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 Abstract
 Introduction
 Methodology
 Results and discussion
 Management considerations
 Acknowledgement
 Reference






Group Title: Lake and Resevoir Management, 6 (2) : pp. 133-141, 1990
Title: Limnological factors influencing bird abundance and species richness on Florida lakes
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Title: Limnological factors influencing bird abundance and species richness on Florida lakes
Series Title: Lake and Resevoir Management, 6 (2) : pp. 133-141, 1990
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Language: English
Creator: Hoyer, Mark V.
Canfield, David E. Jr.
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Publication Date: 1990
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Table of Contents
    Abstract
        Page 133
    Introduction
        Page 133
    Methodology
        Page 134
    Results and discussion
        Page 135
        Page 136
        Page 137
        Page 138
        Page 139
    Management considerations
        Page 140
    Acknowledgement
        Page 141
    Reference
        Page 141
Full Text

LAKE AND RESERVOIR MANAGEMENT, 1990 6(2): 133-141
0 1990 North American Lake Management Society


Limnological Factors Influencing Bird

Abundance and Species Richness on

Florida Lakes


Mark V. Hoyer
Daniel E. Canfield, Jr.
Department of Fisheries and Aquacultre
University of Florida
Gainesville, Florida 32611


Introduction

Florida has more than 7,700 lakes that range in size
from 0.4 ha to over 180,000 ha (Shafer et al. 1986).
Most of the research and lake management con-
ducted on these lakes involves nutrient and aquatic
macrophyte management (Shireman et al. 1983;
Canfield and Hoyer, 1988a; Dierberg et al. 1988;
Joyce, 1989). This work is done primarily for the pur-
poses of potable water supply, flood control, naviga-
tion, recreational boating, swimming, and fishing.
Often little or no consideration is given to the bird
populations that use these lakes and may be affected
by lake management actions.
Aquatic bird studies in Florida generally are done
in marsh systems; only a few studies have examined


factors affecting bird populations in lakes (Gasaway
et al. 1977; Gasaway and Drda, 1977; Montalbano et
al. 1979; Johnson and Montalbano, 1984; Jenni,
1969). Consequently, there is limited information on
the factors influencing bird abundance and species
richness in Florida's lakes. The purpose of this ex-
ploratory study is to present baseline data on bird
populations that use Florida's lakes and to examine
relationships between limnological factors and bird
abundance and species richness. Many factors have
been shown to influence bird populations including
geographic location, habitat condition in nesting and
wintering areas, and climatic factors. However, we
focused our study on the following three major
habitat characteristics that have been shown impor-
tant to bird populations in other studies: lake trophic
status (Nilsson and Nilsson, 1978; Murphy, et al.


ABSTRACT

Forty-six bird species were observed on 33 Florida lakes with some species occurring on only one lake
andothers on as many as 26 lakes. Average annual bird abundance ranged from seven to 750 bird/km2
and total species richness ranged from two to 30 species per lake. Regression analyses were used to ex-
amine the effects of lake trophic status, aquatic macrophyte abundance, and lake morphology on
average annual bird abundance and total species richness. All trophic state parameters (total phos-
phorus, total chlorophyll a, etc.) accounted for significant portions of the variance in average annual
bird abundance, but total chlorophyll a concentrations (pgQL) accounted for the highest percentage (47
percent) of the variance. The best fit regression equation was: Log Bird Abundance 1.35 + 0.56 Log
Total Chlorophyll a. Lake area, shoreline length, and all trophic state parameters accounted for sig-
nificant portions of the variance in total species richness. Multiple regression analyses indicated that
lake area (kmi) and total chlorophyll a (tig/L accounted for the highest percentage (87 percent) of the
variance in total species richness (species/lake). The best-fit multiple regression equation was: Log
Species Richness = 1.10 + 0.47 Log Lake Area + 0.17 Log Tbtal Chlorophyll a. After accounting for lake
trophic status and lake area, neither aquatic macrophyte abundance nor lake morphology accounted
for additional variances in average annual bird abundance or total species richness.





LAKE AND RESERVOIR MANAGEMENT, 1990 6(2): 133-141
0 1990 North American Lake Management Society


Limnological Factors Influencing Bird

Abundance and Species Richness on

Florida Lakes


Mark V. Hoyer
Daniel E. Canfield, Jr.
Department of Fisheries and Aquacultre
University of Florida
Gainesville, Florida 32611


Introduction

Florida has more than 7,700 lakes that range in size
from 0.4 ha to over 180,000 ha (Shafer et al. 1986).
Most of the research and lake management con-
ducted on these lakes involves nutrient and aquatic
macrophyte management (Shireman et al. 1983;
Canfield and Hoyer, 1988a; Dierberg et al. 1988;
Joyce, 1989). This work is done primarily for the pur-
poses of potable water supply, flood control, naviga-
tion, recreational boating, swimming, and fishing.
Often little or no consideration is given to the bird
populations that use these lakes and may be affected
by lake management actions.
Aquatic bird studies in Florida generally are done
in marsh systems; only a few studies have examined


factors affecting bird populations in lakes (Gasaway
et al. 1977; Gasaway and Drda, 1977; Montalbano et
al. 1979; Johnson and Montalbano, 1984; Jenni,
1969). Consequently, there is limited information on
the factors influencing bird abundance and species
richness in Florida's lakes. The purpose of this ex-
ploratory study is to present baseline data on bird
populations that use Florida's lakes and to examine
relationships between limnological factors and bird
abundance and species richness. Many factors have
been shown to influence bird populations including
geographic location, habitat condition in nesting and
wintering areas, and climatic factors. However, we
focused our study on the following three major
habitat characteristics that have been shown impor-
tant to bird populations in other studies: lake trophic
status (Nilsson and Nilsson, 1978; Murphy, et al.


ABSTRACT

Forty-six bird species were observed on 33 Florida lakes with some species occurring on only one lake
andothers on as many as 26 lakes. Average annual bird abundance ranged from seven to 750 bird/km2
and total species richness ranged from two to 30 species per lake. Regression analyses were used to ex-
amine the effects of lake trophic status, aquatic macrophyte abundance, and lake morphology on
average annual bird abundance and total species richness. All trophic state parameters (total phos-
phorus, total chlorophyll a, etc.) accounted for significant portions of the variance in average annual
bird abundance, but total chlorophyll a concentrations (pgQL) accounted for the highest percentage (47
percent) of the variance. The best fit regression equation was: Log Bird Abundance 1.35 + 0.56 Log
Total Chlorophyll a. Lake area, shoreline length, and all trophic state parameters accounted for sig-
nificant portions of the variance in total species richness. Multiple regression analyses indicated that
lake area (kmi) and total chlorophyll a (tig/L accounted for the highest percentage (87 percent) of the
variance in total species richness (species/lake). The best-fit multiple regression equation was: Log
Species Richness = 1.10 + 0.47 Log Lake Area + 0.17 Log Tbtal Chlorophyll a. After accounting for lake
trophic status and lake area, neither aquatic macrophyte abundance nor lake morphology accounted
for additional variances in average annual bird abundance or total species richness.







M. V HOYER and D. E. CANFIELD, JR.


1984;), lake morphology (MacArthur and Wilson,
1967; Brown and Dinsmore, 1986) and aquatic mac-
rophyte abundance (Johnson and Montalbano, 1984;
Montalbano et al. 1979).



Methods

Data for this study were collected from 33 Florida
lakes (Table 1). Birds observed utilizing aquatic
habitats were counted while we motored once
around the perimeter of each lake in a boat. Birds
were identified to species except gulls, terns, and
crows, which were counted in their respective
groups. Care was taken not to count twice birds that
flushed ahead of the boat. Birds were counted once
on each lake in three different seasons: winter
(November 1, 1988 to February 28, 1989), spring
(March 29, 1989 to May 24, 1989) and summer (July
25, 1989 to September 29, 1989). In addition to in-
dividual seasonal counts, average annual bird num-
bers (number/km2) were calculated by averaging all
three counts for each lake. Species richness (species
per lake) was calculated seasonally for each lake.
Total species richness equalled the sum of all bird
species counted throughout the entire sampling
period for each lake.


Summer water samples were collected from six
stations (three littoral and three open water), and
three open water samples were collected from each
lake once in the winter (November February), and
once in the spring (March May). Water samples
were collected 0.5 m below the surface in acid
cleaned Nalgene bottles, placed on ice, returned to
the laboratory, and analyzed for total phosphorus
(TP, pg/L), total nitrogen (TN, pg/L), total
chlorophyll a (TCHLA, uIg/L), total alkalinity (TALK,
mg/L as CaCOs) and specific conductance (COND,
R.S/cm2 at 25'C). Secchi depth (m) was also measured
at each station where water was collected.
Total phosphorus was analyzed (Murphy and
Riley, 1962) after a persulfate oxidation (Menzel and
Corwin, 1965). Total nitrogen was determined by a
modified Kjeldahl technique (Nelson and Sommers,
1975). Water was filtered through Gelman type A-E
glass fiber filters for TCHLA determinations. Total
chlorophyll a was determined by using the method of
Yentsch and Menzel (1963) and the equations of Par-
sons and Strickland (1963). Total alkalinity was
determined by titrations with 0.02 N sulfuric acid
(Stand. Methods, 1981). Specific conductance was
measured by using a Yellow Springs Instrument
Company Model 31 conductivity bridge. Lake
averages for these parameters were calculated by
date and then lake.


Table 1.-Name and location of 33 Florida lakes sampled with average annual bird abundance and total species
richness listed for each lake.


SPECIES
RICHNESS
(SPECIES/LAKE)
22
25
27
26
10
3
2
3
9
9
16
25
25
17
27
19
21
18
26
25
28
24
24
22
2
4
3
3
10
8
20
30
21


LAKE NAME
Wauberg
Bivens arm
Rowell
Lindsey
Koon
Clay
Lawbreaker
Round pond
Crooked
Catherine
Susannah
Baldwin
Carlton
Live oak
Fish
Clear
Bell
Hunter
Bonny
Patrick
Hartridge
Conine
Hollingsworth
Wales
Barco
Deep
Keys pond
Brim pond
Suggs
Cue
Orienta
Okahumpka
Miona


COUNTY
Alachua
Alachua
Bradford
Hernando
Lafayette
Lake
Lake
Lake
Lake
Marion
Orange
Orange
Orange
Osceola
Osceola
Pasco
Pasco
Polk
Polk
Polk
Polk
Polk
Polk
Polk
Putnam
Putnam
Putnam
Putnam
Putnam
Putnam
Seminole
Sumter
Sumter


LATITUDE
29.31
29.37
29.55
28.37
30.02
29.02
29.10
29.04
29.09
29.11
28.33
28.34
28.45
28.13
28.16
28.20
28.13
28.01
28.02
27.48
28.03
28.03
28.01
27.54
29.40
29.43
29.31
29.31
29.41
29.40
28.39
28.45
28.54


LONGITUDE
-82.18
-82.20
-82.09
-82.21
-83.06
-81.27
-81.37
-81.49
-81.36
-81.49
-81.19
-81.19
-81.39
-81.14
-81.20
-82.15
-82.27
-81.58
-81.55
-81.30
-81.44
-81.43
-81.56
-81.34
-82.00
-82.57
-81.58
-81.59
-82.01
-82.58
-81.22
-82.05
-82.00


BIRD
ABUNDANCE
(BIRDS/km2)
320
290
110
240
110
20
7
25
40
20
750
320
120
24
110
60
250
150
270
40
150
470
220
110
8
100
10
40
9
10
580
450
60








The percentage of lake volume infested with
aquatic macrophytes (PVI) and the percentage of
lake area covered by macrophytes (PAC) were deter-
mined with a Raytheon DE 719 fathometer (Maceina
and Shireman, 1980). The aboveground standing
crop of emergent (EMERG), floating leaf (FLOAT)
and submergent (SUBMERG) vegetation (kg wet
wt/m2) was measured along 10 uniformly placed
transects around the lake. A 0.25 m2 sample of
vegetation was taken in each plant zone (when
present), placed in nylon mesh bags, spun to remove
excess water, and weighed to the nearest 0.10 kg.
Average standing crop for each vegetation zone was
calculated by averaging 10 samples from each zone.
Lake area (LA) was obtained from the Gazetteer
of Florida Lakes (Shafer et al. 1986). Shoreline
length (SL, km), the distance to the nearest lake
(DLAKE, km), and the number of lakes within 5 km
(NO5KM) were measured or counted using aerial
photographs with a 1:20,000 or 1:40,000 reduction.
Mean depth (MEANZ, m) was calculated from the
fathometer transects used for PVI and PAC calcula-
tions. Shoreline development (SD) was calculated ac-
cording to the methods of Wetzel (1975).
Before statistical analyses, data were trans-
formed to base 10 logarithms where needed to meet
the requirements of parametric statistical analysis.


LAKE AND RESERVOIR MANAGEMENT, 1990 6(2): 133-141


Statistical analyses were performed by using the
SYSTAT computer package (SYSTAT, 1987). Unless
stated otherwise, statements of significance imply
phosphorus s 0.05.


Results and Discussion

A wide range of limnological conditions existed in the
33 Florida lakes sampled (Table 2). Mean total phos-
phorus concentrations ranged from 1 to 1040 tg/L
and total chlorophyll a concentrations ranged from
0.7 to 240 tg/L. Water clarity ranged from 0.3 to 5.7
m and total nitrogen concentrations ranged from 100
to 4900 pg/L. Lake area ranged from 0.032 to 2.71
km2 and percentage area covered with aquatic mac-
rophytes ranged from 0 to 100 percent (Table 2). The
ranges of these limnological parameters are similar
to those reported by Canfield and Hoyer (1988b) for
165 Florida lakes. Thus, these lakes range from
oligotrophic to hypereutrophic (Forsberg and
Ryding, 1980), and they should represent Florida
lakes for the purpose of examining the effect of lake
trophic status, aquatic macrophyte abundance, and
lake morphology on bird populations.
Forty-six bird species were observed during the
study period with some occurring on only one lake


Table 2.-Summary statistics for trophic state, aquatic macrophyte, lake morphology,
rameters estimated in 33 Florida lakes.


and bird population pa-


STANDARD
PARAMETERS MEAN RANGE DEVIATION
TROPHIC STATE:
Total phosphorus (Rg/L) 72 1-1040 189
Total nitrogen (ing/L) 1100 100-4900 1100
Total chlorophyll a (pg/L) 36 0.7-240 57
Secchi depth (m) 2.0 0.3-5.7 1.6
Specific conductance (pIS/cm2 25oC) 138 29-384 99
Total alkalinity (mg/L as CaCO3) 28 0-105 30
AQUATIC MACROPHYTES:
Percent volume infested with macrophytes 21 0-98 33
Percent area covered with macrophytes 36 0-100 42
Emergent biomass (kg wet wt/m2) 6.6 0.9-26.8 5.1
Floating leaf biomass (kg wet wt/m2) 2.0 0-11.2 2.8
Submergent biomass (kg wet wt/m2) 2.8 0-16.6 3.9
LAKE MORPHOLOGY:
Lake surface area (km2) 0.796 0.032-2.710 0.666
Shoreline length (km) 3.6 0.7-8.4 2.0
Mean depth (m) 2.8 0.9-5.9 1.2
Shoreline development 1.3 1-2.4 0.4
Distance to nearest lake (km) 0.4 0.2-1.5 0.3
Number of lakes within 5 km 27 3-53 13
BIRD POPULATION:
Bird abundance (number/km2)
Winter 250 0-1300 321
Spring 130 0-840 168
Summer 120 0-650 131
Annual Average 170 7-750 180
Species richness (species/lake)
Winter 11.2 1-25 7.8
Spring 9.7 0-20 6.3
Summer 9.8 1-20 6.1
Annual Total 16.8 2-30 9.4






M. V HOYER and D. CANFIELD, JR.


and others occurring on as many as 26 lakes (Table
3). Thirty-two species occurred on more than 20 per-
cent of the lakes sampled (Table 4). Seasonal bird
abundance and species richness were greatest in the
winter averaging 250 birds/knm and 11 species per
lake (Table 2), which is expected due to the
migratory bird populations utilizing Florida lakes
during that season. Eight of the 32 species occurring
on at least 20 percent of the lakes sampled could be
grouped as strong winter migrants (i.e., birds occur-
ring on significantly more lakes in the winter than
spring or summer, Table 4). Additionally, an un-
known percentage of winter bird abundances are
probably from birds grouped as migrant residents
(i.e., birds occurring on equal number of lakes in all


seasons, Table 4) supplementing resident popula-
tions during winter months.
The correlations between seasonal bird popula-
tion parameters and trophic state, aquatic macro-
phyte, or lake morphology parameters are similar
for all seasons (Table 5). Therefore, the remainder of
analyses were done using average annual bird abun-
dance and total species richness. Average annual
bird abundance and total species richness for these
lakes ranged seven to 750 birds/km2 and two to 30
species per lake, respectively (Tables 1 and 2). Both
average annual bird abundance and total species
richness were significantly correlated with total
phosphorus (r =0.63 and r=0.69, respectively), total
chlorophyll a (r=0.68 and r=0.73, respectively), and


Table 3.-List of bird species Identified and counted on 33 Florida lakes between November 1988 and September
1989. N is the number of lakes on which a bird was observed and the average abundance of a given bird species
is listed with the standard error of the mean (STDERR).
COMMON NAME SCIENTIFIC NAME N BIRDS/km2 STDERR


I Pied-billed Grebe
I American White Pelican
3 Double-crested Cormorant
4 Anhinga
S Least Bittern
6 Great Blue Heron
- Great Egret
V Snowy Egret
Little Blue Heron
IOTricolored\Heron
II Cattle Egret
it Green-backed Heron
13 Black-crowned Night-heron
i4White Ibis
J Glossy Ibis
I Wood Stork
I) Canada Goose
I gFulvous Whistling Duck
Iq Wood Duck
)o Mottled Duck
a Mallard
a 4 Blue-winged Teal
2 3 Ring-necked Duck
. 4 Black Vulture
SSTurkey Vulture
2( Osprey
*A Bald Eagle
a gNorthern Harrier
A I Red-shouldered Hawk
3* Red-tailed Hawk
' I American Kestrel
3 Sora
3) Purple Gallinule
SY Common Moorhen
3 S American Coot
) 6 Limpkin
3 Sandhill Crane
3~ Semipalmated Plover
) Killdeer
&t Lesser Yellowlegs
4f Common Snipe
.L(Gulls (Larinae)
13Terns (Sterninae)
'(Belted Kingfisher
I'Purple Martin
* '/Tree Swallow
1/ Bank Swallow
SrCCrows (Corvidae)
. Red-winged Blackbird
O Boat-tailed Grackle


Podilymbus podiceps
Pelecanus erythrorhynchos
Phalacrocorax auritus
Anhinga anhinga
Ixobrychus exillis
Ardea herodias
Casmerodius albus
Egretta thula
Egretta caerulea
Egretta tricolor
Bubulcus ibis
Butorides striatus
Nycticorax nycticorax
Eudocimus albus
Plegadis falcinellus
Mycteria americana
Branta canadensis
Dendrocygna bicolor
Aix sponsa
Anas fulvigula
Anas platyrhynchos
Anas discors
Aythya collaris
Coragyps atratus
Cathartes aura
Pandion haliaetus
Haliaeetus leucocephalus
Circus cyaneus
Buteo lineatus
Buteo jamaicensis
Falco sparverius
Porzana carolina
Porphyrula martinica
Gallinula chloropus
Fulica americana
Aramus guarauna
Grus canadensis
Charadrius semipalmatus
Charadrius vociferus
Tringa flavipes
Gallinago gallinago


Ceryle alcyon 25.0 3.0 0.8
Progne subis 11.0 14.3 12.5
Tachycineta bicolor 1.0 15.2 0.0
Riparia riparia 1.0 1.3 0.0
26.0 20.0 11.6
Agelaius phoeniceus 22.0 18.2 5.0
Quiscalus major 21.0 48.0 9.4





LAKE AND RESERVOIR MANAGEMENT, 1990 6(2): 133-141


Table 4.-List of bird species identified and counted on at least 20% of the Florida Lakes (n = 33) sampled, with
the number of lakes on which a bird was observed in winter (November 1, 1988 to February 28, 1989), spring
(March 29, 1989 to May 24, 1989) and summer (July 25, 1989 to September 29, 1989) listed.
COMMON NAME SCIENTIFIC NAME WINTER SPRING SUMMER
Migrant-Resident:
Anhinga Anhinga anhinga 19 17 20
Great Blue Heron Ardea herodias 21 22 22
Great Egret Casmerodius albus 22 17 23
Snowy Egret Egretta thula 12 7 16
Little Blue Heron Egretta caerulea 13 9 12
Tricolored Heron Egretta tricolor 12 4 12
White Ibis Eudocimus albus 11 9 9
Wood Duck Aix sponsa 3 8 8
Mallard Anas platyrhynchos 8 8 10
Black Vulture Coragyps atratus 8 6 7
Turkey Vulture Cathartes aura 3 1 5
Osprey Pandion haliaetus 8 18 10
Northern Harrier Circus cyaneus 3 1 3
Purple Gallinule Porphyrula martinica 4 3 5
Common Moorhen Gallinula chloropus 17 18 18
Terns Laridae Sterninae 10 5 7
Crows Corvidae 15 24 17
Red-winged Blackbird Agelaius phoeniceus 13 20 16
Boat-tailed Grackle Quiscalus major 19 20 17
Winter Migrants:
Pied-billed Grebe Podilymbus podiceps 12 2 1
Ring-necked Duck Aythya collaris 7 1 1
Bald Eagle Haliaeetus leucocephalus 6 5 2
Red-shouldered Hawk Buteo lineatus 6 1 1
Double-crested Cormorant Phalacrocorax auritus 18 14 10
American Coot Fulica americana 14 6 3
Gulls Laridae 16 7 1
Belted Kingfisher Ceryle alcyon 23 4 13
Spring Migrants:
Semipalmated Plover Charadrius semipalmatus 0 7 0
Purple Martin Progne subis 0 9 3
Summer Users:
Least Bittem Ixobrychus exilis 0 6 5
Green-backed Heron Butorides striatus 7 16 17
Cattle Egret Bubulcus ibis 2 7 10


Secchi depth (r = -0.59 and r = -0.68, respectively) as ganic base upon which aquatic bird populations
well as other trophic state parameters (Table 5). depend. Total chlorophyll a alone accounts for a large
Average annual bird abundance and total species portion of the variance in total bird abundance (Fig-
richness were significantly correlated to lake surface ure 1). Chlorophyll a also relates to nutrient con-
area (r=0.48 and r=0.89, respectively) and shoreline centrations (Canfield, 1983), and already has been
length (r=0.55 and r=0.86, respectively), successfully used to model other vertebrate popula-
Regression equations are listed in Table 6 to allow tions in lakes (Oglesby, 1977; Jones and Hoyer,
estimates of average annual bird abundance on 1982). In certain situations nutrient concentrations
lakes with one of six different trophic state and Secchi depth measurements can result in
parameters. Linear regression analyses, however, misclassifications of lake trophic status. For ex-
showed that the best-fit regression equation was ample, inorganic suspended solids in Missouri reser-
with total chlorophyll a, which accounted for 47 per- voirs and Lake Okeechobee, Florida, have been
cent of the total variance in average annual bird shown to reduce algal biomass per unit of phos-
abundance (Table 6). Stepwise multiple regression phorus by causing light limitation (Hoyer and Jones,
analyses revealed that, after accounting for lake 1983; Canfield and Hoyer, 1988a).
trophic status (as estimated with chlorophyll a con- Eight linear regression equations presented in
centrations), no multivariate model using aquatic Table 6 indicate that all trophic state parameters
macrophyte or lake morphology parameters ac- and two lake morphology parameters individually
counted for significantly more variance in average accounted for over 45 percent of the variance in total
annual bird abundance. species richness. Lake area, however, accounted for
Where possible, we suggest using chlorophyll a the largest portion of the variance (R2 = 0 .80) in
rather than other trophic state parameters to es- total species richness (Table 6 and Fig. 2). Multi-
timate bird abundance on lakes because total variate regression analyses, with lake area as a
chlorophyll a seems a convenient estimator of the or- primary variable, showed that only the six trophic

137







M. V HOYER and D. CANFIELD, JR.


Table 5.-Correlation matrix for all parameters sampled on 33 Florida lakes (see methods for parameter units).
All absolute r values equal to or greater than 0.35 are significant at a p < 0.05 level.
VARIABLES X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17
Trophic state:
X1..Total phosphorus 1.00
X2..Total nitrogen 0.78 1.00
X3..Total chlorophyll a 0.91 0.85 1.00
X4..Secchi depth -0.88 -0.87 -0.91 1.00
X5..Specifc conductance 0.68 0.72 0.73 -0.63 1.00
X6..Total alkalinity 0.59 0.77 0.72 -0.66 0.63 1.00
Aquatic macrophytes:
X7..PVI -0.29 -0.08 -0.28 0.20 -0.28 0.01 1.00
X8..PAC -0.47 -0.22 -0.46 0.40 -0.32 -0.06 0.88 1.00
X9..Emergent biomass 0.20 0.00 0.13 -0.08 -0.08 0.00 0.14 0.15 1.00
X10..Floating biomass 0.08 0.16 0.12 -0.16 -0.12 0.18 0.47 0.42 0.25 1.00
X11..Submergent biomass -0.52 -0.42 -0.52 0.47 -0.42 -0.24 0.54 0.64 0.47 0.33 1.00
Lake morphology:
X12..Surface area 0.59 0.60 0.59 -0.60 0 0. 0. 0.3 0.02 -0.08 0.00 -0.03 -0.19 1.00
X13..Shoreline 0.54 0.52 0.55 -0.53 0.54 0.52 -0.01 -0.07 0.06 0.02 -0.15 0.91 1.00
X14..Mean depth -0.19 -0.32 -0.20 0.35 -0.08 -0.23 -0.50 -0.38 -0.09 -0.44 -0.03 -0.22 -0.20 1.00
X15..Shoreline development -0.11 -0.20 -0.09 0.16 -0.26 -0.26 -0.08 0.01 0.14 0.12 0.11 -0.24 0.20 0.04 1.00
X16..Distance to nearest lake 0.23 0.26 0.23 -0.26 0.30 0.22 0.09 -0.02 -0.24 0.05 -0.30 0.54 0.44 -0.31 -0.24 1.00
X17..Numberof lakeswithin 5km -0.35 -0.40 -0.33 0.37 -0.38 -0.21 -0.23 -0.16 0.07 -0.31 0.10 -0.46 -0.41 0.49 0.11 -0.57 1.00
Bird abundance:
Y1..Winter abundance 0.60 0.64 0.65 -0.54 0.51 0.71 -0.12 -0.24 0.16 0.00 -0.24 0.51 0.54 -0.12 0.07 0.25 -0.18
Y2..Spring abundance 0.50 0.62 0.59 -0.51 0.46 0.56 0.08 -0.02 0.05 0.20 -0.26 0.42 0.49 -0.30 0.15 0.12 -0.14
Y3..Summer abundance 0.54 0.49 0.55 -0.53 0.45 0.46 -0.11 -0.20 0.05 -0.05 -0.27 0.50 0.56 -0.03 0.12 0.32 -0.18
Y4..Annual abundance 0.63 0.66 0.68 -0.59 0.52 0.67 -0.04 -0.16 0.16 0.05 -0.26 0.48 0.55 -0.17 0.16 0.21 -0.16
Bird species richness:
Y5..Wlnter species 0.72 0.76 0.77 -0.68 0.77 0.76 -0.01 -0.15 0.02 0.02 -0.32 0.84 0.79 -0.23 -0.12 0.49 -0.44
Y6..Sprlng species 0.53 0.65 0.62 -0.56 0.56 0.56 0.05 -0.08 -0.02 0.20 -0.26 0.62 0.65 -0.27 0.07 0.30 -0.27
Y7..Summer species 0.68 0.69 0.67 -0.67 0.67 0.70 -0.10 -0.19 -0.05 -0.08 -0.32 0.90 0.85 -0.11 -0.15 0.47 -0.37
Y8..Total species 0.69 0.74 0.73 -0.68 0.70 0.76 -0.04 -0.14 0.02 0.07 -0.29 0.89 0.86 -0.24 -0.09 0.47 -0.40
Bird abundance: Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8
Y1..Winter abundance 1.00
Y2..Spring abundance 0.58 1.00
Y3..Summer abundance 0.68 0.45 1.00
Y4..Annual abundance 0.92 0.72 0.83 1.00
Bird species richness:
Y5..Winter species 0.79 0.67 0.67 0.79 1.00
Y6..Spring species 0.56 0.91 0.46 0.63 0.76 1.00
Y7..Summer species 0.70 0.54 0.75 0.72 0.89 0.65 1.00
Y8..Total species 0.72 0.71 0.66' 0.74 0.96 0.81 0.93 1.00


Table 6.-Regression models relating average annual bird abundance (birds/km2) and total species richness
(species/lake) to six trophic state parameters and multivariate regression models relating total species richness
to lake area and six trophic state parameters. All listed regressions are significant at p 0.05. Data were collected
from 33 Florida Lakes.
STANDARD ERROR
DEPENDENT VARIABLE MODEL OF ESTIMATE R2
average annual bird
Abundance (birds/km2):
= 1.23 + 0.54 Log (total phosphorus) 0.47 0.39
= -0.64 + 0.90 Log (total nitrogen) 0.46 0.44
= 1.35 + 0.56 Log (total chlorophyll a) 0.44 0.47
= 2.09 0.94 Log (Secchi depth) 0.48 0.34
= 0.09 + 0.91 Log (specific conductance) 0.51 0.27
= 1.70 + 0.29 Log (total alkalinity) 0.44 0.44
Total Species
Richness (species/lake):
= 0.61 + 0.40 Log (total phosphorus) 0.29 0.47
= -0.74 + 0.65 Log (total nitrogen) 0.27 0.53
= 0.71 + 0.39 Log (total chlorophyll a) 0.27 0.53
= 1.24 0.72 Log (Secchi depth) 0.29 0.46
= -0.52 + 0.81 Log (specific conductance) 0.28 0.49
= 0.94 + 0.22 Log (total alkalinity) 0.26 0.57
= 1.31 + 0.59 Log (lake area) 0.17 0.80
= 0.55 + 1.17 Log (lake shoreline) 0.20 0.75
Total Species
Richness (species/lake):
= 1.10 + 0.49 Log (lake area) + 0.14 Log (total phosphorus) 0.16 0.84
= -0.49 + 0.47 Log (lake area) + 0.27 Log (total nitrogen) 0.15 0.86
= 1.10 + 0.47 Log (lake area) + 0.17 Log (total chlorophyll a) 0.15 0.87
= 1.32 + 0.50 Log (lake area) 0.23 Log (Secchi depth) 0.16 0.83
= 0.83 + 0.51 Log (lake area) + 0.22 Log (specific conductance) 0.17 0.83
= 1.20 + 0.46 Log (lake area) + 0.09 Log (total alkalinity) 0.15 0.86









100
*3 r=0.89
.X n=33
SLog(Y)=1.31+0.59Log(X)

.I L



o
co



.01 1




Lake Area (sq km)

Figure I.-Relation between average annual bird abundance
(birds/kmrn and total chlorophyll a (Vg/L) for 33 Florida lakes.


state parameters accounted for significantly more
variance in total species abundance (Table 6) than
lake area alone. The following best-fit multiple
linear regression indicated that lake area and total
chlorophyll a accounted for 87 percent of the
variance in species richness:
Log Spees Richness 1.10 + 0.47 Log Lake Area









+ 0.17 Log Total Chlo1phyll a

Similar species-area relations have been reported
for many flora and fauna (Flessa and Sep33 Fl oski,
1978; Connor and McCoy, 1979). Williamson (1988)
suggested that there are several possible explanaignificantly more
tions for species area relations: (1) an increase in
area may simply increase. The followingampling size, resultple
ing in more species; (2) an increase in area may cortal
relate with an increase in habitat heterogeneity; and
(3) MacArthur and Wilson, theory of island biogeogArea
raphy may be a factor (see MacArthur and Wilson,
1967).
We found that as lake size in our study lakes in-
creased so did the sampling area and the near shore
terrestrial and aquatic habitat heterogeneity (per-
sonal observation). No effect related to the Mac-
Arthur-Wilson theory of island biogeography was
found (see later discussion), but the relative impor-
tance of each mechanism discussed by Williamson
(1988) may differ under different ecological condire
tions. Separating the mechanisms that determine
species-area relations, however, is beyond the scope
ofthur-Wilson paper.
The direct relation between total chlorophyll a
and species richness supports the suggestion of
several investigators (Hutchinson, 1959; MacArthur
1970; Wright, 1983) that more productive systems


LAKE AND RESERVOIR MANAGEMENT, 1990 6(2): 133-141


1000

0 0
E goo
E 0 0
*0

E *
-S-




r=0.68
m n=33
Log(Y)=1.35+0.56 Log(X)


1 1 0


100 1000


Chlorophyll a (gg/L)

Figure 2.-Relation between total species richness
(species/ake) and lake area (ki2) for 33 Florida lakes.


can support more specialized species, thus yielding
greater species richness. Relations between species
richness and trophic state parameters also have
been reported for vascular plants, snails, fish and
birds in marsh, pond, and lake systems (Nilsson and
Nilsson, 1978; Murphy et al. 1984; Brown and
Dinsmore, 1986). However, Nilsson and Nilsson
(1978) suggest that lakes suffering from cultural
eutrophication will have fewer species than lakes of
equal size and natural trophic status.
Two lakes in our data set (Lake Rowell, Bradford
County, and Lake Conine, Polk County, Table 1) cur-
rently receive point source nutrient enrichment and
can be considered culturally eutrophic. Using lake
area and total chlorophyll a concentrations for these
two lakes and the corresponding equation in Table 6,
the number of species that would be predicted in
each lake was calculated and compared to the ob-
served number of species. At Lake Rowell and Lake
Conine, the observed number of species (27 and 24,
respectively) was similar to the predicted number of
species (22 and 29, respectively). This suggests that
lakes suffering from cultural eutrophication can
have bird species richness that equals the richness of
lakes of equal trophic status and size that have not
received anthropogenic additions of nutrients.
Birds use aquatic macrophytes for nesting, rest-
ing, and refuge sites. Macrophytes are also food for
birds, and the plants provide substrate for inver-
tebrate food items (Odum et al. 1984). However, mul-
tivariate regression analyses indicated that no
aquatic macrophyte parameters related significantly
to average annual bird abundance or total species
richness in the Florida lakes after the effects of
trophic state and lake area were accounted for. This
is surprising considering the reported association be-





M. V HOYBR and D. B. CANFIELD, JR.


tween aquatic birds and aquatic macrophytes, but
our aquatic macrophyte data are extremely general
and may not be suited to examining the relation-
ships between aquatic macrophytes and bird popula-
tions. Individual bird species require different types
and quantities of aquatic macrophytes (Weller and
Spatcher, 1965; Weller and Fredrickson, 1974). For
example, of the seven lakes on which ring-neck
ducks (Aythya collaris) were observed, six main-
tained extensive mats of hydrilla (Hydrilla verticil-
lata), indicating a possible relation between ring-
necked ducks and hydrilla. This relation has also
been observed by other researchers in Florida (Gas-
saway et al. 1977; Johnson and Montalbano, 1984).
Lake morphology parameters, except for lake
area, were also expected to affect annual bird abun-
dance and total species richness. Previous studies
(Nilsson and Nilsson, 1978; Murphy et al. 1984) have
linked mean depth, shoreline development, and lake
isolation parameters with bird population abun-
dance and species richness.
After accounting for trophic status and lake area,
no lake morphology parameters related significantly
to annual bird abundance or total species richness,
but there were significant correlations between two
lake isolation parameters (distance to the nearest
lake, r = 0.47 and number of lakes within a 5 km
radius, r = -0.40) and total species richness (Table 5).
Similar isolation parameters have also been shown
significantly related to species richness in other
aquatic systems ( Murphy et al. 1984; Brown and
Dinsmore, 1986). However, according to island
biogeography theory (MacArthur and Wilson, 1967),
as the distance to another lake increases the number
of species present should decrease, and as the num-
ber of lakes within a 5 km radius increases the num-
ber of species present should increase, which is the
exact opposite of what we observed. Therefore, we
believe our correlations are spurious. Nilsson and
Nilsson (1978) also found no relationship between
isolation parameters and species richness in areas
where lakes are relatively close and abundant. This
is the case for our Florida lakes, which have an
average distance to the nearest lake of 0.4 km and an
average number of lakes within 5 km of 27 (Table 2).
Another explanation for our observed lack of rela-
tions between bird populations and both aquatic
macrophyte and lake morphology parameters may
be that the majority of birds were counted near
shoreline areas in shallow littoral zones. This sug-
gests that many aquatic birds may be limited to
shoreline areas where water is shallow and food for
birds may be concentrated. Nearshore areas may
also be where preferred aquatic and terrestrial
vegetation is found. Thus, whole lake parameters
(e.g., percentage area covered with macrophytes and
lake mean depth) may show no relation to bird
populations simply because many birds are limited
to shoreline areas.


Management Considerations

Because aquatic bird populations are influenced by
several limnological factors, any lake management
program could affect the birds that use lakes. For
many lakes, eutrophication control is a major
management objective. Current lake management
strategies for Florida lakes include attempts to
reduce nutrient concentrations through lake draw-
downs, alum treatments, and nutrient diversions
(Canfield and Hoyer, 1988a; Dierberg et al. 1988).
The positive relationships between average annual
bird abundance or total species richness and lake
trophic status presented in this paper suggest that
successful eutrophication control programs may
reduce bird abundance and species richness. Be-
cause other researchers have made similar findings,
it is now recognized that eutrophication abatement
programs should be planned with full consideration
of the potential trade-off between cleaner water and
reduced fish populations (Yurk and Ney, 1989).
Nuisance growths of aquatic macrophytes are
common in many of the world's lakes. Mechanical
harvesting, chemical treatments, and biological con-
trol of aquatic macrophytes are major lake manage-
ment strategies used in Florida lakes (Shireman et
al. 1983). The effect of aquatic vegetation manage-
ment programs on bird populations, however, is not
clear. Many studies suggested strong relationships
between aquatic vegetation and bird populations
(Weller and Spatcher, 1965; Weller and Fredrickson,
1974; Johnson and Montalbano, 1984), but data
presented in this study indicate that removal of
aquatic vegetation in lakes may have no effect on
total bird abundance or species richness. However,
we believe that the relations between aquatic macro-
phyte and bird populations may be species-specific
and confined to shoreline areas where water depths
are shallow and food for birds may be concentrated
and easily available. Reductions from 80 to 100 per-
cent coverage of aquatic macrophytes (a common oc-
currence in Florida lakes) toward 40 percent
coverage, which is a common target level for
fisheries management (Wiley et al. 1984), should not
affect average annual bird abundance or total
species richness. We also believe that near shore ter-
restrial vegetation may be very important to bird
populations using lakes because most of the birds we
observed were near shoreline areas. Thus, future
studies of bird populations using lakes should not
only investigate species-specific relations between
birds and aquatic macrophytes but also determine
the importance of terrestrial vegetation near lakes to
bird populations because this vegetation is often
cleared by property owners to observe a lake.









ACKNOWLEDGMENTS Journal Series No. R-
00610 of the Florida Agricultural Experiment Station. We
thank Fritz Reid for several reviews of this manuscript and
his numerous constructive comments. Christy Horsburgh
and Mark Jennings were instrumental in collection of data
and conducting bird counts. We thank Mary Rutter for con-
ducting chemical analyses. This research was funded in
part by Bureau of Aquatic Plant Management (Contract
number C 3748), Florida Department of Natural Resour-
ces.


KEYWORDS Florida; bird populations; lakes; water
quality.



References

Brown, M. and J. J. Dinsmore. 1986. Implications of marsh size
and isolation for marsh bird management. J. Wildl. Manage.
50:392-97.
Canfield, D. E. Jr. 1983. Prediction of chlorophyll a concentra-
tions in Florida lakes: The importance of phosphorus and
nitrogen. Water Resour. Bull. 19: 255-62.
Canfield, D. E. Jr. and M. V. Hoyer. 1988a. The eutrophication of
Lake Okeechobee. Lake ReservoirManage. 4:91-9.
- 1988b. Regional geology and the chemical and trophic
state characteristics of Florida, lakes. Lake Reservoir
Manage. 4:21-31.
Connor, E. F. and E. D. McCoy. 1979. The statistics of the species
area relationships. Am. Nat. 113: 791-833.
Dierberg, F. E., V. P. Williams, and W. H. Schneider. 1988.
Evaluating water quality effects of lake management in
Florida. Lake Reservoir Manage. 4: 101-12.
Flessa, K. W. andJ. J. Sepkoski Jr. 1978. On the relationship be-
tween phanerozoic diversity and changes in habitat area.
Paleobiology 4:359-66.
Forsberg, C. and S. R. Ryding. 1980. Eutrophication
parameters and trophic state indices in 30 Swedish waste
receivinglakes. Arch. Hydrobiol. 89:189-207.
Gasaway, R. D. and T. F. Drda. 1977. The effects of grass carp on
waterfowl habitat. Trans. N. Am. Wildl. Nat. Resour. Conf.
42:73-85.
Gasaway, R. D., S. Hardin, and J. Howard. 1977. Factors: in-
fluencing wintering waterfowl abundance in Lake Wales,
Florida. Proc. Annual Conf. S. E. Assoc. Fish Wildl. Agencies
31:77-83.
Hoyer, M. V. andJ. R. Jones. 1983. Factors affecting the relation
between phosphorus and chlorophyll a in midwester reser-
voirs. Can. J. Fish. Aquat. Sc. 40:192-99.
Hutchinson, G. E. 1959. Homage to Santa Rosalia, or Why are
there so many kinds of animals? Am. Nat. 93:137-45.
Jenni, D. A. 1969. Astudy of the ecology of four species of herons
during the breeding season at Lake Alice, Alachua County,
Florida. Ecol Monogr. 39:245-70.
Johnson, F. A. and F. Montalbano. 1984. Selection of plant com-
munities by wintering waterfowl on Lake Okeechobee, Fla.
J. Wildl. Manage. 48:174-78.
Jones, J. R. and M. V. Hoyer. 1982. Sportfish harvest predicted:
by summer chlorophyll a concentrations in midwest lakes;
and reservoir. Trans. Am. Fish. Soc. 111: 176-9.
MacArthur, R. 1970. Species packing and competitive equi-
librium for many species. Theor. Popul. Biol. 1:1-11.
MacArthur, R. and E. O. Wilson. 1967. The theory of island
biogeography. Princeton Univ. Press., NJ.


LAKE AND RESERVOIR MANAGEMENT, 1990 6(2): 133-141


Maceina, M. J. andJ. V. Shireman. 1980. The use ofa recording
fathometer for determination of distribution and biomass of
hydrilla. J.Aquat. Plant Manage. 18:34-9.
Menzel, D. W. and N. Corwin. 1965. The measurement of total
phosphorus in sea waterbased on the liberation oforganical-
lybound fractions by persulfate oxidation. Limno. Oceanogr.
10:280-82.
Montalbano, F., S. Hardin, andW. M. Hetrick. 1979. Utilization
of hydrilla by ducks and coots in central Florida. Proc. Ann.
Conf. S. E. Assoc. Fish Wildl. Agencies 33:36-42.
Murphy, S. M., B. Kessel, and L. J. Vining. 1984. Waterfowl
populations and limnologic characteristics of taiga ponds. J.
Wildl. Manage. 48:1156-63.
Murphy, J. and J. P. Riley. 1962. A modified single solution
method for the determination of phosphate in natural
waters. Anal. Chim. Acta. 21:31-36.
Nelson, W. and L. E. Sommers. 1975. Determination of total
nitrogen in natural waters. J. Environ. Qual. 4:465-68.
Nilsson, S. G. andI. N. Nilsson. 1978. Breedingbird community
densities and species richness in lakes. Oikos. 31:214-21.
Odum, W. E., T. J. Smith III, J. K. Hoover, and C. C. Mclvor.
1984. The ecology of tidal freshwater marshes of the United
States East Coast: a community profile. U.S. Fish Wildl.
Serv. FWS/OBS 83/17.
Oglesby, R. T. 1977. Relationships of fish yield to lake:
phytoplankton standing crop, production, and mor-
phoedaphic factors. J. Fish. Res. Board Can. 34:2271-79.
Parsons, T. R. and J. Strickland. 1963. Discussion of
spectrophotometric determination of marine plant pigments
with revised equations of ascertaining chlorophylls and
caratenoids. Mar. Res. 21:155-63.
Shafer, M. D., R. E. Dickinson, J. P. Heaney, and W. C. Huber.
1986. Gazetteer of Florida lakes. Water Research Program
Engineering and Industrial Experiment Station. Publ. No.
96. Univ. Florida, Gainesville and U.S. Geol. Survey,
Gainesville, FL.
Shireman, J. V., W. T. Haller, D. E. Colle, C. W Watkins, D. F.
Durant, and D. E. Canfield Jr. 1983. Ecological impact of in-
tegrated chemical and biological weed control. NTISPB 83-
264242. Gulf Breeze Lab., U.S. Environ. Prot. Agency.
Standard Methods for the Examination of Water and Was-
tewater. 1981. Am. Public Health Ass. 15th Ed. Washington
DC.
SYSTAT. 1987. The system for statistics. SYSTAT, Inc.
Evanston, IL.
Weller, M. W. and S. Spatcher. 1965. Role of habitat in the dis-
tribution and abundance of marsh birds. Iowa State Univ.
Spec. Rep. 43.
Weller, M. W and L. H. Fredrickson. 1974. Avian ecology of a
managed glacial marsh. Living Bird. 12:269-91.
Wetzel, R. G. 1975. Limnology. W. B. Saunders Co., Philadel-
phia, PA.
Wiley, M. J., R. W. Gorden, S. W. Waite, and T. Powless. 1984.
The relationship between aquatic macrophytes and sport
fish production in Illinois ponds: a simple model. N. Am. J.
Fish Manage. 4:111-19.
Williamson, M. 1988. Relationship of species number to area,
distance and other variables. Pages 91-115 in Chapman and
Hall, eds. Analytical Biogeography.
Wright, D.H. 1983. Species energy theory: an extension of
species-area theory. Oikos 41:496-506.
Yentsch, C. S. and D. W. Menzel. 1963. A method for the deter.
mination of phytoplankton chlorophyll and phaeophytin by
fluorescence. Deep Sea Res. 10:221-31.
Yurk, J. J. and J. J. Ney. 1989. Phosphorus fish community
biomass relationships in southern Appalachian reservoirs:
can lakes be to clean for fish? Lake Reservoir Manage. 5:83-
90.









ACKNOWLEDGMENTS Journal Series No. R-
00610 of the Florida Agricultural Experiment Station. We
thank Fritz Reid for several reviews of this manuscript and
his numerous constructive comments. Christy Horsburgh
and Mark Jennings were instrumental in collection of data
and conducting bird counts. We thank Mary Rutter for con-
ducting chemical analyses. This research was funded in
part by Bureau of Aquatic Plant Management (Contract
number C 3748), Florida Department of Natural Resour-
ces.


KEYWORDS Florida; bird populations; lakes; water
quality.



References

Brown, M. and J. J. Dinsmore. 1986. Implications of marsh size
and isolation for marsh bird management. J. Wildl. Manage.
50:392-97.
Canfield, D. E. Jr. 1983. Prediction of chlorophyll a concentra-
tions in Florida lakes: The importance of phosphorus and
nitrogen. Water Resour. Bull. 19: 255-62.
Canfield, D. E. Jr. and M. V. Hoyer. 1988a. The eutrophication of
Lake Okeechobee. Lake ReservoirManage. 4:91-9.
- 1988b. Regional geology and the chemical and trophic
state characteristics of Florida, lakes. Lake Reservoir
Manage. 4:21-31.
Connor, E. F. and E. D. McCoy. 1979. The statistics of the species
area relationships. Am. Nat. 113: 791-833.
Dierberg, F. E., V. P. Williams, and W. H. Schneider. 1988.
Evaluating water quality effects of lake management in
Florida. Lake Reservoir Manage. 4: 101-12.
Flessa, K. W. andJ. J. Sepkoski Jr. 1978. On the relationship be-
tween phanerozoic diversity and changes in habitat area.
Paleobiology 4:359-66.
Forsberg, C. and S. R. Ryding. 1980. Eutrophication
parameters and trophic state indices in 30 Swedish waste
receivinglakes. Arch. Hydrobiol. 89:189-207.
Gasaway, R. D. and T. F. Drda. 1977. The effects of grass carp on
waterfowl habitat. Trans. N. Am. Wildl. Nat. Resour. Conf.
42:73-85.
Gasaway, R. D., S. Hardin, and J. Howard. 1977. Factors: in-
fluencing wintering waterfowl abundance in Lake Wales,
Florida. Proc. Annual Conf. S. E. Assoc. Fish Wildl. Agencies
31:77-83.
Hoyer, M. V. andJ. R. Jones. 1983. Factors affecting the relation
between phosphorus and chlorophyll a in midwester reser-
voirs. Can. J. Fish. Aquat. Sc. 40:192-99.
Hutchinson, G. E. 1959. Homage to Santa Rosalia, or Why are
there so many kinds of animals? Am. Nat. 93:137-45.
Jenni, D. A. 1969. Astudy of the ecology of four species of herons
during the breeding season at Lake Alice, Alachua County,
Florida. Ecol Monogr. 39:245-70.
Johnson, F. A. and F. Montalbano. 1984. Selection of plant com-
munities by wintering waterfowl on Lake Okeechobee, Fla.
J. Wildl. Manage. 48:174-78.
Jones, J. R. and M. V. Hoyer. 1982. Sportfish harvest predicted:
by summer chlorophyll a concentrations in midwest lakes;
and reservoir. Trans. Am. Fish. Soc. 111: 176-9.
MacArthur, R. 1970. Species packing and competitive equi-
librium for many species. Theor. Popul. Biol. 1:1-11.
MacArthur, R. and E. O. Wilson. 1967. The theory of island
biogeography. Princeton Univ. Press., NJ.


LAKE AND RESERVOIR MANAGEMENT, 1990 6(2): 133-141


Maceina, M. J. andJ. V. Shireman. 1980. The use ofa recording
fathometer for determination of distribution and biomass of
hydrilla. J.Aquat. Plant Manage. 18:34-9.
Menzel, D. W. and N. Corwin. 1965. The measurement of total
phosphorus in sea waterbased on the liberation oforganical-
lybound fractions by persulfate oxidation. Limno. Oceanogr.
10:280-82.
Montalbano, F., S. Hardin, andW. M. Hetrick. 1979. Utilization
of hydrilla by ducks and coots in central Florida. Proc. Ann.
Conf. S. E. Assoc. Fish Wildl. Agencies 33:36-42.
Murphy, S. M., B. Kessel, and L. J. Vining. 1984. Waterfowl
populations and limnologic characteristics of taiga ponds. J.
Wildl. Manage. 48:1156-63.
Murphy, J. and J. P. Riley. 1962. A modified single solution
method for the determination of phosphate in natural
waters. Anal. Chim. Acta. 21:31-36.
Nelson, W. and L. E. Sommers. 1975. Determination of total
nitrogen in natural waters. J. Environ. Qual. 4:465-68.
Nilsson, S. G. andI. N. Nilsson. 1978. Breedingbird community
densities and species richness in lakes. Oikos. 31:214-21.
Odum, W. E., T. J. Smith III, J. K. Hoover, and C. C. Mclvor.
1984. The ecology of tidal freshwater marshes of the United
States East Coast: a community profile. U.S. Fish Wildl.
Serv. FWS/OBS 83/17.
Oglesby, R. T. 1977. Relationships of fish yield to lake:
phytoplankton standing crop, production, and mor-
phoedaphic factors. J. Fish. Res. Board Can. 34:2271-79.
Parsons, T. R. and J. Strickland. 1963. Discussion of
spectrophotometric determination of marine plant pigments
with revised equations of ascertaining chlorophylls and
caratenoids. Mar. Res. 21:155-63.
Shafer, M. D., R. E. Dickinson, J. P. Heaney, and W. C. Huber.
1986. Gazetteer of Florida lakes. Water Research Program
Engineering and Industrial Experiment Station. Publ. No.
96. Univ. Florida, Gainesville and U.S. Geol. Survey,
Gainesville, FL.
Shireman, J. V., W. T. Haller, D. E. Colle, C. W Watkins, D. F.
Durant, and D. E. Canfield Jr. 1983. Ecological impact of in-
tegrated chemical and biological weed control. NTISPB 83-
264242. Gulf Breeze Lab., U.S. Environ. Prot. Agency.
Standard Methods for the Examination of Water and Was-
tewater. 1981. Am. Public Health Ass. 15th Ed. Washington
DC.
SYSTAT. 1987. The system for statistics. SYSTAT, Inc.
Evanston, IL.
Weller, M. W. and S. Spatcher. 1965. Role of habitat in the dis-
tribution and abundance of marsh birds. Iowa State Univ.
Spec. Rep. 43.
Weller, M. W and L. H. Fredrickson. 1974. Avian ecology of a
managed glacial marsh. Living Bird. 12:269-91.
Wetzel, R. G. 1975. Limnology. W. B. Saunders Co., Philadel-
phia, PA.
Wiley, M. J., R. W. Gorden, S. W. Waite, and T. Powless. 1984.
The relationship between aquatic macrophytes and sport
fish production in Illinois ponds: a simple model. N. Am. J.
Fish Manage. 4:111-19.
Williamson, M. 1988. Relationship of species number to area,
distance and other variables. Pages 91-115 in Chapman and
Hall, eds. Analytical Biogeography.
Wright, D.H. 1983. Species energy theory: an extension of
species-area theory. Oikos 41:496-506.
Yentsch, C. S. and D. W. Menzel. 1963. A method for the deter.
mination of phytoplankton chlorophyll and phaeophytin by
fluorescence. Deep Sea Res. 10:221-31.
Yurk, J. J. and J. J. Ney. 1989. Phosphorus fish community
biomass relationships in southern Appalachian reservoirs:
can lakes be to clean for fish? Lake Reservoir Manage. 5:83-
90.




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