Ecological studies of larval Glyptotendipes paripes (Chironomidae: Diptera) in selected central Florida lakes for creati...

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Ecological studies of larval Glyptotendipes paripes (Chironomidae: Diptera) in selected central Florida lakes for creating an exploratory temporal and spatial model of nuisance populations
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Lobinske, Richard J., 1963-
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ECOLOGICAL STUDIES OF LARVAL Glyptotendipes paripes (CHIRONOMIDAE:
DIPTERA) IN SELECTED CENTRAL FLORIDA LAKES FOR CREATING AN
EXPLORATORY TEMPORAL AND SPATIAL MODEL OF NUISANCE
POPULATIONS













By

RICHARD J. LOBINSKE


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA


2001



























Copyright 2001

By

Richard J. Lobinske














ACKNOWLEDGEMENTS

I wish to express gratitude to the members of my committee who provided

valuable insight into design of the study, Drs. Arshad Ali, Charles Cichra, Konda Reddy

and Jerry Stimac. Dr. Jon Allen, a committee member until his retirement, provided

critical information needed to design the computer model. Material and technical support

for this research was provided by the Aquatic Entomology and Ecology program (Dr.

Arshad Ali), University of Florida, Institute of Food and Agricultural Sciences, Mid-

Florida Research and Education Center, Apopka. This program has provided additional

support by allowing me to conduct this research as part of my regular employment as a

Biological Scientist with the University of Florida. Permission and cooperation of the

Florida Fish and Wildlife Conservation Commission for fish collection used for gut

analysis is gratefully recognized. Mr. Bill James and the staff of the University of

Florida's Lake Wauburg Recreation Area provided valuable assistance for the Lake

Wauburg portion of this study. Dr. Jan Frouz provided assistance in multivariate analysis

of the field data and provided access to the necessary computer programs to accomplish

this, and also provided assistance with data collection for the development study,

proofreading and editorial assistance. Mrs. Julie L. Bortles and especially Mr. Robert J.

Leckel, Jr. provided assistance during field collections for the study lakes and long hours

of sample processing. Mrs. Louise Pard-Lobinske provided proofreading and technical

assistance on use of Microsoft Word for preparation of this manuscript.














TABLE OF CONTENTS
page

ACKNOWLEDGEMENTS............................................................................................... iii

LIST O F TA B LE S ............................................................................................................. vi

LIST O F FIG U R E S ......................................................................................................... viii

A B ST R A C T ..................................................................................................................... xiii

CHAPTERS

1 GENERAL INTRODUCTION...................................................................................... 1

2 REVIEW OF RELEVANT LITERATURE .................................................................. 5

3 DESCRIPTION OF STUDY LAKES ......................................................................... 14

4 MAPPING BATHYMETRIC AND SELECTED SEDIMENT PHYSICO-
CHEMICAL CHARACTERISTICS OF STUDY LAKES................................... 17

Introduction................................................................................................................. 17
Materials and Methods ............................................................................................... 17
R results and D discussion ............................................................................................... 19

5 LARVAL DISTRIBUTIONS OF Glyptotendipes paripes IN RELATION TO
WATER AND SEDIMENT PHYSICO-CHEMICAL PARAMETERS IN
STU D Y LA K E S ............................ ............. ..................... ............... ....................... 39

Introduction ........................................................................................... ......................39
Materials and Methods ............................... ................................................................40
R results and D discussion .............................................. ............. ........... ......................... 43

6 FISH PREDATION ON CHIRONOMID MIDGES IN STUDY LAKES .................. 88

Introduction.................................................................................................................88
Materials and Methods .................................... ........................................................... 89
R results and D discussion ............................................................................................... 90








7 DETERMINATION OF TEMPERATURE-RELATED DEVELOPMENT OF
Glyptotendipes paripes..................................................................... ..... ........... 98

Introduction................................................................................................................. 98
Materials and Methods ........................................................................................... 99
Results and D discussion ................................................................. ............................100

8 DEVELOPMENT OF A SPATIO-TEMPORAL COMPUTER MODEL FOR
Glyptotendipesparipes LARVAL DISTRIBUTIONS IN CENTRAL FLORIDA
L A K E S ................. ................................................................................................ 106

Introduction ............................................................... ................................................ 106
M materials and M ethods ............................................................................................. 107
Results and D discussion ............................. ....................................................... ......... 113

9 SUMMARY AND CONCLUSIONS........................................................................ 137

R E FE R EN C E S ................................................................................................................ 142

APPENDIX MATLAB COMPUTER PROGRAMS USED IN STUDY ................. 152

BIOGRAPH ICAL SKETCH ........................................................................................... 161














LIST OF TABLES
page
Table

1. Mean SD of selected sediment physico-chemical parameters and
water depth from mapping survey of Lakes Dora (May-September
1998), Yale (October-December 1998), and Wauburg (February
2000) ...................................................................................................................... 24

2. Comparison of mean percent of sample + SD of sediment particles
retained by sieve series (1,000, 350, 250 and 125-4m pore mesh) from
muck and sand sediments collected from Lake Dora (May-September
1998) and Lake Yale (October-December 1998)................................................... 24

3. Monthly mean + SD of selected water physico-chemical parameters
(water depth, Secchi disk transparency, water temperature, dissolved
oxygen, specific conductance, chlorophyll a, chlorophyll b and total
chlorophyll) and sediment dry weight (DW) for Lake Dora (Lake
County, Florida) from March 1999 to February 2001 ........................................... 54

4. Monthly mean SD of selected water physico-chemical parameters
(water depth, Secchi disk transparency, water temperature, dissolved
oxygen, specific conductance, chlorophyll a, chlorophyll b and total
chlorophyll) and sediment dry weight (DW) for Lake Yale (Lake
County, Florida) from March 1999 to February 2001 ........................................... 55

5. Monthly mean SD of selected water physico-chemical parameters
(water depth, Secchi disk transparency, water temperature, dissolved
oxygen, specific conductance, chlorophyll a, chlorophyll b and total
chlorophyll) and sediment dry weight (DW) for Lake Wauburg
(Alachua County, Florida) from March 2000 to February 2001 ........................... 56

6. Mean monthly density (No./m2) + stratified SD of selected
Chironomidae larvae [Chironomus crassicaudatus, Glyptotendipes
paripes, Cryptochironomus spp. (Crypt.), Tanytarsini (Tanyt., mostly
Cladotanytarsus spp.), Tanypodinae (Tanyp.), total Chironomidae
larvae, G. p. biomass (mg/m2) and total Chironomidae biomass
(mg/m2)] collected for Lake Dora (Lake County, Florida), March
1999-February 2001..................................................... .................................... 57








7. Mean monthly density (No./m2) stratified SD of selected
Chironomidae larvae [Chironomus crassicaudatus, Glyptotendipes
paripes, Cryptochironomus spp. (Crypt.), Pseudochironomus spp.
(Pseud.), Tanytarsini (Tanyt., mostly Cladotanytarsus spp.),
Tanypodinae (Tanyp.), total Chironomidae larvae, G. p. biomass
(mg/m2) and total Chironomidae biomass (mg/m2)] collected for Lake
Yale (Lake County, Florida), March 1999-February 2001.................................... 58

8. Mean monthly density (No./m2) stratified SD of selected
Chironomidae larvae [Glyptotendipes paripes, Tanypodinae (Tanyp.),
total Chironomidae larvae, G. p. biomass (mg/m2) and total
Chironomidae biomass (mg/m2)] collected for Lake Wauburg
(Alachua County, Florida), March 2000-February 2001 ....................................... 59

9. Mean SD of Glyptotendipes paripes larval dry biomass (mg/larva)
by 1-mm size class and cube root of mean value used for calculating a
size/biom ass curve .................................................................................................60

10. Mean length and gut contents of bluegill (Lepomis macrochirus)
collected on four occasions between May 1999 and December 2000
by electrofishing in Lakes Dora and Yale (Lake County, Florida).
Mean length and number of chironomid larvae per fish SD and
percent composition (shown in parentheses) ......................................................... 95

11. Mean + SD development time (hours) for each life stage of
Glyptotendipes paripes reared at a range of constant temperatures 1
C and 14:10 hour light:dark photoperiod. Number of individuals (n)
included in calculations are shown in parentheses .............................................. 104

12. Slope and x-intercept from linear regression equations of mean
development times per life stage of Glyptotendipes paripes with
temperature used to estimate lower temperature development
threshold (To). Number of data points used for each stage is shown in
parentheses........................................................................................................... 105

13. Estimated mean SD degree-days above 9.0 C for each development
stage of Glyptotendipes paripes ........................................................................... 105














LIST OF FIGURES
page
Figure

1. Bathymetric map of Lake Dora (Lake County, Florida), May-
September 1998 and Danek et al. (1991)............................................................... 25

2. Bathymetric map of Lake Yale (Lake County, Florida), October-
December 1998 and Danek et al. (1991) ............................................................... 26

3. Bathymetric map of Lake Wauburg (Alachua County, Florida),
February 2000 and Lakewatch (pers. comm.) ....................................................... 27

4. Sediment percent dry weight in Lake Dora (Lake County, Florida),
M ay 1998-February 2001 ...................................................................................... 28

5. Sediment percent dry weight in Lake Yale (Lake County, Florida),
October 1998-February 2001 ................................................................................. 29

6. Sediment percent dry weight in Lake Wauburg (Alachua County,
Florida), February 2000-February 2001 ................................................................ 30

7. Sediment pH in Lake Dora (Lake County, Florida), May-September
19 9 8 ........................................................................................................................ 3 1

8. Sediment pH in Lake Yale (Lake County, Florida), October-
D ecem ber 1998 ...................................................................................................... 32

9. Sediment pH in Lake Wauburg (Alachua County, Florida), February
2 000 ........................................................................................................ ................ 33

10. Sediment total organic carbon (TOC) in Lake Dora (Lake County,
Florida), M ay-Septem ber 1998.............................................................................. 34

11. Sediment total organic carbon (TOC) in Lake Yale (Lake County,
Florida), October-December 1998......................................................................... 35

12. Sediment total organic carbon (TOC) in Lake Wauburg (Alachua
County, Florida), February 2000 ........................................................................... 36








13. Sediment particle size spatial distributions in Lake Dora (Lake
County, Florida), M ay-September 1998 ................................................................ 37

14. Sediment particle size spatial distributions in Lake Yale (Lake
County, Florida), October-December 1998 ........................................................... 38

15. Spatial larval distributions log(No./m2+ 1) of Glyptotendipes paripes
in Lake Dora (Lake County, Florida), March, May 1999...................................... 61

16. Spatial larval distributions log(No./m2+l) of Glyptotendipes paripes
in Lake Dora (Lake County, Florida), July, September 1999................................ 62

17. Spatial larval distributions log(No./m2+ 1) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), November 1999, January 2000 ................. 63

18. Spatial larval distributions log(No./m2+l) of Glyptotendipes paripes
in Lake Dora (Lake County, Florida), March, April 2000..................................... 64

19. Spatial larval distributions log(No./m2+l) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), May, June 2000......................................... 65

20. Spatial larval distributions log(No./m2+l) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), July, August 2000 ..................................... 66

21. Spatial larval distributions log(No./m2+ 1) of Glyptotendipes paripes
in Lake Dora (Lake County, Florida), September, October 2000 ......................... 67

22. Spatial larval distributions log(No./m+l) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), November, December 2000 ...................... 68

23. Spatial larval distributions log(No./m2+1) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), January, February 2001............................. 69

24. Spatial larval distributions log(No./m2+1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), March, May 1999 ...................................... 70

25. Spatial larval distributions log(No./m2+l) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), July, September 1999 ................................ 71

26. Spatial larval distributions log(No./m2+1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), December 1999, February 2000 ................ 72

27. Spatial larval distributions log(No./m2+1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), March, April 2000 ..................................... 73








28. Spatial larval distributions log(No./m2+l) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), May, June 2000 ......................................... 74

29. Spatial larval distributions log(No./m2+ 1) of Glyptotendipes paripes
in Lake Yale (Lake County, Florida), July, August 2000...................................... 75

30. Spatial larval distributions log(No./m2+l) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), September, October 2000.......................... 76

31. Spatial larval distributions log(No./m2+ 1) of Glyptotendipes paripes
in Lake Yale (Lake County, Florida), November, December 2000....................... 77

32. Spatial larval distributions log(No./m2+l) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), January, February 2001 ............................. 78

33. Spatial larval distributions log(No./m2+l) of Glyptotendipesparipes
in Lake Wauburg (Alachua County, Florida), March, April 2000 ........................ 79

34. Spatial larval distributions log(No./m2+1) of Glyptotendipes paripes
in Lake Wauburg (Alachua County, Florida), May, June 2000............................. 80

35. Spatial larval distributions log(No./m2+l 1) of Glyptotendipes paripes
in Lake Wauburg (Alachua County, Florida), July, August 2000.............. : .........81

36. Spatial larval distributions log(No./m2+l) of Glyptotendipes paripes
in Lake Wauburg (Alachua County, Florida), September, October
2000 ..................................................................................................... ................... 82

37. Spatial larval distributions log(No./m2+l) of Glyptotendipes paripes
in Lake Wauburg (Alachua County, Florida), November, December
2 00 0 ........................................................................................................................ 83

38. Spatial larval distributions log(No./m2+l) of Glyptotendipes paripes
in Lake Wauburg (Alachua County, Florida), January, February 2001 ................ 84

39. Canonical correspondence analysis (CCA) of selected water and
sediment physico-chemical parameters with Chironomidae larval
community in Lake Dora (Lake County, Florida), March 2000 -
February 2001 ........................................................................................................ 85

40. Canonical correspondence analysis (CCA) of selected water and
sediment physico-chemical parameters with Chironomidae larval
community in Lake Yale (Lake County, Florida), March 2000 -
February 200 1 ........................................................................................................ 86








41. Canonical correspondence analysis (CCA) of selected water and
sediment physico-chemical parameters with Chironomidae larval
community in Lake Wauburg (Alachua County, Florida), March 2000
February 2001 ............................................................................... . ............. 87

42. Composite percent composition of midge larvae in bluegill (Lepomis
macrochirus) gut contents and field populations in Lake Dora, May
1999-December 2000. C. crassicaudatus (C. c.), G. paripes (G. p.),
Cryptochironomus (Cryp), Pseudochironomus (Pseu),
Geoldichironomus (Geol), Tanytarsini (Tant), Tanypodinae (Tanp),
and other taxa (O th) ............................................................................................... 96

43. Composite percent composition of midge larvae in bluegill (Lepomis
macrochirus) gut contents and field populations in Lake Yale, May
1999-December 2000. C. crassicaudatus (C. c.), G. paripes (G. p.),
Cryptochironomus (Cryp), Pseudochironomus (Pseu),
Geoldichironomus (Geol), Tanytarsini (Tant), Tanypodinae (Tanp),
and other taxa (O th) ............................................................................................... 97

44. Diagram of spatial population matrix; small box represents population
of life stage z at spatial location (x, y) .................................................................121

45. Lefkovitch population matrix; Nx is population at life stage x, Sx is
survival of life stage x, Dx is chance of development for life stage x, F
is fecundity and t is tim e step..................................... .......................................... 122

46. Flow chart of Glyptotendipesparipes larval distribution model ......................... 123

47. Comparison of model output (bottom) of Glyptotendipes paripes
larval distribution in Lake Jesup under matching conditions with May
1996 field collected data (top). Scale on right is log(No./m2) ........................... 124

48. Comparison of model output (bottom) of Glyptotendipes paripes
larval distribution in Lake Monroe under matching conditions with
April 1996 field collected data (top). Scale on right is log(No./m2) ............. ....... 125

49. Comparison of model output (bottom) of Glyptotendipes paripes
larval distribution in Lake Dora under matching conditions with May
1999 field collected data (top). Scale on right is log(No./m2) ............................. 126

50. Comparison of model output (bottom) of Glyptotendipesparipes
larval distribution in Lake Yale under matching conditions with May
1999 field collected data (top). Scale on right is log(No./m2)............................. 127








51. Comparison of model output (bottom) of Glyptotendipes paripes
larval distribution in Lake Yale under matching conditions with July
2000 field collected data (top). Scale on right is log(No./m2) ............................. 128

52. Comparison of model output (bottom) of Glyptotendipes paripes
larval distribution in Lake Wauburg under matching conditions with
July 2000 field collected data (top). Scale on right is log(No./m2)...................... 129

53. Baseline Glyptotendipes paripes population trend (No./m2) (top) from
computer model run for 50 time steps and final population
log(No./m2) distribution (bottom) ........................................................................ 130

54. Glyptotendipes paripes mean No./m2 population trends from
computer model run for 50 time steps (left) and log(No./m2) final
population distributions (right). Secchi disk transparency 30 (top) and
90 cm (bottom )..................................................................................................... 131

55. Glyptotendipes paripes mean No./m2 population trends from
computer model run for 50 time steps (left) and log(No./m2) final
population distributions (right). Water temperature 12 C (top) and
32 C (bottom ) ..................................................................................................... 132

56. Glyptotendipes paripes mean No./m2 population trends from
computer model run for 50 time steps (left) and log(No./m2) final
population distributions (right). Water elevation -1 m from mean
(top) and +1 m (bottom )....................................................................................... 133

57. Glyptotendipesparipes mean No./m2 population trends from
computer model run for 50 time steps (left) and log(No./m2) final
population distributions (right). Fecundity 760 eggs/female (top) and
3040 eggs/fem ale (bottom ) .................................................................................. 134

58. Glyptotendipesparipes mean No./m2 population trends from
computer model run for 50 time steps (left) and log(No./m2) final
population distributions (right). Strength of density dependence 0.01
(top) and 0.0001 (bottom ) .................................................................................... 135

59. Glyptotendipes paripes mean No./m2 population trends from
computer model run for 50 time steps (left) and log(No./m2) final
population distributions (right). Dispersal standard deviation 1 grid
unit (top) and 4 grid units (bottom )...................................................................... 136















Abstract of Dissertation presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

ECOLOGICAL STUDIES OF LARVAL Glyptotendipesparipes (CHIRONOMIDAE:
DIPTERA) IN SELECTED CENTRAL FLORIDA LAKES FOR CREATING AN
EXPLORATORY TEMPORAL AND SPATIAL MODEL OF NUISANCE
POPULATIONS

By

Richard J. Lobinske

August 2001

Chairman: Arshad Ali
Major Department: Entomology and Nematology

Ecological and physiological influences on the chironomid midge, Glyptotendipes

paripes, were examined to develop a qualitative spatial and temporal computer model of

larval distributions in central Florida lakes. Larval population distributions of G. paripes

were examined over a two-year period in three central Florida lakes (Dora, Yale, and

Wauburg) in relation to selected water and sediment physico-chemical properties. Lake

bathymetry and sediment physical compositions were extensively mapped in each lake.

Composition of midge larvae in the gut contents of fish in relation to the standing crop of

midge larvae in Lakes Dora and Yale was studied. Development times for immature

G. paripes were determined in the laboratory by rearing under a series of constant

temperatures. These data were used to construct an exploratory spatio-temporal

computer model of G. paripes larval distributions in central Florida lakes.








Canonical correspondence analysis indicated that the primary, significant

influences on distributions of G. paripes larvae in the study lakes were water depth and

the following physico-chemical sediment characteristics: dry weight, total organic carbon

and presence of sand, muck or vegetation. While G. paripes larval distributions tended to

be associated with shallower, sandy substrates in Lakes Dora and Wauburg, these larvae

were distributed over/in muck bottom areas of Lake Yale. The development

requirements of this species were calculated to be 716 degree-days above 9.0 C from

egg to emergence. Gut content analysis indicated that bluegill (Lepomis macrochirus)

were indiscriminate feeders on midge larvae in shallower portions of the lakes and larvae

in deeper portions of the lakes perhaps were not within the grazing range of the fish.

When validated against previously collected data from Lakes Jesup and Monroe, the

computer model successfully estimated G. paripes larval distributions. The final model

was effective at estimating larval distributions in Lakes Dora, Yale and Wauburg with the

exception of the field data collected from Lakes Dora and Yale during the latter part of

the field study. Further work is needed to determine and understand the environmental

conditions that produced the unusual changes in G. paripes distributions noted in these

lakes that resulted in model predictions deviating from field data. Theoretical

manipulations of conditions within the model produced results that indicated the model to

be useful in preliminary ecological studies by providing initial hypotheses on G. paripes

larval population responses to selected environmental conditions studies.














CHAPTER 1
GENERAL INTRODUCTION


Non-biting aquatic insects of the family Chironomidae (Order: Diptera) can cause

nuisance because of their large and frequently emanating adult swarms (Ali 1995) and

associated medical problems (Cranston 1995) for waterfront residents, visitors and

business owners. This is especially true in Florida, which is laced with numerous

widespread aquatic ecosystems in urban and suburban areas and significant waterfront

developments. An estimated > 10,000 species of Chironomidae are distributed

worldwide, with >4,000 species identified globally and thus far 280 species in 119 genera

identified from Florida (Epler 1995). Worldwide, 100 or more species of the subfamilies

Chironominae, Orthocladiinae, and Tanypodinae have been reported to emerge at

nuisance levels (Ali 1995). In Florida, Beck and Beck (1969) identified Glyptotendipes

paripes, Chironomus crassicaudatus, Chironomus decorus, Chironomusfulvipilus,

Chironomus cars, Chironomus stigmaterus, and Glyptotendipes lobiferus occurring at

nuisance levels. In central Florida, Ali and Fowler (1985) identified G. paripes and

C crassicaudatus as the dominant pest species. The chironomid nuisance results from

the rather high productivity of these organisms in some habitats. Most nuisance species

generally have short adult lifespans, so accumulations of large numbers of dead and

odorous midges add to the midge nuisance problems. Adult chironomids can soil

buildings and equipment with egg masses and meconium, foul sensitive outdoor








equipment, and in extreme situations accumulate on roads in quantities that produce

slippery driving conditions (Ali 1995). An economic impact study commissioned by the

Greater Sanford Chamber of Commerce, Sanford, FL (Anonymous 1977) revealed that

midges emerging from Lake Monroe (a part of the St. Johns River in Seminole and

Volusia Counties, FL) and other nearby aquatic systems resulted in a loss of 3-4 million

dollars annually for lakefront businesses of the city of Sanford. This study also reported

that at least 10 counties in Florida suffered economic losses because of midge swarms.

Medical problems associated with midges primarily involve allergies

(conjunctivitis, rhinitis, hay fever, and asthma) triggered by inhalation of adult midge

fragments or skin contact with the larval hemoglobins (Cranston 1995). Presently,

midges are not known to be vectors of any disease organism. However, a recent report

has identified Chironomus sp. egg masses from waste-stabilization lagoons as a reservoir

for non-pathogenic biotypes of Vibrio cholerae, the cholera pathogen, and possibly a

reservoir for pathogenic biotypes (Broza and Halpem 2001).

Other problems associated with larval midges include contamination of drinking

water, and their presence as agricultural pests on rice, Japanese horseradish, and several

ornamental plants (Ali 1995, Cranston 1987, Stevens and Warren 1994). The various

problems are often exacerbated by cultural eutrophication of adjacent aquatic habitats,

creating favorable conditions for midge production in large numbers. In many situations,

midge problems intensify due to creation of new midge habitats, such as stormwater

holding ponds, effluent discharge channels, and residential-recreational lakes amid

human population centers.








Despite the problems associated with adult and larval chironomids, midge larvae

and pupae are an important element of most aquatic food webs, often being the dominant

or near dominant organisms in the benthos, providing food for many fish and

macroinvertebrates (Armitage 1995, Tokeshi 1995). Therefore, while developing any

midge control strategies, care must be taken to ameliorate the problems for humans

without having any serious or irreversible effects on the food-chain and overall ecology

of the aquatic habitat from which they emerge.

Within the framework of developing an integrated population management

strategy for midges, a spatio-temporal model for chironomid larval populations seems

necessary. Although a few lakes in central Florida (e.g., eutrophic Lakes Monroe and

Jesup) have been thoroughly investigated for chironomid ecology and productivity in the

past two decades (Ali and Baggs 1982, Ali and Alam 1996, Ali et al. 1996), more

information beyond the present database, including hypereutrophic and mesotrophic

habitats in central Florida, was needed. The objective of the present study was to collect

relevant data from additional central Florida lakes to assemble a spatial and temporal

model of G. paripes larval population distributions. Such a model would enable lake

managers to reduce sampling efforts and selectively target control measures to specific

areas of a habitat with high larval densities, and only at the times when they are abundant.

This would result in control measures interfering in only a relatively small, partial area of

a waterbody. Successful management efforts that reduce adult populations will have

considerable benefits, such as reduced nuisance problems with associated costs and

efforts to clean and maintain lakefront facilities, reduced economic losses to water-related

recreation and tourism industries, and overall a better quality of life for Florida citizens.








Based upon the Sanford Chamber of Commerce estimates (Anonymous 1977), these

savings could be in the millions of dollars statewide.

To develop a spatio-temporal model of G. paripes larval populations in central

Florida lakes, the following specific objectives were required. Detailed bathymetric and

sediment characteristic maps of the three study lakes (Lakes Dora, Yale and Wauburg)

had to be developed. Habitat specific physico-chemical characteristics influencing

chironomid larval populations were elucidated. Predation of chironomid larvae by fish

was analyzed by examining fish gut contents in relation to concurrent standing crop of

midge larvae. Temperature-related effects on G. paripes development were determined

and degree-day requirements for this species were estimated in the laboratory. These

data were used to develop and calibrate a model using the matrix techniques first

described by Allen et al. (1996). This model was qualitatively validated using G. paripes

larval population and physico-chemical environmental data from Lakes Jesup and

Monroe. The utility of the model as a theoretical tool in developing new hypotheses was

tested by varying different parameters within the model.














CHAPTER 2
REVIEW OF RELEVANT LITERATURE


In the past several decades, numerous investigations concerning bionomics and

management of chironomid populations have been undertaken in many countries of the

world as reviewed by Ali (1995). For population management purposes, a variety of

physical, cultural, biological and chemical means have been employed, with a majority of

attempts focused on chemical control. Predators of midges have been investigated, and

many parasites and pathogens have been identified. Commercially-produced bacteria,

Bacillus thuringiensis serovar. israelensis and Bacillus sphaericus, have been used in

attempts to reduce midge larvae in some habitats. Physical and cultural control

techniques have included mechanical means, habitat management and ecological

manipulations, and behavioral manipulations of adult midge populations. Details of

midge bionomics and management studies on a global basis, and in Florida, were

summarized by Ali (1991, 1996 a, b).

In Florida, Provost (1957, 1958, 1959) provided information on productivity, food

habits, and nutrient interactions of chironomids in 13 lakes in the Winter Haven/Polk

County area. Glyptotendipes paripes was the predominant chironomid in most of these

lakes, with a preference for sand (75% of collected larvae) or peat/sand (23% of collected

larvae) bottoms. Larval densities of G. paripes up to 4,730/m2 were reported, and such

high densities generally existed under low water level conditions. This species was








absent from lakes with minimal human influences, as well as from pure muck bottoms.

Gut analysis of G. paripes larvae revealed that 96% of the total diet consisted of blue-

green algae, with the balance consisting of green algae (2%), diatoms and other materials.

It was concluded that feeding of G. paripes larvae was non-selective, since blue-green

algae were by far the most common algae in the feeding zone of the larvae. Nielsen

(1962) studied the life history of imagines (adults) of G. paripes in Lake Cannon, Winter

Haven, FL and reported the unusual dawn mating swarms of this species, and the peak

period of adult emergence within 45-120 minutes after sunset. More than 3 decades ago,

midge larval and adult control by chemical means (primarily organophosphorus

insecticides) in some central Florida situations was studied by Patterson (1964, 1965) and

Patterson and Wilson (1966) who reported an excellent control of G. paripes larvae with

temephos used at rates as low as 0.06 kg active ingredient (AI)/ha.

In another situation in Florida, Lake Thonotosassa, Hillsborough County, was

reported to be highly eutrophic, with chironomid fauna dominated by C. crassicaudatus

(31%), G. paripes (29%), and Polypedilum halterale (13%). The latter two species

preferred sand bottom areas, with P. halterale occurrence limited to mostly shallow

water. Chironomus crassicaudatus was distributed throughout the lake, except during

summer when it was absent from the deep areas of the lake (Cowell et al. 1975). Later,

Cowell and Vodopich (1981) reported the distribution and seasonal abundance of

Chironomidae and other invertebrates in Lake Thonotosassa. Chironomids comprised

37.1% of total invertebrates collected. The dominant chironomid species was

P. halterale, followed by G. paripes and C crassicaudatus. Seasonal peaks of

abundance for P. halterale were spring and summer, for G. paripes summer and fall, and








spring for C. crassicaudatus. Life cycles of these species ranged between 14 and 22 days

and were multivoltine. Fuller and Cowell (1985) studied the invertebrate community

recovery with special reference to Chironomidae in Lake Thonotosassa after disturbances

caused by nesting of the cichlid fish, Saratherodon aurea.

Benthos of three eutrophic lakes (Apopka, Dora, and Griffin) in the Ocklawaha

chain of lakes, Florida, were investigated for three consecutive years by Holcomb et al.

(1974, 1975, 1976). These authors, limiting their identification of chironomids to family

level, reported annual mean larval densities of 641, 364, and 764/m2 in Lake Apopka;

2,094, 9,249, and 6,012/m2 in Lake Dora; and 1,793, 7,896, and 5,546/m2 in Lake Griffin

during 1973, 1974, and 1975, respectively. In Lake Apopka, midge density declined with

water depth, whereas in Lake Dora, low densities occurred at shallow contours,

increasing at the 3-ft (0.91 m) depth, remaining fairly constant down to 11-ft (3.35 m),

and declining significantly below 11-ft (3.35 m) water depths. In Lake Griffin, however,

the midge larval densities gradually increased with water depth. The authors attributed

these midge larval distribution trends to what they described as "poor quality of deep

water" in Lake Apopka, and "gradually improving quality" further downstream (deep

water) in the chain of lakes. In addition, heavy predation by fish in the shallow areas of

Lake Griffin was speculated to limit midge densities at these depths. A U. S.

Environmental Protection Agency survey (EPA 1978) included Lakes Apopka, Dora,

Griffin, and Yale in the National Eutrophication Survey and classified the status of these

lakes as eutrophic or hypereutrophic. Canfield (1981) studied chemistry and trophic state

of lakes in different geographical regions of Florida and included six lakes of the

Ocklawaha chain in his investigation. He reported that overall the lakes in the








Ocklawaha chain were eutrophic hard-water lakes, except for Lake Yale, which was

classified as mesotrophic, a classification that differed from that of the earlier

classification by the EPA for Lake Yale (EPA 1978). Preston (1983) presented a large

amount of historical data and limnological data based on a 4-year study of five lakes

(Apopka, Beauclair, Dora, Eustis, and Griffin) in the Ocklawaha chain reported by

Brezonik et al. (1978, 1981), Tuschall et al. (1979), and Pollman et al. (1980) in four

annual reports. These authors reported the relatively poorest (compared to other lakes in

the study) water quality was in Lakes Apopka and Griffin, which received considerable

farm runoff from nearby agricultural areas, followed by Lakes Beauclair, Dora, and

Eustis. These reports described declining overall water quality and increasing

eutrophication in all lakes during 1977-1980 [Brezonik et al. (1978, 1981), Tuschall et al.

(1979), and Pollman et al. (1980)].

In 1987, Callahan and Morris, though surveying primarily for Culicidae in some

Polk County lakes, reported that G. paripes was the predominant midge species in these

lakes, preferring sand bottom. These authors reported G. paripes mean emergence

densities of 108,625 and 150,012 adults/ha/day from lakes rated "expected good" and

"expected fair", respectively, for production of the Coquillettidia mosquitoes. Butler et

al. (1992) studied benthic invertebrates in Lake Tohopekaliga, Osceola County, for two

years after an extreme drawdown and organic substrate removal program. Among

chironomids, Glyptotendipes sp. I, C. stigmaterus, Procladius sp., and Cryptochironomus

fulvus, in that order, were abundant during the first year. In the second year, a

considerable numerical decline of most benthic invertebrates collected was noted in the

restored areas. Chironomus stigmaterus and Procladius sp. were the most abundant






9

chironomids at that time, though these numbers were over ten fold lower when compared

to the first year after restoration. The authors suggested that the improved aquatic

macrophyte diversity in the restored areas attracted a proportionately greater population

of predatory fish that preyed upon the benthic macroinvertebrates, resulting in the overall

lower densities during the second year after restoration. Warren et al. (1995) studied the

sublittoral benthic communities of highly eutrophic Lake Okeechobee. Chironomidae

were found to compose 25.9% of the total benthic organisms, with Cladotanytarsus sp.

being the most abundant (7.9% of total benthic organisms), followed by C.

crassicaudatus, P. halterale, and Djalmabatistapulcher forming 7.3, 3.0, and 2.2% of the

total benthic organisms, respectively. Seasonal mean larval densities during February,

May, August, and November, respectively, were: 889,616, 3,101, and 600/m2 for

Cladotanytarsus sp., 10, 35, 1,621, and 157/m2 for C. crassicaudatus, and 478, 111,

1,056, and 803/m2 for P. halterale.

During the past two decades, chironomid larval and adult populations and the

physical and chemical limnology of a few lakes in the St. Johns River system, Florida,

have been investigated and reported in the literature. Specifically, Lakes Monroe

(Seminole and Volusia Counties) and Jesup (Seminole County) have been the focus of

these investigations among lentic ecosystems, and in lotic habitats, tributaries of the

Wekiva River. Ali and Baggs (1982) reported seasonal changes of chironomid

populations in Lake Monroe. Glyptotendipes paripes and C. crassicaudatus were

quantitatively important, with larval densities ranging from <100 to 6,000/m2 and <10 to

1,800/m2, respectively. Adults of these species dispersed in significant numbers up to

200 m from the lake, with C. crassicaudatus showing a relatively greater inland dispersal.








At lakefront, up to 350,000 adult midges occurred in a New Jersey light trap/night (Ali

and Fowler 1983). Ali et al. (1983) reported that the two dominant midge species in

Lake Monroe emerged on an almost daily basis at water temperatures between 18-30 C,

resulting in numerous asynchronous generations of these midges in a year. Patterns of

daily adult abundance of these midges were documented and occurrence of oviposition

on an almost daily basis was suggested (Ali et al. 1985). Ali and Fowler (1985)

presented data on midge populations in Lake Monroe between 1979 and 1984. A general

declining trend of G. paripes and C. crassicaudatus populations was noted with

reductions amounting up to 93% between years. Several prominent peaks of adult

emergence occurred between May and November. Ali et al. (1996) presented further

adult chironomid data based on New Jersey light trap collections made from waterfront

land areas of Lake Monroe covering the 1980-1994 period. Total number of adults

fluctuated from annual mean values of 269 adults/trap/day in 1994 to 8,009

adults/trap/day in 1980. Glyptotendipes paripes composed 69.5% of total chironomids

collected over the study period, followed by C. crassicaudatus (26.1%). The latter

species was most abundant in late spring and early summer, while G. paripes was most

abundant in late summer. Overall, strong positive correlation of midge populations with

monthly mean air temperatures was noted, whereas yearly densities were significantly

influenced by water levels in the lake as well as by annual rainfall in the area. Ali et al.

(1988) presented data on water and sediment physico-chemical parameters in Lake

Monroe. Specific conductance of up to 1,832 p.S/cm indicated high levels of dissolved

solids. Mean values of total N and total P were 1.82 and 0.21 mg/L, respectively. No

clear seasonal trends were noted. Organic matter in the sediments ranged from 1 to 182 g








C/kg, indicating wide range of spatial distribution. All measured sediment nutrients were

significantly (P < 0.01) correlated with sediment organic carbon content. Little or no

significant spatial or temporal relationships existed between the studied water and

sediment parameters, though periodic hydrologic flushing of the lake by the St. Johns

River may have obscured some correlations. Ali and Alam (1996) provided quantitative

estimates of nutrients at the sediment-water interface in Lake Jesup. Increases of

turbidity due to wind actions or other factors had a positive influence on soluble reactive

P (SRP) concentrations in water at the sediment-water interface and, in turn, caused

increases of chlorophyll a concentrations in water. Mean concentrations of Kjeldahl

nitrogen, extractable SRP, and total organic carbon in lake sediments were 10.9, 0.019

and 65.5 mg/g, respectively, during the March 1988 to December 1993 period of

investigation. Such levels of concentrations of these chemical characteristics are

indicative of the eutrophic status of the lake. Ali and Lobinske (personal communication)

recently completed some detailed investigations of chironomid larval densities and

selected water and sediment physico-chemical parameters in Lakes Monroe and Jesup,

and in Lake Monroe and a water-cooling reservoir (Ali et al. 2001). Preliminary analysis

of these data indicates a strong relationship between larval spatial distributions and

sediment type as well as water depth. Glyptotendipesparipes had the highest occurrence

frequency in sand although highest larval densities of this species were found in slightly

looser substrates, such as muck or a muck/sand combination. This species was generally

negatively correlated with water depth in the two lakes. Xue and Ali (1997) in a

laboratory study described the case-making behavior of G. paripes larvae and the larval

preference for several ranges of substrate particle size. The most successful case making








was reported for two sand particle ranges, 0.35 and 0.58 mm (100%), and 0.59 and 0.84

mm (98%), indicating the suitability of such substrates (particle size range) for

colonization and propagation of G. paripes in field situations.

Recently, Lobinske et al. (1996, 1997) studied lotic chironomids and other

macroinvertebrates in relation to prevailing selected physico-chemical parameters in

Blackwater Creek and Rock Springs Run, tributaries of the Wekiva River, central

Florida. Chironomidae were numerically the dominant macroinvertebrates, comprising

40.9% and 34.8% of total macroinvertebrates in Blackwater Creek and Rock Springs

Run, respectively. Using the Hilsenhoff biotic index (Hilsenhoff 1977, 1982, 1987),

these streams were rated at fair to good water quality (Lobinske et al. 1997). Lobinske et

al. (1996) reported 24 genera of chironomids in Blackwater Creek and 26 in Rock

Springs Run, with Tanytarsus spp. numerically the most common in the former stream

(29.7%) and Polypedilum spp. the most common in the latter (21.4%). Chironomid

productivity in both streams was 1.1 0.8 g dry weight/m2, indicating their oligotrophic

status. Among the parameters studied, water level in the streams was the dominant

influence on chironomid population fluctuations in the two streams during the study

period (Lobinske et al. 1996).

The existing literature did not provide sufficient specific information to develop a

spatio-temporal larval distribution model of G. paripes. There were no available

quantified relationships of G. paripes larvae with water and sediment characteristics in

Florida lakes that could be readily used. Previous results showing the general trend of

larval G. paripes associated mostly with firm sediments did not provide specific

information on the relative strength of this trend or what kind of transition there was in






13

population levels between firm and soft sediments. While there were some detailed

bathymetric maps available for lakes in central Florida, the only maps available of

sediment characteristics were for soft sediment depth (Danek et al. 1991). Previously,

development time of immature G. paripes had been only crudely estimated and the lower

development threshold temperature had not been determined. While there was general

information on fish predation of chironomid larvae, species specific information on

chironomids consumed was not available.














CHAPTER 3
DESCRIPTION OF STUDY LAKES


Lakes Dora, Yale and Wauburg are located in the Central Valley region of central

Florida in the lowlands between the Mt. Dora Ridge and the Ocala Uplift District (Brooks

1982). These lakes were selected to obtain additional information on G. paripes

population ecology for developing the model. The Ocklawaha chain of lakes in Lake

County is a major geographic component of the area, with eight major lakes (including

Dora and Yale) in the chain having different water qualities, from hypereutrophic

(Apopka, Beauclair) to mesotrophic (Yale, Weir) (Fulton 1995a, b). These lakes share a

common watershed complex and hydrologic base (Fulton 1995b). Several water control

structures in the basin limit natural water fluctuations, so the systems are like managed

reservoirs (Fulton 1995b). The northern portion of the Central Valley district extending

through Marion County into Alachua County contains higher numbers of softwater lakes

(including Lake Wauburg) compared to lakes in the Ocklawaha system.

Lake Dora covers an area of 1,787 ha with a mean water depth of 3.0 m and

maximum depth of 5.2 m. Mean sediment depth was 1.4 m, with the unconsolidated floc

averaging 0.33 m; soft sediments covered 85.0% of the lake bottom (Danek et al. 1991).

Lake Dora was characterized as hypereutrophic by the National Eutrophication Survey

(EPA 1978). Median conductivity value amounted to 320 pS/cm, Secchi disk

transparency 0.4 m, total phosphorus (TP) 0.102 mg/L, ortho-phosphorus (OP) 0.022








mg/L, inorganic nitrogen (IN) 0.240 mg/L, total nitrogen (TN) 3.290 mg/L and

chlorophyll a 60.0 ug/L. Mean physico-chemical values for Lake Dora presented by

Canfield (1981) were as follows: pH 8.9, conductivity 321 uS/cm, TN 3.100 mg/L, TP

0.903 mg/L, chlorophyll a 124 ug/L, and Secchi disk transparency 0.4 m. Mean values

for the east basin of Lake Dora from June 1990 to November 1996, published by the

Florida LAKEWATCH program, were pH 8.7, conductance 416 pS/cm, TP 0.092 mg/L,

TN 3.488 mg/L, chlorophyll (not specified if chlorophyll a or total) 156 ug/L and Secchi

disk transparency 0.4 m (Florida LAKEWATCH, 1997). Aquatic plants covered a mean

of 4% of the lake area, with mean emergent plant biomass of 4.6 kg wet wt/m2, floating

leafed biomass 0.0 kg wet wt/m2, and submerged plant biomass 0.3 kg wet wt/m2 (July

1992 data, Florida LAKEWATCH 1997). Mean values for the west basin of Lake Dora

from June 1990 to November 1996 were pH 8.7, conductance 404 PS/cm, TP 0.073

mg/L, TN 3.464 mg/L, chlorophyll 144 pug/L and Secchi disk transparency 0.4 m.

Aquatic plant cover amounted to 4%, with 3.3 kg wet wt/m2 emergent, 0.2 kg wet wt/m2

floating leafed and 1.5 kg wet wt/m2 submersed plant biomass (July 1992 data, Florida

LAKEWATCH 1997).

Lake Yale covers 1,632 ha, with a mean water depth of 3.7 m and maximum

depth of 7.9 m. Mean sediment depth was 1.9 m, with unconsolidated floc depth of

0.18 m. Soft sediments covered 88.9% of the lake bottom (Danek et al. 1991). Lake

Yale was classified as eutrophic by the EPA (1978), with conductivity amounting to 295

pS/cm, Secchi disk transparency 1.5 m, TP 0.027 mg/L, OP 0.014 mg/L, IN 0.160 mg/L,

TN 1.270 mg/L and chlorophyll a 25.4 ug/L. According to Canfield (1981), Lake Yale

had subjectively better water quality than that reported by the EPA (1978) as indicated by








the following values: pH 8.3, conductivity 264 uS/cm, TN 0.683 mg/L, TP 0.014 mg/L,

chlorophyll a 9.6 tg/L, and Secchi disk transparency 1.4 m. Mean values reported by

Florida LAKEWATCH (1997) for Lake Yale from May 1990 to June 1994 were pH 8.3,

conductance 264 uS/cm, TP 0.011 mg/L, TN 0.805 mg/L, chlorophyll 7 tg/L and Secchi

disk transparency 2.4 m. Canfield (1981) considered Lakes Dora and Yale as hardwater

lakes with mean total hardness of 115-155 mg/L (as CaCO3). Because both of these lakes

tend to be below the piezometric surface, considerable amounts of water inputs to these

lakes are from mineralized groundwater or as run-off from calcareous, nutrient-rich soils.

Lake Wauburg is a much smaller lake, covering 150 ha surface area with mean

water depth of 3.0 m. The lake contains soft water (mean conductance 79 uS/cm, total

alkalinity 19.9 mg/L as CaCO3) and is eutrophic as supported by the following values:

mean TP 0.107 mg/L, TN 1.726 mg/L, chlorophyll 83 ug/L and Secchi disk transparency

0.56 m. These means are based on the March 1990 to December 1996 data of Florida

LAKEWATCH (1997).














CHAPTER 4
MAPPING BATHYMETRIC AND SELECTED SEDIMENT PHYSICO-CHEMICAL
CHARACTERISTICS OF STUDY LAKES


Introduction

The importance of sediment composition and lake bathymetry in determining

distributions of G. paripes has been previously reported (Provost 1957, Curry 1962,

Cowell et al. 1975, McLachlan 1976, Milleson 1978, Cowell and Vodopich 1981,

Callahan and Morris 1987, Ali et al. 1998b). Toward assisting our understanding of the

relation of G. paripes with sediment characteristics, the objective of this study was to

produce systematic maps of basic sediment physico-chemical characteristics and lake

bathymetry. These maps serve an important base component in determining the spatial

distributions of larval populations in the computer model and should provide an effective

tool for lake managers targeting control measures for nuisance midge populations.


Materials and Methods

Systematic sediment core samples using the method of Ali (1984) were taken

from each sample lake. For sampling purposes, Lakes Dora and Yale were mapped with

a grid interval of 0.2 minutes latitude/longitude and Lake Wauburg with a grid interval of

0.05 minutes latitude/longitude. In Lake Dora, 172 sample sites were surveyed between

May and September 1998, while 150 sample sites in Lake Yale were examined between








October and December 1998, and 68 in Lake Wauburg during February 2000. At each

grid interval, three 5-cm deep sediment cores were collected, with overlying water

carefully decanted without disturbing the surface sediments. Presence of sand, muck,

clay, peat, or detritus was recorded. The core samples were composite in a sealed

polyethylene bag and stored on ice until transported the same day to the laboratory,

where they were maintained at -10 C until analyzed. At each grid point in Lakes Dora

and Yale, water depth was measured with a boat-mounted depth finder (Humminbird

Model Wide 100, Techsonic Industries, Inc. Eufaula, AL), while a graduated pole was

used in Lake Wauburg to measure water depth.

For various analyses, samples were thawed and transferred to labeled 1-L beakers

and thoroughly mixed. To estimate particle size distributions in samples from Lakes

Dora and Yale, approximately 1 cm3 of material was transferred to a sieve series (1,000,

350, 250 and 125-tm pore mesh) and material washed through with deionized water.

Material retained in each sieve was carefully washed into labeled, tared 50-mL beakers,

dried for 24 hours at 90 C, and dry material weighed. This analysis was not conducted

with samples from Lake Wauburg. One gram wet-sediment from each sample was

placed into a tared, labeled 50-mL beaker and dried for 24 hours at 90 C to determine

overall sediment dry weight. Sediment pH of wet sediment was determined using a

Model 710A pH/ISE meter (ATI Orion Laboratory Products, Boston, MA). The

remaining material was air dried at room temperature and ground with a mortar and

pestle to pass through a 350-g.m pore sieve and partly utilized to determine total organic

carbon (TOC) using the wet oxidation method of Nelson and Sommers (1982) to assess

relative organic matter content of the sediment.








Bathymetric maps were generated with the software SlideWrite for Windows

Version 5.0 (Advanced Graphics Software Inc., Encinitas, CA) using the study data, as

well as the maps of Danek et al. (1991) for Lakes Dora and Yale, and data provided by

Florida LAKEWATCH (personal communication) for Lake Wauburg. Maps of sediment

TOC, sediment pH, and sediment dry weight were also generated using SlideWrite as

well as a common set of template files for uniform appearance. Sediment dry weight

maps were augmented with additional data collected from Lakes Dora, Yale, and

Wauburg during the ecological study of G. paripes detailed in the following chapter.

This software used the Inverse Distance method to interpolate values between data

points. These were combined with scanned images of lake boundaries prepared from

United States Geologic Survey 7.5-Minute Topographic maps.


Results and Discussion

Mean values of mapped parameters are shown in Table 1 for the three study lakes.

Sediment in all three lakes was acidic, indicating considerable microbial activity, with pH

considerably lower in Lake Wauburg (mean value 6.35 pH units) compared to Lake Dora

(mean value 6.77 pH units), and Lake Yale (mean value 6.68 pH units). The latter two

lakes were comparable to the mean sediment pH value of 6.8 for Lake Jesup reported by

Ali and Alam (1996), but lower than the 7.3-7.5 pH values reported for four major

sediment types in Lake Apopka (Rees et al. 1996). Sediments from Lake Dora had lower

TOC (8.9 %) and higher dry weight (41.0 %) values than Yale (10.6 and 30.6 %,

respectively) and Wauburg (10.9 and 30.1 %, respectively). These TOC values are near

the 75 mg/g (7.5%) reported by Ali et al. (1988) for Lake Monroe and less than the

20.4% reported for Lake Jesup (Ali and Alam 1996). Rees et al. (1996) did not give






20

overall means, but reported TOC values of 402 g/kg (40.2%) for peat sediments, 120 g/kg

(12.0%) for mud, 150 g/kg (15.0%) for littoral (sand/mud), and 13 g/kg (13.0%) for sand

sediments in Lake Apopka. For muck sediments, the mean dry weight values of 10.0%

(Dora), 10.6% (Yale), and 17.4% (Wauburg) were all greater than the 2.9% (derived from

reported 97.1% moisture content) for unconsolidated flock (UCF) from Lake Apopka

reported by Gale and Reddy (1994), though some individual station values in all three

study lakes were comparable. Mean water depth of 3.5 m in Lake Yale was greater than

that of 2.7 m in Lake Dora and 2.8 m in Lake Wauburg.

The deeper (>3 m depth) portions of Lake Dora were divided into two basins

separated by a narrow neck of the lake near 28 47.4' N, 81 40.4' W, with the deepest

portion of the east basin offset from center toward the southwest and the deepest portion

of the west near the narrowest part of the basin (Figure 1). Only a small depression in the

west basin and a narrow trench in the east basin were >5 m in depth. An extensive area

of the southern bay of Lake Yale was comparatively shallow (<3 m deep) as was the

northeast bay near 28 55.1' N, 81 43' W (Figure 2). The deepest part of the lake

formed a rough "C" shape off the southwest shoreline and extended into the center of the

large northern basin. Lake Yale exhibited a >5 m deep trench in the southern part of the

"C", with one area >6 m in depth. Lake Wauburg (Figure 3) was overall the shallowest

of the study lakes, with some scattered locations between 4 and 5 m in depth, though the

nearshore areas in this lake were considerably steeper, with only a narrow band <2 m

deep.

Sediment percent dry weight distributions in Lake Dora exhibited a similar trend

to lake depth (Figure 4). Highest sediment densities were generally found in shallower








areas (<3 m depth) with sand substrates that wave action probably kept clear of soft,

organic sediment. Soft, low-density sediments extended into shallower waters in the

northeast section of the lake, the southeast section of the west basin, and the westernmost

bay. These areas likely are more protected from wind and experience less wave action,

or the organic matter accumulation is faster in these areas than the ones exposed to the

scouring action of waves. A band of firmer sediments in the western portion of the lake

running southwest to northeast corresponded with a slight ridge in the lake bathymetry.

Of interest is the rapid change to firm sediments in the eastern basin just to the south of

the deepest bathymetric trench. Similar general trends were noted in Lake Yale (Figure

5), with the primary exception of the southern bay, which had low density, soft sediments

in the shallows except for one small area. A section of firm sediments extended from the

southwest shoreline into fairly deep water (4-5 m)just to the southeast of the deep trench.

Firm sediments also extended from the center of the northern shore, and from the

northeast comer. The proportion of firmer sediments was considerably lower in Lake

Wauburg than in either Dora or Yale (Figure 6). The largest concentration of firm

sediments was along the southwestern shoreline and in scattered areas along the south

and east shore. Pebbles and rocks were mixed into the sand sediments along the east

shore. A wide band of soft sediments was encountered up the shoreline along the

northwest margin of the lake north of 29 81.85' N. The trend of shallow areas having

firm/sandy substrates and the deeper areas of lakes having soft sediments was also

reported for Lake Monroe (Ali et al. 1988) and for Lake Jesup (Ali and Alam 1996).

Low density, high water content sediments were also reported for large areas of

hypereutrophic Lake Apopka, mostly in the form of UCF (Gale and Reddy 1994).








Sediment pH distributions for Lakes Dora, Yale, and Wauburg are presented in

Figures 7, 8, and 9, respectively. In the two former lakes, the general trend was for lower

pH values from soft sediments (as defined by lower percent dry weight) in the range of

6.2 to 7, while firmer substrates had pH values generally between 6.8 and 7.4. Lake

Wauburg had lower sediment pH values, with no value over 6.8. Total organic carbon

distribution in Lake Dora clearly demonstrated an increase associated with depth, with

the highest values noted in the deepest parts of both basins (Figure 10). A similar trend

was noted for Lake Yale (Figure 11), except for the southern bay, which had elevated

TOC values in the shallows, as well as at the tip of the northeastern bay. This southern

bay was flanked by wetlands and the sediments recorded as containing plant detritus.

Lake Wauburg had some exceptionally high TOC values at the center of the west

shoreline, northern tip, and southeastern comer (Figure 12) near observed wetlands.

These areas were recorded as containing peat and detritus that were likely of

allochthonous origin from the adjacent wetland vegetation.

Sediment particle sizes for muck and sand sediments from Lakes Dora and Yale

are shown in Table 2. Particle sizes were not determined for Lake Wauburg due to

processing errors. For both muck and sand substrates from both lakes, the majority

(67.1-84.7%) of particles was retained by the 250 and 350-gm pore sieves. Significantly

more particles (P < 0.05) were retained at 250-jim from both muck and sand substrates of

Lake Yale, while significantly more particles > 1,000-jim were present in muck

sediments, and retained at 125-jim from sand sediments from Lake Dora.

Spatial distributions of particles are presented in Figure 13 (Lake Dora) and

Figure 14 (Lake Yale). In both lakes, the distributions of 250 to 350-jim particles closely








followed the areas of higher sediment dry weight, corresponding with the firm, sand

substrates. Particles between 350 and 1,000-m were closely associated with the

distributions of soft sediments. Lake Dora had a wider distribution of large (>1000-11m)

particles, especially in the east basin. Also, there was an unusual concentration of fine

(<125-itm) particles in a small eastern bay of Lake Dora.

All three lakes, with local variations, were found to exhibit a similar trend in

bottom morphology. Firm, sandy substrates dominated most of the nearshore areas of

these lakes, except those adjacent to observed wetlands that contained plant detritus.

With increasing depth, soft, organic carbon enriched sediments become dominant, with

slightly lower pH values. These trends are similar to those reported for other central

Florida lakes (Ali and Alam 1996, Ali et al. 1988).










Table 1. Mean + SD of selected sediment physico-chemical parameters and water depth
from mapping survey of Lakes Dora (May-September 1998), Yale (October-
December 1998), and Wauburg (February 2000).

Lake Sediment pH Total Organic Sediment Dry Water Depth
Carbon (%) Weight (%) (inm)
Dora 6.77 +0.20 8.9 +8.3 41.0 +33.5 2.7 1.1
Yale 6.68 +0.21 10.6 7.9 30.6 28.7 3.5+ 1.5
Wauburg 6.35 + 0.13 10.9 + 8.8 30.1 24.0 2.8 1.1


Table 2. Comparison of mean percent of sample + SD of sediment particles retained by
sieve series (1,000, 350, 250 and 125-jtm pore mesh) from muck and sand
sediments collected from Lake Dora (May-September 1998) and Lake Yale
(October-December 1998).

Sieve Pore Size
Lake 1,000-pim 350-tm 250-[im 125-tm >125-tm
Muck
Dora 13.6 +8.4* 37.4 +8.1 29.7 +9.7* 12.9 +8.0 6.5 3.9
Yale 4.9 3.9* 33.8 12.2 43.0+ 11.1* 12.9 5.6 5.4+ 2.9
Sand
Dora 3.4 2.4 23.7+ 10.0 55.6+9.2* 16.3+ 11.7* 1.0+ 1.3
Yale 2.9 2.2 22.3+ 11.1 62.4 9.0* 10.5 +6.8* 2.0 +4.3
*Percent within particle size significantly (P < 0.05) different between lakes by Student's
t-test.













Depth (m)
[---] 0-1
48El -

z 1 1-2
0
00
02-3
47 3-4
..
I ~-

46 E 5-6
46-- ^T


N


45 44 43 42 41 40 39 38
Longitude (Minutes 81 W)
Figure 1. Bathymetric map of Lake Dora (Lake County, Florida), May-September 1998 and Danek et al. (1991).








-Y


56 -




55




54


!I IIII I I ll tllll lll 111 111i 11ll 111111111 1111 nl l


Depth (m)

[I 0-1

1-2

*2-3


* 5-6

*6-7

* 7-8


Longitude (Minutes 810 W)
Figure 2. Bathymetric map of Lake Yale (Lake County, Florida), October-December 1998 and Danek et al. (1991).








32.3


32.2 -

32.1 -

32.0 -

31.9 _

31.8 -


31.7 -

31.6 -

31.5

31.4 _


R1 q


Depth (m)

F-D 0-1

1-2


2-3

3-4

4-5


11111111111111111111111111 I11I~I-T-I liii! 11111 liii Ii


18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 W)
Figure 3. Bathymetric map of Lake Wauburg (Alachua County, Florida), February 2000 and Lakewatch (pers. comm.).
















48 -




47-




46-


N


45 44 43 42 41 40 39 31
Longitude (Minutes 81 W)
Figure 4. Sediment percent dry wieght in Lake Dora (Lake County, Florida), May 1998-February 2001.


Sediment %
Dry Weight
-] 0-20

20-40

* 40-60

*60-80


r--











Sediment %
Dry Weight
56 -
--] 0-20

: 20-40
0
00
55 40-60

60-80

"54




53^ >

S N

52 -..... I I 111111111
47 46 45 44 43 42
Longitude (Minutes 81 W)
Figure 5. Sediment percent dry weight in Lake Yale (Lake County, Florida), October 1998-February 2001.








32.3 -

32.2

32.1 -

32.0 -


31.5

31.4

:31 3:


31 3 I I I I I I I I I I


18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 W)
Figure 6. Sediment percent dry weight in Lake Wauburg (Alachua County, Florida), February 2000-February 2001.


Sediment %
Dry Weight

D] 0-20

20-40

E 40-60

E 60-80


31.9 -

31.8 -

31.7 -

31.6 -












49




48

0
00

S47




46 T
T


N

45 ii1111 11 iiiiii~ iii ii1 ,11,1 11111 11111, 1 Iii iii 1 11111ii1iiii11iii

45 44 43 42 41 40 39 3
Longitude (Minutes 81 W)
Figure 7. Sediment pH in Lake Dora (Lake County, Florida), May-September 1998.


Sediment pH

[- 6.2-6.4

6.4-6.6

S6.6-6.8

m 6.8-7.0

*7.0-7.2

*7.2-7.4













56-



55-



54



53-


~Iii 111111111111111111 III I liii 111111 I 111111 I 11111 I I


Sediment pH

L--Z 6.2-6.4

6.4-6.6

*6.6-6.8

U6.8-7.0

*7.0-7.2

U7.2-7.4


Longitude (Minutes 81 W)
Figure 8. Sediment pH in Lake Yale (Lake County, Florida), October-December 1998.








32.3


32.2 -

32.1 -

32.0 -


31.9


31.8 -


31.7 -


31.6


31.5 -

31.4 _


.... 1 I I I I I I I
18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7
Longitude (Minutes 82 W)
Figure 9. Sediment pH in Lake Wauburg (Alachua County, Florida), February 2000.


17.6
17.6


Sediment pH


F 6.0-6.2

6.2-6.4

E 6.4-6.6

m6.6-6.8


17.5


! | | | | I | |


I


I1 .I










49
Sediment TOC
,(%)
48 Do 0-5
S5-10
0
00
10-15
47 -- [ 15-20

20-25
-46 25-30

I T
N
45 1111111 1111
45 44 43 42 41 40 39 38
Longitude (Minutes 81 W)
Figure 10. Sediment total organic carbon (TOC) in Lake Dora (Lake County, Florida), May-September 1998.













55 -


54 -


53 -


52


1 IllIIIIIlillIIII1111111111111 Il III I 11111111111 T


Sediment TOC
(%)
--- 0-5
5-10
* 10-15
* 15-20
*20-25


Longitude (Minutes 81 W)
Figure 11. Sediment total organic carbon (TOC) in Lake Yale (Lake County, Florida), October-December 1998.


-I


1













Sediment TOC
(%)

S0-5

5-10


32.1 -

32.0 -

31.9 -

31.8 -


31.7 -

31.6 -

31.5 -

31.4 _


31.3


18.5


Figure 12. Sediment total organic


I I I I I I I I I I
18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 W)
carbon (TOC) in Lake Wauburg (Alachua County, Florida), February 2000.


32.3


32.2


10-15

15-20

20-25

25-30

30-35

35-40













> 1000 tim





47











250 350 gm



46


47




46 *,...... I .,yIs........ ,,flS~I... .j.I...... ~ JPIISI5II
45 44 43 42 41 40 as 36


< 125 urm









44-5 i i .i i I .. . . .. .. . . .. .. . .
47 I 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1I II III


44 4S 42 41


125 250 Lm
4,




47'




415 ii6 i i ~ 111 11111'rr i inn T| Tiiwn n 1 p min i l i n n i11 i~f~ii T~llnTT1'
4 P 44 4" 42 41 40 C 36



Percent Compostition


0-10 B 50-60

* 10-20 N 60-70

* 20-30 70-80

30-40 1 80-90

* 40-50


45 44 45 42 41 40 36 36


Figure 13. Sediment particle size spatial distributions in Lake Dora
(Lake County, Florida), May-September 1998.


350 -1000 pim


h1-.............. I....................


40 Sw























47 i 4iiiiiiillllll l l l l l l l l l l l
47 4, 4 1 44 43 42


47 41 41 44 43 42


< 125 pnm



64




53
S;^^




s: ii i l l l l l ll l l l-ll l ll l l l l l l l


> 1000 iLm


47 43 41 44 41 42

Figure 14. Sediment particle size spatial distributions in Lake Yale
(Lake County, Florida), October-December 1998.


350- 1000 im
so




14





47 M 4 44 4 42
17
125 -250 gim
so


I

644





is fl$u 11s1p1s I ;,s 11s. 1sI 1s1u 1 I I 1jlII5,IIlI
47 44 41 44 43 41

Percent Compostition


LI 0-10 50-60

* 10-20 60-70

* 20-30 l 70-80

30-40 80-90

E 40-50


250 350 im














CHAPTER 5
LARVAL DISTRIBUTIONS OF Glyptotendipes paripes IN RELATION TO WATER
AND SEDIMENT PHYSICO-CHEMICAL PARAMETERS IN STUDY LAKES


Introduction

Availability of several years of quantitative larval population data from two

eutrophic central Florida lakes (Lakes Jesup and Monroe) (Ali and Baggs 1982, Ali et al.

1998a, b, Ali and Lobinske, unpublished data) provided the initial basis for development

of a distribution model of G. paripes larvae in central Florida lakes and encouraged

further research into another geographic area of the state, the Central Valley lake region

(Canfield and Hoyer 1988). Previously, distributions of G. paripes larvae have been

studied by several authors: Callahan and Morris (1987), Cowell et al. (1975), Cowell and

Vodopich (1981), Fuller and Cowell (1985), Milleson (1978) and Provost (1957). For

model calibration, two lakes in the Ocklawaha chain of lakes, Lake Dora

(hypereutrophic) and Lake Yale (mesotrophic/eutrophic), and Lake Wauburg (eutrophic)

in the northern area of the Central Valley lake region were included in the investigation

for expanding the larval distribution information on this species into different geographic

locations. Chironomid larvae and selected water and sediment physico-chemical

parameters in these lakes were studied over a two-year period using sampling plans

optimized for G. paripes larval collection (Cochran 1963). With these data, the objective

of this study was to quantify the influence of water and sediment characteristics on spatial

and temporal distributions of G. paripes larvae in central Florida lakes.








Materials and Methods

Preliminary survey of G. paripes larval distributions and selected water and

sediment physico-chemical parameters in Lakes Dora and Yale was made in September

1997; Lake Wauburg was surveyed in September 1999. During the preliminary survey in

Lakes Dora and Yale, thirty stations were sampled, while 12 stations were sampled in

Lake Wauburg. Using a 0.2 precision level and data from the preliminary surveys, the

calculated sample size was 120 (Cochran 1963) for the first phase (year) of the study in

Lakes Dora and Yale. For Lake Wauburg, the calculated sample size was 30. To

enhance sample statistical precision, these stations were randomly assigned over two

strata based on sediment dry weight (DW) (stratum 1 <40% DW and stratum 2 >40%

DW) and allocation optimized using the method of Cochran (1963). These strata were

chosen based on previous G. paripes distributions from Lakes Jesup and Monroe (Ali et

al. 1998a, Ali and Lobinske, unpublished data). For Lake Dora, this allocation was 22

stations in stratum 1 and 98 in stratum 2, while 39 and 81 stations, respectively, were

determined for Lake Yale. For Lake Wauburg, 11 and 19 stations, respectively, were

determined. This optimized allocation increased the number of samples collected from

the stratum with the higher sample variance in the survey study. For the first phase in

Lakes Dora and Yale, samples were collected bimonthly over four consecutive days per

sample effort, with 30 stations sampled per day. After the first year, allocation of

sampling efforts was re-evaluated using the first year's data. This evaluation revealed

that 80 stations were required for the second phase (year) of work, with 15 stations in

stratum 1 and 65 in stratum 2 for Lake Dora, and 26 and 54 (respectively) for Lake Yale.

During the second phase, samples were collected monthly over two days with 40 stations






41

sampled per day. The one-year study of Lake Wauburg was conducted concurrently with

the phase 2 study of Lakes Dora and Yale, with samples collected on a monthly basis.

For each sampling effort, paired latitude and longitude values for each station were

randomly determined by a simple computer protocol operated within the software

Matlab, Version 6.0, Release 12 (The Mathworks Inc., Natik, MA) (Appendix). A 7.3-

m pontoon boat (Lakes Dora and Yale) or a 3-m skiff (Lake Wauburg) was used for

sampling, with a Global Positioning System (GPS) receiver without differential

correction (model GPS 12, Garmin International Inc., Olathe, KS) used to determine and

record each sampling station.

Water depth was measured at each station as previously described in Chapter 4.

In situ measurements of dissolved oxygen (Yellow Springs Instruments Inc., Yellow

Springs, OH, model 54A dissolved oxygen meter), water temperature and conductivity

(Yellow Springs Instruments Inc., Yellow Springs, OH, model 33 salinity-conductivity-

temperature meter) at the sediment-water interface were made. During phase 1, one

1,000-mL water sample for chlorophyll determination was collected at every third station

from the sediment/water interface with a 2.2-L horizontal alpha bottle (Wildlife Supply

Company, Buffalo, NY), stored on ice for transport to the laboratory and at 4 C in a

refrigerator until analyzed within 24 hours. Water samples for chlorophyll determination

in Lakes Dora and Yale were collected at every fourth station during phase 2 and at every

third station in Lake Wauburg. To determine chlorophyll concentration, 250-mL water

subsamples were vacuum filtered through 47-mm diameter, 0.45-gm pore nylon

membranes (Whatman International Ltd, Maidstone, UK, No. 7404-004) in a dark room

(with only a single green light) to reduce photodegradation of chlorophyll. All








subsequent analyses of chlorophyll were also conducted under green light. Filters with

phytoplankton residue were stored in covered dishes wrapped in aluminum foil to

exclude light and maintained at -10 C until processed within 30 days. The filters were

thawed, cut into 5-mm strips and placed into capped test tubes containing 20-mL

(sufficient to completely cover the filter strips) N,N-dimethylformamide. The tubes were

wrapped in aluminum foil and shaken for 24 hours. The extract was filtered through a

0.45-jm pore nylon filter and absorbance determined with a spectrophotometer at 647

and 664.5 nm (Inskeep and Bloom 1985, Moran and Porath 1980). Calculations of

chlorophyll content were made as follows:

chlorophyll a = 12.7ABS664.5 2.79ABS64M7

chlorophyll b = 20.7ABS647 4.62ABS6M64.5

total chlorophyll = 17.6ABS647+ 8.08ABS664.5

For all benthic samples, one 15 x 15 x 15 cm Ekman dredge sample was collected

from each station and washed through a 350-jim mesh sieve bucket. Washed samples

were processed and chironomid larvae counted in a 30 x 40 cm gridded white pan using

standard methods (Ali et al. 1977) and identified using the keys of Epler (1995). Before

washing, approximately 1 cm3 of sediment from each benthic sample was transferred to

labeled polyethylene scintillation vials for sediment DW determination as previously

described (Chapter 4). These DW data were also used to augment the final sediment

maps prepared in Chapter 4. From each benthic sample, G. paripes larvae were separated

and length of each measured (tip of head capsule to tip of terminal segment) to the

nearest mm. Each 1-mm size class was composite and dried at 60 C for 24 hours to

determine dry biomass (Dermott and Paterson 1974); overall weight of each size class






43

was divided by total number of larvae to estimate individual biomass. Larval length and

dry biomass were fitted to a regression function to estimate a length-biomass relationship.

The result of this analysis was used to estimate productivity using the size frequency

method (Hynes and Coleman 1968, Hamilton 1969) with the generation time

modification of Benke (1979) using the formula:

I
T> ~ ~ y~ j *- -V V,+Bni365
Productivity = [i1(nl-n+)( E)
j=i


Where i = number of size classes, nj = mean number of individuals of size class, Bj =

individual biomass for size class, and CPI = cohort production interval in days. For this

study, CPI was determined using overall mean water temperature observed in the lakes

and development time calculated in Chapter 7 for that temperature.

All chironomid larvae other than G. paripes were counted and identified to lowest

possible taxonomic level; these larvae collected from each station were composite and

dried as above to determine biomass. During phase 1 of the study, specific records were

maintained for C crassicaudatus, G. paripes, Tanytarsini, Tanypodinae, other

Chironomidae and total Chironomidae. With the sampling plan re-evaluation after phase

1, additional specific records were also maintained for Cryptochironomus spp. and

Psuedochironomus spp.


Results and Discussion

Monthly mean values of selected water physico-chemical parameters and

sediment DW are presented in Table 3 for Lake Dora. Mean water depth varied between

2.1 and 2.8 m, with generally low water levels occurring during the last four months of








the study because of a prolonged drought in central Florida. Water clarity in this lake

was relatively poor during the entire study, with Secchi disk transparency ranging from

19 to 31 cm. A range of 12.8-28.7 C daytime water temperatures was noted, with water

remaining below 20 C between November and March. Concentration of dissolved

oxygen varied between 5.3 and 9.2 ppm, with lowest values occurring during summer

and highest values during winter. Specific conductance values in the lake ranged from

338 to 473 p.S/cm. Primary productivity indicated by phytoplankton concentration in

Lake Dora was high; chlorophyll a, chlorophyll b, and total chlorophyll amounted to

163.3-316.5, 3.3-46.9, and 177.7-329.0 Pg/m3, respectively. Sediment DW was in the

range of 41.5 to 59.4%.

Monthly mean values of relevant water and sediment DW data from Lake Yale

are presented in Table 4. Mean water depth varied between 2.7 and 3.2 m during the

study period. No samples could be collected from Lake Yale during January 2001

because of inaccessibility due to receded water levels making boat ramps unusable.

Water clarity in Lake Yale was greater than in Lake Dora, as indicated by the 45-127 cm

range of monthly mean Secchi disk transparency. Daytime water temperatures ranged

between 12.9 and 29.3 C, dissolved oxygen 4.6-9.8 ppm, and conductivity 293-425

tS/cm. Phytoplankton concentration in Lake Yale was much lower compared to Lake

Dora; chlorophyll a varied from 13.0 to 94.2 ptg/m3, chlorophyll b from 0.2 to 42.3

uLg/m3, and total chlorophyll from 14.1 to 136.5 ug/m3. Sediment DW ranged between

35.6 and 50.0%.

Water depth in Lake Wauburg ranged between 2.1 and 2.8 m (Table 5). Secchi

disk transparency values ranged between 59 and 85 cm. Lake Wauburg exhibited a wider








range of daytime mean water temperatures (10.5-30.2 C). Dissolved oxygen values

ranging between 6.1 and 10.7 ppm were generally higher compared to Lakes Dora or

Yale. Specific conductance (75-118 tS/cm) was considerably lower than Lakes Dora

and Yale, representing a lower concentration of dissolved solids. Chlorophyll a varied

from 16.9 to 73.2 jig/m3, chlorophyll b 0.9 to 59.2 ug/m3, and total chlorophyll from 17.9

to 134.5 jLg/m3. Dry weight of sampled sediments ranged from 21.3 to 37.7%.

Monthly mean densities of chironomid larvae from Lake Dora are summarized in

Table 6. The target species, G. paripes, comprised only a small proportion of the total

larval samples, forming 7.6% of total chironomids over both phases of the study, and

only 0.9% of the total in the second phase of the study. Initial values ofG. paripes

density were rather high (2,197/m2 in March 1999), but this species declined quickly

through September 1999, with numbers remaining low throughout the rest of the study,

except for modest increases in density during May to July 2000. This rapid decline is

similar to the reported decline in G. paripes adult capture by New Jersey light traps

around Lake Monroe during 1981 and 1982 (Ali and Fowler 1985). It would be of

interest to see if the G. paripes population in Lake Dora increases again in the next 1-2

years in a manner similar to the Lake Monroe population in 1983 and 1984. Tanytarsini

(mostly Cladotanytarsus spp.) larvae were numerically the most abundant, forming

74.3% of total midge larvae collected in this lake. Peak larval densities occurred during

late autumn and early winter (November-January). The pest species Chironomus

crassicaudatus constituted 6.5% and Tanypodinae 1.7% of total larvae collected during

the study. Cryptochironomus spp. amounted to 9.4% of total larvae collected during

phase 2 (the only phase they were specifically recorded). Peak densities of








C. crassicaudatus larvae during spring and early summer were consistent with the trends

reported for this species in Lake Monroe (Ali et al. 1996), though the early population

increase during January and February 2001 was unusual and may have been a result of

the unusually low water levels in the lake after an extended drought. Relatively low

numbers of Tanypodinae were collected from Lake Dora, with monthly mean numbers

ranging between 3 and 116 larvae/m2, and forming 1.7% of total collection. Small

numbers of other chironomids were also identified in Lake Dora, including species of

Orthocladiinae, Polypedilum spp., Pseudochironomus spp., and Geoldichironomus spp.

Larval G. paripes density in Lake Yale (Table 7) was also high during March

1999 (1,782/m2), declining to a minimum of 3/m2 in September 1999 and remaining

below 100/m2 until June 2000. Population trends of G. paripes during summer and fall of

2000 were similar to those previously reported for this species in Lake Monroe (Ali et al.

1996). Glyptotendipes paripes formed a greater proportion of total chironomids (25.4%

of total collection) in Lake Yale than in Lake Dora. Chironomus crassicaudatus

population peaked during May 1999, December 1999 and March 2000, and this trend was

similar to that reported by Ali et al. (1996) in Lake Monroe; however, C crassicaudatus

population in Lake Yale fell below detectable levels after June 2000. Chironomus

crassicaudatus larvae were absent from the samples during the last 8 months of the study;

this species comprised only 2.6% of total collection. Numerically, Tanytarsini (mostly

Cladotanytarsus spp.) were the most common midge in this lake, though densities and

overall proportion (53.9%) were below that of Lake Dora. Population peak was observed

between February and May 2000, and a general increase in the following autumn and

winter, with a notable increase in February 2001. Density of Cryptochironomus spp.






47

larvae in Lake Yale remained generally between 30 and 60/m2 during the second phase of

the study, with a maximum of 78 larvae/m2 during May 2000 and a minimum of 6

larvae/m2 in September. Density of Pseudochironomus spp. ranged between 44 larvae/m2

(September 2000) and 228 larvae/m2 (May 2000). Tanypodinae were slightly more

numerous in Lake Yale compared to Lake Dora (27-124 larvae/m2, 4.1% of total

chironomids). Orthocladiinae and Polypedilum spp. larvae were found in low numbers in

Lake Yale. No samples were collected during January 2001.

Glyptotendipes paripes larvae clearly dominated the chironomid fauna of Lake

Wauburg, comprising 97.8% of collected larvae during the study period (Table 8). Mean

density varied from 5,206 larvae/m2 (August 2000) to 19,442 larvae/m2 (March 2000).

Any obvious seasonal trend was lacking, though there was some tendency for higher

densities to occur closer to cooler months (mean density exceeded 10,000 larvae/m2 in

March, April, November 2000 and January 2001). Tanypodinae in Lake Wauburg were

encountered at higher densities (monthly mean densities 26-361 larvae/m2) compared to

Lakes Dora and Yale, though their percent composition of total chironomids remained

relatively low (1.1%). Chironomus crassicaudatus, Tanytarsini, Polypedilum spp. and

species of Orthocladiinae were found in low numbers in Lake Wauburg during the study.

Density distributions of larval G. paripes were plotted using the same techniques

as the mapping study in Chapter 4. A log(n+l) transformation was used to enhance data

resolution of the highly variable densities recorded. Phase 1 results for G. paripes larvae

in Lake Dora are presented in Figures 15-17, while the phase 2 results are shown in

Figures 18-23. During March 1999, the highest densities were found in the vicinity of

the narrows between the east and west basins of the lake, and peripherally around much








of the west basin; this trend was repeated in May 1999, though the densities were lower.

After May 1999, G. paripes larvae were found only in small, low density clusters, mostly

in the western basin and usually associated with areas of sandy substrates.

Larval G. paripes distributions in Lake Yale are shown in Figures 24-26 (phase 1)

and 27-32 (phase 2). From March to December 1999, G. paripes distributions were

similar to those found in Lake Dora, primarily around the lake margin and associated

with sandy substrates. Starting in February 2000, clusters of G. paripes larvae were

uncharacteristically found in deeper water areas with soft sediments. High densities

(>1,000 larvae/m2) were found in these deep-water, soft sediment areas, especially in the

center of the large northern basin, with low or zero numbers occurring in the peripheral

areas. Starting in November 2000, while still predominant in the lake center, higher

densities of G. paripes were found along the sandy nearshore areas. Only the northern

portion of Lake Yale was sampled in December 2000, and no samples were collected

during January 2001.

As noted in Table 8, Lake Wauburg had dramatically higher densities of

G. paripes larvae, as is also evident in Figures 33-38. Many areas of this lake sustained

very high densities (> 10,000 larvae/m2) throughout the sampling period. These high-

density areas were found around the lake margin in association with the firmer substrates,

with the lowest densities found in the lake center and along the northwest shoreline,

where the soft sediments existed up to the shoreline. Due to crowding from

overabundance, the population of this species extended to the soft sediments close to the

sandy substrates.








The preference of G. paripes larvae in Lakes Dora and Wauburg for sand and

transitional sand to muck substrates is consistent with previously published information

on this species. Ali and Baggs (1982) reported a trend for decreased larval populations in

Lake Monroe and in a nearby water cooling reservoir with increased organic carbon

content of sediments. This was also reported by Ali et al. (1998b) for G. paripes larvae

in Lake Jesup (Seminole County, Florida). Provost (1957) reported a strong preference

for sand or sand/peat bottoms by G. paripes larvae in 13 lakes in the Winter Haven,

Florida area. Lakes in Polk County, Florida with large areas of sandy bottom, reduced

emergent vegetation and more open shoreline generally produced larger numbers of adult

G. paripes than those containing more muck at the bottom (Callahan and Morris 1987).

Curry (1962) in a review classified G. paripes larvae as preferring marl, plants, sand and

peat bottoms. While preferring sand bottom, G. paripes larvae were noted in deeper

waters of Lake Thonotossassa (Hillsborough County, Florida) by Cowell and Vodopich

(1981). Milleson (1978) reported that G. paripes larvae in the Istokpoga lake chain were

predominant in sand or sand/mud substrates. While the occurrence of G. paripes larvae

in deeper, soft sediments has not been previously reported for Florida lakes, a mixed

population of G. paripes and Glyptotendipes glaucus in Lough Neagh, Ireland, was

reported to prefer mud sediments with a water depth of 4-m (Carter 1975). Also,

G. paripes was reported to exist at densities over 1,000 larvae/m2 in a shallow bog lake

(Baxter Lough) in England with a peat/mud bottom (McLachlan 1976).

The influence of water and sediment physico-chemical parameters over time on

G. paripes larval populations was investigated using multiple linear regression on

monthly mean values transformed using log(n+ 1). Contradictory results were found for








Lakes Dora and Yale: Chlorophyll a concentration showed a positive weak correlation

with G. paripes larval density in Lake Dora [G. paripes density = 2.043 + 0.014(Chl a),

r2 = 0.378, P = 0.009], while this relationship was negative in Lake Yale [G. paripes

density = 3.02 0.018(Chl a), r2 = 0.292, P = 0.031]. No other significant correlations of

monthly mean G. paripes larval densities with monthly mean water physico-chemical

parameters were detected in these two lakes. Glyptotendipes paripes larval density was

positively correlated with water depth in Lake Wauburg (larval density = 2.35 +

0.651 depth, r2 = 0.593, P = 0.15). Performing multiple regression on monthly mean

water and sediment physico-chemical parameters and G. paripes larval density from all

three study lakes yielded the following equation: G. paripes larval density = 2.39 +

0.016(Secchi disk transparency) + 0.047(water temperature) 0.006(specific

conductance), indicating highly significant relationship, (r2 = 0.726 and P < 0.0001).

To elucidate the position of G. paripes in the chironomid community of the

investigated lakes, canonical correspondence analysis (CCA) (Braak and Smilauer 1998)

was conducted on the data using the software Canoco for Windows version 4.0 (Centre

for Biometry, CPRO-DLO, Wageningen, Netherlands and Microcomputer Power, Ithaca,

NY). The utility of this analysis to differentiate habitat clusters within the chironomid

community of a lake was established by Stimac and Leong (1977). These authors were

able to indicate that while there were three distinct habitats within the aquatic weeds of

Laguna Lake, CA, these were not a major limiting factor in chironomid abundance and

that only almost complete elimination of the weeds would have a significant effect on

nuisance midge populations. In the first step, the environmental variables that

significantly affect community composition were selected by forward selection (P < 0.05,








Monte Carlo permutation test with 199 permutations). The ordination axes in CCA were

then constrained to these environmental parameters. Results of this analysis for Lake

Dora are shown in Figure 39. Type of sediment, namely presence of sand, muck and DW

comprised one gradient in the community data that corresponded to the first ordination

axis. Water temperature, detritus presence, chlorophyll b and water depth composed

another gradient in community data that corresponded with the second ordination axis. It

is obvious that C crassicaudatus increased with water depth and muck presence, whereas

Cladotanytarsus spp. and other Tanytarsini responded to this trend negatively (Figure

39). Glyptotendipesparipes responded positively to water temperature, while

Polypedilum spp. and Geoldichironomus spp. responded negatively to this parameter.

Sample plots clustered into roughly two groups, shallower sand bottoms and deeper muck

bottoms.

Presence of muck was the strongest predictor of G. paripes density in Lake Yale

using CCA analysis (Figure 40), with water depth also being important.

Cryptochironomus spp. and Cladotanytarsus spp. density increased with sediment DW.

Polypedilum spp., Pseudochironomus spp. and other Tanytarsini species were influenced

by presence of rooted vegetation. The chironomid community in this lake formed three

separate habitat clusters: in shallower water with sand bottom, in sand bottoms with

rooted vegetation, and in deep water muck bottoms.

Tanypodinae increased with muck presence and water depth in Lake Wauburg

(Figure 41), while Tanytarsini increased with Secchi disk transparency, chlorophyll b,

and total chlorophyll. Glyptotendipes paripes showed minimal influence by the

examined parameters. Sample plots generally exhibited a similar clustering (shallower








water/sand bottom and deeper water/muck bottom) to the habitat clustering in Lake Dora

(Figures 39 and 41).

The finding that sediment characteristics and water depth were common

influences on chironomid distributions in these lakes is in agreement with the findings of

Vemrneaux and Aleya (1998), who reported that chironomid communities in Lake Abbaye

(France) were primarily influenced by bathymetric and sediment gradients within the lake

and seasonal variations in water characteristics. The authors also reported that seasonal

variation increased with water depth, with deeper areas having a more pronounced

seasonal change in chironomid fauna.

The size of field-collected G. paripes larvae ranged between 3 and 16 mm in

overall length. Based on the larval sizes recorded during the development study in

Chapter 7, the processed samples retained mostly 3rd and 4th instar larvae, indicating that

actual larval densities were potentially much higher. The lack of data on 1st and 2nd instar

population information also complicated productivity estimates of G. paripes in these

lakes; however, since 3-mm long larvae had relatively small biomass (Table 9), the

overall loss was probably not as great to the estimate. Mean dry biomass of G. paripes

larvae by 1-mm size increment is shown in Table 9. For estimating a larval

length/biomass relationship, the dry biomass values were transformed by the cube root to

correct for the linear length to cubic biomass relationship. This was analyzed by linear

regression and the data fit was exceptional [cube root mg dry biomass = -0.088 +

0.101(mm length); r2 = 0.992, P < 0.0001). Productivity of 3rd and 4th instar G. paripes

larvae between March 2000 and February 2001 was estimated using the size-frequency

method (Hynes and Coleman 1968, Hamilton 1969) with the modification of Benke








(1979). For this modification, CPI was estimated at 51 days using an approximate mean

water temperature of 23 C and the temperature development times estimated in Chapter

7. Lake Dora had the lowest G. paripes annual productivity of the lakes in this study,

205.1 mg/m2 dry biomass; followed by Lake Yale 3,482 mg/m2 dry biomass, and Lake

Wauburg 156,900 mg/m2 dry biomass. This exceptionally high productivity value for

G. paripes larvae in Lake Wauburg is close to the high productivity of 162 g/m2 dry

weight for Glyptotendipes barbipes in a sewage lagoon that was reported by Benke

(1984) and Kimerle and Anderson (1971). Mean standing crop during the same time

interval was 6.8 mg/m2 in Lake Dora, 189.7 mg/m2 in Lake Yale, and 6,081.5 mg/m2 in

Lake Wauburg. These productivity estimates indicate a general trend of increased

G. paripes populations with increased trophic level (such as between Lake Yale and Lake

Wauburg), then decreasing with hypereutrophic conditions (difference between Lake

Wauburg and Lake Dora). Biomass turnover in these lakes was measured by calculating

annual productivity/biomass (P/B) ratios of 30.2 for Lake Dora, 18.4 for Lake Yale, and

25.8 for Lake Wauburg. These values are consistent with those reviewed by Benke

(1984) for lakes with high chironomid productivity.









Table 3. Monthly mean SD of selected water physico-chemical parameters (water
depth, Secchi disk transparency, water temperature, dissolved oxygen, specific
conductance, chlorophyll a, chlorophyll b and total chlorophyll) and sediment dry


weight (DW) for Lake Dora (Lake County, Florida) from March
2001.


1999 to February


Date Depth Secchi Temp. DO Cond. DW Chl a Chl b Total
n (m) Transp. (C) (ppm) (tS/cm) (%) (gg/m3) (gtg/m3) Chl
(cm) (Ig/m3)


Mar 99 2.6


120
May 99
120
Jul 99
60
Sep 99
60
Nov 99
90
Jan 00
120
Mar 00
80
Apr 00
80
May 00
80
Jun 00
80
Jul 00
80
Aug 00
40
Sep 00
80
Oct 00
80
Nov 00
80
Dec 00
80
Jan 01
80
Feb 01
80


0.8
2.4
0.9
2.2
0.8
2.6
0.8
2.6
0.9
2.7
0.9
2.7
0.9
2.4
0.9
2.5
0.8
2.1
0.8
2.3
0.9
2.3
0.6
2.3
0.8
2.3
0.9
2.2
0.7
2.1
0.8
2.2
0.9
2.1
0.9


31 3 17.9
0.8
23 3 24.8
1.4
26 2 28.7
1.5
27 2 25.5
0.3
28 3 18.6
1.6
26 2 16.4
1.1
25 2 20.4
0.7
23 3 22.0
1.6
23 3 23.8
0.7
21 2 27.8
1.0
192 28.1
0.3
19 2 28.1
0.4
21 2 27.9
0.4
21 4 22.3
2.6
22 3 21.9
0.5
22 3 17.3
1.1
28 3 12.8
1.1
25 2 14.4
0.5


9.2 356


1.3
5.9
2.0
5.3
2.1
5.8
0.7
7.9
0.5
9.0
7.7
7.1
1.4
7.4
1.5
6.7
1.2


5.7
1.5
5.4
1.1
5.4
0.9
7.4
0.7
6.4
1.1
8.6
1.6
9.1
0.9
8.5
1.4


3
369
22
421
11
396
5
351
11
338
8
369
5
391
10
415
6
473
8
455
13
446
5
450
6
410
20
428
3
395
6
404
23


46.7
34.7
53.9
31.6
57.3
32.4
41.5
36.3
59.4
30.5
55.2
32.2
54.7
31.7
50.3
34.5
53.2
33.8
57.5
31.8
53.3
33.2
57.5
32.7
49.9
35
54.8
33.4
56.8
31.9
56.6
32.2
47.6
34.9
51.1
17.9


11.7
7.4
12.6
1.5
9.2
3.4
4.8
3.3
11.6
2.7
13.2
6.3
46.9
1.3
10.6
1.8
15.2
2.7
35.7
9.9
8.2
2.0
3.3
0.9
8.6
1.3
12.7
0.9


250.6
18.6
316.5
26.1
210.6
31.3
214.9
32.7
239.0
41.8
204.2
41.8
256.0
15.4
259.1
33.6
234.3
25.9
216.9
30.5
239.4
28.1
218.3
32.7
206.1
30.5
222.7
14.3


218.8
12.1
163.3
19.5
170.6
17.9


262.2
22.1
329.0
27.0
219.8
33.2
219.7
35.3
250.6
44.3
217.4
46.4
302.8
16.3
269.6
35.1
249.4
31.0
252.5
39.2
247.5
29.8
221.5
20.5
214.7
31.6
235.3
14.6


223.8
12.5
208.7
21.8
177.7
19.4


5.0
1.0
45.5
2.8
7.1
1.8









Table 4. Monthly mean + SD of selected water physico-chemical parameters (water
depth, Secchi disk transparency, water temperature, dissolved oxygen, specific
conductance, chlorophyll a, chlorophyll b and total chlorophyll) and sediment dry
weight (DW) for Lake Yale (Lake County, Florida) from March 1999 to February
2001.

Date Depth Secchi Temp. DO Cond. DW Chl a Chl b Total
n (m) Transp. (C) (ppm) (tS/cm) (%) (gg/rn3) (jg/m3) Chl
(cm) (jtg/m3)


Mar 99 3.0
120 1.2
May 99 2.9
80 1.5
Jul 99 2.7
60 1.2
Sep 99 2.9
30 1.3
Dec 99 2.9
30 1.2
Feb 00 3.2
120 1.4
Mar 00 3.0
80 1.6
Apr 00 2.7
60 1.3
May 00 2.7
80 1.1
Jun 00 2.8
80 1.3
Jul 00 3.2
80 1.4
Aug 00 2.8
40 1.3
Sep 00 3.0
80 1.4
Oct 00 2.7
80 1.3
Nov 00 2.7
80 1..1
Dec 00 2.9
24 0.9
Jan 01 -
0
Feb 01 2.7
60 1.2


87 10 23.5
2.1
62 7 27.1
1.1
65 5 29.3
0.6
65 5 26.5
0.8
57 5 18.2
0.6
101 27 14.4
1.5
50 4 20.3
0.3
46 3 20.5
0.9
45 3 24.9
1.1
49 3 28.2
0.6
58 3 28.0
0.7
61 5 28.6
0.7
66 3 27.0
0.4
67 3 20.7
0.5
70 7 16.7
0.5
77 4 12.9
0.1


7.8
0.8
6.3
1.5
5.7
1.3
5.6
1.7
7.5
1.3
8.8
6.5
9.1
0.8
7.8
0.6
7.3
2.6
6.3
1.1
4.6
1.7
6.1
1.6
7.0
0.7
8.0
0.7
9.3
0.5
9.8
0.9


1275 18.0 8.6
0.6 0.7


326
3
388
11
408
7
368
5
313
3
293
12
336
5
340
5
388
10
425
5
425
12
423
6
404
5
365
4
340
7
317
5


44.5 29.2
31.6 7.3
39.6 45.8
29.2 11.4
42.1 57.9
31.6 21.5
47.7 53.6
28.9 14.3
50.0 59.7
31.2 7.9
44.3 22.0
31.3 7.6
45.0 94.2
30.7 6.7
40.7 71.7
30.3 11.7
43.6 66.2
31.4 4.6
42.9 84.3
31.9 7.6
44.1 47.6
33.1 7.2
43.1 42.7
32.5 5.9
42.5 50.3
32.4 5.6
38.8 42.0
31.5 6.5
39.5 -
32.6
35.6 19.1
34.4 2.8


- 42.1 13.0
32.9 2.4


3.2
5.2
4.4
1.5
15.5
30.8
0.2
0.3
4.1
0.7
6.6
2.0
42.3
1.0
5.9
2.3
8.5
0.7
41.5
1.8
1.1
0.6
1.1
0.6
3.3
0.6
7.0
1.0


32.3
10.9
50.2
11.7
73.4
51.1
53.8
14.6
63.8
7.3
28.6
9.0
136.5 +
7.0
77.6
12.6
74.7
5.0
125.7
8.0
48.7
7.5
43.8
6.1
53.6
5.7
49.0
6.7


1.4 20.6
1.0 2.8


1.1 14.1
0.8 2.9








Table 5. Monthly mean SD of selected water physico-chemical parameters (water
depth, Secchi disk transparency, water temperature, dissolved oxygen, specific
conductance, chlorophyll a, chlorophyll b and total chlorophyll) and sediment dry
weight (DW) for Lake Wauburg (Alachua County, Florida) from March 2000 to
February 2001.

Date Depth Secchi Temp. DO Cond. DW Chi a Chl b Total
n (m) Transp. (C) (ppm) (PS/cm) (%) (pg/m3) (pg/m3) Chl
(cm) (g/im3)
Mar00 2.8 796 21.3 8.6 9517 31.0 73.2 47.6 120.8
30 1.1 0.5 2.1 26.7 5.4 1.7 6.1
Apr 00 2.7 85 3 22.7 7.0 91 1 32.9 38.5 11.7 50.2
30 1.2 0.6 1.2 27.2 5.6 9.0 14.5
May 00 67 4 27.4 6.9 109 1 21.9 58.7 15.8 74.5
30 0.7 1.0 26.0 4.5 2.5 5.9
Jun00 72 3 30.2 6.2 118 5 35.4 73.5 49.6 118.1
21 1.2 2.7 29.6 6.2 1.1 7.0
Jul00 63 1 29.2 6.3 115 5 37.2 49.4 4.2 53.6
30 1.6 1.6 30.4 11.3 1.2 12.3
Aug00 2.3 62 3 29.5 7.0 118 5 21.3 16.9 0.9 17.9
18 0.7 0.8 1.8 12.4 13.8 0.5 13.5
Sep00 2.5 63 4 25.2 6.1 103 2 33.6 71.1 11.2 82.2
30 0.9 0.2 1.2 29.4 6.5 1.1 7.4
Oct 00 2.5 62 3 22.5 7.8 99 3 30.2 52.4 10.9 63.2
30 0.9 0.8 1.5 25.9 3.8 1.4 4.6
Nov 00 2.6 592 20.9 8.4 981 31.5 -
30 0.8 0.2 0.7 28.3
Dec00 2.1 61 3 13.7 10.0 81 2 37.7 50.4 6.2 56.6
30 1.1 0.7 0.5 28.7 5.4 1.4 6.6
Jan 01 2.5 80 3 10.5 10.7 75 2 27.8 75.4 59.2 134.5
30 0.9 0.5 0.7 26.5 24.3 37.1 60.7
Feb01 2.3 68 4 19.0 7.4 34.5 72.0 17.1 89.1
30 0.9 0.6 1.6 28.8 7.5 10.5 17.3








Table 6. Mean monthly density (No./m2) stratified SD of selected Chironomidae larvae
[Chironomus crassicaudatus, Glyptotendipes paripes, Cryptochironomus spp.
(Crypt.), Tanytarsini (Tanyt., mostly Cladotanytarsus spp.), Tanypodinae
(Tanyp.), total Chironomidae larvae, G. p. biomass (mg/m2) and total
Chironomidae biomass (mg/rm2)] collected for Lake Dora (Lake County, Florida),
March 1999-February 2001.


Date C. crass. G. paripes Crypt. Tanyt. Tanyp. Total


Mar. 2 2,197 86 26 2,395
99 2 172 13 9 181
May 770 477 1,957 22 3,535
99 129 155 159 4 241
Jul. 86 39 602 9 907
99 22 9 108 4 129
Sep. 13 9 2,499 3 2,589
99 9 4 748 2 744
Nov. 254 3 4,123 22 4,945
99 52 4 206 9 +219
Jan. 73 13 2,864 52 3,307
00 22 4 176 9 181
Mar. 168 9 69 1,686 22 1,965
00 34 4 4 112 9 112
Apr. 237 9 138 1,337 55 1,750
00 52 4 26 168 4 181
May 275 39 215 1,969 13 2,533
00 69 13 34 198 4 237
Jun 82 52 129 882 17 1,264
00 17 17 9 82 4 90
Jul. 43 22 69 254 17 417
00 13 4 4 22 4 30
Aug. 17 9 77 400 9 520
00 13 4 13 60 9 69
Sep. 17 4 77 297 17 426
00 9 2 9 43 4 52
Oct. 9 4 112 774 34 946
00 4 3 13 86 9 95
Nov. 43 30 103 1,281 56 1,531
00 17 13 9 138 9 142
Dec. 86 9 559 4,330 116 5,207
00 34 4 30 245 13 262
Jan. 219 4 194 1,974 86 2,541
01 39 4 17 133 26 142
Feb. 120 1 215 1,264 77 1,707
01 22 1 17 90 17 95


G.p.
biomass
98.9
8.6
34.4
4.3
25.8
4.3
2.2
1.3
1.7+
3.0
8.6
4.3
8.6
4.3
3.4
2.0
12.9
4.3
21.5
8.6
12.9
4.3
1.7
0.9
1.7
0.9
3.9
6.5
8.6
4.3
1.3
0.4
4.3
4.3
0.4
0.4


Total
biomass
146.2
12.9
670.8
64.5
172.0
17.2
313.9
73.1
1,333.9
68.8
602.0
38.7
245.1
25.8
172.0
21.5
210.7
34.4
137.6
8.6
64.5
8.6
43.0
8.6
38.7+
8.6
51.6
8.6
94.6
8.6
270.9
21.5
399.9
43.0
301.0
21.5









Table 7. Mean monthly density (No./m2) stratified SD of selected Chironomidae larvae
[Chironomus crassicaudatus, Glyptotendipes paripes, Cryptochironomus spp.
(Crypt.), Pseudochironomus spp. (Pseud.), Tanytarsini (Tanyt., mostly
Cladotanytarsus spp.), Tanypodinae (Tanyp.), total Chironomidae larvae, G. p.
biomass (mg/m2) and total Chironomidae biomass (mg/m2)] collected for Lake
Yale (Lake County, Florida), March 1999-February 2001.


Feb.
01


0 359 50 9 177 1,171 54 1,836 197.8 348.3
0 126 24 123 14 183 116.9 123.0


Date C.
crass.
Mar. 1
99 1
May 173
99 29
Jul. 10
99 5
Sep. 1
99 3
Dec. 168
99 223
Feb. 31
00 11
Mar. 168
00 34
Apr. 8
00 4
May 3
00 4
Jun. 2
00 1
Jul. 0
00 0
Aug. 0
00 0
Sep. 0
00 0
Oct. 0
00 0
Nov. 0
00 0
Dec. 0
00 0


G.
paripes
1,782
163
182
34
123
34
3
1
9
7
75
15
10
4
52
16
81
52
171
58
377
130
342
284
461
272
648
237
235
61
691
284


Crypt. Pseud. Tanyt. Tanyp. Total G. p. Total
biomass biomass
193 45 2,038 52.0 140.2
7 6 168 6.2 10.8
243 34 1,141 156.5 482.9
44 7 143 28.4 56.8
110 47 452 108.8 246.0
14 12 67 34.0 64.5
30 43 188 9.5 2.2 83.0
3 21 26 14.2
418 60 890 3.4 1.3 500.9
48 23 233 373.7
1,535 124 2,202 64.0 595.6
116 16 123 14.2 41.7
67 6 1,684 22 1,964 9.5 4.3 245.5
111 8 114 25.4
47 8 161 1,008 60 1,350 52.9 194.4
24 155 10 162 21.8 33.2
78 9 228 2,327 97 2,779 20.4 182.3
28 309 11 314 8.0 20.6
374 71 11 550 27 864 47.3 94.6
67 7 101 18.6 24.6
48 13 130 153 43 767 318.2 399.9
27 16 13 141 120.0 124.6
283 8014 170 43 669 313.9 356.9
77 14 281 264.5 265.3
61 44 7 64 38 625 172.0 210.7
11 14 271 105.8 109.7
12 4 61 20 225 61 1,026 653.6 722.4
29 11 241 247.7 250.7
396 56 7 1,138 51 1,528 133.3 202.1
103 12 129 41.7 44.3
48 11 72 21 885 65 1,765 167.7 270.9
208 18 342 92.0 86.4








Table 8. Mean monthly density (No./m2) stratified SD of selected Chironomidae larvae
[Glyptotendipes paripes, Tanypodinae (Tanyp.), total Chironomidae larvae, G. p.
biomass (mg/mr2) and total Chironomidae biomass (mg/m2)] collected for Lake
Wauburg (Alachua County, Florida), March 2000-February 2001.


Date
Mar. 00

Apr. 00

May 00

Jun. 00

Jul. 00

Aug. 00

Sep. 00

Oct. 00

Nov. 00

Dec. 00

Jan. 01

Feb. 01


G. paripes
19,442
2,262
10,295 +
2,187
6,143
1,303
8,565
1,982
7,749
991
5,206
1,342
8,747
2,282
6,808
1,022
14,507
3,652
7,588
2,382
10,816
2,005
6,167
1,174


Tanyp.
361
79
181
43
149
30
72
27
76
21
100
46
34
26
70
28
61
13
56
19
26
13
34
16


Total
20,085
2,275
10,508
2,228
6,317
1,302
8,670
2,009
7,898
1,018
5,306
1,355
8,897
2,292
6,884
1,026
14,568
3,646
8,091
2,460
11,149
2,030
6,210
1,172


G. p. biomass
15,721.2
1,660.2
8,942.3
1,479.6
3,302.4
462.3
7,142.3
1,594.9
5,639.5
793.8
2,673.7
619.6
6,011.4
1,387.6
3,799.9
565.0
5,096.8
1,130.9
3,077.5
844.1
6,530.0
1,178.0
5,040.5
860.9


Total biomass
15,863.1
1,662.0
9,182.7
1,465.9
3,392.3
461.0
7,184.9
1,385.5
5,672.6 +
797.7
2,729.6
622.6
6,040.2
1,386.3
3,830.9
567.2
5,132.9
1,127.9
3,182.0
857.9
6,601.4
1,182.5
5,072.7
859.1








Table 9. Mean SD of Glyptotendipes paripes larval dry biomass (mg/larva) by 1-mm
size class and cube root of mean value used for calculating a size/biomass curve.

Size class (mm) Mean dry biomass Cube root of mean dry biomass
(mg/larva) SD
3 0.015 0.008 0.24
4 0.032 0.012 0.32
5 0.055 0.021 0.38
6 0.120 0.048 0.49
7 0.241 0.096 0.62
8 0.344 0.109 0.70
9 0.479 0.207 0.78
10 0.833 0.409 0.94
11 1.270 0.419 1.08
12 1.658 0.330 1.18
13 1.729 0.866 1.20
14 2.586 0.449 1.37
15 2.861 1.396 1.42
16 3.133 0.503 1.46
Pupa 2.147 0.905 -
Not required for length/biomass curve but used for productivity estimates

























~lI I II IIII IIII IlIrlil'l~lill ii | 1ii l iil h ii11 iiii i II ii i ii i I l illll iii
45 44 43 42 41 40 39 38


May 1999













4I5 IIIlll l ll lll ll l l 44 43 42 41 40 39l 38llh 'l
45 44 43 42 41 40 39 38


Longitude (Minutes 81 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

S0.5-1.0 1.5-2.0 2.5-3.0 N 3.5-4.0 4.5-5.0
Figure 15. Spatial larval distributions log(No. / m2 + 1) of Glyptotendipes paripes
in Lake Dora (Lake County, Florida), March, May 1999.


March 1999












July 1999


44 43 42


41 40 39 38


Longitude (Minutes 81 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

0.5-1.0 1.5-2.0 2.5-3.0 0 3.5-4.0 4.5-5.0

Figure 16. Spatial larval distributions log(No. / m2 +1) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), July, September 1999.


45 44 43 42 41 40 39 38



September 1999















II1 II I1| I III I1| 11' 11 II II I III 1 I III II 1 |1111111 I11111 1I I I111


























{Fq 46 !I1III[ II fII I 1111111|I I I I I1 1 1111111111 i11i i i l i i ii iii ii l li i i ii 1111iiiii
W 45 44 43 42 41 40 39 38


4 January 2000
S49 =


48






46 -
46-

4 i ll tllll l t 1111 11111 11 11111ll t llllllll t ltliii Il lil 'ii
45 44 43 42 41 40 39 38

Longitude (Minutes 81 West)

H 0-0.5 0 1.0-1.5 H 2.0-2.5 3.0-3.5 4.0-4.5

m 0.5-1.0 E 1.5-2.0 m 2.5-3.0 m 3.54 0 E 4.5-5.0

Figure 17. Spatial larval distributions log(No. / m2 + 1) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), November 1999, January 2000.


November 1999











March 2000


45 44 43 42 41 40 39 38


April 2000
















45 44 43 42 41 40 39 38


Longitude (Minutes 81 West)


0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.04.5

0.5-1.0 1.5-2.0 2.5-3.0 0 3.5-4.0 4.5-5.0

Figure 18. Spatial larval distributions log(No. / m2 + 1) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), March, April 2000.







65


50 --o


May 2000
489



48



47






z
0
00
S 45 44 43 42 41 40 39 38
6 50


J June 2000
48 7







47



46 -



-IIIIIIIIlIlIlllllllIlIllIllllIllllllIIIIlIlllllllIllllIlllIIIllllllll
45 44 43 42 41 40 39 38

Longitude (Minutes 81 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5


0.5-1.0 1.5-2.0 2.5-3.0 0 3.5-4.0 4.5-5.0

Figure 19. Spatial larval distributions log(No. / m2 + 1) of Glyptotendipesparipes

in Lake Dora (Lake County, Florida), May, June 2000.






66


50

July 2000
49


48


47


48

z
-
('4 45-
C4 46 IIIIIII pillllllllllI l1 llll1 ll1 llll11 l1111 l11 ll111111 l1 lllllllillllllm
0 45 44 43 42 41 40 39 38
6 50


I' August 2000

49
: ^^





47


46



46 44 43 42 41 40 39 38

Longitude (Minutes 81 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

0.5-1.0 1.5-2.0 2.5-3.0 M 3.54.0 4.5-5.0

Figure 20. Spatial larval distributions log(No. / m2 +1) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), July, August 2000.










560 -


September 2000
49



48



47



46


o
00
S 45 44 43 42 41 40 39 38
60


October 2000



48




47



46 -

45


45 44 43 42 41 40 39 38

Longitude (Minutes 81 West)

0-0.5 1.0-1.5 0 2.0-2.5 3.0-3.5 E 4.0-4.5


0.5-1.0 0 1.5-2.0 0 2.5-3.0 0 3.5-4.0 0 4.5-5.0

Figure 21. Spatial larval distributions log(No. / m2 + 1) of Glyptotendipes paripes
in Lake Dora (Lake County, Florida), September, October 2000.











November 2000


45 44 43 42 41 40 39 38


SDecember 2000















45 44 43 42 41 40 39 38


Longitude (Minutes 81 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

0.5-1.0 1.5-2.0 2.5-3.0 0 3.5-4.0 4.5-5.0

Figure 22. Spatial larval distributions log(No. / m2 + 1) of Glyptotendipesparipes
in Lake Dora (Lake County, Florida), November, December 2000.







69


so
60 -: -----------------------------------------------______


January 2001
49

48 -





47



48

z
00
I "


0 46 44 43 42 41 40 39 38
60-


February 2001
49



48



47 -




46 -

45


45 44 43 42 41 40 39 38

Longitude (Minutes 81 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5


0.5-1.0 1.5-2.0 2.5-3.0 I 3.5-4.0 4.5-5.0

Figure 23. Spatial larval distributions log(No. / m2 + 1) of Glyptotendipesparipes

in Lake Dora (Lake County, Florida), January, February 2001.























53 -


Ol I I I II
47 46 45 44 43 42
57
6 May 1999









54 -


53


52 I I-
47 48 45 44 43 42
Longitude (Minutes 81 West)
S0.0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

0.5-1.0 o 1.5-2.0 2.5-3.0 3.5-4.0 4.5-5.0

Figure 24. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), March, May 1999.


March 1999








57------------------

July 1999


66

65





i Bl







^~September 1999
54
53-
z
0
52---2



















47 46 45 44 43 42
Longitude (Minutes 81 West)
J 0.0-0.5 B 1.0-1.5 f 2.0-2.5 3.0-3.5 J 4.0-4.5

m o.5-1.o i 1.5-2.o m 2.5-3.o mm3.5-4.o m 4.5-5.o

Figure 25. Spatial larval distributions log(No./m2 + 1)) of Glyptotendipes paripes
7in Lake Yale (Lake Coty, Florida), Jy, September 1999.
September 1999
566


55


64-


53


52 -
47 48 456 4 43 42
Longitude (Minutes 810 West)
0.0-0.5 E 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

0 0.5-1.0 1.5-2.0 E 2.5-3.0 3.5-4.0 0 4.5-5.0

Figure 25. Spatial Larval distributions log(No./m2 + 1)) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), July, September 1999.












566






54-


i "i
53-

0
00 52-
C III I I
S 47 46 45 44 43 42
6 7 -------------------
SFebruary 2000
56-



55


54-
5-- --- -------- ---- ---


53-


52 1 I 1
47 46 45 44 43 42
Longitude (Minutes 81 West)
S0.0-0.5 E 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

0 0.5-1.0 1.5-2.0 2.5-3.0 3.5-4.0 4.5-5.0

Figure 26. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), December 1999, February 2000.


December 1999




























64 "O -! I I I I I
W 47 46 45 44 43 42
i 57--

6 April 2000
56



55-



64-



53-


52
47 46 45 44 43 42
Longitude (Minutes 81 West)

I 0.0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

1 0.5-1.0 1.5-2.0 I 2.5-3.0 N 3.5-4.0 4.5-5.0

Figure 27. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), March, April 2000.


March 2000


























4 bz-1 111--- 1 I
S47 46 45 44 43 42


June 2000
FA .



55


54


53-


52- 1 1 I
47 46 45 44 43 42
Longitude (Minutes 81 West)
0.0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 M 4.0-4.5

0.5-1.0 1 .5-2.0 2.5-3.0 3.5-4.0 4.5-5.0

Figure 28. Spatial larval distributions log( No./m2 + l)of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), May, June 2000.


May 2000









57

July 2000
56



55



54




53

z
0
00 _________________________________________
00 52-
S 47 46 45 44 43 42

57 -
August 2000

56



655



54



53



52-
47 48 45 44 43 42

Longitude (Minutes 81 West)

i 0.0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

i 0.5-1.0 1.5-2.0 N 2.5-3.0 3.5-4.0 4.5-5.0

Figure 29. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), July, August 2000.


























F4 "-1 1 1 I II
M 47 46 45 44 43 42


October 2000








54 ,


53


52-
47 46 45 44 43 42
Longitude (Minutes 81 West)
0 0.0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

M 0.5-1.0 M 1.5-2.0 0 2.5-3.0 3.5-4.0 4.5-5.0

Figure 30. Spatial larval distributions log(No./m2 + 1) of Glyptotendipes paripes
in Lake Yale (Lake County, Florida), September, October 2000.


September 2000






















53 -


November 2000


I I I I I
47 46 45 44 43


47 46 45 44 43 42
Longitude (Minutes 81 West)
0.0-0.5 f 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

S0.5-1.0 M 1.5-2.0 M 2.5-3.0 3.5-4.0 4.5-5.0

Figure 31. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), November, December 2000.









January 2001






No samples collected


-7 "


Oz I I I I
47 48 45 44 43 42
Longitude (Minutes 81 West)
0.0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5
0.5-1.0 1.5-2.0 2.5-3.0 3.5-4.0 4.5-5.0

Figure 32. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Yale (Lake County, Florida), January, February 2001.


February 2001












32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 _


31.3
32.3 1

32.2 -

32.1 -

32.0-

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 -


March
2000


S1 I I I 1 1 I I 1
8.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 1


April
2000


31.3 I 1 1 I I I I1 1 1 1
18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5


I 0.5-1.0 1.5-2.0 2.5-3.0 N 3.5-4.0 4.5-5.0

Figure 33. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Wauburg (Alachua County, Florida), March, April 2000.












32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 -


31.3
.,, 11


32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 _


May
2000


I I I I I I I I I 1
1.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 1


June
2000


. I I I I I I I I I I
18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 West)

S0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5


0.5-1.0 1.5-2.0 2.5-3.0 3.5-4.0 4.5-5.0

Figure 34. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Wauburg (Alachua County, Florida), May, June 2000.


0 X-. 1










32.3 -

32.2

32.1

32.0

31.9

31.8

31.7

31.6

31.5


31.4

31.3 -
32.31


32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -


31.4

31 9 -


July

2000


I I I I I I I I I 1 1
8.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 1


August

2000


I I I I I I I I I~


18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 West)

0-0.5 1.0-1.5 M 2.0-2.5 3.0-3.5 4.04.5


0.5-1.0 1.5-2.0 E 2.5-3.0 0 3.5-4.0 4.5-5.0

Figure 35. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes

in Lake Wauburg (Alachua County, Florida), July, August 2000.










32,3 -

32.2 -

32.1 -

32.0

31.9

31.8

31.7

31.6 -

31.5 -

31.4


31.3 -
32.3 1

32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 _

qj a -


September

2000


,I i I I I i


I I I I I I
.5 18.4 18.3 18.2 18.1 18.0 17.9


I I I 1
17.8 1717 17.6 17.5


October

2000


. I I I I I I I I I I
18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5


* 0.5-1.0 1.5-2.0 2.5-3.0 3.5-4.0 4.5-5.0

Figure 36. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes

in Lake Wauburg (Alachua County, Florida), September, October 2000.










32.3

32.2 -A


32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 _


31.3 -
,n, 11


OZ.,


32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 _


November

2000


I I I I I I I I I
1.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 1


December

2000


... I I I I I I I I I I
18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 17.5
Longitude (Minutes 82 West)

0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5


0.5-1.0 1.5-2.0 2.5-3.0 0 3.54.0 4.5-5.0

Figure 37. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes

in Lake Wauburg (Alachua County, Florida), November, December 2000.














January
2001


32.3 -

32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31.7 -

31.6 -

31.5 -

31.4 -

31.3 -
32.31

32.2 -

32.1 -

32.0 -

31.9 -

31.8 -

31,7 -

31.6 -


February
2001


I I I I I I I I I
18.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7
Longitude (Minutes 82 West)


1 I
17.6 1


0-0.5 1.0-1.5 2.0-2.5 3.0-3.5 4.0-4.5

0.5-1.0 1.5-2.0 2.5-3.0 0 3.5-4.0 4.5-5.0

Figure 38. Spatial larval distributions log(No./m2 + 1) of Glyptotendipesparipes
in Lake Wauburg (Alachua County, Florida), January, February 2001.


I I I I I I I I I
.5 18.4 18.3 18.2 18.1 18.0 17.9 17.8 17.7 17.6 1


31.5

31.4 _



















































Figure 39. Canonical correspondence analysis (CCA) of selected water and sediment
physico-chemical parameters with Chironomidae larval community in Lake
Dora (Lake County, FL), March 2000 February 2001

















Other Tanytarsini U



Polypedilum
0


Vegetation
0 ,
'..C.
*40:. cI

Chlorophyll a *
Pseudochironomus Q0
............................................................ -.--- ---.....--
Cladotanytarsus **i *^
DW DO '"
Cryptochironomus


crassicaud
0


atus
, Muck
Tanypodinae
U^^ l. ..................
G0paripes
Water Depth


Figure 40. Canonical correspondence analysis (CCA) of selected water and sediment
physico-chemical parameters with Chironomidae larval community in Lake
Yale (Lake County, FL), March 2000 February 2001