pathways and the self-design

reorganization than occurs in ecological communities in response to varying quantities and qualities of

stressors. AS this research is accomplished significant advances can be made regarding development of

indicators of ecological status, refinement of boundaries between nominal and subnominal, and efficiency

of detection of subnominal populations.























































Figure 1. Energy diagram of a forested wetland showing components and causal pathways of energy and matter exchange.
Systems diagrams can be used to illuminate community level responses, solve conflicting response indicators,
and identify probable stressors.


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