ECOLOGY OF BENTHIC MACROINVERTEBRATES IN EXPERIMENTAL PONDS
by
Van D. Christman
Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of
DOCTOR OF PHILOSOPHY
in
Entomology
APPROVED: Okbehlh LER Voshell, Jr., Ch rman [ik MSE LoL. ~ AL Buikema, Jy. RL. Pienkowski
Sd. Weshe D0 Oder
L. A. Helfrich D.G. Cochran
September 1991
Blacksburg, Virginia Zw 5655V8 5 1IG/ CE ECOLOGY OF BENTHIC MACROINVERTEBRATES IN EXPERIMENTAL PONDS
by
Van D. Christman
Committee Chairman: J. Reese Voshell, Jr. Entomology
( ABSTRACT)
I studied life history parameters of 5 taxa of aquatic insects in the orders Ephemeroptera and Odonata, successional patterns over 2 years of pond development, and precision of 15 biological metrics ina series of 6 replicate experimental ponds from March 1989 to April 1990. I determined voltinism, emergence patterns, larval growth rates and annual production for Caenis amica (Ephemeroptera: Caenidae), Callibaetis floridanus (Ephemeroptera: Baetidae), Anax junius (Odonata:
Aeshnidae), Gomphus exilis (Odonata: Gomphidae), and Enallagma civile
(Odonata: Coenagrionidae). Growth rates ranged from 0.011 to 0.025 mg
DW/d for Ephemeroptera and from 0.012 to 0.061 mg DW/d for Odonata.
Annual production ranged from 5 to 11 mg DW/sampler/yr for Ephemeroptera and from 10 to 673 mg DW/sampler/yr for Odonata.
Comparison of the benthic macroinvertebrate community at the end of year 1 to the benthic macroinvertebrate community at the end of year
2 showed no significant differences for community summary measures
(total density, taxa richness, diversity, Bray-Curtis similarity index); however, some individual taxa densities were significantly lower at the end of year 2. Physicochemical parameters measured indicated that the ponds were oligotrophic. Submerged macrophytes colonized and became established in most of the ponds during year 2. A few noninsect taxa were not present in expected numbers, probably due to lack of efficient dispersal mechanisms.
Fifteen metrics were analyzed by a statistical procedure that indicates the percent change that must occur (detection limit) to detect true differences between two means. The metrics with the lowest detection limits (usually < 20%) were taxa richness, EOT index (number of taxa in the orders Ephemeroptera, Odonata, and Trichoptera), proportion of Chironominae/Orthocladiinae, and proportion of collector- gatherers. Detection limits of < 20% on all dates were also obtained for taxa richness and EOT index metrics when analyzed using dip net samples. Density metrics only allowed detection limits of about 50% on most dates.
This study provided needed information on the life history of taxa important in shallow, lentic ecosystems, ecological succession in newly created ponds, and statistically sound and ecologically meaningful metrics. This study also provides a valuable baseline for impact assessment work in experimental ponds. ACKNOWLEDGMENTS
I would like to express my sincere thanks to Dr. J. Reese Voshell,
Jr. for his assistance throughout this project. His advise and assistance helped me to keep things in perspective as I worked on many different projects. His friendship during my stay at Virginia Tech is greatly appreciated.
I am also grateful for the assistance of those associated with the experimental pond project. Raymond J. Layton offered assistance and encouragement both in the laboratory and in the field and provided a wealth of information from the first year of the ponds existence. Ray also offered a listening ear and helpful advise as I battled with the almost never ending modifications and adjustments. Michael 0. West and
Lourdes M George spent long tedious hours in sorting most of the pond samples and without their help this project would not have been possible. Stephen W. Hiner helped in field sampling and laboratory support. Dr. James L. Tramel, Jr. and W. B. Wilkinson, III did most on- site administration and management of the experimental pond facility.
My committee, J.R. Voshell, Jr., AL. Buikema, Jr., D.G. Cochran,
L.A. Helfrich, and R.L. Pienkowski were very helpful throughout this research. I thank them for their patience and encouragement. I also thank them for offering their knowledge freely and sometimes at inconvenient times.
This research was partially supported by the Virginia Agricultural
Experiment Station, Hatch Program
iv The greatest support for this project, however, came from my family. My wife, my children (Jason and Ana Marie) and both sets of parents gave unlimited support and encouragement throughout this project. It is to my family and especially to my wife, Ellie, that I owe the greatest thanks for helping me to survive and complete this project. TABLE OF CONTENTS
Page
List of Tables e e e » e ° ° s ° c ° « ° e e ® ® e e e List of Figures ...... +4.6+ +408. VIIL
INTRODUCTION . . © 2 2 6 © 2 © © © © © we ow ww ww
LITERATURE REVIEW . . oe ee ew we ew LIFE HISTORY PARAMETERS ee o 8 LIFE HISTORY OF SELECTED EPHEMEROPTERA ee we ow LIFE HISTORY OF SELECTED ODONATA...... ECOLOGICAL SUCCESSION IN NEW PONDS ...... BIOLOGICAL ENDPOINTS FOR EXPERIMENTAL POND STUDIES... . « 6
STUDY SITE . . . « «© «© © © «© © © «@
METHODS DATA° COLLECTION e s ....e s ° 0.0.... e ° e a eee DATA ANALYSIS ...... 200 08 QUALITY ASSURANCE ...... MANUSCRIPT I: LIFE HISTORY, GROWTH, AND PRODUCTION OF EPHEMEROPTERA IN EXPERIMENTAL PONDS . INTRODUCTION. .. 1... ee eee METHODS .....2.2. ee eee RESULTS 2...ee ee ee ees DISCUSSION. . tee eee
MANUSCRIPT II: LIFE HISTORY, GROWTH, AND PRODUCTION OF ODONATA IN EXPERIMENTAL PONDS...... INTRODUCTION... . eens METHODSRESULTS .» e . e e es e es Dee e e e e a een °. e a DISCUSSION .
MANUSCRIPT III: SUCCESSIONAL CHANGES IN THE BENTHIC MACROINVERTEBRATES OF NEW EXPERIMENTAL PONDS . . . INTRODUCTION...... er er oe METHODS . . «2 6 © © © © © © wo we oe ew ew tw ww RESULTS . . «© 2 2 2 © © © © we ew we ow DISCUSSION . o 8 ee oo.
MANUSCRIPT IV: EVALUATION OF BIOMETRICS FOR BENTHIC MACROINVERTEBRATES IN EXPERIMENTAL PONDS ...... INTRODUCTION . . «© «© 2 © © © © © © © © @ we ew METHODS . «© «© © © © © © © © © © we we wo we wo ww RESULTS . . «© «© 2 © © © © © © we ew ew ew ew we es DISCUSSION . . . «© © «© «© © © © @ we ew ew we we
CONCLUSIONS . . 2. © «© «6 © 2 © © «© oe we we ew we ww 124
LITERATURE CITED. . . 2. «© «© © © © © © ww ew we ww 128
APPENDIX . 2. « «© © © © «© © © © © ee oe we te ee we 141
VITA . 2 2 ee 6 © © we ee we ww wh we wh wt wl 217
vi LIST OF TABLES
MANUSCRIPT I
l. Summary of production parameters for Ephemeroptera .
2. Ranges for environmental characteristics measured in the ponds
MANUSCRIPT II.
l. List of Odonata taxa collected . 67
2. Summary of production parameters for Odonata . 78
3. Ranges for environmental characteristics measured in the ponds 83
MANUSCRIPT III.
l. Annual mean and range of taxa collected during year 1
and year 2... » 98
Statistical analysis of community measures between year 1 and year 2 100
Bray-Curtis similarity matrices ° 101
Ranges for environmental characteristics measured in the ponds 103
vii LIST OF FIGURES
INTRODUCTION - METHODS
1. Experimental pond facility, diagram .... Artificial substrate sampler ...... Deployment of artificial substrate sampler . Retrieval of artificial substrate sampler .
MANUSCRIPT I. l. Ephemeroptera head width/ body weight regression 51
2. Mean density of Caenis and Callibaetis ..... 53
3. Size frequency of Caenis amica...... e 55 4. Size frequency of Callibaetis floridanus . 58 5. Pond temperature, March 25, 1989-April 5, 1990 60
MANUSCRIPT II.
l. Odonata head width/ body weight regression . e 72
2. Mean density of Anax, Gomphus, and Enallagma « 75 3. Size frequency of Anax junius ...... 76 4. Size frequency of Gomphus exilis ...... 79
5. Size frequency of Enallagma civile..... 81 6. Pond temperature, March 25, 1989-April 5, 1990 84
MANUSCRIPT III.
l. Mean density, taxa richness, and diversity (2 years) 95
2. Community composition: Orders and functional groups 96 3. Pond temperature, March 1, 1988-March 1, 1990 104
MANUSCRIPT IV.
l. Detection limits: taxa richness, proportion of abundance 117 2. Detection limits: densities ...... e«.-. 119 3. Detection limits: metrics analyzed from dip net samples 121
viii INTRODUCTION
Mesocosms have been defined as outdoor, experimental ecosystems that simulate a natural ecosystem, or a part of one, and are small enough to be replicated (Voshell 1989). Mesocosms are not natural ecosystems but are models of these systems and usually contain self- sustaining portions of natural ecosystems (Buikema and Voshell 1991).
Experimental ponds have been used previously to determine the impact of environmental perturbations on ecosystems, and recently, they have been recommended as the test systems to be used for the environmental studies required in pesticide registration testing (Touart 1988). Urban and
Cook (1986) indicated that the U.S. E..-ironmental Protection Agency
(EPA) was moving toward a fourth tier in the environmental testing of new pesticides, which was field testing in experimental ecosystems.
Field tests are now being required when laboratory tests of a pesticide show that it may pose unacceptable risks to the environment at expected environmental concentrations (Touart 1988). Replicated experimental ponds are being used as the test systems for many of these pesticide registration tests. Because benthic macroinvertebrates (mostly aquatic insects) are important components of aquatic ecosystems, they are one of the biological components emphasized in these field tests. Although benthic macroinvertebrates have been studied extensively, there is still critical information lacking in our knowledge about the life history and ecology of many species, including many of the aquatic insects that inhabit experimental ponds. My research on benthic macroinvertebrates in experimental ponds had three objectives:
1) to determine life history parameters and secondary production of selected Ephemeroptera and Odonata from the experimental ponds;
2) to analyze successional changes that occur in the community during the second year after pond construction and;
3) to analyze various metrics and determine their usefulness as biological end points in mesocosm tests for pesticide registration.
Benthic macroinvertebrates have been used to determine the environmental impacts of pesticides, in many instances, without any attempt to understand the life histories of the taxa being studied
(Buikema and Benfield 1979). This has probably been a major cause of misinterpretation of information. The need for life history information is becoming increasingly important as field studies of environmental impacts increase. Almost no emphasis has been placed on determining the life history parameters of aquatic insects that may be involved in pesticide registration tests in experimental ponds (Touart 1988). I determined that certain species of Ephemeroptera and Odonata were ecologically important in experimental ponds and that specific life history information on them was lacking.
The EPA guidance document for conducting pesticide registration tests in experimental ponds suggests that newly constructed ponds should be allowed to colonize naturally for 1 year so that adequate benthic biota will develop (Touart 1988). An alternate suggestion is to line new ponds with sediment from an established pond and wait only 6 months.
If the natural colonization alternative is followed, one year may not be enough time to allow the complex interactions of an ecosystem to develop sufficiently (Odum 1969, Barnes 1983). In the experimental ponds that were available for my research, Layton and Voshell (1991) had investigated colonization by benthic macroinvertebrates during the first year after construction. This gave me the opportunity to study the successional changes that might occur during the second year after construction and to determine the possible implications of further successional changes for interpreting the results of pesticide registration tests.
The original intent of conducting environmental studies of pesticides in the field was to allow the presumption of adverse effects to be negated by complex ecological processes (Touart 1988). Metrics measured during field testing of a pesticide should provide information on the ecological processes that are important to the structure and function of the ecosystem and should have sufficient statistical precision for scientists to be able to determine the magnitude of changes in the ecosystem caused by the pesticide. Most metrics originally proposed for use in pesticide registration tests only provide information on structure; the only functional measure is for one biological component (fish), made once at the end of the test (Touart
1988). In addition, little is known about what levels of precision could be expected for various metrics. I thought that by analyzing a variety of benthic macroinvertebrate metrics, I would find some metrics that contributed to a better understanding of ecosystem structure and function and were precise enough to be used for pesticide evaluation.
I have organized my dissertation in a format that includes detailed explanation of background information and concise presentation of results and discussion in manuscripts ready to be submitted for publication. The detailed background information includes a review of the use of experimental ponds and benthic macroinvertebrates in environmental studies, ecology of taxa that I selected for study, description of study site, complete account of all methods, and appendices containing all data and calculations. The results and discussion are presented in four separate manuscripts in accordance with the objectives listed above (two manuscripts for objective 1). The advantages of this format are that it provides a permanent repository for details that might be needed later to answer questions, and it facilitates prompt submission of manuscripts at the time of graduation.
However, a disadvantage of this format is that some of the methods and results are repeated in several places. At the end of the dissertation,
I have included a summary section that relates the findings reported in the four separate chapters. LITERATURE REVIEW
USE OF EXPERIMENTAL PONDS TO DETERMINE ENVIRONMENTAL EFFECTS OF
PESTICIDES
Layton (1989) provided a comprehensive review of this topic; therefore, my review will be brief. It is inevitable that pesticides will reach non-target areas and organisms, so it is important to know how these materials affect populations and processes that are vital to the functioning of ecosystems. Many authors have written about the impact of pesticides on various non-target organisms (e.g., Hurlbert et al. 1972, Macek et al. 1972, Mula and Darwazeh 1976, Mula et al. 1978.
Rodrigues et al. 1983, Rodrigues and Kaushik 1986). Most of the work to date has been laboratory oriented, using only a few test species
(Buikema and Voshell 1991). This information is used to predict impact when pesticides come into contact with organisms in the natural environment. Due to the lack of adequate information on insect life histories and on ecosystem function, laboratory tests may not accurately predict environmental impacts. Concern has been expressed about extrapolating laboratory data to the "real world" (Dickson 1982, Cairns
1983, deNoyelles and Kettle 1985, Giddings and Franco 1985, Kimball and
Levin 1985, Clements et al. 1989). As a result, researchers have tried various field approaches to determine environmental impacts (Cooper and
Barmuta 1991), such as whole ecosystem studies (Yan and Strus 1980), upstream-downstream comparisons (Gore 1980), before-after comparisons
(Wallace et al. 1986, Wallace et al. 1989), and replicated experimental ecosystems, such as mesocosms. However, absence of life history
information about the species studied remains a major problem in field
tests (Rosenberg 1979), and functional parameters within ecosystems are
not fully understood (Wallace 1989).
Another problem encountered with most field testing, especially in
aquatic systems, is what Hurlbert (1984) referred to as
"pseudoreplication." This includes temporal or spatial segregation of
replicates, or the lack of true replication, due to subsampling, of
treatments and controls. Because there is no true replication or randomization, inferential statistics cannot be used to test for
significant differences between controls and treatments. Experimental
ecosystems, either in the laboratory (microcosms) or in the field
(mesocosms), have been used to reduce this problem ‘The advantage of
using experimental ecosystems is that they can be replicated and still
closely resemble natural ecosystems. A disadvantage is that microcosms
usually are simple species assemblages, and extrapolation to the natural
environment may suffer from the same problems as single species tests
(Heath 1980). Mesocosms (Odum 1984) are outdoor systems that are small
enough to be replicated but large enough to simulate natural ecosystems.
Mesocosms are advantageous for toxicity testing because they allow many
environmental factors to be taken into account when considering the
overall effect of a treatment.
Experimental ponds have been used as mesocosms for many years to
investigate basic ecological questions (Touart and Slimak 1989). The
first study that used experimental ponds to determine the impact of a pesticide was probably conducted by Jones and Moyle (1963), in which the effect of chlorinated hydrocarbon residuals on phytoplankton were studied. Since 1963, there have been many other studies in experimental ponds to determine the effect of chemical contaminants on the environment (e.g., Hurlbert et al. 1970; Hurlbert et al. 19723 Macek et al. 1972; Mauck et al. 1976; Boyle 1980; Crossland 1982; Crossland 1984;
Crossland and Bennett 1984; Giddings et al. 1984; Crossland and Hillaby
1985; Crossland and Wolff 1985; Wolff and Crossland 1985; Stephenson and
Mackie 1986). A few of these studies that involved pesticides are summarized below. Hurlbert et al. (1972) studied the density fluctuations of phytoplankton, zooplankton and insect populations when exposed to an organophosphate (Dursban). Mauck et al. (1976) looked at the residues of a herbicide (Simazine) in the mud, water, benthic macroinvertebrates, and fish. Boyle (1980) studied the effect of a herbicide (2,4-D DMA) on phytoplankton and fish growth. Crossland and
Bennett (1984) followed the biodegradation of an insecticide (Methyl
Parathion) in water, sediment, and fish. Most of these studies reported only measures of community structure (density, taxa richness, diversity) and information on the toxicity of a chemical to a particular species.
In all of these studies, little attention was given to functional measures or to evaluating the statistical precision of the measures that were used.
In recent years, experimental ponds have begun to be used for field tests for pesticide registration or reregistration (Urban and Cook
1986, Touart 1988). Recent reviews (Voshell 1989, Buikema and Voshell 1991) have identified deficiencies in the use of mesocosms to determine
the environmental effects of pesticides including: (1) not
incorporating life history information, (2) not using functional measurements, (3) not evaluating the precision of measures being used, and (4) not considering successional changes that might occur for several years after construction.
LIFE HISTORY PARAMETERS
Oliver (1979) defined life history as all those events that allow a species or population to survive and continue their existence. These events include longevity, pattern and rate of growth, and response to environmental factors (Waters 1979). Life histories of benthic macroinvertebrates have been studied for many years. Parameters studied have ranged from the basic biology of a species (Trost and Berner 1963) to complex interactions between species and communities and the environment in which they live (Peckarsky 1984, Sweeney 1984). Waters
(1979) indicated that basic life history information was lacking for many benthic macroinvertebrates and that one of the major research needs was complete life history information on an organism as it related to its environment. Rosenberg (1979) noted that more studies were emphasizing numerical and quantitative approaches rather than natural
history approaches. While there have been many life history studies since 1979, few have been conducted on lentic organisms. My review of life history will focus on growth rate, voltinism, emergence patterns, and secondary production, with emphasis on
Ephemeroptera and Odonata.
Growth Rate
Ecologists have two concepts of growth rate. For terrestrial insects, growth rate is thought of as the rate at which a population increases in number over time (intrinsic rate of growth) (Birch 1948,
Lefkovitch 1965, Demetrius 1969). For aquatic insects, growth rate usually refers to the rate at which an average individual increases in biomass or length through time (instantaneous growth rate) (Laird et al.
1965, Butler 1984). I will deal exclusively with the latter concept of growth rate.
Instantaneous growth rate is the rate that a population changes in weight or length over a given time period (Mackay 1972). Growth of an individual within a population can be affected by many factors.
Temperature (Sweeney 1978, Leggott and Pritchard 1985, Sweeney et al.
1986), nutrition (Bird and Kaushik 1984, Richardson 1984, Webb and
Merritt 1987), crowding (Hill and Knight 1987, Pickup and Thompson
1990), and toxicants (Hamilton and Timmons 1980) have all been shown to affect the rate at which an organism grows, as well as the relative
"health" of that organism The growth rates of most species of benthic macroinvertebrates have not been determined, and there have been fewer studies of pond species than stream species. Voltinism
Voltinism is the number of life cycles that a population of insects completes in a year (Butler 1984). Most aquatic insects are thought to be univoltine. In the Ephemeroptera and Odonata, there is considerable variation within species in the number of life cycles completed/ year, depending on altitude and latitude. In both orders, there is also variation within species in the number of larval instars needed to complete development. Clifford (1982) surveyed the literature regarding voltinism of different species of Ephemeroptera. He found that 60% of the studies reported univoltine life cycles and 302 reported multivoltine life cycles. He also found that individual species were reported to have different life cycle patterns at different study areas.
Corbet (1980) found that voltinism is also somewhat variable within the
Odonata, depending on climate. Most Odonata, however, are univoltine or semivoltine. It is apparent that results of studies on voltinism cannot necessarily be extrapolated to other areas within the distribution of a species. Kormondy and Gower (1965) even reported variation of some life cycle patterns in the same habitat over two years. Depending on temperature, food, and other factors, a population may be bivoltine, univoltine, semivoltine, or split, where part of the population exhibits one pattern and another part of the population exhibits a different pattern.
10 Emergence Patterns
The emergence pattern of aquatic insects includes information such as: number of insects emerging, when they emerge during the day or during the year, the duration of the emergence period, the length of time that they are present in the adult stage, and the degree of synchronization of the population. This concept of emergence pattern is broader than phenology, which is restricted to the daily and seasonal timing of life cycles (Butler 1984). Corbet (1964) gives a good review of emergence patterns in aquatic insects. Some variation in emergence pattern has been reported within species at different study sites and during different years (Kormondy and Gower 1965). Ephemeroptera, which have a short lived adult stage (1 to 14 days), tend to have highly synchronized emergence patterns. This synchrony can be established in a population during any stage of the life cycle but is most commonly established during the period of adult emergence (Butler 1984). Cues such as water temperature and photoperiod probably help to synchronize the population. A threshold water temperature may trigger growth in the spring so that a population is ready to emerge by a certain time. Also, smaller individuals may have a lower temperature threshold and begin growing sooner so that the whole population reaches maturity at about the same time (Corbet 1964). Photoperiod may trigger the population to emerge. Many Odonata have the same or similar synchronizing mechanisms as Ephemeroptera. Most aquatic insects emerge around dusk or dawn, probably to avoid the extreme daytime and nighttime temperatures and to be somewhat concealed from predators. Odonata have been classified into
11 spring species and summer species (Corbet 1954). Spring species have fairly synchronous emergence and a short flight season early in the year
(May - July). Summer species are characterized by an extended emergence period over several months and a long flight season (May - October).
Most Ephemeroptera emerge early in the year (April - June), but species that have more than one generation/ year emerge until September or
October (Brigham et al. 1982). The flight period of adult Ephemeroptera is always short (1 - 6 weeks). This is longer than the adult life span of any individual, but emergence of a population usually takes place over a period of several weeks.
Production
Secondary production is the rate at which biomass is accumulated in a given area over a specified length of time. Production combines population growth with survivorship to estimate the amount of food available to the next higher trophic level. Production is a functional measure that has been used in perturbation studies as well as basic life history studies (Benke 1984, Downing and Rigler 1984, Heisey and Hoenig
1986, Morin et al. 1987, Iversen and Dall 1989).
Methods for calculating production of benthic macroinvertebrates fall into two categories. The most accurate production estimates are obtained by using cohort dependent methods, such as the Allen curve, increment-summation, removal-summation, and instantaneous growth methods
(Waters 1977). These methods are appropriate only for species with fairly synchronous development of their populations. Quantitative
12 samples are collected over the life cycle of the species, and growth and survivorship curves are computed from the data. These methods work well when cohorts are easy to recognize and organisms can be identified to species. Hynes (1961) recognized that these criteria cannot usually be met in aquatic studies, and he proposed a method for determining the production of an entire community with order-of-magnitude accuracy.
This method has been modified several times since the original proposal, until now it is possible to make much more accurate estimates of production for individual species or a group of coexisting species with similar growth characteristics (Hynes and Coleman 1968, Hamilton 1969,
Benke 1979). The original method proposed by Hynes (1980) has come to be known as the size-frequency method. The basis for this method is that the average size-frequency distribution over 1 year will approximate the survivorship of the average cohort of a particular species (Hamilton 1969). In order to correct for life cycles that take more or less than 1 year to complete, Benke (1979) proposed the cohort production interval (CPI) correction factor. The CPI is the amount of time spent in the aquatic stage relative to one year (Benke 1984).
LIFE HISTORY OF SELECTED EPHEMEROPTERA
Considerable information is available on life history of
Ephemeroptera (see reviews by Berner 1959, Brittain 1982, Clifford
1982). My literature review will focus on the two species that were abundant during my studies, Callibaetis floridanus and Caenis amica.
13 Callibaetis is a relatively common genus in the family Baetidae, with 24 species found in North America (Berner and Pescador 1987). Of these, Callibaetis floridanus Banks, C. fluctuans (Walsh), and ¢C. petriosus Banks have been reported from Virginia (Kondratieff and
Voshell 1983). There is limited information on the life history of
Callibaetis species. Trost and Berner (1963) gave detailed information on the life history of €. floridanus in Florida, but their results are probably not applicable to Virginia. Callibaetis species have been reported as usually having multivoltine life cycles with up to six generations/ year in some areas (Clifford 1982, Berner and Pescador
1987). The adult female is relatively long lived for Ephemeroptera, with an average life span of 5 to 13 days. Callibaetis species are among the few ovoviviparous Ephemeroptera, and females can lay 450-500 eggs. Eggs hatch immediately after oviposition, and the larvae search for submerged vegetation. There have been no reports of diapause in this genus. Callibaetis larvae are considered to be in the collector- gatherer functional feeding group (Merritt and Cummins 1984). They are swimmers and clingers and are most often found in areas of vegetation.
I found no information on the growth of Callibaetis species, except that it proceeds at a rapid rate, especially when temperatures are favorable.
Caenis is one of two genera in the family Caenidae, with eleven species currently recognized from North America (Provonsha 1991). Of these, Caenis amica Hagen, C. diminuta Walker, C. latipennis Banks, C. punctata McDunnough, C. anceps Traver, C. hilaris (Say), ¢. macafferti
Provonsha, and C. tardata McDunnough have been reported from Virginia
14 (Provonsha 1991). Provonsha (1991) recently revised the genus Caenis and recognized fewer species because of synonymies. One common species,
C. simulans, was synonymized with the species that I studied, C. amica.
Different life cycle patterns have been reported for Caenis species
(Mackey 1978, Bradbeer and Savage 1980, Clifford 1982, Rodgers 1982,
Corkum 1985, Provonsha 1991). About half of the papers indicate a univoltine life cycle, and the other half indicate a bivoltine life cycle. Lyman (1955) reported that C. amica (as C. simulans) had an extended emergence with two peaks, one in early June and the other in late July and early August. Others have also reported an extended emergence patterns for several species of Caenis (Berner 1959, Brigham et al. 1982, Rodgers 1982, Corkum 1985). Caenis adults are one of the shortest lived Ephemeroptera. Usually the subimagal molt occurs within
5 min of emergence, and the adult lives a maximum of 24 hr (Berner and
Pescador 1987). Berner and Pescador (1987) reported that the egg stage of C. diminuta lasts for 5 to 11 d in Florida. Rodgers (1982) reported that larval development of C. amica could be completed in 124 din
Alabama. I found no reports of any diapause in this genus. Caenis larvae are classified in the collector-gatherer or scraper functional feeding group by Merritt and Cummins (1984) and are most often found sprawling on bottom sediments. I found no reports on the growth rate of
Caenis.
15 LIFE HISTORY OF SELECTED ODONATA
There is a lot of biological information available on Odonata (see reviews by Needham 1903, Garman 1917, Corbet 1963, Corbet 1980), but much information about their life histories is lacking (Brigham et al.
1982). Taxonomy of Odonata larvae is poorly known, so I was usually only able to identify larvae to genus and in some cases only family. My literature review will focus on the four taxa that I treated in my studies: Gomphus (Gomphidae), Anax (Aeshnidae), Libellulidae, and
Enallagma (Coenagrionidae).
There are at least 44 species of Gomphus recognized in North
America (Merritt and Cummins 1984), and Carle (1982) reported that 30 species of Gomphus probably occur in Virginia. Gomphus species appear to be either univoltine or semivoltine with a 2-yr life cycle. Many species emerge in early spring (April - June) in fairly synchronous patterns (Paulson and Jenner 1971), some emerge in the late summer
(August - October) and are less synchronized. Adults have been reported to live 2 - 4 wk. Brigham et al. (1982) indicate that very little is known of the immature stages. I found no information on the egg stage of this genus. The larval stage has been studied slightly but most often to determine the patterns of adult emergence rather than to find patterns of larval growth.
There are 4 species of Anax recognized in North America (Merritt and Cummins 1984). Of these, A. junius (Drury) and A. longipes Hagen have been reported from Virginia (Carle 1982). My research only involved
16 A. junius. Calvert (1934) determined that A. junius larvae needed 341 d to develop in Canada, but Macklin (1963) found a group of A. junius in
Illinois that required only 111 d to complete development. The apparent discrepancy was resolved by Tottier (1971), who found that two distinct populations of A junius occurred in Canada. A resident population overwintered as larvae, which required about 11 mo to develop. Adults of the resident population emerged in late June, and eggs of the next generation hatched in mid-July. A nonresident, migratory population consisted of adults that arrived from the south about May and laid eggs that hatched in June. Larvae of the migratory population completed development in about 3 mo, and adults emerged in September and migrated south to overwinter. The relative abundance of the resident and migratory populations in Canada has not been investigated, nor has anyone studied the life history of the migratory population at its southern overwintering sites. Paulson and Jenner (1971) determined that
A junius was univoltine in North Carolina with adults occurring from
March through October. They found that A. junius overwintered as larvae in five different instars. I found no reports indicating any diapausing stages, and I found no information on the growth rate of any Anax species.
There are at least 93 species of Libellulidae recognized in North
America (Merritt and Cummins 1984), and 52 species have been reported from Virginia (Carle 1982). Most of Libellulidae species have univoltine life cycles. Development varies from as little as 35 d for
Pantala hymenaea (Bick 1951) to more than 1 yr for some species of
17 Libellula (Paulson and Jenner 1971). The adult flight period for all
Libellulidae species extends from April through October in North
Carolina, with adults of most individual species having flight periods of 2 to 5 months (Paulson and Jenner 1971).
At least 35 species of Enallagma have been recognized in North
America (Merritt and Cummins 1984), and 13 species have been reported from Virginia (Voshell personal communication). Most Enallagma species are univoltine, but a few species are partially bivoltine (Ingram and
Jenner 1976). Adults of Enallagma species emerge over an extended period between April and October. Flight periods of individual species vary from 8 wk (E. divagans) to the entire summer (E. civile). There is conflicting information on the length of adult life. Garrison (1979) reported that the average adult life span of E. civile was 2.5 d; however, Brigham et al. (1982) reported that the average time from emergence to reproductive maturity in E. civile was 3.5 d with a maximum of 13 d. I found no information on the development of Enallagma larvae.
ECOLOGICAL SUCCESSION IN NEW PONDS
The topic of ecological succession is very important if newly constructed ponds are to be used as mesocosms for pesticide registration tests because: (1) the ponds are intended to be models of mature, natural lentic ecosystems and (2) if the use of less than mature ecosystems is accepted, then it is essential to be able to distinguish successional changes from changes caused by pesticide treatment. Layton
18 (1989) gave a thorough review of pertinent studies that have been conducted on the colonization and succession of benthic macroinvertebrates in man-made ponds and reservoirs, and I will not repeat those details in my dissertation. Most previous studies are not directly related to my study because the new lentic environments were filled with flowing surface waters that transported colonizing aquatic organisms (e.g., Burris 1952, Paterson and Fernando 1970, Street and
Titmus 1979, Danell and Sjoberg 1982, Voshell and Simmons 1984). One study that was applicable to my study involved a series of independent ball-clay ponds of various ages (Barnes 1983). Although colonization was rapid and somewhat predictable, succession continued to take place for
16 yr. Barnes (1983) also found that complex interactions, such as plant colonization, food webs, and interactions between colonizing species, had to be considered to account for the species assemblages that developed in the ponds. The presence or absence of macrophytes and the type of macrophytes have also been shown to influence the community structure of lentic environments (McLachlan 1969, Voshell and Simmons
1984) and the rate at which colonization takes place (Barnes 1983).
I was able to investigate successional changes of benthic macroinvertebrates in the VPI&SU experimental ponds during the second year after construction because detailed information on colonization during the first year had been provided by Layton (1989) and Layton and
Voshell (1991). A few Chironomus and Ceratopogonidae larvae were collected within 4 wk after the ponds were first filled with water in late January. The sequence of taxa that arrived in the ponds was:
19 Diptera (primarily several genera of Chironomidae), Coleoptera,
Ephemeroptera, and Odonata. The sequence of arrival corresponded to adult flight periods. Noninsect taxa (Oligochaeta, Nematoda, Amphipoda) were collected in relatively low numbers and only late in the first year. Twenty-nine taxa were collected, 13 of which were present in all
12 ponds. Mean density of total organisms increased slowly throughout the spring and summer of the first year, then increased rapidly during the autumn. Mean number of taxa and diversity increased rapidly during the first 7 mo, but never became very high. Community structure was dominated by Chironomidae (~ 85%). Ephemeroptera and Odonata were the second and third most abundant organisms, comprising about 9 and 2% of the community, respectively. Ephemeroptera larvae collected in the ponds during the first year included Callibaetis, Leptophlebia, Caenis, and Hexagenia. Callibaetis and Caenis were much more abundant than the others. Odonata larvae included Coenagrionidae (mostly Enallagma),
Gomphus exilis, Anax junius, and Libellulidae. Coenagrionidae were the most abundant Odonata. Trophic function was dominated by collector- gatherers (~79%). Layton (1989) and Layton and Voshell (1991) determined that the main factors that influenced benthic macroinvertebrate colonization of the VPI&SU experimental ponds during the first year were: lack of connection to colonized waters, small size, lack of macrophytes to diversify habitat, and rich supply of terrestrial detritus and low supply of plankton for food. They speculated that number of taxa and community diversity of benthic macroinvertebrates would increase in following years as the terrestrial
20 detritus decomposed, plankton populations increased, and macrophytes colonized the ponds.
BIOLOGICAL ENDPOINTS FOR EXPERIMENTAL POND STUDIES
One of the major unresolved issues in using experimental ponds as mesocosms for field toxicity studies is the choice of biological endpoints (Buikema and Voshell 1991). Biological endpoints should be judged according to two criteria: ecological meaning and statistical meaning. To be ecological meaningful, an endpoint should consistently reflect important structural or functional changes in an ecosystem that occur as a result of perturbation. The EPA protocol for field testing environmental impacts of pesticides emphasizes fish parameters as endpoints, because fish serve as integrators of all aspects of the ecosystem (Touart 1988). While the importance of fish cannot be disputed, there are some problems with using fish metrics as biological endpoints in mesocosm toxicity tests. Fish can only be sampled at the end of a study, because more frequent fish sampling might disrupt the balance of these relatively small study systems. Also, fish are the least natural of the biological components in pond mesocosms, because only a single species is stocked shortly before the pesticide treatment
(Touart 1988). Macroinvertebrate endpoints are ecologically meaningful in mesocosm toxicity tests because macroinvertebrates: can be sampled throughout a study; establish reasonably natural communities (Layton and
Voshell 1991); serve as food for many fish species (Healey 1984); are
21 important in ecosystem dynamics, such as detritus processing (Merritt et al. 1984); and are often sensitive to toxic substances, such as pesticides (Wiederholm 1984).
In spite of the ecological meaning of macroinvertebrate metrics, only a few structural parameters, such as total density, individual taxa density, number of taxa, and diversity index, have been used as endpoints in mesocosm toxicity tests (Buikema and Voshell 1991).
Buikema and Voshell (1991) indicated that functional as well as structural parameters need to be measured to fully assess the impact a chemical may have on an ecosystem A number of new macroinvertebrate metrics have been proposed as part of the "rapid bioassessment" protocols that have been developed to give an early warning of changes taking place in streams and rivers (Ohio EPA 1987, Plafkin et al. 1989,
Resh and Jackson 1991). The list of metrics recommended in the EPA rapid bioassessment protocol (Plafkin et al. 1989) includes: taxa richness, modified Hilsenhoff biotic index, ratio of scraper and collector-filterer functional feeding groups, ratio of Ephemeroptera,
Plecoptera, Trichoptera (EPT) and Chironomidae abundances, percent contribution of dominant taxon abundance, EPT taxa richness, community similarity index, and ratio of shredder functional feeding group abundance and total abundance. Because rapid bioassessment metrics include structural and functional parameters that were selected for their ecological meaning, some of them could probably be modified for use in lentic ecosystems and would be ecologically meaningful endpoints for mesocosm toxicity tests.
22 In addition to the ecological meaning of endpoints used in mesocosm toxicity tests, endpoints should also be evaluated according to how well they can be used in statistical tests of treatment effects.
The major concern for statistical meaning of an endpoint is precision, which is a measure of the similarity of replicate measurements. Benthic macroinvertebrate data are often highly variable, which causes estimates of means to have low precision and prevents concluding that differences in means are not the result of chance. Little work has been conducted on the amount of natural variability that occurs with benthic macroinvertebrates in lentic ecosystems; however, Resh and McElravy
(1991) reported on the variability associated with some parameters in lotic ecosystems. They reported that the variation for number of taxa, within the same stream, was as high as 128% in some cases, and variation reached 500% for individual taxa density. The precision of a parameter, with a given number of replicates, can be determined if the mean and standard deviation are known (Elliot 1977). Usually in benthic macroinvertebrate studies, a precision of 40% is considered to be reasonable (95% confidence that the sample mean is within 7 40% of the true population mean, Elliot 1977). A modification of a formula from
Sokal and Rohlf (1981) can be used to determine the amount of change that a metric must exhibit to allow a treatment effect to be separated from the natural variability of a system Resh and McElravy (1991) recommended that this equation be used during the design of studies in which the objective is to detect differences in biotic variables over space or time.
23 STUDY SITE
The experimental pond facility is located at the Southern Piedmont
Agricultural Experiment Station, which is operated by Virginia
Polytechnic Institute and State University, near Blackstone, Virginia
(longitude 77°57’ 30"W latitude 37°5’30"N). The facility is on a 2-ha cleared plot that was previously forested with loblolly pine ( Pinus taeda). Elevation of the site is 128 m above mean sea level. Soils at the site are sandy-loam at the surface with clayey subsoils (Soil
Conservation Service, Farmville, Va., unpublished data). Several small impoundments ranging in size from 0.04 to 2 ha, are located near the experimental pond facility.
The entire facility consists of 12 square 0.04-ha experimental ponds and a 0.36-ha water supply reservoir (Fig. 1). Each experimental pond measures 20.1 X 20.1 m at the water surface, is 2.1 m deep, and holds about 520 m of water. The bottom of the ponds consists of 15 cm of compacted clay covered with 15 cm of topsoil. Each pond is surrounded by a 0.5-m berm that prevents the entry of surface runoff, and the distance between ponds is 3 m The supply reservoir is 3 m deep and contains about 8, 850 m> of water at normal capacity. The experimental ponds are plumbed so that all 12 can be filled simultaneously or individually from the reservoir, directly from two wells, or by way of a temporary firehose connection to the Fort Pickett municipal water supply. A complete description of the history of
24
Od Wells
Reservoir ] 2 5
|
| 4 5 6
7 8 9
10 11 i,
N
q vce GcseesnseeeiesreereeaseestehCocccccccceesseeseeeseessie DaQe we
+ b [oe ceceeeeeneeeee ceeeeeeeeeeeeeee. pl “ Legend: a. PVC rack — 1m b. PVC rack — 2.1m Cc, cross ropes d. dock
| N
Figure l. Layout of the experimental pond facility showing reservoir, 12 experimental ponds, and plumbing system Bottom inset shows location of PVC pipe racks in each pond, dock, and cross ropes used in maneuvering boats.
25 construction of the experimental pond facility was provided by Layton
(1989).
All experimental ponds were first filled January 25-31, 1988.
Only the municipal water supply was used for initial filling because: production of the wells was inadequate, the reservoir was not constructed until summer 1988, and it was certain that the chlorinated tap water would not introduce any organisms. The only management of the ponds during the first 2 yr was to add water to compensate for evaporation losses. Water levels were kept the same in all ponds by adding only well water during the first year and reservoir water during the second year. The reservoir was always filled from the municipal water supply, but water from the reservoir was not added to the ponds for at least 1 wk after receiving municipal water to allow chlorine to dissipate. There were no fish in the ponds or reservoir during the entire study.
The Southern Piedmont Agricultural Experiment Station is located in the Piedmont Physiographic Province in a transition zone between northern and southern climates, and is characterized by a long (206 d),
humid growing season (Virginia Cooperative Extension Service 1984). The mean annual temperature at Blackstone, Va. is 14.4 °c, while mean annual precipitation is 105.8 cm On the average, nearly one fourth of the total annual precipitation falls in July and August (24.2 cm). These are also the warmest months of the year. Total mean degree-day accumulation for air temperature using 0 °C as a base is 5,254.
26 METHODS
DATA COLLECTION
Design
Six ponds were chosen at random from the 12 ponds available for study at the experimental pond facility. I sampled benthic macroinvertebrates for 14 mo from March 1989 through April 1990.
Benthic samples were collected every 4 wk from November through April and every 2 wk from May through October. Ponds were sampled in a different random sequence on each sampling date to make sure that colonization trends were not caused by the transport of organisms from one pond to another during sampling. Adult insects were sampled on selected dates when benthic samples were collected.
Unfortunately, the available financial resources for this project did not allow me to make detailed measurements of environmental characteristics. Temperature was continuously recorded throughout the study in one pond (pond #5). I measured the following physicochemical parameters in all 12 ponds on one date (April 5, 1990) at the end of my studies: Secchi depth, temperature, dissolved oxygen, pH, hardness, conductivity, alkalinity, nitrate, and nitrite. Data on the same parameters for the year before my studies were available from Jenkins
(1990). I made qualitative observations on the types and abundance of aquatic macrophytes throughout my field sampling.
27 Benthic Macroinvertebrate Sampling
To obtain complete life history information about the taxa being studied, both adult and immature stages were sampled. I used a light trap to sample adult Ephemeroptera. A DC battery-powered blacklight
(BioQuip Products, El Segundo, CA) was placed near the center of the 12 ponds so as to attract mostly specimens that had emerged from the ponds.
Adult specimens were preserved in 702 ethyl alcohol.
Adult Odonata, which are not attracted to lights, were sampled with an aerial net around the ponds. JZygoptera were collected by sweeping vegetation at the edge of the ponds. The larger and faster- flying Anisoptera were sampled by seeking specific individuals.
Specimens collected were first put in paper triangles, then placed in acetone for about 24 hr, removed and allowed to dry, and finally stored in individual cellophane envelopes. The acetone extraction technique preserves natural colors and makes identification easier (Steyskal et al. 1986).
To determine the numbers and patterns of emerging Odonata, which crawl out of the water for their final molt, I developed shore emergence structures. The shore emergence structures consisted of 0.45 KX 10-m sections of nylon window screen stapled to wooden stakes. They were placed in the water about 0.30 m from the shore. The nylon screen was secured so that the bottom edge was flush with the pond bottom and the top edge extended 0.20 m above the water surface. On each sampling date, all exuviae were removed with soft forceps, and preserved in 702% ethyl alcohol.
28 An artificial substrate sample was taken from a depth of 1 min each pond on each sampling date to obtain a quantitative sample of benthic macroinvertebrates. The artificial substrate samplers (Fig 2) were the same as those used by Layton (1989). The samplers were made from 10. 8-cm tall, 12.2-cm diameter, round plastic buckets. To allow access for colonizing organisms while retaining the artificial substrate materials, 3.8-cm holes were drilled in the top and sides of the samplers. A1.5-cm layer of topsoil from the site was placed in the bottom of each sampler and seven 5-cm diameter tri-pack units (Jaeger
Products Inc., P.O. Box 16117, Houston, Texas) were placed above the soil. Tri-packs are used as surface enhancers in many biological and chemical applications. The soil and tri-pack units provided habitat for a wide range of organisms including burrowers, climbers, and clingers.
The surface area available for habitation was approximately 1820 om’, with about 642 of this being attributed to the tri-pack units.
The samplers were deployed initially for Layton’s studies in
December 1987, before the ponds were filled with water. I replaced the samplers for my studies in March 1989, while the ponds were filled with water. I constructed a special placement tool that consisted of a modified electrical cover plate attached to the end of a PVC pipe (Fig
3). The samplers were held against the plate with the retrieval line, and the samplers were then imbedded into the pond bottom so that the soil in the bucket was approximately even with the pond substratum
Samplers were deployed at depths of 1 m and 2 m and were attached to a
PVC crossbar at each depth with a braided nylon retrieval line. I only
29
Figure 2. Artificial substrate sampler and 1 tri-pack unit. (see text for explaination).
30 PVC pipe used for deployment — = PVC Pipe: Rack eee Retrieval Line —— —— Retrieval Line Plate covering sampler Sampler
Pond Bottom V7.
Figure 3. Deployment of the artificial substrate samplers. Left side of diagram shows deployment of sampler. Right side shows sampler in place following deployment.
31
retrieved samplers from 1 m for my studies. No samplers were retrieved until they had been in place for at least 30 d. The first samplers retrieved for my study were ones that had not been removed by Layton.
The artificial substrate samplers to be retrieved on each date were selected by generating a random number and counting samplers from west to east. To retrieve a sampler, I placed an inverted plastic funnel over the retrieval line and allowed the funnel to settle onto the sampler. The funnel completely covered the sampler so that water was deflected during retrieval (Fig 4). As soon as the funnel was visible underwater, a 100-ym mesh net was placed under it to collect any organisms that might wash off as the sampler was removed from the water.
The entire sampler and the contents of the net were placed in a labeled plastic bucket, which was filled with 52 formalin for preservation of specimens.
In the laboratory, the artificial substrate samples were first washed over a 106-ym mesh soil sieve. Each tri-pack unit was scrubbed with a soft bristle brush over the sieve. The samples were washed until water flowing through the sieve was almost clear. Samples were then placed in a washtub with about 1 oz of liquid dishwasher detergent and a small amount of water to break up oily clay particles and allow them to pass through the sieve during the next washing. After standing for several min in the detergent solution, samples were thoroughly washed over the 106-ym sieve again to remove as much of the fine particles and detergent as possible. When the sample water was clear and no longer soapy, samples were washed for the final time over a 355-ym screen.
32 PVC Pipe Rack —
—_ —-— os on
Retrieval Line ——
Funnel covering sampler A/S during retrieval Sampler
Pond Bottom Ls
Figure 4. Retrieval of the artificial substrate samplers. Left side of diagram shows sampler in place with retrieval line tied to crossbar. Right side shows retrieval using funnel that was slipped down the retrieval line to cover sampler.
33
This time samples were washed gently to retain as many organisms as
possible, while washing as much silt as possible through the sieve. All
material retained on the 355-um mesh sieve was preserved in a glass
bottle with 702 ethyl alcohol. Although Layton (1989) analyzed all organisms retained on a 106-ym mesh sieve in his study in the same ponds, I compared the numbers and kinds of organisms retained on a 355-
um versus a 106-ym mesh sieve and found that only a very few early instar Chironomidae, representing < 5% of total organisms, passed through a 355-ym mesh sieve. The advantage of using a 355-ym mesh sieve was that samples could be washed cleaner, which made it easier to sort organisms from debris. I used a 106-ym mesh sieve in the first two steps of washing so that a strong jet of water could be directed upon
the samples without breaking the organisms or forcing them through the
mesh.
Organisms were sorted from the remaining detritus and sand with a
stereomicroscope at 4-10X magnification. Organisms were initially sorted into five taxonomic groups: Ephemeroptera, Odonata, Trichoptera,
Chironomidae, and miscellaneous taxa. Specimens were counted preliminarily as they were sorted, but final counting was done when the specimens were identified to the lowest possible taxonomic level.
Qualitative benthic samples were taken with a D-frame dip net having a 1000-yum mesh catch net. Dip net samples were standardized by sampling a square area of bottom that was approximately the width of the
net (0.3 m) at a depth of 0.5 m This was repeated on each side of a
pond, and the four subsamples were pooled. This protocol was designed
34 to sample all of the different microhabitats that occurred in shallow water. Qualitative samples were taken on each sampling date and preserved in 5% formalin.
In the laboratory, the qualitative samples were washed over a 355- um mesh sieve until the wash water became clear. Material that was retained on the sieve was preserved in 702 ethyl alcohol. Organisms were sorted from debris and sand with a stereomicroscope at 4-10X magnification. Organisms were initially sorted into four taxonomic groups: Ephemeroptera, Odonata, Trichoptera, and miscellaneous taxa.
Because the purpose of the qualitative samples was to augment the data for the life history studies, Chironomidae were not sorted from these samples. Individual specimens were counted in the next step when they were identified to the lowest possible taxonomic level.
Taxonomic Identification
Specimens of immature stages of insects and all stages of other macroinvertebrates were identified to the lowest possible taxonomic level with the most recent general literature (Brigham et al. 1982,
Merritt and Cummins 1984, Pennak 1978). I was able to identify most specimens to the genus level. For identifying adult insects to the species level, specialized taxonomic literature was used for each group:
Ephemeroptera (Burks 1953, Berner and Pescador 1987, Provonsha 1991),
Anisoptera (Needham and Westfall 1954, Carle 1982), Zygoptera (Johnson and Westfall 1970, Johnson 1972). Chironomidae were identified only as
35 belonging to the subfamily Tanypodinae or the combination of two subfamilies, Chironominae and Orthocladiinae.
Environmental Characteristics
A Tempmentor® (Ryan Instruments, Redmond, Wash.) was used to record the temperature in one pond (pond #5) at a depth of 1 m every 2 hr throughout the study. In addition, I measured selected physicochemical parameters at 1 m in the centers of all ponds on one occasion, as follows. Temperature and dissolved oxygen were measured in situ with a YSI Model 32 meter. Secchi depth was also measured in all ponds. A water sample was used to measure pH on site with an Orion model 407A meter. Water samples were collected and taken to the laboratory for analysis of hardness, conductivity, alkalinity, nitrate, and nitrite, using standard methods described by American Public Health
Association et al. (1985). Chlorophyll a was assayed with a Gilford model 250 spectrophotometer. Hardness and alkalinity were measured titrimetrically. Conductivity was measured with a YSI model 32 meter.
Nitrate and nitrite were assayed with a Dionex Model 14 ion chromatograph.
As I was collecting benthic samples, I made qualitative observations on the types of macrophytes and their abundance in each pond. As new taxa appeared, representative specimens were collected by hand and taken to the laboratory for identification.
36 DATA ANALYSIS
Life History Parameters
I determined life history parameters for Caenis amica
(Ephemeroptera: Caenidae), Callibaetis floridanus (Ephemeroptera:
Baetidae), Anax junius (Odonata: Aeshnidae), Gomphus exilis (Odonata:
Gomphidae), and Enallagma civile (Odonata: Coenagrionidae). The life history parameters that were evaluated during this study were growth rate, voltinism, and emergence patterns (including phenology).
Growth rate was measured by the instantaneous growth method
(Mackay 1972):
IGR = (loge Wy - loge Wo)/t
where, W,. is the mean individual weight at the end of the time period,
Wo is the mean individual weight at the start of the time, and
t is the amount of time between samples.
Mean individual weights were obtained from a head capsule width/ body weight regression line. I measured all insects with a Zeiss/Boeckeler filar eyepiece interfaced with an IBM-PC microcomputer for automatic recording of data. The widest distance across the head capsule was measured. Weights of preserved individuals, of a given head capsule width, were determined by drying them at 60 °C for 24 hr and weighing them on a Mettler AE163 electronic microbalance. Only completely intact
37 individuals were used for weight analysis. I calculated regression equations for each taxon, using a log-log transformation of the data.
Weights of individual specimens were estimated by measuring their head widths and using the regression equation.
I determined voltinism and emergence patterns by examining size frequency graphs of immature stages through time in conjunction with my data on adult flight periods. Head capsule width was the measurement used for size frequency analysis. I determined size classes for populations of each taxon by plotting a histogram of all larval head widths and separating the peak frequencies. Data were organized according to numbers of individuals in each size class on each sampling date, and a histogram of size classes over time was constructed with
Lotus Freelance Plus Graphics software package (Lotus Development
Corporation, Cambridge, MA). Data from aerial nets, light traps, and shore emergence structures were summarized according to total number of individuals of each taxon.
Production
I measured secondary production, which is the amount of biomass accumulated/unit area of bottom in a given length of time, for Caenis amica, Callibaetis floridanus, Enallagma civile, Gomphus exilis, Anax junius, and the family Libellulidae by the size-frequency method
(Hamilton 1969, Waters 1977, Benke 1979, Benke 1984). A detailed explanation of the size-frequency method can be found in Benke (1984), and Layton (1989) explained how he used the method in the VPI&SU
38 experimental ponds; therefore, I will only provide an overview of the method. The size-frequency method has become a standard technique for measuring production of populations of benthic macroinvertebrates that have indistinguishable, overlapping cohorts. The premise is that "an average size-frequency distribution calculated from samples taken over a period of a year will approximate the average survivorship of a hypothetical average cohort" (Benke 1984, p. 299). Production can be measured by determining the numbers of individuals in and the weights of the average size classes. The following equation summarizes the steps taken to calculate annual production by the size-frequency method:
k P = s« Ny -Naa1) (( Wy*Wy41) & 5) k( 365/ CPL)
i=l
Where:
P = annual production (mg DW/ m2/ yr) k = number of size groups
Ny = average density of size group i (no./sampler)
Ni+] = average density of size group i + 1 (no./sampler)
Wy = average individual dry weight for size group i
Wi4] = average individual dry weight for size group i + l
CPI = cohort production interval (days)
39 I calculated production of each taxon in each pond separately to obtain an estimate of the variation that existed among ponds. Negative production values between size classes were set to zero as suggested by
Benke and Wallace (1980). Production estimates were corrected using the cohort production interval (CPI) as suggested by Benke (1979). The CPI for each taxon was computed by determining the average time spent in the larval stage. For Anax junius, the time spent in the larval stage was determined by adding the amount of time from appearance of first instar larvae to emergence of final instar larvae for each population present in the ponds. For each of the other taxa, the time spent in the larval stage was determined by calculating the amount of time spent in non- producing stages (egg and adult) and subtracting from 365. I reported my results as mg DW/sampler/yr, because I sampled with artificial substrates.
Successional Changes
I compared my results from the second year after the ponds were filled to the results that were obtained by Layton (1989) during the first year to determine if there were changes in the benthic macroinvertebrate community. The parameters that I compared were: total density, taxa richness, diversity, density of dominant taxa, and proportions of functional feeding groups. Mean total density on artificial substrates was calculated by dividing the total number of organisms collected during the study period by the number of sampling dates. Taxa richness was determined by counting the number of taxa
40 collected in each pond on each sampling date and taking a mean.
Diversity was determined using the Shannon diversity index. I prepared line graphs of the number of taxa, total density, individual taxa densities, percent of collector-gatherers and percent of predators from the artificial substrate samples on each date in both years that the ponds were studied. The community at the end of the first year was compared to the community at the end of the second year using the Bray-
Curtis similarity index to test for differences (Hruby 1987).
My results were not completely comparable to those of Layton
(1989) because he sampled all 12 experimental ponds, whereas I sampled only 6 ponds. Also, I included qualitative dip net samples from shallow water. Data from shore emergence structures, light traps, and aerial captures during the first year were obtained from Voshell,
(unpublished). To make the comparison more reasonable, only those six ponds from Layton (1989) and Voshell (unpublished), corresponding to the six I studied, were used in making comparisons between years.
Biometrics
I evaluated a variety of biometrics in terms of the percent change that must occur to be attributed to a treatment effect (detection limit) by the following formula, which is a modification of a formula from
Sokal and Rohlf (1981):
41 6 2 ((2/n) > * CV * (t wyyt t 2(1-p)(v)))
where, 6 is the detection limit,
n is the number of ponds used for each treatment,
CV is the coefficient of variation,
a is the confidence of the test,
p is the power desired in the test,
v is the degrees of freedom, and
t is the value from a t-distribution table.
The alpha level was set at 0.2 and the power of the test was set at 0.8 in order to be consistent with recommendations of Stunkard (1989, 1991) for how the EPA should determine the effect of a pesticide treatment.
Structural metrics that were analyzed in this manner included: taxa richness, EOT Index (number of taxa in the orders Ephemeroptera,
Odonata, Trichoptera), ratio of EOT density to Chironomidae ( Diptera) density, percent of total density comprised by EOT taxa, percent
Chironominae/ Orthocladiinae (Diptera: Chironomidae), percent Tanypodinae
(Diptera: Chironomidae), total density, Chironominae/ Orthocladiinae density, Tanypodinae density, Coenagrionidae (Odonata) density,
Libellulidae (Odonata) density, Callibaetis (Ephemeroptera: Baetidae) density, and Caenis (Ephemeroptera: Caenidae) density. Functional metrics included: percent of collector-gatherer and predator functional feeding groups. All of the above utilized data from the artificial substrate samplers. Many were modifications of rapid bioassessment
42 metrics intended for stream studies (see Literature Review and Plafkin et al. 1989).
It was not possible to evaluate all of the metrics listed above with data from the dip net samples. The qualitative dip net samples were originally intended only for determining life history parameters of selected Ephemeroptera and Odonata. For some other taxa, primarily
Chironomidae, not all specimens were retained during sorting.
Structural metrics that were analyzed for the dip net samples included: taxa richness (minus Chironomidae), EOT index, total density of organisms (minus Chironomidae), EOT density, Coenagrionidae density,
Libellulidae density, Callibaetis density, and Caenis density.
Functional metrics included: number of collector-gatherers (minus
Chironomidae) and number of predators (minus Chironomidae). Analyses of these biometrics facilitated some comparisons between the results obtained with dip net samples and artificial substrate samples.
QUALITY ASSURANCE
Each benthic sample was identified with a plastic label bearing a unique 16 digit code that included the date, pond, sample type, depth, and sampling method. The label was placed in the sample container when the sample was retrieved from the pond. In addition, the same information was written on the outside of the sample container. The plastic label was transferred with the sample as it was washed, sorted, and identified.
43 Three notebooks were used to keep detailed records of all activities in the field and laboratory. One notebook was kept at the experimental pond facility to log every entry to the facility, summarize all activities for each visit, and record water depths and any unusual conditions of the ponds. Another notebook was used in the field to record information related to sampling, such as which artificial substrate samplers were removed, the sequence of sampling the ponds, and biological notes about organisms that were seen in or around the ponds.
A third notebook was kept in the laboratory and was used to track the chain of custody for each sample as it progressed through each step of analysis. The date and initials of the person performing the task were recorded for the following steps: washing, sorting, and identifying, along with any unusual information about the sample.
44 MANUSCRIPT I: LIFE HISTORY, GROWTH, AND PRODUCTION OF EPHEMEROPTERA IN
EXPERIMENTAL PONDS
ABSTRACT
I determined voltinism, emergence patterns, larval growth rates
(instantaneous growth method), and annual production (size-frequency method) for Caenis amica and Callibaetis floridanus in six experimental ponds. Larvae were sampled with artificial substrates and a dip net, and adults were sampled with a light trap. Both species were bivoltine.
C. amica emerged in June and July-August; C. floridanus emerged in April and September. Growth rates were 0.015 and 0.025 mg DW/d for the first and second generations of C. amica and 0.011 and 0.015 mg DW/d for the
first and second generations of C. floridanus, respectively. Annual production was relatively low, 5 mg DW/sampler/yr for C. amica and 11 mg
DW/sampler/yr for C. floridanus. The number of generations of C. floridanus and the growth and production of both species in the experimental ponds were lower than what has been reported in other studies. Some of the observed differences may have been at least partly caused by temperature (lower accumulated degree-days), food (less algae), and habitat (sparse macrophytes).
45 INTRODUCTION
Mayflies show remarkable variation in life history (Brittain 1982,
Clifford 1982). Temperature, food, habitat, and photoperiod are factors that contribute to the observed natural variability. Mayflies can vary the number of larval molts before emergence, allowing them to adjust to adverse conditions by emerging sooner, although smaller in size, and still complete their life cycle. Life history variability make it difficult to interpret environmental impact studies involving mayflies.
Buikema and Benfield (1979) explained that life history parameters of test organisms must be understood and quantified to accurately interpret the results of toxicity tests.
The purpose of this study was to determine the growth rates, voltinism, emergence patterns, and annual production of Caenis amica
Hagen (Caenidae) and Callibaetis floridanus Banks (Baetidae) in a set of experimental ponds designed for environmental toxicity tests. Within the four genera of Ephemeroptera collected in the ponds (also
Leptophlebia and Hexagenia), only C. amica and C. floridanus were collected in sufficient numbers to analyze their life histories. Both species are common. C. amica is distributed throughout southern Canada south to Florida (Provonsha 1991). Caenis simulans McDunnough was recently synonymized with €. amica by Provonsha (1991). Some life history information on C. amica (and the former C. simulans) is
available (Lyman 1955, Berner 1959, Rodgers 1982, Corkum 1985, Berner and Pescador 1987), but there have been no life history studies in the
46 mid-Atlantic region. C. floridanus occurs in the southeastern United
States (Edmunds et al. 1976), but the only life history information is
from Florida (Trost and Berner 1963). Callibaetis species are among the
few mayflies that are ovoviviparous (Gibbs 1979). This study should
contribute to the basic knowledge of mayfly life history, as well as
provide background information that would be necessary for interpreting the results of future toxicity tests in the experimental pond facility.
METHODS
This research was conducted in the Virginia Polytechnic Institute and State University experimental pond facility, which is located at the
Southern Piedmont Agricultural Experiment Station near Blackstone,
Virginia (longitude 77°57’ 30"W latitude 37°5’30"N). The facility consists of 12 0.04-ha experimental ponds, each measuring 20.1 X 20.1 m at the water surface and holding about 520 m> of water at a depth of 2.1 m The experimental ponds were first filled with water in January 1988.
The only management of the ponds has been to maintain a constant water level. There have been no experimental treatments, and there have been no fish in the ponds. Additional details about the facility can be found in the study site section of this dissertation, Layton (1989), and
Layton and Voshell (1991).
Six ponds, which were chosen randomly, were sampled for this study. I sampled for 14 mo from March 1989 through April 1990. I collected samples every 4 wk from November through April and every 2 wk
47 from May through October. An artificial substrate sample was taken from each pond on each sampling date to obtain a quantitative sample of larvae. The samplers were 10.8-cm tall x 12.2-cm diameter, round plastic buckets with 3.8-cm holes drilled in the top and sides. A 1.5- em layer of topsoil from the site was placed in the bottom of each sampler, and seven 5-cm diameter tri-pack units (Jaeger Products Inc.,
P.O. Box 16117, Houston, Texas) were placed above the soil. The samplers were deployed in March 1989 and allowed to colonize for 30 d prior to being retrieved. I randomly selected the artificial substrate samplers to be collected on each date. Samplers were retrieved by means of a boat. To avoid loss of organisms during retrieval, I placed an inverted plastic funnel over the sampler before it was removed from the bottom, and I placed a 100-um mesh net under the sampler as soon as it was visible underwater. A complete description of the artificial substrate samplers and how they were retrieved can be found in the methods section of this dissertation, Layton (1989), and Layton and
Voshell (1991). The entire sampler and the contents of the net were placed in a labeled plastic bucket, which was filled with 5% formalin for preservation of specimens.
I took qualitative benthic samples with a D-frame dip net having a
1000-ym mesh catch net to help interpret life histories. Dip net samples were standardized by sampling a square area of bottom that was approximately the width of the net (0.3 m) at a depth of 0.5 m This was repeated on each side of a pond, and the four subsamples were pooled. This protocol was designed to sample all of the different
48 microhabitats that occurred at the edges of the ponds. Qualitative samples were taken on each sampling date and preserved in 5% formalin.
In the laboratory, the artificial substrate and dip net samples were washed over a 355-um mesh soil sieve until water flowing through the sieve was clear. For the artificial substrate samples, each tri- pack unit was also scrubbed with a soft bristle brush. The material retained on the sieve was preserved in 70% ethyl alcohol. Larvae were sorted later from the detritus and sand with a stereomicroscope at 4-10X magnification.
I collected adults with a DC battery-powered blacklight (BioQuip
Products, El Segundo, CA) placed near the center of the experimental pond facility. The light trap was operated on selected nights from June to August in conjunction with benthic sampling. Adults specimens were preserved in 70% ethyl alcohol.
Growth rate of larvae was measured by the instantaneous growth method (Mackay 1972):
IGR = (loge We - loge Wo)/t
where, W, is the mean individual weight at the end of the time period,
Wo is the mean individual weight at the start of the time, and
t is the amount of time between samples.
I determined mean individual weights from a head capsule width/ body weight regression equation for each species, with a log-log
49 transformation of the data. I measured the widest distance across the head with a Zeiss/Boeckeler filar eyepiece system interfaced with an
IBM-PC microcomputer for automatic recording of data. Weights were determined by drying undamaged, preserved individuals at 60 °C for 24 hr and weighing them on a Mettler AE163 electronic microbalance. I measured and weighed 100 to 120 individuals of each species to develop the regression equations, after which I measured all other specimens with the filar eyepiece and estimated their weights from the appropriate regression equation (Fig. 1).
I determined voltinism and emergence patterns by examining size frequency graphs through time in conjunction with my data on adult flight periods. I determined size classes for populations of each taxon by plotting a histogram of all larval head widths and separating the peak frequencies. Data were organized according to numbers of individuals in each size class on each sampling date, and a histogram of size classes over time was constructed with the Lotus Freelance Plus
Graphics software package (Lotus Development Corporation, Cambridge,
MA).
I calculated secondary production, which is the amount of biomass accumulated/unit area for 1 yr, for each species with the size-frequency method (Hamilton 1969, Waters 1977, Benke 1984). I calculated production separately for each pond to obtain an estimate of the variation that existed among ponds. Negative production values between size classes were set to zero as suggested by Benke and Wallace (1980).
Production estimates were corrected using the cohort production interval
50 Figure
Ln Weight (mg) Ln Weight (ma) l. —44 —44 —6 24 —? —6 O 2 OF 2
+
4 4 Regression transformation capsule a4
LnW=LnHC(2.690)-19.629 LnW=LnHC(3.220)~23.914 Ln Ln ed Capsule Head Head R?=0.97 R“=0.98 Callibaetis —t width 6 8 6 Caenis ° Capsule lines and of floridanus amica for Width Width body the 8 + 51 the data. (um) (um) weight relationship 10 10
following between a log-log head (CPI) as suggested by Benke (1979). The CPI for both species was calculated by determining the days spent in non-producing stages (egg, subimago, adult), multiplying by the number of generations produced/ year, and subtracting the total from 365 d. I reported my production results as mg dry weight (DW)/sampler/yr + standard deviation.
Water temperature at 1 m was recorded in one pond every 2 hr throughout the study with a Tempmentor® (Ryan Instruments, Redmond,
Wash.). I measured several physicochemical parameters (Secchi depth, temperature, dissolved oxygen, pH, hardness, conductivity, alkalinity, nitrate, nitrite) at the end of the study on April 5, 1990, using standard methods (American Public Health Association et al. 1985). The same parameters had been measured from February 5, 1988 to February 10,
1989 (Jenkins 1990). I made qualitative observations on the types of macrophytes and their abundance in each pond. As new taxa appeared, representative specimens were collected by hand and taken to the laboratory for identification.
RESULTS
Caenis amica. A total of 2,969 larvae were collected in the
artificial substrate and dip net samples. Numerical abundance of larvae ranged from 3.2 to 33.5/artificial substrate sampler (Fig. 2). Highest abundance of larvae was in March, and the lowest abundance was in June.
I collected adults from June to August.
52 40 + Ja|Guios Ja|Guios Caenis amica
O+ /StuUSIUDDIO /StuUSIUDDIO
©
WN
!
_
Oo
+ / “ON “ON
oO
M AMMJd JJ Jd
40 ~ Ja|dups Ja|dups Callibaetis floridanus
30 + /SusiuDbbi0 /SusiuDbbi0
20+
10+
“ON “ON
0
Figure 2. Mean density (+ standard deviation) of larvae collected on artificial substrate samplers on each date from March 25, 1989 to April 5, 1990.
53 The life cycle of C, amica was bivoltine (Fig. 3). There was a slow developing generation, which overwintered in several size classes, followed by a fast developing summer generation. Peak emergence of the first generation was in June. Some of the first generation probably emerged in May, before I began light trapping. The second generation emerged during July and August. Early instars were present from June through October, indicating an extended period of emergence and recruitment.
The growth rate of C. amica larvae was 0.015 mg DW/d for the first
generation and 0.025 mg DW/d for the second generation. Although the overwintering first generation grew at a slower rate, larvae achieved a larger mean individual weight at maturity than larvae in the second generation that developed more rapidly in summer (0.227 and 0.138 mg DW, respectively). Annual production on the artificial substrates was 5.2 +:
1.4 mg DW/sampler/yr. Other production parameters are presented in
Table 1. I determined that the average CPI was 173.5 d, based upon two generations/ year, 8 d as eggs (Berner and Pescador 1987), Od as subimagoes (Berner and Pescador 1987), and 1 d as adults (Berner and
Pescador 1987).
Callibaetis floridanus. A total of 3,684 larvae were collected in the artificial substrate and dip net samples. Numerical abundance of larvae ranged from 0.3 to 11.7/artificial substrate sampler (Fig. 2).
Highest abundance of larvae was in March, and the lowest abundance was in June. I collected adults in April and September.
54 HdV HdV
|
HWW HWW
A0J A0J ‘sotdues ‘sotdues
syuapts syuapts
dad dad
NWP NWP
jou jou
etnsdeo etnsdeo
dtp dtp
O50 O50
pue pue
AON AON
peoy peoy
ejeajsqns ejeajsqns
LOO LOO
jo jo
LOO LOO
(sse[o (sse[o
[epoTyyj3ae [epoTyyj3ae
d3S d3S
azts azts
das das
*PeR@T[OO *PeR@T[OO
yous yous ONV ONV
jo jo
Jo Jo
ONV ONV
ejfsodmod ejfsodmod
- -
queodied) queodied)
szTNpe szTNpe
Ine Ine = _ _ =
| | |
anr anr
uo uo sajzep sajzep
uotangtiajstp uotangtiajstp
peseq peseq
NAP NAP
‘sauTT ‘sauTT
Nar Nar
aeArvT aeArvT
NAP NAP TeqIuozZTAcy TeqIuozZTAcy
Aouenbezz Aouenbezz
BOTS BOTS
AVW AVW
AVA AVA
BSypuseD BSypuseD
ozts ozts
pTog pTog ddv ddv
| | |
—r
VIN VIN
‘€ ‘€
SHNPY SHNPY
eansty eansty
- - - + + - - H H
- - T T - -- --
+ +
r r Tob Tob
Sz'0 Sz'0 B6°0 B6°0 OL'O OL'O
620 620
68°0 68°0 OO'L OO'L
Sp'0 Sp'0
€5°0 €5°0 6L'0 6L'0
19°0
1e0 1e0 bt bt (WLU) SASSBID 8ZIS
55 Table l. Summary of production by Ephemeroptera in experimental ponds. N, mean number of individuals collected (average number of individuals/sampler/date); B, mean standing stock biomass (mg/sampler/date); P, annual production (mg/sampler/yr); P/B, production to biomass ratio. Each value is followed by its standard deviation.
Species N B P P/B
Callibaetis floridanus 3,741.6 0.7+0. 2 11.5+4.4 16.4
Caenis amica 10. 2+3.6 0.4+0.1 5. 2241.4 13.0
56 The life cycle of C. floridanus was bivoltine (Fig. 4). The two generations required about the same length of time to develop.
Emergence of the first generation peaked in May but may have begun as early as March. The second generation emerged in September. Early instars were present throughout most of the year, indicating extended periods of emergence and recruitment.
The growth rate of C. floridanus larvae was 0.011 mg DW/d for the first generation and 0.015 mg DW/d for the second generation. Mean individual weight of larvae at maturity was 0.867 mg DW for the first generation and 0.643 mg DW for the second generation. Annual production on the artificial substrates was 11.5 + 4.4 mg DW/sampler/yr. Other production parameters are presented in Table 1. I determined that the average CPI was 175.5 d, based upon two generations/ year, 0d as eggs
(Trost and Berner 1963), 1 d as subimagoes (Trost and Berner 1963), and
6 das adults (Trost and Berner 1963).
Environmental Characteristics. Results of physicochemical measurements are presented in Table 2 and Fig. 5. These values indicate that water quality in the ponds was not detrimental to aquatic life
(USEPA 1976); however, nutrient and chlorophyll a concentrations were indicative of oligotrophic conditions. Water temperature was very warm but typical for ponds at this latitude and elevation. Emergent macrophytes were well established at the edges of the ponds at the beginning of the study, including: Carex, Cyperus, Eleocharis,
Hypericum, Juncus, Ludwigia, and Typha (Rosenzweig 1990). A submerged macrophyte, Potamogeton, was first observed in one pond in June 1989.
57 HYdvV HYdvV
[] [| [|
7 Cc qeu
10} 10}
HV HV
dtp dtp
syaptm syaptm
Gad Gad
pue pue
NVf NVf
ajevaqeqns ajevaqeqns etnsdeo etnsdeo
O30 O30
AON AON
pesy pesy
TefoTyT3ae TefoTyT3ae
LOO LOO
jo jo
LOO LOO
(sse{to (sse{to
‘pa ‘pa
qoeTTOo qoeTTOo
d3S d3S
jo jo
[ [ | |
ezts ezts
aqfsodwod aqfsodwod
daS daS
- -
| |
sya sya
youe youe
onv onv —Mpe —Mpe
a | |
ONV ONV Jo Jo
uo uo
sajep sajep
queodjzed) queodjzed)
paseq paseq
Nr Nr
‘souTT ‘souTT
nr nr
seareT seareT tf tf
| | | |
uotangtaqstp uotangtaqstp
NAr NAr
[equoztaocy [equoztaocy | |
| |
SNUBPTACTF SNUBPTACTF
NAP NAP
NAP NAP
Aouenbaaraz Aouenbaaraz
pjTog pjTog
AWW AWW
SFIeeqt SFIeeqt 1 1
AVW AVW
-‘seTdues -‘seTdues
| | | |
[ [
ddv ddv
azts azts
— —
a a
[ey [ey
HVA HVA
| | | |
synpy synpy *y *y
~- ~-
--99'0 --99'0 L | 980 980 -8'0 -8'0 _€b'0 _€b'0 -~OS'0 -~OS'0 - - zh zh -Q0'L r r
LEE LEE eek eek
-26'0 -26'0
ve" ve"
O€'0 O€'0
70 70 €8'0 €8'0
19'L aan3sty aan3sty
(uw) SOSSB]D @ZIS
58 Table 2. Ranges for environmental characteristics measured in experimental ponds.
Parameter year 1 Feb. 10, 1989 Apr. 5, 1990
Temperature, °C 3. 9-30.0 11.6-12.8 11.8-14.0
Dissolved oxygen, mg/liter 5. 8-12.8 11.6-12.8 9.8-11.8 pH 6. 6-8.6 7.5-7.7 7.1-8.5
Alkalinity, mg CaC03/liter 26. 0-60. 8 34. 2-49. 8 20. 0O-37.1
Hardness, mg CaC0O3/liter 20. 0-85. 0 50. 0-70. 0 50. 0-70. 0
Conductivity, sumhos 25% 132. 6-252.5 148. 7-185. 1 68. 0-125. 0
NO2, mg/liter 0. 0-1. 68 0. 0-0. 03 0. 0-0.0
NO3, mg/liter 0. 0-1. 76 Q. 0-0. 03 0. 09-0.28
Secchi, m 0. 3-2. 2 1.1-1.4 0. 6-2.1
Chlorophyll a, mg/liter 0. 0-21. 2 2.1-12.3 0.0-4.7
59 Degrees C 30 Figure
5. WU WU 1989 Temperature AA... Accumulated \ to vy April 60 of degree-days 5, Pond V 1990. 5 (above at 1 m 0°C) from = 6694 March
25, By the end of this study, Potamogeton was present in five of the ponds that were included in this study and covered approximately 5 to 952% of the bottom of those ponds.
DISCUSSION
The life history of both species matches type Bl in the classification scheme for mayfly life histories suggested by Landa
(1968). Type Bl mayflies have two generations/ year, with eggs of the first generation hatching in autumn, larvae developing during winter, and adults emerging in spring, followed by a second generation that develops during summer. The life history of C. amica in the
experimental ponds agrees with most previous reports for this species, but there is a discrepancy with previous reports for G floridanus. C. amica has been reported as univoltine in Illinois (as C. simulans, Lyman
1955), bivoltine in Alberta Canada (as C. simulans, Corkum 1985), and bivoltine in Alabama (Rodgers 1982). Most species of Callibaetis have been reported as having multivoltine life cycles (Clifford 1982), including C. floridanus in Florida (Trost and Berner 1963).
There is little information available on production or growth of the two species that I investigated, but it appears that production and growth were low in the experimental ponds. Rodgers (1982) reported that production of C. amica was 676 mg DW/ m¢/ yr in slow-moving experimental streams in Alabama. Comparison of results is difficult, because she used a combination of sample types: 282% scrapings from concrete walls,
61 24% rock basket artificial substrates placed in current, and 482% bottom samples from soft substratum in pools. Converting my results to bottom area sampled by the artificial substrates (0.012 m-), gives an estimated production of only about 400 mg DW/ m@/ yr by C. amica in the experimental ponds, and this is probably an overestimate of actual production in the ponds because the artificial substrate samplers were much more complex than the natural substratum Welton et al. (1982) found the combined production of the two most abundant species of mayflies in experimental streams, Baetis rhodani and Ephemerella ignita, to be 10,000 mg
DW/ m2/ yr, whereas I measured total production of the two most abundant species in the experimental ponds to be only about 1,400 mg DW/ m/ yr
(converted to bottom area).
Growth rates of both species in the experimental ponds were at the low end of the range reported for growth rates of other species. For example, Bird and Kaushik (1984) found that Ephemerella subvaria grew
0.003 to 0.056 mg DW/d, and Hawkins (1986) measured growth rates from
0.008 to 0.58 mg DW/d for several species of Ephemerellidae.
Temperature, food, and habitat are factors that could have affected the success of C. amica and C. floridanus in the experimental ponds (Minshall 1984, Sweeney 1984). Temperature differences might partially explain the lower annual production of C. amica and the fewer generations of C. floridanus observed in the experimental ponds as compared to other studies (Rodgers 1982 and Trost and Berner 1963, respectively). Although these other authors did not report accumulated degree-days, it can be assumed that the number of accumulated degree-
62 days was higher in Alabama and Florida than in Virginia. Trost and
Berner (1963) found that C. floridanus could complete a generation in 60 to 75 d at 18 to 20 °C.
Temperature does not explain the low growth rates observed for the two species in the experimental ponds. Trost and Berner (1963) found that C. floridanus completed a generation in 27 to 35 d at 28 to 32 %, whereas the second generation of this species required about 77 d to develop in the experimental ponds at similar temperatures. Low food quantity or quality and lack of preferred habitat probably contributed to the low growth rates in the experimental ponds. Both species feed on a combination of algae and detritus (Berner 1959, Edmunds 1984), but algae is more nutritious food (Cummins and Klug 1979). Periphyton was very abundant in the experimental streams in which high production of C. amica was reported (Armitage 1980, Rodgers 1982). Secchi disk,
nutrient, and chlorophyll a values (Table 2) indicate that the experimental ponds are oligotrophic and not much algae is produced. New lentic environments are often rich in terrestrial detritus, but that food source usually disappears after the first year (Voshell and Simmons
1984). Production of C. amica and C. floridanus was higher in the first year after filling (8 and 14 mg DW/sampler/yr, respectively; Layton
1989) than in the second year after filling reported in this study.
Both species are most abundant in macrophytes, with C. amica dwelling on the bottom at the base of the plants and C. floridanus climbing on the plants (Berner 1959, Trost and Berner 1963). Macrophytes, especially submerged macrophytes, were sparse during much of this study. Growth
63 and production of these two species may increase slightly in future years as the submerged macrophyte Potamogeton becomes more abundant; however, growth and production will likely remain relatively low because of the overriding influence of low food resources brought about by the oligotrophic status of the experimental ponds.
ACKNOWLEDGEMENTS
We are grateful for the assistance of James L. Tramel, Jr. and W.
B. Wilkinson, III for on-site administration and management of the experimental pond facility. Persons who provided valuable technical assistance included: Stephen W. Hiner, Michael 0. West, T. Michael
Williams, and Lourdes M George. This research was partially supported by the Virginia Agricultural Experiment Station, Hatch Program
64 MANUSCRIPT II: LIFE HISTORY, GROWTH, AND PRODUCTION OF ODONATA IN
EXPERIMENTAL PONDS
ABSTRACT
I determined voltinism, emergence patterns, larval growth rates
(instantaneous growth method), and annual production (size-frequency method) for Anax junius, Gomphus exilis, and Enallagma civile in six experimental ponds. In addition, annual production was determined for a group of Libellulidae species. Larvae were sampled with artificial substrates and a dip net, exuviae were collected on shore emergence structures, and adults were sampled with an aerial net. All species were univoltine. Resident populations of A. junius emerged as adults from June to August, and non-resident populations emerged in September and October. G. exilis emerged from May to June, and E. civile emerged from April to October. Larval growth rates were 0.028 mg DW/d and 0.061 mg DW/d for the resident and migratory populations of A junius, respectively. Growth rates were 0.017 mg DW/d for G. exilis and 0.012 mg DW/d for E. civile. Annual production was 673 mg DW/dip net sample/yr for A. junius, 39 mg DW/dip net sample/yr for G. exilis, 10 mg
DW artificial substrate sampler/yr for E. civile, and 34 mg
DW/ artificial substrate sampler/yr for Libellulidae. Production of
Odonata in the experimental ponds appears to be low, compared to reports from other lentic environments. Some of the observed differences may
65 have been at least partly caused by food (low production of prey) and habitat (sparse macrophytes).
INTRODUCTION
Odonata show remarkable variation in life history (Corbet 1980).
Temperature, food, and photoperiod are factors that contribute to the observed variability. Odonata can vary the number of larval molts before emergence, allowing them to adjust to adverse conditions by emerging sooner, although smaller in size, and still complete their life cycle. Life history variabilities make it difficult to interpret environmental impact studies involving Odonata. Buikema and Benfield
(1979) explained that life history parameters of test organisms must be understood and quantified to accurately interpret the results of toxicity tests.
The purpose of this study was to determine the growth rates, voltinism, emergence patterns, and annual production of Anax junius
(Drury) (Aeshnidae), Gomphus exilis Selys (Gomphidae), and Enallagma civile (Hagen) (Coenagrionidae) in a set of experimental ponds designed for environmental toxicity tests. Of all the Odonata collected in the ponds (Table 1), only these three species were collected in sufficient numbers to analyze their life histories. All three species are common.
& junius is distributed from southern Canada south to Jamaica and west to the Coast of Asia (Carle 1982). Some life history information on A junius is available (Calvert 1934, Macklin 1963, Tottier 1971), but
66 Table l. List of Odonata collected from experimental ponds from March 25, 1989 to April 5, 1990.
ANISOPTERA Aes hnidae x junius :
Gomphidae Gomphus exilis
Macromiidae Macromia
Corduliidae Tetragoneuria cynosura
Libellulidae Celithemis elisa C. eponina C. fasciata Erythemis simplicicollis Erythrodiplax minuscula Ladona deplanata Libellula incesta L. luctuosa Pantala flavescens P. hymenea Perithemis tenera Sympetrum vicinum
ZYGOPTERA Lestidae Lestes disjunctus australis
Coenagrionidae Anomalagrion hastatum Enallagma aspersum E. basidens E. civile E. signatum Ischnura posita
67 there have been no life history studies in the mid-Atlantic region. G. exilis occurs in southeastern Canada and the eastern United States
(Carle 1982), but the only life history information available is on patterns of emergence in North Carolina (Lutz and McMahan 1973). E, civile occurs from southern Canada south to the West Indies and
Colombia, and from the east to the west coasts of United States (Walker
1953). There have been a few studies on some aspects of the life history of E. civile (Bick and Bick 1963, Bick and Hornuff 1966), but these studies dealt mainly with reproductive behavior and were not conducted in the mid-Atlantic region. In addition, I determined the annual production for a group of Libellulidae species (Table 1), whose larvae could not be distinguished reliably even to genus. My study contributes to the basic knowledge of Odonata life history, as well as providing background information that is necessary for interpreting the results of future toxicity tests in the experimental pond facility.
METHODS
This study was conducted in the Virginia Polytechnic Institute and
State University experimental pond facility, which is located at the
Southern Piedmont Agricultural Experiment Station near Blackstone
(longitude 77057’ 30"W latitude 3705’30"N). The facility consists of 12
0.04-ha experimental ponds, each measuring 20.1 X 20.1 m at the water surface and holding about 520 m? of water at a depth of 2.1 m The experimental ponds were first filled with water in January 1988. The
68 only management of the ponds has been to maintain a constant water level. There have been no experimental treatments and there have been no fish in the ponds. Additional details about the facility can be found in the study site section of this dissertation, Layton (1989), and
Layton and Voshell (1991).
Six ponds, which were chosen randomly, were sampled for this study. I sampled for 14 mo from March 1989 through April 1990. I collected samples ever 4 wk from November through April and every 2 wk from May through October. An artificial substrate sample was taken from each pond on each sampling date to obtain a quantitative sample of larvae. The samplers were 10.8-cm tall X 12.2-cm diameter, round plastic buckets with 3.8-cm holes drilled in the top and sides. A1.5- em layer of topsoil from the site was placed in the bottom of each sampler, and seven 5-cm diameter tri-pack units (Jaeger Products Inc.,
P.O. Box 16117, Houston, Texas) were placed above the soil. The samplers were deployed in March 1989 and allowed to colonize for 30 d prior to being retrieved. I randomly selected the artificial substrate samplers to be collected on each date. Samplers were retrieved by means of a boat. To avoid loss of organisms during retrieval, I placed an inverted plastic funnel over the sampler before it was removed from the bottom, and I placed a 100-ym mesh net under the sampler as soon as it was visible underwater. A complete description of the artificial substrate samplers and how they were retrieved can be found in the methods section of this dissertation, Layton (1989), and Layton and
Voshell (1991). The entire sampler and the contents of the net were
69 placed in a labeled plastic bucket, which was filled with 5% formalin for preservation of specimens.
I took qualitative benthic samples with a D-frame dip net having a
1000-um mesh catch net. Dip net samples were standardized by sampling a square area of bottom that was approximately the width of the net (0.3 m) at a depth of 0.5 m This was repeated on each side of a pond, and the four subsamples were pooled. This protocol was designed to sample all of the different microhabitats that occurred at the edges of the ponds. Qualitative samples were taken on each sampling date and preserved in 52 formalin.
In the laboratory, the artificial substrate and dip net samples were washed over a 355-um mesh soil sieve until water flowing through the sieve was almost clear. For the artificial substrate samples, each tri-pack unit was also scrubbed with a soft bristle brush. The material retained on the sieve was preserved in 70% ethyl alcohol. Larvae were sorted later from the detritus and sand with a stereomicroscope at 4-10X magnification.
I collected adult Odonata with an aerial net. Damselflies were collected by sweeping vegetation at the edge of the ponds, and dragonflies were sampled by seeking specific individuals. Specimens were first put in paper triangles, then placed in acetone for about 24 hr, removed and allowed to dry, and finally stored in individual cellophane envelopes. The acetone extraction technique preserves natural colors and makes identification easier (Steyskal et al. 1986).
Exuviae were collected on shore emergence structures that consisted of
70 0.45 K 10-m sections of nylon window screen stapled to wooden stakes.
One emergence structure was placed in each pond about 0.3 m from shore, with the bottom edge flush with the bottom and the top edge extending
0.2 m above the water surface.
Growth rate of larvae was measured by the instantaneous growth method (Mackay 1972):
IGR = (loge We - loge Wo)/t
where, W, is the mean individual weight at the end of the time period,
Wo is the mean individual weight at the start of the time, and
t is the amount of time between samples.
I determined mean individual weights from a head capsule width/ body weight regression equation for each species, with a log-log transformation of the data. I measured the widest distance across the head with a Zeiss/Boeckeler filar eyepiece system interfaced with an
IBM-PC microcomputer for automatic recording of data. Weights were determined by drying undamaged, preserved individuals at 60 °C for 24 hr and then weighing them on a Mettler AE163 electronic microbalance. I measured and weighed 50 to 100 individuals of each taxon to develop the regression equations, after which I measured all other specimens with the filar eyepiece and estimated their weights from the appropriate regression equation (Fig. 1).
71 Anax Junius Gomphus exilis
6 6 LAW = LnHC(3.857)-30.104 LnW=LnHC(3.084)~22 988 7 R*=0.99 47 R2=0.99
2+ (mg) (mg) 0+ 5 0 + ‘oO
= Weight Weight —? + s 94
Ln Ln | —44 —4 a ; O |
—6 + — —6 4 4 6 8 10 4 6 8 Ln Head Capsule Width (um) Ln Head Capsule Width (um)
Enallagma civile
6 LnW=LnHC(2.982)— 23.204 47 R*=0.98
? +
(mg) o+
Weight —2+ O
Ln
—~44 }
—§ | t 4 6 8 10 Ln Head Capsule Width (um)
Figure l. Regression lines for the relationship between head capsule width and body weight following a log-log transformation of the data.
72 I determined voltinism and emergence patterns by examining size frequency graphs through time in conjunction with my data on adult flight periods and exuviae. I determined size classes for populations of each taxon by plotting a histogram of all larval head widths and separating the peak frequencies. Data were organized according to numbers of individuals in each size class on each sampling date, and a histogram of size classes over time was constructed with the Lotus,
Freelance Graphics software package (Lotus Development Corporation,
Cambridge, MA).
I calculated secondary production, which is the amount of biomass accumulated/unit area for l yr, for each species with the size-frequency method (Hamilton 1969, Waters 1977, Benke 1984). I calculated production separately for each pond to obtain an estimate of the variation that existed among ponds. Negative production values between size classes were set to zero as suggested by Benke and Wallace (1980).
Production estimates were corrected using the cohort production interval
(CPI) as suggested by Benke (1979). The CPI for each species was calculated by either subtracting the days spent in non-producing stages
(egg, adult) from 365 d or by adding the number of days spent in the larval stage. I reported my production results as mg dry weight
(DW) /sample/yr + standard deviation.
Water temperature at 1 m was recorded in one pond every 2 hr throughout the study with a Tempmentor® (Ryan Instruments, Redmond,
Wash.). I measured several physicochemical parameters (Secchi depth, temperature, dissolved oxygen, pH, hardness, conductivity, alkalinity,
73 nitrate, nitrite) at the end of the study on April 5, 1990, using standard methods (American Public Health Association et al. 1985). The same parameters had been measured from February 5, 1988 to February 10,
1989 (Jenkins 1990). I made qualitative observations on the types of macrophytes and their abundance in each pond. As new taxa appeared, representative specimens were collected by hand and identified in the laboratory.
RESULTS
Anax junius. A total of 431 larvae were collected in the artificial substrate and dip net samples. Mean numerical abundance of larvae ranged from 0 to 1.8/artificial substrate sampler and from 0 to
25.5/dip net sample (Fig. 2). Highest abundance of larvae was in July and the lowest abundance was in May.
The life cycle of A. junius was univoltine (Fig. 3); however, there appeared to be two different populations in the ponds that were similar to the resident and migratory populations reported by Tottier
(1971). Adults were collected in early May, but exuviae were not found until mid-June. It is unlikely that exuviae of A. junius were overlooked from early May to mid-June because this was an abundant species and its exuviae were large and conspicuous. Therefore, the adults collected at the ponds in early May may have migrated from the south, as Tottier (1971) demonstrated for a pond in Canada. Eggs of the migratory population hatched in late May and June, larvae developed
74 30 T Anax junius & a A € o 2 20 + ” € 2 c is 10+ i 3Le /| 8 S / | TT } < + Ai A-A~Z T + 4 _ QO —0 ap ei zh ne Qka7 ft qkolece = VARA ol fa
0 q TO NN rs re es | ~T eT t qT | | TT Fey MVM pT M eAMMJ4JsJJSSAAS S00 +N DG FM A
30 + Gomphus exills v | Oo. a & oO nO NN oO E 2 Cc Oo 2 oO O° Zz
100 + Enallagma civile & ESao 80 J + a a
5 \/ a Oo 60 Tr 4 € 2 oc mo Oay ° Zz M AMMJJdJJst J VAAS SOO N DS FM A
Figure 2. Mean density (+ standard deviation) of larvae collected on each date from March 25, 1989 to April 5, 1990. Circle, artificial substrate sample; triangle, dip net sample.
75
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76 during summer, and adults emerged in late September and early October.
Adults of the migratory population then left the vicinity of the ponds without laying eggs. Adults of the resident population emerged from late June through August, and eggs hatched in July and August. Larvae of the resident population developed slowly, reaching middle size classes by October and November, then spent winter and spring in several large size classes.
The growth rates of A. junius larvae were 0.061 mg DW/d for the migratory population and 0.028 mg DW/d for the resident population.
Annual production was 673.2 + 314.5 mg DW/dip net sample/ yr. Other production parameters are presented in Table 2. Production was calculated only from the dip net samples, because too few larvae were collected on the artificial substrate samplers. I determined that the average CPI was 245.5 d by averaging the number of days that each population spent as larvae.
Gomphus exilis. A total of 636 larvae were collected in the artificial substrate and dip net samples. Mean numerical abundance of larvae ranged from 0 to 0.2/artificial substrate sampler and from 0.2 to
26.2/dip net sample (Fig. 2). Highest abundance of larvae was in June and July, and the lowest abundance was in April.
The life cycle of G exilis was univoltine (Fig. 4). Although exuviae were only collected in early June, adults apparently began emerging in early May and continued until at least late June. Peak emergence of adults was in late May and early June. Small size classes
77 Table 2. Summary of production by Odonata in experimental ponds. N, mean number of individuals collected (average number of individuals/sample/date); B, mean standing stock biomass (mg/sample/date); P, annual production (mg/sample/ yr); P/B, production to biomass ratio. Each value is followed by its standard deviation.
Taxon N B P P/B
Anax junius 3,741.2 37.6425. 9 673. 24314. 6 17.9
Gomphus exilis 6,141.3 3,241.7 38. 6417.8 12.1
Enallagma civile 5.5+1.5 1.3+0.5 10.3+3.1 7.9
Libellulidae 9.02+4.5 4,542.7 34.4418.9 7.6
78
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79 of larvae were present from June until July. Larvae overwintered in several medium to large size classes.
The growth rate of G exilis larvae was 0.017 mg DW/d. Annual production was 38.6 + 17.8 mg DW/dip net sample/yr. Other production parameters are presented in Table 2. Production was calculated only from the dip net samples, because too few larvae were collected on the artificial substrate samplers. I determined that the average CPI was
323.5 d, based upon 365 d minus 22.5 d as eggs (Corbet 1980) and 14 d as adults (Corbet 1980).
Enallagma civile. A total of 2,517 larvae were collected in the artificial substrate and dip net samples. Mean numerical abundance of larvae ranged from 0.5 to 12.0/artificial substrate sampler and from 4.2 to 82.0/dip net sample (Fig. 2). Highest abundance of larvae was in
June and July and the lowest abundance was in April and May. The following species of damselflies in the family Coenagrionidae also occurred in the ponds and could not be distinguished reliably from E. civile as larvae: E. aspersum (Hagen), E. basidens Calvert, E. signatum
(Hagen), Ischnura posita (Hagen), and Anomalagrion hastatum (Say).
Based upon collections of adults that could be identified to species, I estimated that >90% of larvae in the ponds were E. civile.
The life cycle of E. civile was univoltine (Fig. 5). Extended adult emergence from April to October resulted in corresponding extended recruitment of larvae from May to October and overwintering in almost all size classes. Collections of exuviae and adults indicated peaks of adult emergence in early May and early August.
80
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81 The growth rate of E. civile larvae was 0.012 mg DW/d. Annual production was 10.3 + 3.1 mg DW/artificial substrate sampler/yr. Other production parameters are presented in Table 2. I determined that the average CPI was 336.5 d, based upon 365 d minus 21.5 d as eggs (Brigham et al. 1982), and 7 d as adults (Bick and Bick 1963).
Libellulidae. Because there were so many species of Libellulidae in the ponds that could not be reliably distinguished as larvae (Table
1), it was not possible to analyze voltinism, emergence patterns, and larval growth rates; however, the size-frequency method is appropriate for determining production of groups of similar size taxa (Hynes and
Coleman 1968). Production of all Libellulidae was 34.4 + 18.9 mg
DW/artificial substrate sampler/yr. Other production parameters are presented in Table 2. I determined that the average CPI was 323.5 d, based upon 365 d minus 22.5 d as eggs (Corbet 1980), and 19 d as adults
(Brigham et al. 1982).
Environmental Characteristics. Results of physicochemical measurements are presented in Table 3 and Fig. 6. These values indicate that water quality in the ponds was not detrimental to aquatic life
(USEPA 1976); however, nutrient and chlorophyll a concentrations were indicative of oligotrophic conditions. Water temperature was very warm but typical for ponds at this latitude and elevation. Emergent macrophytes were well established at the edges of the ponds at the beginning of the study, including: Carex, Cyperus, Eleocharis,
Hypericum, Juncus, Ludwigia, and Typha (Rosenzweig 1990). A submerged macrophyte, Potamogeton, was first observed in one pond in June 1989.
82 Table 3. Ranges for environmental characteristics measured in experimental ponds.
Parameter year 1 Feb. 10, 1989 Apr. 5, 1990
Temperature, °C 3. 9-30. 0 11.6-12.8 11. 8-14.0
Dissolved oxygen, mg/liter 5. 8-12. 8 11.6-12.8 9.8-11.8 pH 6. 6-8.6 7.5-7.7 7.1-8.5
Alkalinity, mg CaC0O3/liter 26. 0-60. 8 34. 2-49. 8 20. 0-37.1
Hardness, mg CaC03/liter 20. 0-85. 0 50. 0-70. 0 50. 0-70. 0
Conductivity, mumhos 25% 132. 6-252.5 148. 7-185. 1 68. 0-125. 0
NO2, mg/liter 0. 0-1. 68 0. 0-0. 03 0.0-0.0
NO3, mg/liter 0. 0-1. 76 0. 0-0. 03 0. 09-0. 28
Secchi, m 0. 3-2.2 1.1-1.4 0.6-2.1
Chlorophyll a, mg/liter 0.0-21.2 2.1-12.3 0.0-4.7
83
Accumulated degree-days (above 0°C) = 6694
A Low ,
C | _f\ Prey he, Wy wr Degrees a} v
F M A
Figure 6. Temperature of Pond 5 at 1 m from March 25, 1989 to April 5, 1990.
84 By the end of this study, Potamogeton was present in five of the ponds
that were included in this study and covered approximately 5 to 95% of the bottom of those ponds.
DISCUSSION
Corbet (1954) classified Odonata into types according to their life cycles. In this study G exilis fit the spring species type (those
with short synchronous emergences), and A. junius and E. civile fit the summer species type (those with asynchronous emergence periods lasting several months).
The life histories of A junius, G. exilis, and E. civile in the experimental ponds agree with most previous reports for these species.
A. junius has been reported to take 326 d to complete development in southern Canada (Calvert 1936), which is similar to the length of time required for the resident population in the experimental ponds (330 d).
A. junius has also been reported to take 111 d to complete development in Illinois (Macklin 1963), which is similar to the length of time
required for the migratory population in the experimental ponds (150 d).
Tottier (1971) determined that resident and migratory populations
inhabiting the same pond in Canada required 11 mo and 3 mo to develop,
respectively. G. exilis has been reported to have an early spring emergence (Lutz and McMahan 1973), with the possibility of being
semivoltine (Paulson and Jenner 1971) in North Carolina. E. civile has
been reported to be univoltine with extended adult flight period
85 (Montgomery 1942, Johnson et al. 1980). Ingram and Jenner (1976) found that about 8% of a population of Enallagma aspersum (Hagen) was bivoltine in North Carolina. It is possible that a portion of the E. civile population in the experimental ponds maybe bivoltine. Evidence to support partial bivoltinism was a second peak of adult emergence in early August followed by a slight increase in recruitment of small size classes (Fig. 5).
There is little comparable information on production of Odonata in lentic environments, but production appears to be low in the experimental ponds. Benke (1976) reported that the combined production of the three most abundant taxa of Odonata in the littoral zone of a farm pond, Ladona deplanata Rambur, Epitheca spp., and Celithemis fasciata Kirby, was 5,890 mg DW/ m@/ yr. I converted results from artificial substrate samples and dip net samples to area of pond bottom using the areas of the samples as conversion factors (0.012 m2 and 0. 36 m*, respectively. Production of dragonflies (A. junius, G. exilis, all
Libellulidae) was estimated to be about 4,840 mg DwW/ m*/ yr in the experimental ponds; however, this estimate includes production of 17 species, and production of Libellulidae is probably overestimated by the conversion because the artificial substrate samplers are more complex than the natural pond bottom
Temperature, food, and habitat are factors that could cause low production of Odonata in the experimental ponds (Benke 1984, Minshall
1984, Sweeney 1984); however, temperature does not appear to be a factor. The mean annual temperatures in the farm pond in Georgia where
86 Benke (1976) conducted his study and the experimental ponds used in this study were very similar (16 °c and 18 °c, respectively). If the 2 °c difference in mean annual temperature of the two study sites exerted a significant influence, production would be expected to be higher in the experimental ponds.
Low quantity of food and lack of preferred habitat probably contributed to the low production values in the experimental ponds. All
Odonata are predators, feeding opportunistically on a variety of prey such as Chironomidae, Ephemeroptera, Trichoptera, and zooplankton
(Dudgeon 1989, Wissinger 1988, Paulson and Jenner 1971, Thorp and
Cothran 1984, Benke 1978). Of the potential prey for Odonata in the experimental pond, I only measured production of Ephemeroptera during the same year, but I found Ephemeroptera production to be quite low (see
Chapter I of this dissertation). Secchi disk, nutrient, and chlorophyll a values (Table 3) indicate that the experimental ponds are oligotrophic, which would limit production of prey organisms, such as
Ephemeroptera, for Odonata. Most of the Odonata found in the experimental ponds are most abundant on macrophytes (Tottier 1971,
Crowley and Johnson 1982). Macrophytes, especially submerged macrophytes, were sparse during much of this study. Production of
Odonata may increase slightly in future years as the submerged macrophyte, Potamogeton becomes more abundant; however, growth and production will likely remain relatively low because of the overriding influence of low food resources brought about by the oligotrophic status of the experimental ponds.
87 ACKNOWLEDGEMENTS
We are grateful for the assistance of James L. Tramel, Jr. and W.
B. Wilkinson, III for on-site administration and management of the experimental pond facility. Persons who provided valuable technical assistance included: Stephen W. Hiner, Michael 0. West, T. Michael
Williams, and Lourdes M George. This research was partially supported by the Virginia Agricultural Experiment Station, Hatch Program.
88 MANUSCRIPT III: SUCCESSIONAL CHANGES IN THE BENTHIC MACROINVERTEBRATES
OF NEW EXPERIMENTAL PONDS
ABSTRACT
The objective of this study was to determine if the community structure of a set of experimental ponds changed significantly during the second year of their existence. Comparison of the community at the end of year 1 to the community at the end of year 2 showed no significant differences for community summary measures (total density, taxa richness, diversity, Bray-Curtis similarity index); however, some individual taxa densities were significantly lower at the end of year 2.
Physicochemical parameters measured indicated that the ponds were oligotrophic. Submerged macrophytes colonized and became established in most of the ponds during year 2. The experimental pond communities followed expected seasonal patterns of fluctuation and resembled the communities that would be expected in shallow lentic environments, with the exception of a few noninsect taxa.
INTRODUCTION
Experimental ponds have been used for a long time to study fisheries management (Swingle 1947, 1950), ecological principles (Hall et al. 1970), and effects of various perturbations (see review in
Buikema and Voshell 1991). Odum (1984) explained the importance of
89 ecological studies in mesocosms, which he defined as "... bounded and partially enclosed outdoor experimental setups...falling between laboratory microcosms and the large, complex, real world macrocosms"
(p.558). Experimental ponds are a type of mesocosm (Buikema and Voshell
1991), and the U. S. Environmental Protection Agency has begun to require simulated field studies in pond mesocosms as part of registration requirements for some pesticides (Touart 1988, Touart and
Slimak 1989). Benthic macroinvertebrates are some of the organisms most often studied in experimental ponds (Buikema and Voshell 1991). When new lentic environments are constructed, benthic macroinvertebrate communities undergo changes for a number of years (Paterson and Fernando
1970, Street and Titmus 1979, Danell and Sjoberg 1982, Barnes 1983,
Voshell and Simmons 1984). Several studies have described the initial colonization of replicate experimental ponds (Howick et al. 1991,
Ferrington et al. 1991, Layton and Voshell 1991); however, there have been no studies of benthic macroinvertebrate succession, even though such information is important for interpreting the results of any experiment conducted in replicate ponds.
The purpose of this study was to describe and explain the successional changes in benthic macroinvertebrates that occurred during the first 2 yr in a set of replicate experimental ponds. The ponds were not managed except to maintain constant water level and received no experimental treatments. There were no fish in the ponds during the study.
90 METHODS
This study was conducted in the Virginia Polytechnic Institute and
State University experimental pond facility, which is located at the
Southern Piedmont Agricultural Experiment Station near Blackstone
(longitude 77°57’ 30"W latitude 37°5’30"N). The facility consists of 12
0.04-ha experimental ponds, each measuring 20.1 X 20.1 m at the water surface and holding about 520 m> of water at a depth of 2.1 m The experimental ponds were first filled with water in January 1988.
Additional details about the facility can be found in the study site section of this dissertation, Layton (1989), and Layton and Voshell
(1991).
Layton and Voshell (1991) had already determined the numbers and kinds of benthic macroinvertebrates that occurred in all ponds during the first year after filling (January 1988 to February 1989). In this study, I chose six ponds randomly. and sampled the benthic macroinvertebrates in them from March 1989 to April 1990. I used the same sampling methods and analyzed samples taken at the same interval (4 wk) as Layton and Voshell (1991). When I compared the benthic macroinvertebrates between years, I only used data from the same six ponds for the first year.
An artificial substrate sample was taken from each pond on each sampling date to obtain a quantitative sample of benthic macroinvertebrates. The samplers were 10.8-cm tall x 12.2-cm diameter, round plastic buckets with 3.8-cm holes drilled in the top and sides. A
91 1.5-cm layer of topsoil from the site was placed in the bottom of each sampler, and seven 5-cm diameter tri-pack units (Jaeger Products Inc.,
P.O. Box 16117, Houston, Texas) were placed above the soil. I placed enough samplers for the entire year in March 1989 and allowed them to colonize for 30 d before retrieving the first ones. The samplers retrieved in March 1989 had been placed previously by Layton and Voshell
(1991). I randomly selected the artificial substrate samplers to be collected on each date. Samplers were retrieved by means of a boat. To avoid loss of organisms during retrieval, I placed an inverted plastic funnel over the sampler before it was removed from the bottom, and I placed a 100-ym mesh net under the sampler as soon as it was visible underwater. A complete description of the artificial substrate samplers and how they were retrieved can be found in the methods section of this dissertation, Layton (1989), and Layton and Voshell (1991). The entire sampler and the contents of the net were placed in a labeled plastic bucket, which was filled with 5% formalin for preservation of specimens.
I collected adult insects with a DC battery-powered blacklight (BioQuip
Products, El Segundo, CA) placed near the center of the experimental pond facility and by aerial netting throughout the facility. Adult insects were collected on selected dates from April to October in conjunction with benthic sampling.
In the laboratory, the artificial substrate samples were washed over a 355-um mesh soil sieve until water flowing through the sieve was almost clear. Each tri-pack unit was scrubbed with a soft bristle brush. The material retained on the sieve was preserved in 702% ethyl
92 alcohol. Benthic macroinvertebrates were sorted later from the detritus
and sand with a stereomicroscope at 4-10X magnification, then identified
to the lowest possible taxonomic level. To determine if significant
changes in the benthic macroinvertebrate community occurred in the second year, the following measures were compared at the end of year 1
(February 10, 1989) and the end of year 2 (March 5, 1990) using 2-sample
t-tests: total density, taxa richness, Shannon diversity index, percent
of density comprised by major functional feeding groups, and density of
common individual taxa (those with annual mean density >= 1 organism/sampler). In addition, the Bray-Curtis similarity index was
also used to compare the entire community following the design and analysis of Hruby (1987).
Water temperature at 1 m was recorded in one pond every 2 hr throughout both years with a Tempmentor® (Ryan Instruments, Redmond,
Wash.). I measured several physicochemical parameters (Secchi depth, temperature, dissolved oxygen, pH, hardness, conductivity, alkalinity, nitrate, nitrite) at the end of the study on April 5, 1990, using standard methods (American Public Health Association et al. 1985). The same parameters had been measured from February 5, 1988 to February 10,
1989 by Jenkins (1990). I made qualitative observations on the types of macrophytes and their abundance in each pond. As new taxa appeared,
representative specimens were collected by hand and taken to the
laboratory for identification. Similar observations on macrophytes in the ponds had been made during the first year by Rosenzweig (1990).
93 RESULTS
Benthic macroinvertebrates showed cyclic trends in total density throughout the study. High densities in autumn were followed by low densities in late spring (Fig. 1). Mean total density of benthic macroinvertebrates during year 1 peaked during autumn at about 600 organisms/sampler. Following the peak, densities dropped to about 400 organisms/sampler. During year 2, this drop continued until late spring, to a low of about 100 organisms/sampler. Densities remained relatively stable for several months, and then increased to a maximum of about 800 organisms/sampler in autumn. Densities declined from this peak to about 300 organisms/sampler by the end of year 2 (Fig. 1).
These fluctuations in total density were mostly causéd by emergence and recruitment of Chironomidae. Taxa richness and diversity increased progressively during the first 8 mo of year 1, then stabilized at about
9 and 1.6, respectively. Taxa richness and diversity did not exhibit extreme fluctuations in year 2 as were observed for density (Fig. 1).
Community structure was dominated during both years by members of the Diptera (87% year 1, 90% year 2; Fig. 2). Three other orders of insects (Ephemeroptera, Odonata, Trichoptera) accounted for almost all ef the remainder of the benthic macroinvertebrate community in both years. Ephemeroptera declined in relative abundance in year 2, whereas
Odonata and Trichoptera increased in relative abundance. The community was comprised predominantly of two functional feeding groups in both years: collector-gatherers and predators (Fig. 2). Collector-gatherers
94
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eet FM AM JJASONDODJIFMAMIJISASOONDVFM
Figure l. Measures of benthic macroinvertebrate community structure on each sampling date during first 2 yr after experimental ponds were constructed (February 25, 1988 to March 5, 1990). All valuse are means of six ponds (+ standard deviation).
95 Orders
Year 1 Year 2
Other (0.4%) Odonata (4.2%)
Trichoptera (0.9%)
Functional Feeding Groups
Year 1 Year 2
Collector-gatherers (78.4%) Collector-gatherers (63.6%) x Pd a. & Oo S “ Oo Pusd ao oo ® _ ® wo xe ® oO
Figure 2. Summary of structure and function of benthic macroinvertebrate community in experimental ponds during each of first 2 yr after construction. Values are percents of total numbers collected in all six ponds during the entire year. Year l, February 25, 1988 to February 25, 1989; Year 2, March 25, 1989 to April 5, 1990.
96 were the highest proportion of the community in both years, but their proportion decreased somewhat in year 2. The relative abundance of predators increased in year 2, and a third functional feeding group
(piercer-herbivores) achieved a measurable level of abundance (Fig. 2).
Of the 48 taxa collected during the 2-yr study, 34 were collected in year 1 and 45 were collected in year 2 (Table 1). In the second year, 3 taxa previously present did not reappear and 14 taxa appeared for the first time. Almost two-thirds of all taxa (31 of 48) occurred in both years. Of the taxa lost in year 2, none were considered to be common (annual mean 21 organism/sampler). Only Oxyethira was a common taxon among those gained in year 2. The most abundant taxa in both years were Chironominae/Orthocladiinae and Tanypodinae from the family
Chironomidae (Table 1). It was not feasible to identify the chironomid larvae beyond the subfamily level.
Statistical Analysis. Results of the statistical comparison of the community occurring at the end of year 1 to the community occurring at the end of year 2 are shown in Tables 2 and 3. Statistical tests were not conducted for annual means because the samples of benthic macroinvertebrate populations on successive dates were not independent.
The question addressed in these statistical tests was: "Did an additional year of natural development in the pond ecosystem result in a benthic macroinvertebrate community that was significantly different from the one that existed at the end of the first year?"
Total density, taxa richness, diversity, and percent of each functional feeding group were not significantly different between the
97 Table l. Density of individual taxa occurring in experimental ponds during each of first 2 yr after construction. Means and ranges are expressed as number of organisms/artificial substrate sampler for the entire year. Year 1, February 25, 1988 to February 25, 19893; Year 2, March 25, 1989 to April 5, 1990; *, mean < 0.1 organism/artificial substrte sampler; +, taxa present but unable to be quantified because early instars could not be distinguished consistently.
Year l Year 2
Taxa Mean Range Mean Range
Nematoda * * Annelida Oligochaeta 0.7 (0-8. 3) 0.8 (0-6. 5) Crustacea Amphipoda Talitridae Hyalella 0.1 (0-0. 7) Arachnida Acari * * Insecta Ephemeroptera Baetidae Callibaetis 15.8 (0-73. 5) 4.6 (0.3-11.7) Leptophlebiidae Leptophlebia 0.1 (0-0. 2) * Caenidae Caenis 12.6 (0-38. 2) 11.7 (3.1-33.5) Ephemeridae Hexagenia 0.8 (0-2.7) 0.2 (0O-1.0) Odonata Aeshnidae Anax 0.7 (0-2. 7) 0.4 (0-1.0) Gomphidae Gomphus 0.1 (0-0. 3) * Macromiidae Macromia * Corduliidae Tetragoneuria + * Libellulidae 1.3 (0-4. 3) 9.0 (0. 8-25. 5) Celithemis + + Erythemis + Erythrodiplax + Ladona + + Libellula + + Pantala + + Perithemis + + Sympetrum + + Coenagrionidae 4.0 (0-16. 8) 5.0 (0. 5-12. 3) Argia * Anomalagrion + Enallagma + 4.8 (0.5-12.0) Ishnura + +
98 Table 1. Cont.
Taxa
Hemiptera Corixidae Notonectidae 0.1 (0-1. 3) Buenoa Notonecta QO.1 (0-1. 3) Trichoptera Polycentropodidae Cernotina 0.1 (0-0. 8) Hydroptilidae Hydroptila Orthotrichia Oxyethira 2.4 (0-10. 5) Leptoceridae Oecetis 0.7 (0-2.7) 0.2 (0-0. 5) Phryganeidae rypnia 0.3 (0-1. 3) Coleoptera Haliplidae Peltodytes Gyrinidae Dineutus 0.1 (0-1. 0) 0.1 Dytiscidae 0.4 (0-2. 5) Agabus Bidessonotus Hydroporus
Laccophilus +++? Hydrophilidae 0.4 (0.1.2) 0.2 (0-1.
Berosus 0.2 (0-1. Tropisternis * Diptera Tipulidae Chaoboridae * Ceratopogonidae 6.1 (0-12. 7) 14.1 (0. 3-48. 8) Chironomidae Chiro/ Ortho 10.4 (0-458. 0) 197.6 (72. 3-352. 3) Tanypodinae 53.1 (0-144. 2) 112.4 (17. 8-389. 5) Tabanidae 0.6 (0-2. 2) Gastropoda Limnophila Ancylidae
99 Table 2. Comparison of community structure at end of year 1 (Feb. 10, 1989) and end of year 2 (Mar. 5, 1990). Means are for six ponds. All density values are numbers of organisms/artificial substrate sampler.
Feb. 10, 1989 Mar. 5, 1990 Parameter Mean Ss. D. Mean S. D.
Total Density 403. 2% 145.1 310. 5% 56.3
Taxa Richness 8. 5% 1.6 7.8? 1.9
Diversity (Shannon) 1.6% 0.4 1.5% 0.2
Percent Collectors 71.3% 12.3 61.0% 9.0
Percent Predators 28.7% 12.2 38. 89 8.8 Callibaetis Density 20. 78 15.8 3.0 2.4 Caenis Density 11.28 4.7 4, 7° 3.9 Coenagrionidae Density 16. 8? 16.2 3.0 3.0 Libellulidae Density 3.7% 6.2 9.7% 8.6
Ceratopogonidae Density 6.7% 3.8 9. 3% 11.4
Tanypodinae Density 84, 5% 63.2 105.7% 32.1
Chironominae Density 253.8% 84.3 172. 0% 48.8
Means across rows followed by different letters are significanly different; 2-sample T-test (n=6); P < 0.05.
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101 end of year 1 and the end of year 2 (Table 2). Density of the two most abundant taxa, Chironominae/Orthocladiinae and Tanypodinae, also were not significantly different between the ends of the two years. The only statistically significant differences were for three individual taxa
(Callibaetis, Caenis, Coenagrionidae), all of which were lower at the end of year 2. Although a t-test was not appropriate because Oxyethira was not present in year 1, the density attained during year 2 (2.4 organisms/sampler) was a significant change.
The Bray-Curtis similarity index was probably the most informative measure for comparing the communities between years because it analyzes the presence and relative abundance of all taxa simultaneously. This index can range from 0 (least similar) to 1 (most similar). The mean values reported in Table 3 indicate a high degree of similarity, both within and between years. More importantly, an analysis of variance conducted according to Hruby (1987) indicated that there were no significant differences (p < 0.05) in similarity.
Environmental Characteristics. Results of physicochemical measurements are presented in Table 4 and Fig. 3. These values indicate that water quality in the ponds was not detrimental to aquatic life
(USEPA 1976); however, nutrient and chlorophyll a concentrations were indicative of oligotrophic conditions. Water temperature was very warm but typical for ponds at this latitude and elevation. Annual temperature patterns were almost identical during both years (Fig. 3).
It was not possible to make statistical comparisons between years for the physicochemical parameters listed in Table 4 because measurements
102 Table 4. Ranges for environmental characteristics measured in experimental ponds.
Parameter year l Feb. 10, 1989 Apr. 5, 1990
Temperature, °c 3. 9-30.0 11.6-12.8 11.8-14.0
Dissolved oxygen, mg/liter 5. 8-12. 8 11.6-12.8 9.8-11.8
pH 6. 6-8. 6 7.5-7.7 7. 1-8. 5
Alkalinity, mg CaC03/liter 26. 0-60. 8 34. 2-49. 8 20. 0-37.1
Hardness, mg CaC0O3/liter 20. 0-85. 0 50. 0-70. 0 50. 0-70. 0
Conductivity, smhos 25% 132. 6-252. 5 148. 7-185.1 68. 0-125. 0
NO2, mg/liter 0.0-1.68 © 0. 0-0. 03 0. 0-0. 0
NO3, mg/liter 0. 0-1. 76 0. 0-0. 03 0. 09-0. 28
Secchi, m 0. 3-2.2 1.1-1.4 0. 6-2. 1
Chlorophyll a, mg/liter 0.0-21.2 2.1-12.3 0. 0-4. 7
103
30 ] ve AA a
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Figure 3. Temperature of Pond 5 at 1 m from March l, 1988 to February 28, 1990. Year 1: March 1, 1988 to February 28, 1989 Annual mean temperature = 17.6 °C Accumulated degree-days = 6414 Year 2: March 1, 1989 to February 28, 1990 Annual mean temperature = 17.5 °C Accumulated degree-days = 6400
104 were not made on similar dates. Ranges among ponds for the one date on which measurements were made in year 2 (April 5, 1990) generally
overlapped with ranges of the same parameters among ponds in year l.
This was true for the ranges from all of year 1 and on February 10,
1989, which was the last date that physicochemical data were available from year 1. The only exception was conductivity, which was lower in year 2.
Emergent macrophytes were well established at the edges of the ponds throughout most of year 1, including: Carex, Cyperus, Eleocharis,
Hypericum, Juncus, Ludwigia, and Typha (Rosenzweig 1990). A submerged macrophyte, Potamogeton, was first observed in one pond about midway through year 2 (June 1989). By the end of year 2, Potamogeton was present in five of the ponds that were included in this study and covered approximately 5 to 95% of the bottom of those ponds.
DISCUSSION
An additional year of natural development in the experimental
ponds brought about very few changes in the benthic macroinvertebrate
community. Total density fluctuated a lot in both years, but the
overall magnitude was similar. Taxa richness and diversity reached
plateaus within year 1 and changed very little thereafter. The same
orders of insects and functional feeding groups were dominant in both
years. A high proportion of taxa occurred in both years, and almost all
of the taxa gained or lost between years were considered to be rare. A
105 statistical analysis of a measure that integrated presence and relative abundance of all members of the community (Bray-Curtis Similarity Index) showed no significant differences between the community at the end of year 1 and the community at the end of year 2. Results from the experimental ponds appear to disagree with other studies that have found significant changes in the benthic macroinvertebrate community for several years after the construction of new lentic environments, especially between the first and second years (Barnes 1983, Voshell and
Simmons 1984).
There are several factors that may explain why the community in the experimental ponds changed so little between years 1 and 2. There were numerous sources of colonizing organisms close to the experimental ponds (Layton and Voshell 1991), and most of the taxa having the necessary adaptions for life in shallow lentic environments were able to reach the ponds during the first year. Other investigators have speculated that changes in available food and habitat are largely responsible for observed changes in the benthic macroinvertebrate community. Often, new lentic environments contain large quantities of terrestrial organic matter, which provides a temporary food source for some taxa. In addition, the decomposition of the terrestrial organic matter releases nutrients that cause plankton to be especially abundant during the first year. Usually, aquatic macrophytes, which are essential habitat for some taxa, do not become well established until 1 or more yr after a new lentic environment is constructed. In the experimental ponds, food and habitat for benthic macroinvertebrates
106 probably were very similar in the first 2 yr. All terrestrial vegetation was removed with bulldozers during construction, and the topsoil used to line the pond bottoms had low concentrations of organic matter and nutrients (Layton 1989, Jenkins 1990). Although submerged macrophytes did not appear in the experimental ponds until year 2, emergent macrophytes were well established early enough in year 1 to provide suitable habitat for organisms requiring vegetative substrate to maintain their positions or to lay their eggs. Lastly, there were no changes in water quality between years that would be expected to bring about biological effects.
Ecological succession is a phenomenon that takes place over a much longer time period than was investigated in this study. Subtle differences in the benthic macroinvertebrate community between the first
2 yr, such as the statistically significant changes in a few common taxa and the gain or loss of some rare taxa, are evidence that succession is taking place in the experimental ponds. Factors such as the continuing increase in abundance of the submerged macrophyte Potamogeton may contribute to further subtle changes in the benthic macroinvertebrate community. However, the major attributes of the structure and function of the benthic macroinvertebrate community were established during the first year after construction of the experimental ponds and did not change significantly during the second year.
107 ACKNOWLEDGEMENTS
We are grateful for the assistance of James L. Tramel, Jr. and W.
B. Wilkinson, III for on-site administration and management of the experimental pond facility. Persons who provided valuable technical assistance included: Stephen W. Hiner, Michael 0. West, T. Michael
Williams, and Lourdes M George. This research was partially supported by the Virginia Agricultural Experiment Station, Hatch Program
108 MANUSCRIPT IV: EVALUATION OF BIOMETRICS FOR BENTHIC MACROINVERTEBRATES
IN EXPERIMENTAL PONDS
ABSTRACT
The objective of this study was to analyze the precision of various biometrics for benthic macroinvertebrates, in terms of the percent change that must occur to distinguish treatment effects from natural variability when conducting field toxicity tests in replicate experimental ponds. This was done by a statistical procedure that indicates the percent change that must occur to detect true differences between two means. I evaluated 15 biometrics that included various measures of community structure and function. There was a wide range in detection limits among the biometrics, with number of taxa metrics ranged from 2 to 502%, proportion of numerical abundance metrics ranged from 1 to 65%, and density metrics ranged from 10 to 140%. The benthic macroinvertebrate metrics that appear to be especially useful for detecting treatment effects in experimental pond studies are: taxa richness, EOT index, total density, density and proportion of dominant taxon (Chironominae/Orthocladiinae), and proportion of dominant functional feeding group (collector-gatherers). Detection limits for number of taxa metrics were lower for dip net samples than artificial substrate samples. Detection limits for density metrics were about equal for dip net samples and artificial substrate samples. For most metrics, use of 6 replicate mesocosms, as compared to 3 replicates,
109 would appreciably improve the ability to detect differences between treatments. As a general guideline, statistically realistic detection limits would be: <20% for metrics involving number of taxa, <402 for metrics involving proportions of numerical abundance, and <50% for density metrics.
INTRODUCTION
Experimental ponds have long been used to study fisheries management (Swingle 1947, 1950), ecological principles (Hall et al.
1970), and effects of various perturbations (see review in Buikema and
Voshell 1991). Odum (1984) explained the importance of ecological studies in mesocosms, which he defined as "... bounded and partially enclosed outdoor experimental setups...falling between laboratory microcosms and the large, complex, real world macrocosms" (p.558).
Experimental ponds are a type of mesocosm (Buikema and Voshell 1991), and the U. S. Environmental Protection Agency has begun to require simulated field studies in pond mesocosms as part of registration requirements for some pesticides (Touart 1988, Touart and Slimak 1989).
Benthic macroinvertebrates are frequently studied in experimental ponds (Buikema and Voshell 1991); however, results of field studies of benthic macroinvertebrates are difficult to analyze statistically because intersample variability is usually high (Elliott 1977, Allan
1984). Detecting differences in biotic variables, such as benthic macroinvertebrates, is usually the main objective of studies conducted
110 in replicate experimental ponds. For example, Stunkard (1989, 1991) has recommended that the EPA use an hypothesis-testing design in which an applicant for a pesticide registration is required to refute with statistical tests the presumption of adverse effects when the pesticide is applied in experimental ponds. No studies have evaluated biometrics used for benthic macroinvertebrates in replicate experimental ponds.
The objective of this study was to analyze various biometrics used for benthic macroinvertebrates in experimental ponds in terms of the percent of change that can be attributed statistically to a treatment effect versus the percent of change that occurs from natural variability. I conducted a l-yr study in a set of untreated experimental ponds that were not managed in any way except to maintain constant water level. Colonization of benthic macroinvertebrates in the l-yr old ponds had stabilized, and the community was generally typical of shallow lentic environments (Layton and Voshell 1991, succession chapter in this dissertation). My analyses followed the statistical design recommended by the EPA for pesticide registration tests (Touart
1988), but the results are applicable to any experiment that has an objective of detecting changes in benthic macroinvertebrates in replicate ponds.
METHODS
This study was conducted in the Virginia Polytechnic Institute and
State University experimental pond facility, which is located at the
111 Southern Piedmont Agricultural Experiment Station near Blackstone
(longitude 77057' 30"W latitude 3705’30"N). The facility consists of 12
0.04-ha experimental ponds, each measuring 20.1 X 20.1 m at the water surface and holding about 520 m> of water at a depth of 2.1 m The experimental ponds were first filled with water in January 1988. The only management of the ponds has been to maintain a constant water level. There have been no experimental treatments and there have been no fish in the ponds. Additional details about the facility can be found in the study site section of this dissertation, Layton (1989), and
Layton and Voshell (1991).
Six ponds, which were chosen randomly, were sampled for this study. I sampled for 14 mo from March 1989 through April 1990. I collected samples every 4 wk from November through April and every 2 wk from May through October. An artificial substrate sample was taken from each pond on each sampling date to obtain a quantitative sample of larvae. The samplers were 10.8-cm tall X 12.2-cm diameter, round plastic buckets with 3.8-cm holes drilled in the top and sides. A 1.5- em layer of topsoil from the site was placed in the bottom of each sampler, and seven 5-cm diameter tri-pack units (Jaeger Products Inc.,
P.O. Box 16117, Houston, Texas) were placed above the soil. The samplers were deployed in March 1989 and allowed to colonize for 30 d prior to being retrieved. I randomly selected the artificial substrate samplers to be collected on each date. Samplers were retrieved by means of a boat. To avoid loss of organisms during retrieval, I placed an inverted plastic funnel over the sampler before it was removed from the
112 bottom, and I placed a 100-um mesh net under the sampler as soon as it was visible underwater. A complete description of the artificial substrate samplers and how they were retrieved can be found in the methods section of this dissertation, Layton (1989), and Layton and
Voshell (1991). The entire sampler and the contents of the net were placed in a labeled plastic bucket, which was filled with 5% formalin for preservation of specimens.
I took qualitative benthic samples with a D-frame dip net having a
1000-ym mesh catch net. Dip net samples were standardized by sampling a square area of bottom that was approximately the width of the net (0.3 m) at a depth of 0.5 m This was repeated on each side of a pond, and the four subsamples were pooled. This protocol was designed to sample all of the different microhabitats that occurred at the edges of the ponds. Qualitative samples were taken on each sampling date and preserved in 5% formalin.
In the laboratory, the artificial substrate and dip net samples were washed over a 355-ym mesh soil sieve until water flowing through the sieve was almost clear. For the artificial substrate samples, each tri-pack unit was also scrubbed with a soft bristle brush. The material retained on the sieve was preserved in 70% ethyl alcohol. Larvae were sorted later from the detritus and sand with a stereomicroscope at 4-10X magnification. Organisms were identified to the lowest possible taxonomic level, using either Brigham et al. (1982) or Merritt and
Cummins (1984), then counted. Taxa were assigned to functional feeding groups using Merritt and Cummins (1984).
113 I evaluated a variety of biometrics in terms of the percent change that must occur to be attributed to a treatment effect (detection limit) by a modification of a formula from Sokal and Rohlf (1981):
6 2 ((2/n) %°* CV * (t yt t 2(1-p)(v)))
where, 6 is the detection limit,
n is the number of ponds used for each treatment,
CV is the coefficient of variation,
a is the confidence of the test,
p is the power of the test, and
v is the degrees of freedom
The alpha level was set at 0.2 and the power of the test was set at 0.8 to be consistent with the recommendations of Stunkard (1989, 1991) for how the EPA should determine the effect of a treatment. I determined the detection limits when using six and three replicate ponds. Six was the maximum number of ponds that could be analyzed within the financial resources of the project. Three was the number of replicate ponds recommended in EPA pesticide registration tests (Touart 1988) and was the number of replicates reported most often in a review of quantitative lentic studies (Resh and McElravy 1991).
Fifteen metrics were evaluated. Structural metrics included: taxa richness, EOT index (number of taxa in the orders Ephemeroptera,
Odonata, Trichoptera), ratio of EOT density to Chironomidae (Diptera)
114 density, percent of total density comprised by EOT taxa, percent
Chironominae/Orthocladiinae (Diptera: Chironomidae), percent Tanypodinae
(Diptera: Chironomidae), total density, Chronominae density, Tanypodinae density, Coenagrionidae (Odonata) density, Libellulidae (Odonata) density, Callibaetis (Ephemeroptera: Baetidae) density, and Caenis
(Ephemeroptera: Caenidae) density. Functional metrics included: percent of collector-gatherer and predator functional feeding groups.
All of the above metrics were evaluated with data from the artificial substrate samplers. Some of these were rapid bioassessment metrics
(taxa richness, EOT index, ratio of EOT density to Chironomidae density, and percent dominant taxon (Chironomidae)) intended for stream studies that I modified for use in ponds (Plafkin et al. 1989).
The qualitative dip net samples were sorted originally for use in determining life history parameters of selected Ephemeroptera and
Odonata. Some other taxa, primarily Chironomidae, were not retained.
Therefore, when I decided later to analyze biometrics calculated from dip net samples, it was not possible to analyze all of the metrics that were used in the artificial substrate samples. Metrics that were analyzed for the dip net samples included: taxa richness, EOT index,
Libellulidae density, and Caenis density. These biometric analyses facilitated some comparisons between the results obtained with dip net samples and artificial substrate samples.
115 RESULTS
I graphed the detection limits of all metrics that would be obtained with an artificial substrate sample in each of 6 and 3 replicate ponds (Figs. 1 and 2). The graphs include data for benthic macroinvertebrates from March 1989 to April 1990. On each date the treatment would have to cause a change in the metric greater than the amount indicated in order to be distinguished from natural variability.
In the following paragraphs, I report the range of detection limits that would usually be obtained for the various metrics; most of these ranges were exceeded, both higher and lower, on a few occasions.
Detection limits for the various metrics ranged from 1 to 140%.
With 6 replicates, overall taxa richness had detection limits of 6 to
152% on most dates, and with 3 replicates detection limits were 6 to 202
(Fig. 14). The EOT Index, a subset of overall taxa richness, usually had detection limits that ranged from 6 to 20% with 6 replicates and 6 to 30% with 3 replicates (Fig. 1B). Detection limits for the proportion of Chironominae/Orthocladiinae and proportion of collector-gatherers were both usually 10 to 20% with 6 and 3 replicates (Figs. 1C and 1E).
The proportion of Chironominae/Orthocladiinae metric represents the proportion of the numerically dominant taxon. Chironominae and
Orthocladiinae were the most common subfamilies of Chironomidae, which were impractical to identify to genus. The proportion of collector- gatherers is the numerical proportion of the most abundant functional feeding group, which ingests fine particles of detritus from sediment.
116 Taxa Richness LOT Index 100 7 100 + A B
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Percent 207 IN 20+ aN 4 <5 _NA BA, he8 ooo) =m ee, 4 60 er am 6= and
0 O+-+-+-4+-4+-+- ++ 4+ +++ +4 +t M AMMJJJI JAASSOO N A Mw AMMJJJJJAASSOO~ N OBO SF M oa
Proportion of Chironominae/Orthocladiinae Proportion of Tanypodinae rT 100 + Cc D
80+ 80+ o mn < 60 + 3 60 + / a Oo a
Change 404 \ :> 404 LAA \ | or IRS \ o “ ° Lf °\ a
Percent a 4 / iy \a a 20+ Na. rel © a 4 °-9 “NN Loe ° “2 at NEE 4 PRY a £. ey oo Ng a ™
Ot ttt ttt tt tt ttt ttt ttt Ot tt tt tt tt ttt M AMMJJSJUSAASSOO N DJ A M AMMJJSJUAASSOO N D 5S F M A
Proportion of Coilector—Gatherers Proportion of Predators 100 7 100 + E F
BO+ 80+
QD oO 607 S 60 ft
Change 5 f\ Cc aot 3 40+ / 9 2 / a & o “/ 9 2 L\/4 iNNes
Percent 20+ A 2 204° fo YAS \ ZN an a. 4 9/0 a4 VeVor Neo, 4S\, ANYe Ze oONe 3 geo oo on 6
O ttt ttt ttt tt ttt ttt ttt a O ttt ttt ttt ttt tt ttt tt ttttt ttt
M AMMJJJUVSJAASSOGO N D JY F M A M AMMJJ JS UAASSOG N OF 4S F M A
Proportion of EOT Ratio of EOT Density to Chironomidae Density 1007 100 7 G H
80 80 +
vo 9eo 604 | [ | a 60 + a s ;
Change pteana Ly \ f c aN, 4 fmm } $ 40+ os Ine. Any y j o oN ‘4 oO oO
Percent a ‘ \ YN AYAA of \V/ \ 204 WY 204 oN —
04 +++ Pt ttt tt ttt tt tt M AMMiudddJ JAASSOO N O M AMMJJJUVJAASSOO N D J FM A
Figure l. Detection limits (percent change that must occur to detect a treatment effect) for number of taxa and proportion of numerical abundance metrics from artificial substrate samplers, March 25, 1989 to April 5, 1990. Circle, 6 replicate ponds; triangle, 3 replicate ponds.
117 The detection limits of the proportion of collector-gatherers were usually about the same as those for the proportion of
Chironominae/Orthocladiinae, because the majority of the collector- gatherers were members of these two Chironomidae subfamilies. The proportion of predators usually had detection limits from 10 to 252% with
6 replicates and 10 to 35% with 3 replicates (Fig. 1F). Predators were the second most abundant functional feeding group. Detection limits for proportion of Tanypodinae, the other major subfamily of Chironomidae, were 10 to 30% with 6 replicates and 15 to 50% with 3 replicates (Fig.
1D). Detection limits for proportion of EOT, the proportion of the total density represented by the pollution sensitive orders
Ephemeroptera, Odonata, and Trichoptera, were 15 to 35% with 6 replicates and 20 to 50% with 3 replicates (Fig. 1G).° The ratio of EOT density to Chironomidae density had detection limits of 20 to 45% with 6 replicates and 20 to 60% with 3 replicates (Fig. 1H). This metric indicates dominance in a community by either pollution sensitive or pollution tolerant organisms.
I analyzed seven density metrics, which had detection limits from
30 to 55% with 6 replicates and 40 to 902 with 3 replicates (Fig. 2).
With 6 replicates, detection limits were usually 10 to 30% for total density, and with 3 replicates they were usually 15 to 40% (Fig. 2A).
Detection limits for density of individual taxa exhibited an inverse relationship with density. Chironominae/Orthocladiinae density and
Tanypodinae density detection limits were similar at 10 to 352% and 15 to
35% with 6 replicates, and 20 to 50% and 20 to 55% with 3 replicates,
118 Totai Density Chironominae/ Orthocladiinae Density 100+ 1004 A ls
60+ 80 {
a 60 + R 60+ / \ ‘
Change a Change 40 ] / /\:A ° 40+ a _
Percent /\ RA alt \ eS Percent 20+ < oe RO at on / ao NON 20+ ° o
gp tht ttt O etttt Et tt M AMMysvJIJVAASSOO N DJ FOoM A M AMMJJUDGAASSOO0. N DB
Tanypodinae Density Caenis Density 100 + 100 7 Cc D 80 + 4 80 + & a
a \A 60 \ k 4
Change ° Change 9 \y A N | ° wo“| “AY-\ a [VAa 4 \ N . a & sh A FN o . 9
Percent \V Wh J VA / Percent od \) Pn zt Yo APN 20+
Ott tt ttt ttttt M AMMJ ddd JAASSOO N D J F M A M AMMJJJJJAASSOONO J FM A
Coenagrionidae Density Libellulidae Density 1207 4 120, E . 100 + 100
a go LL “4 a | . oly [VA tf Am a / a
Change "A\A d +R , —_ \ Change 60 + vn \ A\ vo | . Pee ° man “ ° 4o+ \\ \ i ° \\ \ pv / \ 40 + a WASi °. / heme
Percent Percent Qo On go 4 9 \ ° ~ | a-o a . 207 8 0 20+ ~P-AQ4 ° °
O++-+ Bttt tt ttt ttt M AMMJJJUJAASSOO N DB J F M A M TAMMIJUJJJAASSOO N OO J F M A
Callibaetis Density 1407 a 4 G \ 1207 \
100 +
4 a
Change ao; Lak \ / a a pn p °0} 4 L 4 ° oN on ° o o / ‘o” ae \f So \ \ Percent 40 |
oO 20+ 3 ° a
Ott ttttt Ht HH HHA M AMMJJJUJVAASSOO N ODO GS Fo oM A
Figure 2. Detection limits (percent change that must occur to detect a treatment effect) for density metrics from artificial substrate samplers, March 25, 1989 to April 5, 1990. Circle, 6 replicate ponds; triangle, 3 replicate ponds.
119 respectively (Figs. 2B and 2C). These were the most abundant individual taxa found in the ponds. The next most abundant taxon was Caenis, which had detection limits of 25 to 50% with 6 replicates and 35 to 60% with 3 replicates (Fig. 2D). Coenagrionidae and Libellulidae density metrics were the same at 20 to 55% with 6 replicates and 40 to 802% with 3 replicates (Figs. 2E and 2F). The individual taxon with the lowest density that was evaluated was Callibaetis, which had detection limits of 30 to 55% with 6 replicates and 40 to 90% with 3 replicates (Fig.
2G).
Four metrics were evaluated from dip net samples (Fig. 3). Taxa richness and EOT Index had detection limits of 2 to 15% for both 6 and 3 replicates (Figs. 3A and 3B). Caenis density had detection limits of 25 to 602% for 6 replicates and 25 to 80% for 3 replicates (Fig. 3C).
Libellulidae density had detection limits of 25 to 552 for 6 replicates and 35 to 70% for 3 replicates (Fig. 3D).
DISCUSSION
The detection limits reported for the experimental ponds in this study are lower than those reported for other field studies. For example, Resh and McElravy (1991) found that the variability of a mayfly species in a stream was so high that only changes in mean density = 200% were detectable, even with ten replicates. My results suggest that several benthic macroinvertebrate metrics may be especially useful for detecting treatment effects in experimental pond studies: taxa
120 Percent Change Percent Change Figure 100 100 80+ 207 80 201 40+ 60+ 60+ “y O4 a + 7
A c ptt 3. MMJJUJITAASSOO MMJJdJUAASSOO a 087 AA ° a 8 VMN ° Detection Circle, a from raced CL °se / treatment am Caenis Taxa /\ tt / \ a / dip Richness ¢ 4 Density ya A 6 ppp net a D N 4 N replicate limits DB effect) samples, J J a fm °. FooOM FooOM \ (percent 3 ponds; for 121 March number | | a oO 3 a < Ew. a © o © & 5 change triangle, 25, 100 100 20+ °°] so+ 407 60+ 40 20 60+ O Ott + 4 4 4 +
of aah tte 1989 fe) B that WMJJZI0ARSSO0 MMJ i\ wFXS, taxa tt JJ 3 to must \ tt JIJAASSOO MA tt and replicate acgstnecg Libellulidae April ttt - EOT density occur \/ Index 6 Og Density 5, Or, Ne tt $$ 0 N D N ponds. to 1990. ++ metrics a +--+ detect J J ttt A ++ F F oe \ + a M M richness, EOT index, total density, density and proportion of dominant taxon (Chironominae/Orthocladiinae), and proportion of dominant functional feeding group (collector-gatherers).
The results of my study can be grouped according to several categories of metrics. For those metrics that involve number of taxa, it would be feasible to detect changes of <20%. For those metrics involving the proportion of numerical abundance comprised by dominant taxa or proportion of functional feeding groups, a change of <402 could be detected. Lastly, a change of <502 could be detected for those metrics that involve densities.
For most metrics evaluated in this study, use of 6 replicates, as compared to 3 replicates, appreciably improved detection limits.
However, if financial resources do not permit the use of 6 replicates, many of the benthic macroinvertebrate metrics, other than density, give adequate detection limits with 3 replicates.
The metrics evaluated for artificial substrate and dip net samples gave similar results. Use of a standardized, or "semiquantitative," dip net sample could shorten the time required to analyze a sample. Dip net sampling reaches more microhabitats and increases the accuracy of taxa richness and EOT index metrics. With some refinement, it may be feasible to use dip net samples, exclusively, for evaluating treatment effects on benthic macroinvertebrates in experimental pond studies.
In a properly designed experiment, hypotheses are proposed a priori as to whether the values of metrics will increase or decrease in response to the treatment, and criteria for accepting or rejecting the
122 hypotheses are designated. Many authors have stated the need for acquiring and analyzing preliminary data before designing field studies
(e.g., Green 1979, Resh and McElravy 1991). I suggest that the approach
I have used for determining the level of change that can be detected statistically can improve the design of experimental pond studies that are to be conducted according to an hypothesis-testing design. This approach makes it possible to establish biological criteria that are statistically realistic for a particular study.
ACKNOWLEDGEMENTS
I am grateful for the assistance of James L. Tramel, Jr. and W. B.
Wilkinson, III for on-site administration and management of the experimental pond facility. Persons who provided valuable technical assistance included: Raymond J. Layton, Stephen W. Hiner, Michael 0.
West, and Lourdes M George. This research was partially supported by the Virginia Agricultural Experiment Station, Hatch Program.
123 CONCLUSIONS
This study began as an attempt to identify metrics that could be used in pesticide registration tests using experimental ponds. In the process of developing the study, the need for basic life history information on benthic macroinvertebrates in experimental ponds became apparent. The taxa chosen for life history analysis were those that were abundant in the ponds, did not have a lot of information available about them, and were likely to be affected by a pesticide treatment.
LIFE HISTORY PARAMETERS
I studied growth rate, voltinism, emergence patterns, and annual production of Caenis amica, Callibaetis floridanus, Anax junius, Gomphus exilis, and Enallagma civile. Growth rates were 0.015 and 0.025 mg DW/d for the first and second generations of €. amica and 0.011 and 0.015 mg
DW/d for the first and second generations of C. floridanus, respectively. Both Ephemeroptera were bivoltine, with emergence in June and August for C, amica and emergence in May and September for C. floridanus. Production of C. amica and C. floridanus was 5 and 11 mg
DW artificial substrate sampler/yr, respectively. Growth rates for
Odonata were 0.028, 0.061, 0.017, and 0.012 mg DW/d for resident and nonresident populations of A. junius, for G exilis, and for E. civile, respectively. All Odonata exhibited univoltine life cycles. Emergence occurred from June to September for A, junius, April to June for G.
124 exilis, and April through October for E. civile. Production was 673, and 39 mg DW/dip net sample/yr for A. junius and G. exilis, respectively, and for E. civile, production was 10 mg DW/artificial substrate sampler/yr. The growth rate and production values reported for both Ephemeroptera and Odonata were low for lentic ecosystems; however, the experimental ponds were oligotrophic, which limited growth and production rates by limiting food resources.
Information from this study can be used when assessing the impact of perturbations on aquatic systems or simply to further our knowledge of the basic biology of species present in shallow lentic ecosystems.
SUCCESSIONAL CHANGES
I studied the successional changes that took place in a series of experimental ponds during the second year of their existence.
Comparison of the community at the end of year 1 to the community at the end of year 2 showed no significant differences for community summary measures (total density, taxa richness, diversity, Bray-Curtis similarity index); however, some individual taxa densities were significantly lower at the end of year 2. At higher levels of classification (order), little change was evident between years. A total of 48 taxa were collected with artificial substrate samplers over
2 years. Of these taxa, 34 were collected in year 1, and 45 were collected in year 2. In year 2, 3 taxa previously present did not reappear and 14 taxa appeared for the first time. Submerged macrophytes
125 colonized the ponds during the second year, providing additional habitat. BIOMETRY I analyzed 15 biometrics by a statistical procedure that indicates the percent change that must occur (detection limit) to detect true differences between two means. There was a wide range in detection limits among the metrics, with number of taxa metrics ranging from 2 to 50%, proportion of numerical abundance metrics ranging from 1 to 652), and density metrics ranging 10 to 140%. Detection limits for number of taxa metrics were lower for dip net samples than artificial substrate samples. Detection limits for density metrics were about equal for dip net samples and artificial substrate samples. The metrics with the lowest detection limits (usually < 20%) were taxa richness, EOT index, proportion of Chironominae/Orthocladiinae, and proportion of collector- gatherers. Detection limits of < 202 on all dates were obtained for taxa richness and EOT index metrics from dip net samples. 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Canadian Journal of Fisheries and Aquatic Sciences 37: 2282-2293. 140 Appendix CONTENTS: Appendix Tables 1 - 38: Densities for individual taxa in each sample. Appendix Tables 39 - 74: Production tables for each taxon from each pond. Appendix Table 75: Soil chemistry data from February 1988 to April 1990. 141 Appendix 1. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, March 25, 1989. Organisms Pond Mean & of 1 2 4 6 9 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0 Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancylidae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.9 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 30 7 2 7 1 23 11.7 2.6% Leptophlebia 0.0 0.0% Caenis 7 52 64 37 4 37 33.5 7.3% Hexagenia 1 1 1 0.5 0.1% SUBTOTAL 37 60 67 44 5 61 45.7 10.0% ODONATA Argia 2 0.3 0.1% Enal Lagma 8 4 30 18 7 5 12.0 2.6% - Gomphus 1 0.2 0.0% Anax junius 1 1 1 1 0.7 0.1% Libel Lulidae 1 6 6 5 3.0 0.7% SUBTOTAL 10 11 36 25 9 6 16.2 3.5% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 2 0.3 0.1% Agrypnia 0.0 0.0% SUBTOTAL 0 0 0 0 2 0 0.3 0.1% COLEOPTERA Gyrinidae 1 0.2 -0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 2 2 4 2 1.2 12.7% SUBTOTAL 2 0 2 1 3 0 1.3 0.3% DIPTERA Tabanidae 0.0 0.0% Chaoborus 0.0 0.0% Ceratopogonidae 11 2 7 3 2 6 5.2 1.1% CHIRONOMIDAE Tanypodi nae 63 82 113 181 40 167 107.7 23.6% Chironominae 325 285 199 345 264 259 279.5 61.3% SUBTOTAL 399 369 319 529 306 432 392.3 86.1% Density 448 (440 — 4 599 305 499 455.8 Number of Taxa 9 9 9 10 10 8 9.2 EOT Index 5 6 5 6 5 5 5.3 EOT/Chironomidae 12.1% 19.3% 33.0% 13.1% 5.3% 15.7% 16.4% % Chironominae 72.5% 64.8% 46.9% 57.6% 81.2% 51.9% 62.5% % Tanypodinae 14.1% 18.6% 26.7% 30.2% 12.3% 33.5% 22.6% % EOT 10.5% 16.1% 24.3% 11.5% 4.9% 13.4% 13.5% 142 Appendix 2. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, April 22, 1989. Organisms Pond Mean h Of T 2 4 6 9 17 Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites Nematoda Oligochaeta Ancyl idae SUBTOTAL 0 0 0 0 0 0 ooooo ooooo HEMIPTERA Corixidae Be Buenoa 2€ Notonecta at SUBTOTAL 0 0 0 0 0 0 oooo oooo°o o0o00 oooo ae EPHEMEROPTERA Callibaetis 2 1 0. Leptophlebia 0. Caenis 11 33 10 8 12. 0 Hexagenia SUBTOTAL 11 O-- 37 11 10 14. NONOUM ODONATA Argia Enal lagma 1 2 10 16 2 4 Gomphus Anax junius 1 1 1 Libellulidae 2 2 3 1 3 SUBTOTAL 4 4 10 20 3 8 o-Ooue o-Ooue NOWOOWO NOWOOWO TRICHOPTERA Cernotina o Oxyethira Hydroptila e Oecetis 1 1 1 e Agrypnia « SUBTOTAL 1 0 1 0 1 0 o MOwWnada oooo0o0o e COLEOPTERA Gyrinidae Dytiscidae So Tropisternus oO Berosus SUBTOTAL 0 0 0 0 0 0 ooaQqooo aooo0ooo OIPTERA Tabanidae 0. 0.0% Chaoborus 0. Ceratopogonidae 5 1 13 10 4 18 8. WNWOO 2.0% CHIRONOMIDAE Tanypodinae 51 37 82 82 81 94 71. 16.8% Chi ronominae 298 310 192 501 406 218 320. SUBTOTAL 354 348 287 593 491 330 86. 400. 94.6% Wen Density 5/0 561 © $05 650 906 548 4235.5 Number of Taxa 8 7 9 8 9 8.0 EOT Index 5 4 6 5 6 5.0 EOT/Chironomidae 4.6% 64 9.8% 3.1% 5.8% 5.6% % Chironominae 80.5% 63.0% 77.1% 80.2% 62.6% 74.9% 00 % Tanypodinae 13.8% = 26.9% 12.6% 16.0% 27.0% 17.8% *% EOT 4.3% wow SRRNe~ 5.9% 8.8% 3.0% 5.2% 5.1% 143 Appendix 3. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, May 6, 1989. Organisms Pond Mean % of. 1 2 a 6 gy WW Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 1 1 2 Nematoda Oligochaeta Ancy| idae SUBTOTAL 1 0 1 2 0 0 Qoo0oo NOOON HEMIPTERA Corixidae 1 Buenca 1 Notonecta SUBTOTAL 0 0 1 0 0 1 oaQ0o°o Wann EPHEMEROPTERA Callibaetis 1 3 Leptophlebia 1 oe OO ot 3e Caenis 7 2 9 UW = ad Hexagenia 1 2 SUBTOTAL 8 2 1 1 Or wn aQuonr WoOonoae NW BS ODONATA Argia o o Enal Lagma 2 8 1 Gomphus 1 . 1 Anax junius Libel Lulidae 1 2 SUBTOTAL 0 1 3 10 1 1 =oO00-0 OWO OWO QRARRA QRARRA NUOWOO NUOWOO NOOoO0-0 NOOoO0-0 TRICHOPTERA Cernotina Oxyethira Hydroptila a Oecetis 1 2 e Agrypnia s SUBTOTAL 0 0 0 1 2 0 oaoo0oo0oo e MoOoOWMOdOo COLEOPTERA Gyrinidae 2 Dytiscidae 3 4 2 Tropisternus 1 Berosus SUBTOTAL 6 0. 4 2 0 0 NOO-o oOOoONnuUWN DIPTERA Tabanidae s Chaoborus 1 . foo NAN} Ceratopogoni dae 16 4 5 e CHIRONOMIDAE Tanypodinae 41 9 51 48 17 15 s wo Chironominae 132 191 55 108 82 54 e ood ood SUBTOTAL 189 200 110 161 99 70 ah sad e NNN Density 204 203 T36 180 T05 _ Number of Taxa 4 11 10 6 EOT Index 5 EOT/Chi ronomidae 1.5% 13.2% 9.6% 6.1% 2. ekiNy % Chironominae 94.1% 42.3% 60.0% 78.1% 74, Bound % Tanypodinae 4.4% 39.2% 26.7% 16.2% 20. % EOT 1.5% 10.8% 8.3% 5.7% 2. HKRRRnvova us Ru wSk» RRARnwo 144 Appendix 4. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, May 20, 1989. Organisms Pond Mean & Of 1 2 4 6 9 11 Total COMMUNITY STRUCTURE (number /sampl|er) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 1 0.2 0.1% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 0 0 1 0 0.2 0.1% HEMIPTERA Cor ixidae 1 0.2 0.1% Buenoa 0.0 0.0% Notonecta 1 1 0.3 0.2% SUBTOTAL 0 0 1 1 1 0 0.5 0.3% EPHEMEROPTERA Callibaetis 6 1 1.2 0.6% Leptophlebia 0.0 0.0% Caenis 8 3 1 8 5 4 4.8 2.6% Hexagenia 0.0 0.0% SUBTOTAL 14 4 1 8 5 4 6.0 3.2% ODONATA Argia 0.0 0.0% Enal lagma 1 1 1 0.5 0.3% Gomphus 0.0 0.0% Anax junius 0.0 0.0% Libel lulidae 2 1 2 0.8 0.4% SUBTOTAL 0 3 0 1 1 3 1.3 0.7% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 1 1 0.3 0.2% Agrypnia 1 0.2 0.1% SUBTOTAL 1 0 0 1 0 1 0.5 0.3% COLEOPTERA Gyr inidae 1 1 1 0.5 0.3% Dytiscidae 2 2 0.7 0.4% Tropisternus 1 0.2 0.1% Berosus 0.0 0.0% SUBTOTAL 0 0 3 1 1 3 1.3 0.7% DIPTERA Tabanidae 0.0 0.0% Chaoborus 0.0 0.0% Ceratopogonidae 2 2 4 3 1.8 1.0% CHIRONOMIDAE Tanypodi nae 44 16 51 46 20 86 43.8 23.3% Chironominae 91 222 33 197 120 135 133.0 70.8% SUBTOTAL 137 238 86 247 140 224 178.7 94 .8% Density 152 245 a7 250 129 239 +188.5 Number of Taxa 6 & 7 8 7 9 7.2 EOT Index 3 4 1 3 2 4 2.8 EOT/Chironomidae 11.1% 2.9% 1.2% 4.1% 4.3% 3.6% 4.5% % Chironominae 59.9% 90.6% 36.3% 76.1% 80.5% 57.4% 66.8% % Tanypodinae 28.9% 6.5% 56.0% 17.8% 13.4% 36.6% 26.6% % EOT 9.9% 2.9% 1.1% 3.9% 4.0% 3.4% 4.2% 145 Appendix 5. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, June 2, 1989. Organisms Pond Mean & of 4 2 4 6 9 1 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 1 0.2 0.1% Nematoda 1 0.2 0.1% Oligochaeta 16 2.7 1.2% Ancylidae 0.0 0.0% SUBTOTAL 16 0 0 1 1 0 3.0 1.3% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 11 3 2 1 2 3.2 1.4% Leptophlebia 0.0 0.0% Caenis 16 8 3 3 3 9 7.0 3.1% Hexagenia 1 0.2 0.1% SUBTOTAL 27 11 5 3 4 12 10.3 6% ODONATA Argia 0.0 0.0% Enal lagma 10 4 19 9 14 14 11.7 5.1% Gomphus 1 0.2 0.1% Anax junius 0.0 0.0% Libel lulidae 6 4 7 3 6 4.3 1.9% SUBTOTAL 16 8 19 16 18 20 16.2 7.1% TRICHOPTERA Cernotina 1 0.2 0.1 Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 2 2 1 0.8 0.4% Agrypnia 0.0 0.0% SUBTOTAL 0 3 0 0 2 1 1.0 0.4% COLEOPTERA Gyrinidae 4 4 1 1 0.7 0.3% Dytiscidae 1 2 1 3 1.2 0.5% Tropisternus 0.0 0.0% Berosus 2 0.3 3.4% SUBTOTAL 1 1 3 2 2 4 2.2 1.0% DIPTERA Tabanidae 0.0 0.0% Chaoborus 1 1 0.3 0.1% Ceratopogonidae 4 2 4 5 2.5 1.1% CHIRONOMIDAE Tanypodinae 103 66 51 98 30 79 71.2 31.4% Chironominae 41 170 56 224 103 128 §=6120.3 53.0% SUBTOTAL 148 238 107 326 134 213 194.3 85.6% Density 208 261 134 548 16] 220 3=ee?.0 Number of Taxa 9 10 7 8 12 12 9.7 EOT Index 4 6 3 3 6 6 4.7 EOT/Chironomidae 29.9% 9.3% 22.4% 5.9% 18.0% 15.9% 16.9% % Chironominae 19.7% 65.1% 41.8% 64.4% 64.0% 51.2% 51.0% % Tanypodinae 49.5% 25.3% 38.1% 28.2% 18.6% 31.6% 31.9% *% EOT 20.7% 8.4% 17.9% 5.5% 14.9% 13.2% 13.4% 146 Appendix 6. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, June 15, 1989. Organisms Pond Mean & Of 4 2 4 6 9 11 Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 1 0.2 0.1% SUBTOTAL 0 0 1 0 0 0 0.2 0.1% EPHEMEROPTERA Callibaetis 1 1 0.3 0.3% Leptophlebia 0.0 0.0% Caenis 7 4 3 3 2 3.2 2.4% Hexagenia 1 0.2 0.1% SUBTOTAL 1 7 4 4 3 3 3.7 2.8% ODOWATA Argia 0.0 0.0% Enal lagma 4 10 6 14 2 32 11.3 8.7% Gomphus 0.0 0.0% Anax junius 0.0 0.0% Libellutlidae 1 | 1 6 1.5 1.1% SUBTOTAL 4 11 7 14 3 38 12.8 9.8% TRICHOPTERA Cernotina 1 0.2 0.1% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 2 0.3 0.3% Agrypnia 0.0 0.0% SUBTOTAL 0 1 0 0 2 0 0.5 0.4% COLEOPTERA Gyrinidae 1 0.2 0.1% Dytiscidae 1 0.2 0.1% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 0 0 1 0 1 0 0.3 0.3% DIPTERA Tabanidae 0.0 0.0% Chaoborus 0.0 0.0% Ceratopogonidae 2 0.3 0.3% CHIRONOMIDAE Tanypodinae 13 36 30 55 37 41 35.3 27.0% Chironominae 11 64 167 126 40 57 77.5 59.3% SUBTOTAL 24 100 197 183 77 98 «113.2 86.6% Density eg 119 210 © 207 86 159s «150.7 Number of Taxa 4 6 7 6 7 6 6.0 EOT Index 2 4 3 3 4 4 3.3 EOT/Chironomidae 20.8% 19.0% 5.6% 9.9% 10.4% 41.8% 17.9% % Chironominae 37.9% 53.8% 79 5% 62.7% 46.5% 41.0% 53.6% % Tanypodinae 44.8% 30.3% 14.3% 27.4% 43.0% 29.5% 31.5% % EOT 17.2% 16.0% 5.2% 9.0% 9.3% 29.5% 14.4% 147 Appendix 7. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, June 30, 1989. Organisms Pond Mean *% of 1 2 4 6 9 7 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites Nematoda So So Oligochaeta a oe oe Ancylidae s SUBTOTAL 0 0 0 0 0 0 ooco°o ooo0oo ooo0oo a a HEMIPTERA Corixidae Buenoa Notonecta 1 1 SUBTOTAL 0 0 1 0 0 1 oooo WWOoOoe EPHEMEROPTERA Callibaetis 4 1 2 1 Leptophlebia Caenis 6 3 2 Lv Hexagenia SUBTOTAL 10 4 4 a-n on aonro- NANO ODONATA Argia Enal lagma 7 9 10 Gomphus 1 1 Ze Anax junius 1 VE FE FE Nn Nn Libel lulidae 9 9 oo 28 28 SUBTOTAL 16 11 20 OoNW NUOOOO NUOOOO —_i —_i QO@QWaOo QO@QWaOo OWoono OWoono QSussks QSussks FE FE TRICHOPTERA Cernotina Oxyethira Hydroptila Oecetis Agrypnia e 8 @ SUBTOTAL 0 0 0 0 0 0 oooo00oo0 oo000o oooo°c]e e909000 RRRARR COLEOPTERA Gyrinidae 1 Dytiscidae Tropisternus Berosus SUBTOTAL 0 0 0 0 0 1 aqQoooo nNooorn DIPTERA Tabanidae Chaoborus 1 Ceratopogonidae 2 1 1 2 5 =-=oO9o°o e @NO CHIRONOMIDAE mh Tanypodinae 31 7 37 & 23 49 ~ oo ae Chironominae 81 146 1146 64 215 wd SUBTOTAL 114 154 152 89 269 a Pw nNS SSE UWN Density 140 We 112 106 289 —" n es Number of Taxa 7 EOT Index 4 EOT/Chironomidae 23.2% 15.9% 18.1% 44.8% 6.8% —_ 64.4% 53.6% 50.0% 74.4% % Chironominae 57.9% ¥ % Tanypodinae 22.1% Bo 0 20.9% 30.4% 18.0% 17.0% ooh ao» ao» 13.6% 15.2% 30.5% 6.2% % EOT 18.6% a BARRNAN RREVuw0Gs anh 148 Appendix 8. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, July 14, 1989. Organisms Pond Mean -& of T é 4 6 9 | Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 1 0.2 0.1% Nematoda 0.0 0.0% Oligochaeta 9.0 0.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 1 0.2 0.1% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 1 2 3 1 1 1.3 1.1% SUBTOTAL 1 2 3 1 1 0 1.3 1.1% EPHEMEROPTERA Callibaetis 4 8 5 1 1 2 3.5 2.9% Leptophlebia 0.0 0.0% Caenis 9 3 3 1 3 3 3.7 3.0% Hexagenia 1 0.2 0.1% SUBTOTAL 13 11 8 3 4 5 7.3 6.1% ODONATA Argia 0.0 0.0% Enal lagma 7 10 6 11 3 3 6.7 5.5% Gomphus 4 0.2 0.1% Anax junius 1 1 1 0.5 0.4% Libet Lul idae 12 4 9 7 1 9 7.0 5.8% SUBTOTAL 20 15 16 19 4 42 14.3 11.9% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptita 0.0 0.0% Oecetis 1 0.2 0.1% Agrypnia 0.0 0.0% SUBTOTAL 0 0 0 1 0 0 0.2 0.1% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 1 0.2 1.8% SUBTOTAL 0 0 1 0 0 0 0.2 0.1% DIPTERA Tabanidae 1 0.2 0.1% Chaoborus 0.0 0.0% Ceratopogoni dae 2 2 2 1 2 1.5 1.2% CHIRONOMIDAE Tanypodinae 28 20 15 13 19 42 22.8 19.0% Chironominae 66 183 72 25 58 30 72.3 60.1% SUBTOTAL 96 205 90 39 77 74 96.8 80.5 Density 150 | 255 118 65 86 92 120.5 Number of Taxa 9 9 11 11 7 8 9.2 EOT Index 5 5 5 7 4 4 5.0 EOT/Chironomidae 35.1% 12.8% 27.6% 60.5% 10.4% 23.6% 28.3% % Chironominae 50.8% 78.5% 61.0% 39.7% 67.4% 32.6% 55.0% % Tanypodinae 21.5% 8.6% 12.7% 20.6% 22.1% 45.7% 21.9% % EOT 25.4% 11.2% 20.3% 36.5% 9.3% 18.5% 20.2% 149 Appendix 9. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, July 28, 1989. Organisms Pond __ Mean & Of 1 2 4 6 9 WW Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites Nematoda Ol igochaeta Ancylidae SUBTOTAL 0 0 0 0 0 0 ooo0coo ooooo HEMIPTERA Corixidae Buenoa Notonecta 1 1 ae ae ~~ ~~ o o oooo oooo SUBTOTAL 0 0 0 1 0 1 WWOO EPHEMEROPTERA Callibaetis 4 3 1 3 8 Leptophlebia 3e ON ae Oo —_ Caenis 10 23 6 w Hexagenia 3 a SUBTOTAL 14 26 10 at NODOW NUIO FOWO— SRRQr ODONATA Argia Enal lagma 13 13 6 16 5 3 Gomphus 1 Owvoo Owvoo =20 =20 Anax junius 2 2 2 OMWO OMWO 0 0 Libel lulidae 19 32 17 67 m= NINE NINE FODOWO FODOWO Q SUBTOTAL 34 48 25 2 — RANRRR RANRRR VIN VIN yin yin TRICHOPTERA Cernotina Oxyethira Hydroptila Oecetis Agrypnia SUBTOTAL 0 0 0 0 0 0 oooqo0ooo oooo0°o COLEOPTERA Gyrinidae 1 1 1 0 Dytiscidae 1 0 Tropisternus 0. Berosus 0 SUBTOTAL 0 2 0 0 1 1 0 DIPTERA Tabanidae 0 Chaoborus 1 0 Ceratopogoni dae 12 7 1 4 2 4. CHIRONOMIDAE Tanypodinae 44 88 65 29 82 65 62. Chironominae 169 193 132 148 156 65 143. SUBTOTAL 213 293 204 178 243 132 ©6210. Density 261 569 » Zor 207 2bf del 260.7 Number of Taxa 7 11 9 8 10 9 9.0 EOT Index 5 6 6 4 5 4 5.0 EQT/Chironomidae 22.5% 26.3% 17.8% 15.8% 9.7% 66.9% 26.5% % Chironominae 64.8% 52.3% 55.2% 71.5% 58.4% 29.4% 55.3% % Tanypodinae 16.9% 23.8% 27.2% 14.0% 30.7% 29.4% 23.7% % EOT 18.4% 20.1% 14.6% 13.5% 8.6% 39.4% 19.1% 150 Appendix 10. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, August 11, 1989. Organisms Pond _ Mean - Of 4 2@ 4 6 9 4 Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 1 5 1.0 0.7% Ancyl idae 0.0 0.0% SUBTOTAL 1 5 0 0 0 0 1.0 0.7% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 5 3 5 2 1 3 3.2 2. Leptophlebia 0.0 0.0% Caenis 12 11 17 11 2 3 9.3 6.5% Hexagenia 1 0.2 0.1% SUBTOTAL 17 14 23 13 3 6 12.7 8.8% ODONATA Argia 0.0 0.0% Enal Lagma 6 7 10 1 1 4.2 2.9%. Gomphus 1 0.2 0.1% Anax junius 1 1 1 0.5 0.3% Libel Lut idae 22 24 19 8 2 9 14.0 9.8% SUBTOTAL 23 31 26 18 5 10 18.8 13.1% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 1 0.2 0.1% Agrypnia 0.0 0.0% SUBTOTAL 1 0 0 0 0 0 0.2 0.1% COLEOPTERA Gyr inidae 0.0 0.0 Dytiscidae 1 0.2 0.1% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 0 0 1 0 0 0 0.2 0.1 DIPTERA Tabanidae 3 1 0.7 0.5% Chaoborus 1 0.2 0.1% Ceratopogonidae 1 6 2 2 1 2.0 1.4% CHIRONOMIDAE Tanypodinae 19 17 11 11 42 28 21.3 14.9% Chironominae 93 88 102 85 125 25 86.3 60.2% SUBTOTAL 117 112 115 96 169 54 110.5 77.1% Density 159 162 165 Tae VW 70 = 145.5 Number of Taxa 11 10 9 6 9 7 8.7 EOT Index 5 5 5 4 6 4 4.8 EOT/Chi ronomidae 36.6% 42.9% 43.4% 32.3% 4.8% 30.2% 31.7% % Chironominae 58.5% 54.3% 61.8% 66.9% 70.6% 35.7% 58.0% % Tanypodinae 11.9% 10.5% 6.7% 8.7% 23.7% 40.0% 16.9% % EOT 25.8% 27.8% 29.7% 24.4% 4.5% 22.9% 22.5% 151 Appendix 11. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, August 24, 1989. Organisms Pond Mean & of 1 ee 4 6 9 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 3 0.5 0.3% Ancylidae 0.0 0.0% SUBTOTAL 0 3 0 0 0 0 0.5 0.3% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 24 22 3 1 1 8.8 4.7% Leptophlebia 0.0 0.0% Caenis 4 12 15 21 1 6 9.8 5.3% Hexagenia 2 0.3 0.2% SUBTOTAL 28 34 18 22 4 19.0 10.2% ODONATA Argia 0.0 0.0% Enal Lagma -3 7 8 12 2 3 5.8 3.1% Gomphus 1 0.2 0.1% Anax junius 1 1 | 0.5 0.3% Libel tutidae 19 11 14 6 1 7 9.7 5.2% SUBTOTAL 22 18 22 19 4 12 16.2 8.7% TRICHOPTERA Cernotina 0.0 0.0% oxyethira 11 2 2.2 1.2% Hydroptila 1 0.2 0.1% Oecetis 0.0 0.0% Agrypnia 0.0 0.0% SUBTOTAL 1 0 0 11 0 2 2.3 1.2% COLEOPTERA Gyrinidae 1 2 0.5 0.3% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 0 1 0 0 2 0 0.5 0.3% DIPTERA Tabanj dae 1 0.2 0.1% Chaoborus 0.0 0.0% Ceratopogoni dae 2 1 16 3 2 2 4.3 2.3% CHIRONOMIDAE Tanypodinae 46 63 47 31 29 37 42.2 22.6% Chironominae 99 146 147 77 86 55 101.7 54.4% SUBTOTAL 147 211 210 111 117 94 8148.3 79 4% Density 198 — 26 220 165 127 116 = 186.8 Number of Taxa 8 10 7 9 10 10 9.0 EOT Index 5 4 4 6 6 7 5.3 EOT/Chironomidae 35.2% 24.9% 20.6% 48.1% 7.0% 23.9% 26.6% % Chironominae 50.0% 54.7% 58.8% 47.2% 67.7% 47.4% 54.3% % Tanypodinae 23.2% 23.6% 18.8% 19.0% 22.8% 31.9% 23.2% *% EOT 25.8% 19.5% 16.0% 31.9% 6.3% 19.0% 19.7% 152 Appendix 12. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, September 8, 1989. Organisms Pond Mean & of 1 é 4 6 a) VW Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites Nematoda 2k 2k Oligochaeta 2 e Arcylidae 1 ae re re SUBTOTAL 0 2 0 0 1 0 ooooo ooooo ooo0o°o ooo0o°o W=NAOO W=NAOO ViNIWOO ViNIWOO ae ae HEMIPTERA Cor ixidae Buenoa Notonecta SUBTOTAL 0 0 0 0 0 0 oooo oo0o°0o EPHEMEROPTERA Callibaetis 6 1 1 1 5 Leptophlebia Fe o— o— Caenis 12 7 6 9 Fe nN nN Fe Hexagenia Fe ~OORON ~OORON SUBTOTAL 18 8 7 10 feu oOnuow wor Youeul ODONATA Argia Enal lagma 3 5 13 1 2 Gomphus wi Anax junius 1 1 Libeltulidae 9 14 14 15 ad SUBTOTAL 9 1 OO 20 28 17 wing w= &oooro VINWOOO ODAOONE —= —h TRICHOPTERA Cernotina OS Oxyethira 1 o Hydroptila 1 e e Oecetis e Agrypnia a SUBTOTAL 0 0 1 0 1 0 oocooo e WOONN COLEOPTERA Gyrinidae 0.0 Dytiscidae 0.0 Tropisternus 0.0 Berosus 1 0.2 SUBTOTAL 0 1 0 0 0 0 0.2 DIPTERA Tabanidae 2 3 0 Chaoborus 0 Ceratopogonidae 1 1 0. CHIRONOMIDAE Tanypodinae 24 19 11 16 14 23 17 Chi ronominae 141 136 149 126 87 42 +113. SUBTOTAL 167 158 161 143 101 65 132. Density 194 180 189 181 109 89 = 157.0 Number of Taxa 6 9 9 8 8 6 7.7 EOT Index 3 4 6 5 5 4 4.5 EOT/Chironomidae 16.4% 12.3% 17.5% 26.8% 5.9% 36.9% 19.5% % Chironominae 72.7% 75.6% 78.8% 69.6% 79.8% 47.2% 70.6% % Tanypodinae 12.4% 10.6% 5.8% 8.8% 12.8% 25.8% 12.7% % EOT 13.9% 10.6% 14.8% 21.0% 6.4% 27.0% 15.6% 153 Appendix 13. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, September 27, 1989. Organisms Pond Mean ” of 1 2! 4 6 9 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 2 0.3 0.2% Ancylidae 10 1.7 1.0% SUBTOTAL 0 2 0 0 10 0 2.0 1.2% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 5 1 4 2 2.0 1.2% Leptophlebia 0.0 0.0% Caenis 14 33 7 20 5 13.2 7.7% Hexagenia 0.0 0.0% SUBTOTAL 14 38 8 0 24 7 15.2 8.8% ODONATA Argia 0.0 0.0% Enal lagma 3 3 3 1 2 2.0 1.2% Gomphus 0.0 0.0% Anax junius 1 0.2 0.1% Libellulidae 17 12 18 11 2 14 12.3 7.2% SUBTOTAL 20 15 21 12 5 14 14.5 8.5% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 1 1 4 7 1 2.3 1.4% Hydroptila 0.0 0.0% Oecetis 0.0 0.0% Agrypnia 0.0 0.0% SUBTOTAL 1 1 4 7 0 1 2.3 1.4% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 3 1 0.7 8.2% SUBTOTAL 0 3 0 1 0 0 0.7 0.4% DIPTERA Tabanidae 1 1 1 0.5 0.3% Chaoborus 0.0 0.0% Ceratopogonidae 3 4 4 8 3.2 1.8% CHIRONOMIDAE Tanypodinae 55 42 18 14 30 38 32.8 19.1% Chironominae 158 127 86 28 158 45 100.3 58.5% SUBTOTAL 217 174 108 43 188 91 136.8 79.8% Density One 233° 141 65 2ef hh Number of Taxa 8 11 8 7 8 7 8.2 EOT Index 4 5 5 3 5 4 4.3 EOT/Chironomidae 16.4% 32.0% 31.7% 45.2% 15.4% 26.5% 27.9% % Chironominae 62.7% 54.5% 61.0% 44.4% 69.6% 39.8% 55.3% % Tanypodinae 21.8% 18.0% 12.8% 22.2% 13.2% 33.6% 20.3% % EQT 13.9% 23.2% 23.4% 30.2% 12.8% 19.5% 20.5% 154 Appendix 14. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, October 6, 1989. Organisms Pond Mean ” of 1 2 4 6 y 17 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 8 1.3 0.8% Ancyl idae 0.0 0.0% SUBTOTAL 0 8 0 0 0 0 1.3 0.8% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 2 10 6 3.0 1.9% Leptophlebia 0.0 0.0% Caenis 16 21 17 5 24 13.8 8.7% Hexagenia 1 0.2 0.1% SUBTOTAL 18 31 18 5 30 0 17.0 10.7% ODONATA Argia 0.0 0.0% Enal lagma 4 5 4 3 3 3.2 2.0% Gomphus 0.0 0.0% Anax junius 1 0.2 0.1% Libel lulidae 8 8 8 9 1 5.7 3.6% SUBTOTAL 12 13 13 12 4 0 9.0 5.6% TRICHOPTERA Cernotina 1 0.2 0.1% Oxyethira 2 1 2 2 1.2 0.7% Hydroptila 0.0 0.0% Oecetis 2 0.3 0.2% Agrypnia 0.0 0.0% SUBTOTAL 2 1 4 3 0 0 1.7 1.0% COLEOPTERA Gyrinidae 0.0 0.0 Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0 DIPTERA Tabanidae 2 0.3 0.2% Chaoborus 1 0.2 0.1% Ceratopogonidae 3 1 14 2 5 4.2 2.6% CHIRONOMIDAE Tanypodinae 17 41 32 14 105 34.8 21.9% Chironominae 95 150 72 43 185 90.8 57.0% SUBTOTAL 115 194 119 59 295 Q 130.3 81.8% Density 147 eae 154 9 529 0 159.5 Number of Taxa 8 10 11 8 7 0 7.3 EOT Index 5 5 7 5 4 0 4.3 EOT/Chironomidae 28.6% 23.6% 33.7% 35.1% 11.7% ERR ERR % Chironominae 64.6% 60.7% 46.8% 54.4% 56.2% ERR ERR % Tanypodinae 11.6% 16.6% 20.8% 17.7% 31.9% ERR ERR % EOT 21.8% 18.2% 22.7% 25.3% 10.3% ERR ERR 155 Appendix 15. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, October 20, 1989. Organi sms Pond Mean ” of 1 2 4 6 y 71 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 35 3 1 6.5 1.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 35 0 3 0 1 6.5 1.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 13 2 8 5 3 1 5.3 0.8% Leptophlebia 0.0 0.0% Caenis 29 34 20 12 11 10 19.3 2.9% Hexagenia 2 0.3 0.1% SUBTOTAL 42 36 30 17 14 11 25.0 3.8% ODONATA Argia 0.0 0.0% Enal lagma 2 6 4 5 2 1 3.3 0.5% Gomphus 0.0 0.0% Anax junius 1 1 1 0.5 0.1% Libel lulidae 17 6 13 15 3 13 11.2 1.7% SUBTOTAL 19 12 17 21 6 15 15.0 2.3% TRICHOPTERA Cernotina 1 3 0.7 0.1% Oxyethira 2 9 3 20 1 4 6.5 1.0% Hydroptila 1 1 0.3 0.1% Oecetis 0.0 0.0% Agrypnia 1 0.2 0.0% SUBTOTAL 3 11 3 23 2 4 7.7 1.2% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 1 1 0.3 3.2% SUBTOTAL 1 0 0 0 0 1 0.3 0.1% DIPTERA Tabanidae 1 0.2 0.0% Chaoborus 0.0 0.0% Ceratopogonidae 23 10 122 20 8 123 51.0 7.7% CHIRONOMIDAE Tanypodinae 192 501 142 171 189 165 226.7 34.3% Chironominae 244 686 140 354 417 134 329.2 49.8% SUBTOTAL 459 1197 404 546 614 422 607.0 91.8% Density 324 1291 494 610 656 454 661.5 © Number of Taxa 10 11 9 12 10 11 10.5 EOT Index 6 7 6 7 7 6 6.5 EOT/Chironomidae 14.7% 5.0% 17.7% 11.6% 3.6% 10.0% 10.4% % Chironominae 46.6% 53.1% 30.8% 58.0% 65 .6% 29.5% 47.3% % Tanypodinae 36.6% 38.8% 31.3% 28.0% 29.7% 36.3% 33.5% *% EOT 12.2% 4.6% 11.0% 10.0% 3.5% 6.6% 8.0% 156 Appendix 16. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, November 16, 1989. Organisms Pond Mean * Of. 1 2 4 6 a) 17 Total COMMUNITY STRUCTURE (number/samp|er) MISC. INVERTEBRATES Mites 1 0.2 0.0% Nematoda 0.0 0.0% Oligochaeta 1 4 0.8 0.1% Ancyl idae 0.0 0.0% SUBTOTAL 0 1 1 4 0 0 1.0 0.1% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 17 4 5 12 5 4 7.8 0.9% Leptophlebia 0.0 0.0% Caenis 24 30 16 17 10 10 17.8 2.1% Hexagenia 0.0 0.0% SUBTOTAL 41 34 21 29 15 14 25.7 3.1% ODONATA Argia 0.0 0.0% Enal lagma 7 2 7 2 2 3.3 0.4% Gomphus 0.0 0.0% Anax junius 1 1 1 0.5 0.1% Libellulidae 7 10 17 11 20 10.8 1.3% SUBTOTAL 7 18 19 19 2 23 14.7 1.8% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 2 13 13 21 1 8.3 1.0% Hydroptila 0.0 0.0% Oecetis 1 0.2 0.0% Agrypnia 1 2 0.5 0.1% SUBTOTAL 3 13 13 21 3 1 9.0 1.1% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 3 0.5 0.1% Tropisternus 0.0 0.0% Berosus 1 1 0.3 3.3% SUBTOTAL 0 0 3 1 0 1 0.8 0.1% DIPTERA Tabanidae 4 8 1 2.2 0.3% Chaoborus 0.0 0.0% Ceratopogonidae 13 15 147 17 3 98 48.8 5.8% CHIRONOMIDAE Tanypodinae 279 623 366 371 248 450 389.5 46.7% Chironominae 297 385 305 545 209 318 343.2 41.1% SUBTOTAL 593 1023 818 941 460 867 783.7 93.9% Density 644 1089 8m 7015 480 906 854.8 Number of Taxa 9 10 10 12 8 11 10.0 EOT Index 5 6 5 6 5 6 5.5 EOT/Chironomidae 8.9% 6.4% 7.9% 7.5% 4.4% 4.9% 6.7% % Chironominae 46.1% 35.4% 34.9% 53.7% 43.5% 35.14% 41.4% % Tanypodinae 43.3% 57.2% 41.8% 36.6% 51.7% 49.7% 46.7% *% EOT 7.9% 6.0% 6.1% 6.8% 4.2% 4.2% 5.9% 157 Appendix 17. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, December 19, 1989. Organisms Pond _ Mean % of 1 e 4 6 yy 4 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 1 0.2 0.0% Oligochaeta 0.0 0.0% Ancy| idae 0.0 0.0% SUBTOTAL 0 0 1 0 0 0 0.2 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 1 0.2 0.0% SUBTOTAL 0 9 0 1 0 0 0.2 0.0% EPHEMEROPTERA Callibaetis 3 15 10 1 2 6 6.2 1.4% Leptophlebia 0.0 0.0% Caenis 13 28 18 4 8 11 13.7 3.1% Hexagenia 1 0.2 0.0% SUBTOTAL 16 43 29 5 10 17 20.0 4.6% ODONATA Argia 0.0 0.0% Enal lLagma 1 é 3 1 1 7 3.2 0.7% Gomphus 0.0 0.0% Anax junius 1 2 1 1 1 1.0 0.2% Libel Lulidae 5 18 9 8 2 42 14.0 3.2% SUBTOTAL 7 26 13 10 3 50 18.2 4.2% TRICHOPTERA Cernotina 0.0 -0% Oxyethira 11 16 8 28 10.5 2.4% Hydroptila 0.0 0.0% Oecetis 0.0 0.0% Agrypnia 1 0.2 0.0% SUBTOTAL 0 11 16 8 0 29 10.7 2.4% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 2 1 0.5 5.2% SUBTOTAL 0 0 2 0 1 0 0.5 0.1% DIPTERA Tabanidae 3 0.5 -1% Chaoborus 0.0 0.0% Ceratopogonidae 2 9 65 9 4 69 26.3 &.0% CHIRONOMIDAE Tanypodinae 135 256 152 76 156 278 «=6175.5 40.2% Chironominae 180 233 165 214 123 190 184.2 42.2% SUBTOTAL 320 498 382 299 283 537 386.5 88.6% Density «565 | 78 445 525 eve 655 456.2 Number of Taxa 9 9 12 10 8 10 9.7 EOT Index 5 6 7 6 4 7 5.8 EOT/Chironomidae 7.3% 16.4% 18.3% 7.9% 4.7% 20.5% 12.5% % Chironominae 52.5% 40.3% 37.2% 66.3% 41.4% 30.0% 44.6% % Tanypodinae 39.4% 44.3% 34.3% 23.5% 52.5% 43.9% 39.7% % EOT 6.7% 13.8% 13.1% 7.1% 4.4% 15.2% 10.1% 158 Appendix 18. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, January 16, 1990. Organisms Pond Mean - Of 1 2 a 6 9 a Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 9 24 4 7 5 7 9.3 1.4% Leptophlebia 0.0 0.0% Caenis 25 26 11 & 9 9 14.7 2.3% Hexagenia 0.0 0.0% SUBTOTAL 34 50 15 15 14 16 24.0 3.7% ODONATA Argia 0.0 0.0% Enal Lagma 6 12 4 6 1 5 5.7 0.9% Gomphus 0.0 0.0% Anax junius 1 1 0.3 0.1% Libel Lulidae 8 16 10 36 1 82 25.5 3.9% SUBTOTAL 14 28 14 43 3 87 31.5 4.8% TRICHOPTERA Cernotina 5 0.8 0.1% Oxyethira 16 8 8 7 6.5 1.0% Hydroptila 0.0 0.0% Oecetis 2 1 0.5 0.1% Agrypnia 4 2 2 1.3 0.2% SUBTOTAL 0 25 8 10 4 8 9.2 1.4% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 1 1 0.3 0.1% Tropisternus 0.0 0.0% Berosus 1 0.2 1.7% SUBTOTAL 1 0 0 1 0 1 0.5 0.1% DIPTERA Tabanidae 2 1 3 1.0 0.2% Chaoborus 0.0 0.0% Ceratopogonidae 1 17 60 7 1 59 24.2 3.7% CHIRONOMIDAE Tanypodinae 128 441 164 178 125 213 208.2 32.0% Chironominae 333 565 212 557 210 237» 3=— 3352.3 54.1% SUBTOTAL 464 1024 436 742 336 512 585.7 90.0% Density 315 V12F 4/5 B11 355¢ 6e4 =650.8 Number of Taxa 9 11 8 11 10 11 10.0 EOT Index 4 7 5 7 7 6 6.0 EOT/Chironomidae 10.4% 10.2% 9.8% 9.3% 6.3% 24.7% 11.8% % Chironominae 64.9% 50.1% 44.8% 68.7% 58.8% 38.0% 54.2% % Tanypodinae 25.0% 39.1% 34.7% 21.9% 35.0% 34.1% 31.6% % EOT 9.4% 9.1% 7.8% 8.4% 5.9% 17.8% 9.7% 159 Appendix 19. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, February 8, 1990. Organisms Pond Mean * of 1 2 4 6 9 11 Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 7 6 10 5 7 6 6.8 2.0% Leptophlebia 0.0 0.0% Caenis 9 18 5 6 7 2 7.8 2.3% Hexagenia 1 0.2 0.0% SUBTOTAL 16 24 16 11 14 8 14.8 4.3% ODONATA Argia 0.0 0.0% Enallagma 3 5 4 2 3 3 3.3 1.0% Gomphus 0.0 0.0% Anax junius 0.0 0.0% Libel lulidae 10 2 12 21 20 10.8 3.2% SUBTOTAL 13 7 16 23 3 23 14.2 4.1% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 3 0.5 0.4% Hydroptila 0.0 0.0% Cecetis 0.0 0.0% Agrypnia 2 1 1 1 1 1.0 0.3% SUBTOTAL 2 1 3 1 1 1 1.5 0.4% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% DIPTERA Tabanidae 1 1 2 0.7 0.2% Chaobdorus 0.0 0.0% Ceratopogonidae 3 21 2 54 13.3 3.9% CHIRONOMIDAE Tanypodi nae v2 129 143 62 104 126 106.0 30.9% Chironominae 139 353 163 235 107 161 193.0 56.2% SUBTOTAL 212 485 328 299 211 343 3313.0 91.1% Density 245 517 365 $54 229 5/5 = $45.5 Number of Taxa 8 8 10 8 6 9 8.2 EOT Index 5 5 6 5 4 5 5.0 EOT/Chironomidae 14.7% 6.6% 11.4% 11.8% 8.5% 11.1% 10.7% % Chironominae 57.2% 68.3% 44.9% 70.4% 46.7% 42.9% 55.1% % Tanypodinae 29.6% 25.0% 39.4% 18.6% 45.4% 33.6% 31.9% % EOT 12.8% 6.2% 9.6% 10.5% 7.9% 8.5% 9.2% 160 Appendix 20. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, March 8, 1990. Organisms Pond Mean * of 1 2 4 6 9 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 3 0.5 0.2% Ancyl idae 0.0 0.0% SUBTOTAL 3 0 0 0 0 0 0.5 0.2% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 2 1 2 5 7 1 3.0 1.0% Leptophlebia 0.0 0.0% Caenis 12 6 2 2 4 2 4.7 1.5% Hexagenia 0.0 0.0% SUBTOTAL 14 7 4 7 11 3 7.7 2.54 ODONATA Argia 0.0 0.0% Enal Lagma 1 8 2 2 5 3.0 1.0%. Gomphus 0.0 0.0% Anax junius 1 0.2 0.1% Libel Lulidae 7 4 8 24 15 9.7 3.1% SUBTOTAL 9 12 10 26 0 20 12.8 4.1% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 1 0.2 0.1% Hydroptila 0.0 0.0% Oecetis 1 0.2 0.1% Agrypnia 1 1 0.3 0.1% SUBTOTAL 1 1 1 0 1 0 0.7 0.2% COLEOPTERA ‘Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% DIPTERA Tabanidae 5 5 1 1.8 0.6% Chaoborus 0.0 0.0% Ceratopogonidae 4 20 5 27 9.3 3.0% CHIRONOMIDAE Tanypodinae 128 115 153 92 72 74 «105.7 34.0% Chironomi nae 179 221 105 229 131 167 172.0 55.4% SUBTOTAL 316 341 278 327 203 268 288.8 93.0% Density 345 561 293 360 215 291 310.5 Number of Taxa 11 8 8 8 5 7 7.8 EOT Index 6 5 5 4 3 4 4.5 EOT/Chironomi dae 7.8% 6.0% 5.8% 10.3% 5.9% 9.5% 7.6% % Chironominae 52.2% 61.2% 35.8% 63.6% 60.9% 57.4% 55.2% % Tanypodinae 37.3% 31.9% 52.2% 25.6% 33.5% 25.4% 34.3% % EOT 7.0% 5.5% 5.1% 9.2% 5.6% 7.9% 6.7% 161 Appendix 21. Benthic macroinvertebrates collected at the Experimental Pond Project using artificial substrates at the one meter depth, April 5, 1990. Organisms Pond Mean % of 1 2 4 6 9 14 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 1 0.2 -0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancylidae 0.0 0.0% SUBTOTAL 1 0 0 0 0 0 0.2 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 3 3 2 1.3 0.3% Leptophlebia 0.0 0.0% Caenis 4 4 2 1 2 1 2.3 0.6% Hexagenia 1 0.2 0.0% SUBTOTAL 7 7 3 1 4 1 3.8 1.0% QDONATA Argia 0.0 0.0% Enal Lagma 3 1 1 2 2 1.5 0.4% Gomphus 0.0 0.0% Anax junius 1 0.2 0.0% Libel lutidae 8 5 3 9 5 5.0 1.2% SUBTOTAL 11 6 3 10 2 8 6.7 1.7% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 0.0 0.0% Agrypnia 1 1 2 1 0.8 0.2% SUBTOTAL 1 1 0 0 2 1 0.8 0.2% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 1 0.2 0.0% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 1 0 0 0 0 0 0.2 0.0% DIPTERA Tabanidae 3 1 1 1 1.0 0.2% Chaoborus 0.0 0.0% Ceratopogonidae 2 17 79 32 21.7 5.4% CHIRONOMIDAE Tanypodinae 71 260 112 28 110 148 121.5 30.3% Chironominae 8&9 594 159 102 206 320 245.0 61.1% SUBTOTAL 162 874 351 131 316 501 389.2 97.1% Density T83 888 357 142 324 21T = 400.8 Number of Taxa 10 9 7 6 6 9 7.8 EOT Index 5 5 3 3 4 5 4.2 EOT/Chi ronomi dae 11.9% 1.6% 2.2% 8.5% 2.5% 2.1% 4.8% % Chironominae 48.6% 66.9% 44.5% 71.8% 63.6% 62.6% 59.7% % Tanypodinae 38.8% 29.3% 31.4% 19.7% 34.0% 29.0% 30.3% % EOT 10.4% 1.6% 1.7% 7.7% 2.5% 2.0% 4.3% 162 Appendix 22. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, May 6, 1989. Organisms Pond Mean - of 1 2 4 6 _) 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 1 2 0.5 0.4% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancylidae 0.0 0.0% SUBTOTAL 0 0 0 1 2 0 0.5 0.4% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 56 18 3 14 6 15 18.7 15.7% Leptophlebia 0.0 0.0% Caenis 20 57 67 62 18 50 45.7 38.5% Hexagenia 3 0.5 0.4% SUBTOTAL 76 75 70 79 24 65 64.8 54.6% ODONATA Argia 0.0 0.0% Enal Lagma 1 4 2 21 9 4 6.8 5.8% Gomphus 2 1 3 5 1.8 1.5% Anax junius 1 1 0.3 0.3% Libel lulidae 9 4 5 8 3 4 5.5 4.6% SUBTOTAL 10 9 10 30 15 13 14.5 12.2% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 2 13 2 20 6.2 5.2% Agrypnia 0.0 0.0% SUBTOTAL 2 13 2 0 0 20 6.2 5.2% COLEOPTERA Gyrinidae 1 1 1 1 0.7 0.6% Dytiscidae 14 2 10 5 2 18 8.5 7.2% Tropisternus 0.0 0.0% Berosus 8 3 12 11 6 6 7.7 63.9% SUBTOTAL 23 5 23 17 8 25 16.8 14.2% DIPTERA Tabanidae 1 1 0.3 0.3% Chaoborus 2 1 1 | 9 2.3 2.0% Ceratopogonidae 4 5 1 3 1 24 6.3 5.3% CHIRONOMIDAE Tanypodinae 0.0 0.0% Chironominae 1 3 4 22 1 10 6.8 5.8% SUBTOTAL 5 10 6 26 4 44 15.8 13.3% Density 16 V1W2— 171 155 635 167 118.F Number of Taxa 10 11 13 13 12 13 12.0 EOT Index 5 6 7 6 5 6 5.8 Collector-gatherers 81 83 75 104 26 99 78.0 Predators 27 26 24 38 21 62 33.0 EOT Density 88 97 82 109 39 98 85.5 163 Appendix 23. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, May 20, 1989. Organisms Mean -& Of 1 2 4 6 g9 WW Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 1 0.2 0.1% Oligochaeta 0.0 0.0% Ancylidae 0.0 0.0% SUBTOTAL 0 0 0 0 1 0 0.2 0.1% HEMIPTERA Corixidae 0.0 0.0% Buenoa 1 0.2 0.1% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 1 0.2 0.1% EPHEMEROPTERA Cailibaetis 15 21 12 3 9 10.0 8.5% Leptophlebia 0.0 0.0% Caenis 24 78 43 34 12 42 38.8 33.1% Hexagenia 2 1 0.5 0.4% SUBTOTAL 39 99 43 48 15 52 49.3 42.0% QDONATA Argia 0.0 0.0% Enal Lagma 4 1 6 11 3 4.2 3.6% Gomphus 6 3 2 1 2 2.3 2.0% Anax junius 1 2 0.5 0.4% Libel lulidae 7 18 2 16 3 6 8.7 7.4% SUBTOTAL 13 26 5 22 17 11 15.7 13.4% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 3 2 2 2 1.5 1.3% Agrypnia 0.0 0.0% SUBTOTAL 0 3 2 2 0 2 1.5 1.3% COLEOPTERA Gyrinidae , 1 0.2 0.1% Dytiscidae 3 5 10 1 9 11 6.5 5.5% Tropisternus 0.0 0.0% Berosus 21 6 14 12 7 7 11.2 90.5% SUBTOTAL 24 11 24 13 17 18 17.8 15.2% DIPTERA Tabanidae 1 1 1 1 0.7 0.6% Chaoborus 1 2 1 1 0.8 0.7% Ceratopogonidae 44 14 6 18 3 50 22.5 19.2% CHIRONOMIDAE Tanypodinae 1 1 2 7 1.8 1.6% Chironominae 5 4 9 12 3 8 6.8 5.8% SUBTOTAL 52 20 16 34 7 67 32.7 27.8% Density 128 159° 90 119 af 1570 117.5 Number of Taxa 11 13 10 12 13 15 12.3 EOT Index 4 7 5 6 6 7 5.8 Collector-gatherers 88 117 58 78 22 110 78.8 Predators 19 36 18 29 28 34 27.3 EOT Density 52 128 50 72 32 65 66.5 Appendix 24. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, June 2, 1989. Organisms Mean - of q 2 4 6 9 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 1 1 0.3 0.3% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancyl idee 0.0 0.0% SUBTOTAL 1 0 0 0 0 1 0.3 0.3% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 31 42 6 5 & 4 16.0 13.0% Leptophlebia 0.0 0.0% Caenis 4 32 16 23 12 19 17.7 14.3% Hexagenia 1 0.2 0.1% SUBTOTAL 35 74 22 28 20 24 33.8 27.4% ODONATA Argia 0.0 0.0% Enal lL agma 31 48 15 16 16 49 29.2 23.6% Gomphus 6 1 1 7 6 5 4.3 3.5% Anax junius 2 1 1 1 1 1.0 0.8% Libellulidae 35 27 16 12 11 31 22.0 17.8% SUBTOTAL 74 77 33 35 34 86 56.5 45.8% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Cecetis 3 15 1 10 4.8 3.9% Agrypnia 0.0 0.0% SUBTOTAL 0 3 45 4 0 10 4.8 3.9% COLEOPTERA Gyr inidae 1 1 0.3 0.3% Dytiscidae 5 3 4 2 2 10 4.3 3.5% Tropisternus 0.0 0.0% Berosus 13 5 3 11 12 3 7.8 68.1% SUBTOTAL 18 9 7 13 15 13 12.5 10.1% DIPTERA Tabanidae 0.0 0.0% Chaoborus 1 0.2 0.1% Ceratopogonidae 17 6 3 7 12 22 11.2 9.1% CHIRONOMIDAE Tanypodi nae 0.0 0.0% Chi ronominae 2 3 3 4 7 5 4.0 3.2% SUBTOTAL 20 9 6 11 19 27 15.3 12.4% Density 146 1f2 85 338 88 161 125.5 Number of Taxa 12 12 11 10 11 13 11.5 EOT Index 6 7 7 6 6 8 6.7 Collector-gatherers 54 83 28 39 39 51 49.0 Predators 81 84 52 38 37 107 66.5 EOT Density 109 154 70 64 54 120 95.2 Appendix 25. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, June 15, 1989. Organisms Pond Mean % of 4 2 4 6 9 11° Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 2 1 0.5 0.2% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancy| idae 0.0 0.0% SUBTOTAL 2 0 0 0 1 0 0.5 0.2% HEMIPTERA Corixidae 2 0.3 0.2% Buenoa 0.0 0.0% Notonecta 1 4 1 1.0 0.5% SUBTOTAL 1 0 0 4 2 1 1.3 0.6% EPHEMEROPTERA Callibaetis 55 16 11 14 9 18 20.5 9.6% Leptophlebia 0.0 0.0% Caenis 30 5 12 14 5 5 11.8 5.6% Hexagenia 0.0 0.0% SUBTOTAL 85 21 23 28 14 23 32.3 15.2% ODONATA Argia 0.0 0.0% Enal lagma 78 71 111 120 44 59 80.5 37.8% | Gomphus 34 31 39 32 15 6 26.2 12.3% Anax junius 5 3 6 7 9 3 5.5 2.6% Libel lulidae 54 8 7 30 2 21 20.3 9.5% SUBTOTAL 171 113 163 189 70 89 = 132.5 62.2% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 6 15 24 3 3 16 11.2 5.2% Agrypnia 0.0 0.0% SUBTOTAL 6 15 24 3 3 16 11.2 5.2% COLEOPTERA Gyrinidae 1 1 0.3 0.2% Dytiscidae 5 2 6 6 11 5.0 2.3% Tropisternus 0.0 0.0% Berosus 11 5 7 24 24 9 13.3 102.6% SUBTOTAL 17 7 13 24 31 20 18.7 8.8% DIPTERA Tabanidae 1 1 0.3 0.2% Chaoborus 1 4 3 1.3 0.6% Ceratopogoni dae 5 3 5 13 4 24 9.0 4.2% CHIRONOMIDAE Tanypodi nae 0.0 0.0% Chironominae 6 2 2 10 13 3 6.0 2.8% SUBTOTAL 13 5 7 27 21 27 16.7 7.8% Density 295 161 250 en 142 176 = 215.2 Number of Taxa 16 11 11 12 16 12 13.0 EOT Index 7 7 7 7 7 7 7.0 Collector-gatherers 96 26 30 51 31 50 47.3 Predators 188 130 193 200 85 117 = 152.2 EOT Density 262 149 210 220 8&7 128 176.0 166 Appendix 26. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, June 30, 1989. Organisms Pond Mean & Of T 2 4 6 g 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 1 0.2 0.1% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancy| idae 4 0.7 0.4% SUBTOTAL 0 0 1 0 4 0 0.8 0.5% HEMIPTERA Corjixidae 1 0.2 0.1% Buenoca 0.0 0.0% Notonecta 1 & 1.2 0.7% SUBTOTAL 0 0 0 1 0 7 1.3 0.8% EPHEMEROPTERA Callibaetis 11 8 4 8 10 16 9.5 5.6% Leptophlebia 0.0 0.0% Caenis 46 13 16 9 6 4 15.7 9.3% Hexagenia 0.0 0.0% SUBTOTAL 57 21 20 17 16 20 25.2 14.9% ODONATA Argia 0.0 0.0% Enal Lagma 129 39 60 90 25 26 61.5 36.5% Gomphus 18 12 6 9 20 14 13.2 7.8% Anax junius 32 6 3 12 10 1 10.7 6.3% Libel lulidae 55 4 18 31 1 69 29.7 17.6% SUBTOTAL 234 61 87 142 56 110 115.0 68.2% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 2 1 5 4 2.0 1.2% Agrypnia 0.0 0.0% SUBTOTAL 2 1 5 0 0 4 2.0 1.2% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 1 1 1 13 2.7 1.6% Tropisternus 0.0 0.0% Berosus 5 3 2 10 9 6 5.8 46.1% SUBTOTAL 5 4 3 11 9 19 8.5 5.0% DIPTERA Tabanidae 2 1 1 4 4 3 2.0 1.2% Chaoborus 1 2 3 1.0 0.6% Ceratopogoni dae 3 1 4 5 2 17 5.3 3.2% CHIRONOMIDAE Tanypodi nae 0.0 0.0% Chironomi nae 2 1 3 2 2 34 7.3 4.4% SUBTOTAL 8 3 8 10 11 54 15.7 9.3% Density 506— 90 T24 481 96 214 168.5 Number of Taxa 12 12 13 13 12 14 12.7 EQT Index 7 7 7 6 6 7 6.7 Collector-gatherers 62 23 27 24 20 71 37.8 Predator 239 64 95 147 63 136 124.0 EOT Density 293 83 112 159 72 134 142.2 167 Appendix 27. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, July 14, 1989. Organisms Pond Mean * of 1 2 4 6 9 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 1 3 1 0.8 0.4% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 1 0 3 1 0.8 0.4% HEMIPTERA Corixidae 0.0 0.0 Buenoa 0.0 0.0% Notonecta 1 0.2 0.1% SUBTOTAL 0 0 0 0 1 0 0.2 0.1% EPHEMEROPTERA Callibaetis 11 14 12 19 17 56 21.5 10.9% Leptophlebia 0.0 0.0% Caenis 18 10 4 14 3 17 10.5 5.3% Hexagenia 0.0 0.0% SUBTOTAL 29 24 16 30 20 73 32.0 16.3% ODONATA Argia 0.0 0.0% Enal lagma 73 117 90 154 28 30 82.0 41.7% Gomphus 9 10 21 23 2 12 12.8 6.5% Anax junius 17 35 39 22 23 17 25.5 13.0% Libel lulidae 17 8 32 61 2 25 24.2 12.3% SUBTOTAL 116 170 182 260 55 84 144.5 73.4% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 7 3 1 3 5 3.2 1.6% Agrypnia 0.0 0.0% SUBTOTAL 7 3 1 3 0 5 3.2 1.6% COLEOPTERA Gyrinidae 1 1 1 0.5 0.3% Dytiscidae 1 1 1 0.5 0.3% Tropisternus 0.0 0.0% Berosus 2 4 1 14 5 3 4.8 39.7% SUBTOTAL 3 5 2 15 5 5 5.8 3.0% DIPTERA Tabanidae 1 10 3 4 1 5 4.0 2.0% Chaoborus 1 3 0.7 0.3% Ceratopogonidae 2 7 6 1 6 3.7 1.9% CHI RONOMIDAE Tanypodinae 0.0 0.0% Chironominae 3 4 5 2.0 1.0% SUBTOTAL 1 13 13 14 10 11 10.3 5.2% Density 156 215 215 520 94 179 = 196.8 Number of Taxa 10 12 13 12 13 13 12.2 EOT Index 7 7 7 7 6 7 6.8 Collector-gatherers 29 26 26 40 26 79 37.7 Predators 125 185 188 268 63 97 = 154.3 EQT Density 152 197 199 293 75 162 179.7 168 Appendix 28. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, July 28, 1989. Organisms Pond Mean *” Of 1 é 9 11 Total COMMUNITY STRUCTURE (number /sampl er) MISC. INVERTEBRATES Mites 4 0.2 0.1% Nematoda 0.0 0.0% Oligochaeta 1 0.2 0.1% Ancylidae 1 0.2 0.1% SUBTOTAL 0 0 4 0 1 4 0.5 0.3% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 2 2 4 3 6 2.8 1.5% SUBTOTAL 2 2 0 4 3 6 2.8 1.5% EPHEMEROPTERA Callibaetis 41 8 27 31 16 31 25.7 13.4% Leptophlebia 0.0 0.0% Caenis 22 19 35 33 10 7 21.0 10.9% Hexagenia 4 11 3 3.0 1.6% SUBTOTAL 63 27 66 75 29 38 49.7 25.9% ODONATA Argia 0.0 0.0% Enal lagma 41 4 21 19 24 1 18.3 9.5% Gomphus 17 8 16 10 10 19 13.3 6.9% Anax junius 19 3 14 4 5 4 8.2 4.3% Libel Lutidae 63 23 80 92 6 62 54.3 28.3% SUBTOTAL 140 38 131 125 45 86 94.2 49.0% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 1 0.2 0.1% Oecetis 8 2 1 4 2 2.8 1.5% Agrypnia 0.0 0.0% SUBTOTAL 8 0 2 4 3 3.0 1.6% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 3 1 4 1 1.5 0.8% Tropisternus 0.0 0.0% Berosus 7 12 2 17 10 3 8.5 66.2% SUBTOTAL 10 13 2 17 14 4 10.0 5.24% DIPTERA Tabanidae 4 6 4 4 3.0 6% Chaoborus 0.0 0.0% Ceratopogonidae 2 60 48 21 10 24 27.5 14.3% CHIRONOMIDAE Tanypodinae 0.0 0.0% Chironominae 1 4 2 1 1.3 0.7% SUBTOTAL 2 65 52 29 14 29 31.8 16.6% Density 225 145 254 251 110 16/ = 192.0 Number of Taxa 11 12 12 13 14 15 12.8 EOT Index 7 é 8 8 8 8 7.5 Collector-gatherers 65 88 119 98 39 63 78.7 Predators 153 45 133 136 60 100 104.5 EOT Density 211 65 199 201 78 127 146.8 169 Appendix 29. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, August 11, 1989. Organisms Pond Mean a” of T 2 4 6 9 TW Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancy| idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% HEMIPTERA Corixidae Q.0 0.0% Buenoa 0.0 0.0% Notonecta 0.90 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% EPHEMEROPTERA Callibaetis 28 9 6 3 7.7 14.4% Leptoph lebia 0.0 0.0% Caenis 9 4 17 7 9 7.7 14.4% Hexagenia 0.0 0.0% SUBTOTAL 9 32 17 16 15 3 15.3 28.8% QDONATA Argia 0.0 0.0% Enal Lagma 8 4 11 1 9 3 6.0 11.3% Gomphus 11 3 8 4 4 5 5.8 11.0% Anax junius 3 2 6 1 2 2.3 4.4% Libel lulidae 23 21 26 12 1 17 16.7 31.3% SUBTOTAL 45 30 51 18 14 27 30.8 58.0% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Oecetis 1 1 0.3 0.6% Agrypnia 0.0 0.0% SUBTOTAL 1 0 1 0 0 0 0.3 0.6% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 1 4 0.8 1.6% Tropisternus 0.0 0.0% Berosus 3 3 4 7 3 3.3 40.8% SUBTOTAL 4 3 4 7 0 7 4.2 7.8% DIPTERA Tabanidae 1 5 1 4 1.8 3.4% Chaoborus 1 0.2 0.3% Ceratopogonidae 0.0 0.0% CHIRONOMIDAE Tanypodinae 0.0 0.0% Chironominae 1 1 1 0.5 0.9% SUBTOTAL 1 1 5 3 5 0 2.5 4.7% Density 60° 66 3 44 54 St 53.2 Number of Taxa 9 8 8 10 7 7 8.2 EOT Index 6 6 6 6 5 5 5.7 Collector-gatherers 10 32 17 17 16 3 15.8 Predators 47 31 57 20 18 31 34.0 EOT Density 55 62 69 34 29 30 46.5 170 Appendix 30. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, August 24, 1989. Organisms Pond Mean & of 1 2 he 6 &g 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancy|idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 3 3 4 1 1.8 2.0% SUBTOTAL 3 3 4 0 0 : 1.8 2.0% EPHEMEROPTERA Callibaetis 20 15 38 6 13.2 14.2% Leptophlebia 0.0 0.0% Caenis 11 24 8 & 16 1 11.0 11.9% Hexagenia 0.0 0.0% SUBTOTAL 11 24 28 21 54 7 24.2 26.1% OOONATA Argia 0.0 0.0% Enal lagma 14 7 14 2 6 2 7.5 8.1% Gomphus 10 1 8 10 2 6 6.2 6.7% Anax junius 6 3 1 2 1 2.2 2.3% Libel lulidae 22 67 49 77 15 13 40.5 43.8% SUBTOTAL 52 78 71 90 25 22 56.3 60.9% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 2 0.3 0.4% Oecetis 0.0 0.0% Agrypnia 0.0 0.0% SUBTOTAL 0 0 0 2 0 0 0.3 0.4% COLEOPTERA Gyr inidae 1 0.2 0.2% bytiscidae 6 3 1.5 1.64 Tropisternus 0.0 0.0% Berosus 9 4 2 1 4 2 3.7 37.9% SUBTOTAL 18 4 2 1 8 2 5.3 5.8% DIPTERA Tabanidae 4 4 2 fr) 3 3.2 3.4% Chaoborus 0.0 0.0% Ceratopogonidae 0.0 0.0% CHIRONOMIDAE Tanypodinae 0.0 0.0% Chironominae 1 1 1 1 3 1 1.3 1.4% SUBTOTAL 5 5 1 3 9 4 4.5 4.9% Density 86 114 — 106 V7 —696 56 92.5 Number of Taxa 10 9 8 10 11 10 9.7 EQT Index 5 5 5 7 6 6 5.7 Col lector-gatherers 12 25 29 22 57 8 25.5 Predators 65 85 75 92 35 26 63.0 EOT Density 63 102 99 113 79 29 80.8 171 Appendix 31. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, September 8, 1989. Organisms Pond Mean & of 1 20 4 6 9 14 Total COMMUNITY STRUCTURE (number/samoler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 3 3 1 4 2 2.2 3.1% SUBTOTAL 3 3 1 4 2 0 2.2 3.1% EPHEMEROPTERA Cailibaetis 30 5 2 18 3 3 10.2 14.6% Leptophlebia 0.0 0.0% Caenis 5 4 3 6 3.0 4.3% Hexagenia 0.0 0.0% SUBTOTAL 35 9 2 21 9 3 13.2 18.9% QDONATA Argia 0.0 0.0% Enal Lagma 37 13 3 8 4 1 11.0 15.8% Gomphus 1 4 2 1 1 1.5 2.2% Anax junius 2 3 2 1 2 1.7 2.4% Libetlulidae 31 37 30 86 13 16 35.5 51.1% SUBTOTAL 71 53 39 97 20 18 49.7 71.5% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 2 1 0.5 0.7% Oecetis 1 0.2 0.2% Agrypnia 0.0 0.0% SUBTOTAL 2 1 0 0 0 1 0.7 1.0% COLEOPTERA Gyrinidae 4 1 0.3 0.5% Dytiscidae 1 0.2 0.2% Tropisternus 0.0 0.0% Berosus 2 3 3 1 1 6 2.7 30.2% SUBTOTAL 3 3 3 1 2 7 3.2 4.6% DIPTERA Tabanidae 1 1 1 0.5 0.7% Chaoborus 0.0 0.0% Ceratopogonidae 0.0 0.0% CHIRONOMIDAE Tanypodinae 0.0 0.0% Chi ronomi nae 1 0.2 0.2% SUBTOTAL 0 1 1 0 1 1 0.7 1.0% Density 114 4) 46 123 34 30 69.5 Number of Taxa 10 9 8 8 10 8 8.8 EOT Index 7 6 5 6 6 5 5.8 Collector-gatherers 35 9 2 21 10 3 13.3 Predators 7 58 41 101 23 20 53.0 EOT Density 108 63 41 118 29 22 63.5 172 Appendix 32. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, September 27, 1989. Organisms Pond Mean ® Of 1 2 4 & 9 4 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 0.0 0.0% Ancyl idae 0.0 0.0% SUBTOTAL 0 0 0 0 0 0 0.0 0.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 1 1 2 1 0.8 0.9% SUBTOTAL 1 1 2 0 1 0 0.8 0.9% EPHEMEROPTERA Callibaetis 34 13 5 14 11 10 14.5 15.7% Leptophlebia 0.0 0.0% Caenis 9 11 4 5 18 5 8.7 9.4% Hexagenia 1 7 1.3 1.4% SUBTOTAL 43 25 9 19 36 15 24.5 26.6% ODONATA ‘Argia 0.0 0.0% Enal lagma 17 6 4 1 19 1 8.0 8.7% Gomphus 1 3 é 11 5 1 4.5 4&.9% Anax junius 2 1 0.5 0.5% Libel lulidae 32 38 28 95 10 66 44.8 48.6% SUBTOTAL 52 48 38 107 34 68 57.8 62.7% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 1 3 1 11 9 4.2 4.5% Hydroptila 0.0 0.0% Oecetis 1 0.2 0.2% Agrypnia 0.0 0.0% SUBTOTAL 1 3 1 12 0 9 4.3 4.7% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 12 3 2 4 3.5 41.2% SUBTOTAL 0 12 0 3 2 4 3.5 3.8% DIPTERA Tabanidae 4 2 1.0 1.1% Chaoborus 0.0 0.0% Ceratopogonidae 1 0.2 0.2% CHIRONOMIDAE Tanypodi nae 0.0 0.0% Chi ronominae 0.0 0.0% SUBTOTAL 0 5 0 0 2 0 1.2 1.3% Density a 94 30 147 to 96 92.2 Number of Taxa 8 12 7 8 9 7 8.5 EOT Index 7 8 6 7 6 6 6.7 Collector-gatherers 43 26 9 19 36 15 24.7 Predators 53 53 40 108 37 68 59.8 EOT Density 96 76 48 138 70 92 86.7 173 Appendix 33. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, October 6, 1989. Organisms Pond Mean % Of 7 2 4 6 9 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 5 30 5.8 2.8% Ancyl idae 0.0 0.0% SUBTOTAL 0 5 30 0 0 0 5.8 8% HEMIPTERA Corixidae 1 0.2 0.1% Buenoa 0.0 0.0% Notonecta 1 1 2 3 1.2 0.6% SUBTOTAL 1 1 2 1 3 0 1.3 0.6% EPHEMEROPTERA Callibaetis 33 22 10 10 96 4 29.2 14.1% Leptophlebia 0.0 0.0% Caenis 4 13 11 2 19 2 8.5 4.1% Hexagenia 3 0.5 0.2% SUBTOTAL 37 35 21 12 118 6 38.2 18.4% ODONATA Argia 0.0 0.0% Enal Lagma 12 3 13 39 2 11.5 5.5% Gomphus 1 6 12 3 8 3 5.5 2.7% Anax junius 1 1 2 4 1.3 0.6% Libel lulidae 46 54 26 67 33 43 44.8 21.6% SUBTOTAL 60 64 53 70 84 48 63.2 30.4% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 3 2 8 13 3 4.8 2.3% Hydroptila 0.0 0.0% Oecetis 1 1 0.3 0.2% Agrypnia 1 0.2 0.1% SUBTOTAL 3 3 10 13 0 3 5.3 2.6% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 0.0 0.0% Tropisternus 0.0 0.0% Berosus 1 9 7 3 2 1 3.8 31.1% SUBTOTAL 1 9. 7 3 2 1 3.8 1.8% DIPTERA Tabanidae 1 0.2 0.1% Chaoborus 0.0 0.0% Ceratopogonidae 11 14 11 8 1 42 14.5 7.0% CHI RONOMIDAE Tanypodinae 17 16 30 15 15 10 17.2 8.3% Chironominae 61 62 26 78 77 44 58.0 28.0% SUBTOTAL 8&9 92 68 101 93 96 89.8 43.3% Density 197 © 209 © 197 200 500 154 207.5 Number of Taxa 12 14 16 10 12 10 12.3 EOT Index 7 8 9 5 7 6 7.0 Collector-gatherers 109 116 88 98 196 92 116.5 Predators 78 82 87 85 102 58 82.0 EOT Density 100 102 84 95 202 57 106.7 174 Appendix 34. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, October 20, 1989. Organisms Pond Mean * of 1 2 4 6 y 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 2 7 10 1 3.3 1.0% Ancy| idae 0.0 0.0% SUBTOTAL 2 7 10 1 0 0 3.3 1.0% HEMIPTERA Corixidae 0.0 0.0% Buenoa 0.0 0.0% Notonecta 6 1 3 1.7 0.5% SUBTOTAL 6 0 0 1 3 0 1.7 0.5% EPHEMEROPTERA Callibaetis 78 13 16 52 87 7 42.2 13.2% Leptophlebia 0.0 0.0% Caenis 19 16 17 17 15 11 15.8 4.9% Hexagenia 1 4 0.8 0.3% SUBTOTAL 97 30 33 69 106 18 58.8 18.4% ODONATA Argia 0.0 0.0% Enal lagma 17 4 9 8 23 9 11.7 3.6% Gomphus 2 4 5 7 3.0 0.9% Anax junius 3 1 2 1 1.2 0.4% Libel lLulidae 106 46 52 180 22 43 74.8 23.4% SUBTOTAL 128 54 67 188 47 60 90.7 28.3% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 8 13 23 18 10 12.0 3.7% Hydroptila 0.0 0.0% Oecetis 0.0 0.0% Agrypnia 5 2 2 18 4.5 1.4% SUBTOTAL 13 13 25 18 2 28 16.5 5.2% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 1 0.2 0.1% Tropisternus 0.0 0.0% Berosus 1 10 1 2 1 3 3.0 22.8% SUBTOTAL 1 10 1 2 2 3 3.2 1.0% DIPTERA Tabanidae 4 3 3 1 1.8 0.6% Chaoborus 0.0 0.0% Ceratopogonidae 5 53 125 10 2 72 44.5 13.9% CHIRONOMIDAE Tanypodinae 10 11 21 8 8 21 13.2 4.1% Chironominae 87 93 85 96 112 46 86.5 27.0% SUBTOTAL 102 161 234 114 125 140 = 146.0 45.6% Density 549 af 5/0 595 oBD 249 = 320.2 Number of Taxa 14 13 14 11 14 13 13.2 EOT Index 8 7 8 5 7 8 7.2 Collector-gatherers 191 183 253 176 220 136 193.2 Predators 144 69 91 197 62 82 3107.5 EOT Density 238 97 125 275 155 106 166.0 175 Appendix 35. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, November 16, 1989. Organisms Pond Mean % of 1 2 4 6 9 11 Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 4 21 3 3 2 5.5 1.1% Ancy| idae 0.0 0.0% SUBTOTAL 4 21 3 3 0 2 5.5 1.1% HEMIPTERA Corixidae 1 1 1 0.5 0.1% Buenoa 0.0 0.0% Notonecta 2 5 2 2 1.8 0.4% SUBTOTAL 2 6 0 2 1 3 2.3 0.5% EPHEMEROPTERA Callibaetis 160 146 59 97 183 58 117.2 22.9% Leptophlebia 0.0 0.0% Caenis 25 46 17 13 103 28 38.7 7.6% Hexagenia 0.0 0.0% SUBTOTAL 185 192 76 110 286 86 155.8 30.4% ODONATA Argia 1 0.2 0.0% Enallagma 9” 71 70 49 52 57 66.3 13.0% Gomphus 4 3 4 3 1 2.5 0.5% Anax junius 7 3 1 2 4 2.8 0.6% Libel lulidae 34 68 62 185 19 107 79.2 15.5% SUBTOTAL 145 145 137 239 71 169 151.0 29.5% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 3 34 56 155 50 49.7 9.7% Hydroptila 0.0 0.0% Oecetis 0.0 0.0% Agrypnia 9 8 3 17 39 11 14.5 2.8% SUBTOTAL 12 42 59 172 39 61 64.2 12.5% COLEOPTERA ‘Gyrinidae 3 0.5 0.1% Dytiscidae 14 4 8 3 6 4 6.5 1.3% Tropisternus 2 0.3 0.1% Berosus 2 0.3 2.3% SUBTOTAL 14 9 10 3 6 4 7.7 1.5% DIPTERA Tabanidae 1 1 0.3 0.1% Chaoborus 0.0 0.0% Ceratopogonidae 5 3 8 4 1 17 6.3 1.2% CHI RONOMI DAE Tanypodinae 34 27 13 17 30 33 25.7 5.0% Chi ronominae 71 123 87 85 104 88 93.0 18.2% SUBTOTAL 110 154 108 106 136 138 125.3 24.5% Density 4/2 369 595 655 (5359 465 517.8 Number of Taxa 15 18 14 14 11 15 14.5 EOT Index 9 & 8 8 5 8 7.7 Collector-gatherers 265 339 174 202 394 193 260.7 Predators 195 185 158 261 108 208 185.8 EOT Density 342 379 272 521 396 316 371.0 176 Appendix 36. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, January 16, 1990 Organisms Pond Mean & Of dT 2 4 6 gd 11° Total COMMUNITY STRUCTURE (number /sampler) MISC. INVERTEBRATES Mites 1 0.2 0.1% Nematoda 0.0 0.0% Oligochaeta 3 3 21 2 4.8 2.1% Ancylidae 0.0 0.0% SUBTOTAL 3 4 21 2 0 0 5.0 2.2% HEMIPTERA Corixidae 3 1 0.7 0.3% Buenoa 0.0 0.0% Notonecta 2 1 0.5 0.2% SUBTOTAL 5 2 0 0 0 0 1.2 0.5% EPHEMEROPTERA Callibaetis 127 65 9 31 92 16 56.7 25.1% Leptophlebia 0.0 0.0% Caenis 3 2 1 9 3 3.0 1.3% Hexagenia 0.0 0.0% SUBTOTAL 130 67 10 31 101 19 59.7 26.5% ODONATA Argia 0.0 0.0% Enal lagma 1 11 1 2 5 5 4.2 1.8% Gomphus 1 0.2 0.1% Anax junius 0.0 0.0% Libel lulidae 15 32 47 63 18 17 32.0 14.2% SUBTOTAL 16 43 48 66 23 22 36.3 16.1% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 3 2 2 1.2 0.5% Hydroptila 0.0 0.0% Oecetis 0.0 0.0% Agrypnia 18 2 3 8 7 4 7.0 3.1% SUBTOTAL 18 5 5 10 7 4 8.2 3.6% COLEOPTERA Gyrinidae 0.0 0.0% Dytiscidae 19 4 6 4 5.5 2.4% Tropisternus 0.0 0.0% Berosus 0.0 0.0% SUBTOTAL 19 4 6 0 4 0 5.5 2.4% DIPTERA Tabanidae 1 0.2 0.1% Chaoborus 0.0 0.0% Ceratopogonidae 3 6 13 5 1 49 12.8 5.7% CHIRONOMIDAE Tanypodi nae 22 15 6 10 19 18 15.0 6.7% Chironominae 49 105 8&8 112 92 44 81.7 36.2% SUBTOTAL 74 126 107 127 113 111. 109.7 48.6% Density 265 O51 197 236 048 156 205.5 Number of Taxa 12 14 11 10 10 8 10.8 EOT Index 5 6 6 6 5 5 5.5 Collector-gatherers 185 181 132 150 194 112 159.0 Predators 59 64 60 76 47 40 57.7 EOT Density 164 115 63 107 131 45 104.2 177 Appendix 37. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, February 8, 1990. Organisms Pond Mean » of 1 2 4 6 9 17 Total COMMUNITY STRUCTURE Cnumber/sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochaeta 25 7 15 37 7 15.2 5.7% Ancylidae 0.0 0.0% SUBTOTAL 25 7 15 0 37 7 15.2 5.7% HEMIPTERA Corixidae 1 0.2 0.1% Buenoa 1 1 2 1 0.8 0.3% Notonecta 1 0.2 0.1% SUBTOTAL 1 1 4 0 1 0 1.2 0.4% EPHEMEROPTERA Callibaetis 170 63 17 23 182 54 84.8 32.2% Leptophlebia 0.0 0.0% Caenis 14 5 3 2 32 12 11.3 4.3% Hexagenia 0.0 0.0% SUBTOTAL 184 68 20 25 214 66 96.2 36.4% ODONATA Argia 0.0 0.0% Enal lagma 8 2 5 1 9 6 5.2 2.0% Gomphus 1 1 1 3 1.0 0.4% Anax junius 1 2 0.5 0.2% Libel Lulidae 30 76 48 114 8 35 51.8 19.6% SUBTOTAL 39 81 53 116 18 44 58.5 22.2% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 1 3 0.7 0.3% Hydroptila 0.0 0.0% Oecetis 1 0.2 0.1% Agrypnia 1 1 1 1 2 1.0 0.4% SUBTOTAL 1 1 1 1 2 5 1.8 0.7% COLEOPTERA Gyrinidae 0.9 0.0% Dytiscidae 11 6 1 9 4.5 1.7% Tropisternus 0.0 0.0% Berosus 1 0.2 1.4% SUBTOTAL 11 7 0 1 9 0 4.7 1.8% DIPTERA Tabanidae 1 1 0.3 0.1% Chaoborus 0.0 0.0% Ceratopogonidae 3 10 21 5 34 12.2 4.6% CHIRONOMIDAE Tanypodi nae 21 10 3 5 11 8 9.7 3.7% Chironominae 52 66 60 50 51 106 64.2 24.3% SUBTOTAL 76 86 84 60 63 149 86.3 32.7% Density 530 2o1 V7 205 544 eft 265.8 Number of Taxa 12 14 12 10 13 12 12.2 EOT Index 6 7 5 6 7 7 6.3 Collector-gatherers 264 151 116 80 302 213. 187.7 Predators 72 98 59 122 41 53 74.2 EOT Density 224 150 74 142 234 115 156.5 178 Appendix 38. Benthic macroinvertebrates collected at the Experimental Pond Project using a dip net, March 8, 1990. Organisms Pond Mean * of 1 2 4 é 9 11) Total COMMUNITY STRUCTURE (number/sampler) MISC. INVERTEBRATES Mites 0.0 0.0% Nematoda 0.0 0.0% Oligochseta 2 2 1 4 2 1.8 0.9% Ancylidae 0.0 0.0% SUBTOTAL 2 2 1 4 0 2 1.8 0.9% HEMIPTERA Corixidae 1 0.2 0.1% Buenoa 1 4 1 2 1.3 0.6% Notonecta 1 0.2 0.1% SUBTOTAL 2 5 1 0 2 0 1.7 0.8% EPHEMEROPTERA Callibaetis 63 37 15 31 81 26 42.2 20.4% Leptophlebia 0.0 0.0% Caenis 13 13 6 3 31 7 12.2 5.9% Hexagenia 2 0.3 0.2% SUBTOTAL 76 50 21 34 114 33 54.7 26.5% ODONATA Argia 0.0 0.0% Enal Lagma 5 9 4 2 6 2 4.7 2.3% Gomphus 1 2 1 1 2 1.2 0.6% Anax junius 1 1 2 0.7 0.3% Libel Lulidae 37 49 38 65 15 25 38.2 18.5% SUBTOTAL 44 60 43 68 24 29 44.7 21.6% TRICHOPTERA Cernotina 0.0 0.0% Oxyethira 0.0 0.0% Hydroptila 0.0 0.0% Decetis 2 0.3 0.2% Agrypnia 2 1 0.5 0.2% SUBTOTAL 0 0 0 2 3 0 0.8 0.4% COLEOPTERA Gyrinidae , 0.0 0.0% Dytiscidae 1 4 0.8 0.4% Tropisternus 0.0 0.0% Berosus 1 0.2 1.4% SUBTOTAL 0 1 1 0 4 0 1.0 0.5% DIPTERA Tabanidae 1 2 1 0.7 0.3% Chaoborus 0.9 0.0% Ceratopogonidae 11 13 30 19 55 21.3 10.3% CHIRONOMIDAE Tanypodinae 9 23 21 19 11 14 16.2 7.8% Chironominae 32 72 64 78 74 62 63.7 30.8% SUBTOTAL 53 110 115 116 86 131 101.8 49.3% Density VT 228 «182 224 253 195 006.5 Number of Taxa 13 13 11 10 14 9 11.7 EOT Index 6 5 5 6 9 5 6.0 Collector-gatherers 121 137 116 135 188 152. 141.5 Predators 55 90 66 87 44 43 64.2 EOT Density 120 110 64 104 141 62 = 100.2 179 Appendix 39. Calculation of production for Caenis amica in Pond 1 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.} Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 12) 1 0.19 0.0014 0.0002 -0.52 0.002 -0.001 -0.01 2 0.71 0.0023 0.0016 -0.19 0.003 -0.001 -0.01 3 0.90 0.0043 0.0039 -0.48 0.006 -0.003 -0.03 4 1.38 0.0078 0.0108 -0.52 0.010 -0.005 -0.06 5 1.90 0.0137 0.0261 0.38 0.018 0.007 0.08 6 1.52 0.0230 0.0350 -0.29 0.029 -0.008 -0.10 7 1.81 0.0377 0.0682 0.86 0.048 0.041 0.50 8 0.95 0.0616 0.0587 -0.10 0.076 -0.007 -0.09 9 1.05 0.0936 0.0981 0.19 0.115 0.022 0.26 10 0.86 0.1418 0.1215 0.43 0.174 0.075 0.90 11 0.43 0.2136 0.0915 0.33 0.262 0.087 1.05 12 0.10 0.3218 0.0306 0.10 0.322 0.031 0.37 N= Te B= 0.5463 Uncorrected P (mg/A.S.) = 3.15 Correction factor (365/CPI) x 2.10 Annual P (mg/A.S.) = 6.62 * negative values not included In production summation (Benke and Wallace 1980). 180 Appendix 40. Calculation of production for Caenis amica in Pond 2 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.$.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 12) 1 0.29. 0.0017 0.0003 -0.52 0.002 ~0.001 -0.01 2 0.81 0.0023 0.0019 -0.95 0.003 -0.003 ~0.04 3 1.76 0.0043 0.0076 -1.05 0.006 -0.006 -0.07 4 2.81 0.0078 0.0219 0.71 0.010 0.007 0.09 5 2.10 0.0137 0.0287 -0.10 0.018 -0.002 -0.02 6 2.19 0.0230 0.0504 0.00 0.029 0.000 0.00 7 2.19 0.0377 0.0826 0.38 0.048 0.018 0.22 8 1.81 0.0616 0.1115 0.33 0.076 0.025 0.30 9 1.48 0.0936 0.1382 1.00 0.115 0.115 1.38 10 0.48 0.1418 0.0675 . 0.29 0.174 0.050 0.60 11 0.19 0.2136 0.0407 0.14 0.262 0.037 0.45 12 0.05 0.3218 0.0153 0.05 0.322 0.015 0.18 N= T6 B= 0.5665 Uncorrected P (mg/A.S.) = 3.23 Correction factor (365/CPI) x 2.10 Annual P (mg/A.S.) = 6.77 * negative values not tncludedtn production summation (Benke and Wallace 1980). 181 Appendix 41. Calculation of production for Caenis amica in Pond 4& Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) cmg} = (mg@/A.S.) (loss x 12) qT 0.174 ~~ 0.0077 0.0002 -0.43 0.002 -0.001 -0.01 2 0.57 0.0023 0.0013 -0.76 0.003 -0.002 -0.03 3 1.33 0.0043 0.0057 -0.43 0.006 -0.002 -0.03 4 1.76 0.0078 0.0137 0.48 0.010 0.005 0.06 5 1.29 0.0137 0.0176 -0.14 0.018 -0.003 -0.03 6 1.43 0.0230 0.0329 0.10 0.029 0.003 0.03 7 1.33 0.0377 0.0503 0.00 0.048 0.000 0.00 8 1.33 0.0616 0.0821 0.24 0.076 0.018 0.22 9 1.10 0.0936 0.1025 0.57 0.115 0.066 0.79 10 0.52 0.1418 0.0743 0.29 0.174 0.050 0.60 11 0.24 0.2136 0.0509 0.19 0.262 0.050 0.60 12 0.05 0.3218 0.0153 0.05 0.322 ~ 0.015 0.18 N= TI B= 0.4468 Uncorrected P (mg/A.S.) = 2.48 Correction factor (365/CPI) x 2.10 Annual P (mg/A.S.) = B21 * negative values not includedin production summation (Benke anda Wallace 1980). 182 Appendix 42. Calculation of production for Caenis amica in Pond 6 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.§.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 12) 1 0.24 0.0011 0.0005 -0.29 0.002 -0.0005 -0.01 2 0.52 0.0023 0.0012 -0.24 0.003 -0.001 -0.01 3 0.76 0.0043 0.0033 -0.71 0.006 -0.004 -0.05 4 1.48 0.0078 0.0115 0.00 0.010 0.000 0.00 5 1.48 0.0137 0.0202 0.62 0.018 0.011 0.13 6 0.86 0.0230 0.0197 -0.10 0.029 -0.003 -0.03 7 0.95 0.0377 0.0359 0.29 0.048 0.014 0.17 8 0.67 0.0616 0.0411 -0.24 0.076 -0.018 -0.22 9 0.90 0.0936 0.0847 0.19 0.115 0.022 0.26 10 0.71 0.1418 0.1013 0.43 0.174 0.075 0.90 11 0.29 0.2136 0.0610 0.05 0.262 0.012 0.15 12 0.24 0.3218 0.0766 0.24 0.322 0.077 0.92 N= 9 B= 0.4568 Uncorrected P (mg/A.S. = 2.52 Correction factor (365/CP1) x 2.10 Annual P (mg/A.S.) = 5.30 * negative values not included in production summation (Benke and Wallace 1980). 183 Appendix 43. Calculation of production for Caenis amica in Pond 9 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 12) 1 0.05 0.0077 0.0001 -0.14 0.002 -0.0002 -0.003 2 0.19 0.0023 0.0004 -0.29 0.003 -0.001 -0.01 3 0.48 0.0043 0.0020 -0.29 0.006 -0.002 -0.02 4 0.76 0.0078 0.0059 -0.19 0.010 -0.002 -0.02 5 0.95 0.0137 0.0130 0.00 0.018 0.000 0.00 6 0.95 0.0230 0.0219 0.24 0.029 0.007 0.08 7 0.71 0.0377 0.0269 0.00 0.048 0.000 0.00 8 0.71 0.0616 0.0440 -0.24 0.076 -0.018 -0.22 9 0.95 0.0936 0.0891 0.24 0.115 0.027 0.33 10 0.71 0.1418 0.1013 0.48 0.174 0.083 0.99 11 0.24 0.2136 0.0509 0.14 0.262 0.037 0.45 12 0.10 0.3218 0.0306 0.10 0.322 0.031 0.37 N= ? B= 0.3863 Uncorrected P (mg/A.S.) = 2.23 Correction factor (365/CPI) x 2.10 Annual P (mg/A.S.) = 5.67 * negative values not included IN production summation (Benke and Wallace 1980). 184 Appendix 44. Calculation of production for Caenis amica in Pond 11 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S8.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 12) 1 0.24 0.0077 0.0005 0.14 0.002 0.0002 0.003 2 0.10 0.0023 0.0002 -0.48 0.003 -0.001 -0.02 3 0.57 0.0043 0.0025 -0.86 0.006 -0.005 -0.06 4 1.43 0.0078 0.0111 0.38 0.010 0.004 0.05 5 1.05 0.0137 0.0144 0.05 0.018 0.001 0.01 6 1.00 0.0230 0.0230 0.19 0.029 0.006 0.07 7 0.81 0.0377 0.0305 0.38 0.048 0.018 0.22 & 0.43 0.0616 0.0264 0.14 0.076 0.011 0.13 9 0.29 0.0936 0.0267 0.00 0.115 0.000 0.00 10 0.29 0.1418 0.0405 0.10 0.174 0.017 0.20 11 0.19 0.2136 0.0407 0.10 0.262 0.025 0.30 12 0.10 0.3218 0.0306 0.10 0.322 0.031 0.37 N= 6 B= 0.2469 Uncorrected P (mg/A.S.) = 1.34 Correction factor (365/CPI) x 2.10 Annual P (mg/A.S.) = 2.80 * negative values not included in production summation (Benke and Wallace 1980). 185 Appendix 45. Calculation of production for Callibaetis floridanus in Pond 1 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 15) 1 0.81 ~—60.0122 ~—- 0.0099 0.38 0.02 0.01 0.09 2 0.43 0.0220 0.0094 -0.33 0.03 -0.01 -0.14 3 0.76 0.0357 0.0272 0.19 0.05 0.01 0.13 4 0.57 0.0570 0.0326 -0.05 0.07 -0.00 -0.05 5 0.62 0.0827 0.0512 0.00 0.10 0.00 0.00 é 0.62 0.1131 0.0700 -0.14 0.13 -0.02 -0.28 7 0.76 0.1563 0.1191 0.29 0.19 0.05 0.80 8 0.48 0.2210 0.1052 0.24 0.25 0.06 0.90 9 0.24 0.2905 0.0692 0.05 0.32 0.02 0.23 10 0.19 0.3631 0.0692 . 0.14 0.41 0.06 0.88 11 0.05 0.4615 0.0220 -0.19 0.53 -0.10 -1.50 12 0.24 0.598 0.1424 0.19 0.68 0.13 1.95 13 0.05 0.7777 0.0370 0.05 0.85 0.04 0.61 14 0.00 0.9295 0.0000 0.00 1.02 0.00 0.00 15 0.00 1.1270 0.0000 0.00 41.13 0.00 0.00 N= 6 B= 0.7643 Uncorrected P (mg/A.S.) = 5.59 Correction factor (365/CPI) x 2.08 Annual P (mg/A.S.) = 1T.62 * negative values not includedtn production summation (Benke and Wallace 1980). 186 Appendix 46. Calculation of production for Callibaetis floridanus in Pond 2 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.$.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) = (mg/A.S.) (loss x 15) 1 0.71 —68.0122 0.0087 0.43 0.02 0.01 0.11 2 0.29 0.0220 0.0063 -0.67 0.03 -0.02 -0.28 3 0.95 0.0357 0.0340 0.76 0.05 0.03 0.52 4 0.19 0.0570 0.0109 0.00 0.07 0.00 0.00 5 0.19 0.0827 0.0158 0.05 0.10 0.005 0.07 6 0.14 0.1131 0.0162 0.00 0.13 0.00 0.00 7 0.14 0.1563 0.0223 -0.33 0.19 -0.06 -0.93 8 0.48 0.2210 0.1052 0.00 0.25 0.00 0.00 9 0.48 0.2905 0.1383 0.33 0.32 0.11 1.62 10 0.14 0.3631 0.0519 -0.48 0.41 -0.19 -2.92 11 0.62 0.4615 0.2857 0.52 0.53 0.28 4.13 12 0.10 0.598 0.0570 0.00 0.68 0.00 0.00 13 0.10 0.7777 0.0741 0.05 0.85 0.04 0.61 14 0.05 0.9295 0.0443 -0.05 1,02 -0.05 -0.73 15 0.10 1.1270 0.1073 0.10 1.13 0.11 1.61 N= 5 B= 0.9778 Uncorrected P (mg/A.S.) = 8.66 Correction factor (365/CPI) x 2.08 Annual P (mg/A.S.) = 78.07 * negative values not included tn production summation (Benke and Wallace 1980). 187 Appendix 47. Calculation of production for Callibaetis floridanus in Pond 4 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 15) 1 60.57 (0.0122 0.0070 0.38 0.02 0.01 0.09 2 0.19 0.0220 0.0042 0.05 0.03 0.001 0.02 3 0.14 0.0357 0.0051 0.10 0.05 0.004 0.06 4 0.05 0.0570 0.0027 -0.24 0.07 -0.02 -0.25 5 0.29 0.0827 0.0236 0.05 0.10 0.005 0.07 6 0.24 0.1131 0.0269 0.05 0.13 0.01 0.09 7 0.19 0.1563 0.0298 0.00 0.19 0.00 0.00 8 0.19 0.2210 0.0421 -0.10 0.25 -0.02 -0.36 9 0.29 0.2905 0.0830 0.05 0.32 0.02 0.23 10 0.24 0.3631 0.0865 0.00 0.41 0.00 0.00 11 0.24 0.4615 0.1099 0.19 0.53 0.10 1.50 12 0.05 0.598 0.0285 0.05 0.68 0.03 0.49 13 0.00 0.7777 0.0000 0.00 0.85 0.00 0.00 14 0.00 0.9295 0.0000 0.00 1.02 0.00 0.00 15 0.00 1.1270 0.0000 0.00 1.13 0.00 0.00 N= 3 B= 0.4492 Uncorrected P (mg/A.S.) = 2.56 Correction factor (365/CPI) x 2.08 Annual P (mg/A.S.) = 5.33 * negative values not included in production summation (Benke and Wallace 1980). 188 Appendix 48. Calculation of production for Callibaetis floridanus in Pond 6 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.$.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 15) j 0.00 0.0122 0.0000 -0.10 0.02 -0.002 -0.02 2 0.10 0.0220 0.0021 -0.10 0.03 -0.003 -0.04 3 0.19 0.0357 0.0068 0.14 0.05 0.01 0.10 4 0.05 0.0570 0.0027 -0.14 0.07 -0.01 -0.15 5 0.19 0.0827 0.0158 0.10 0.10 0.01 0.14 6 0.10 0.1131 0.0108 -0.24 0.13 -0.03 -0.47 7 0.33 0.1563 0.0521 0.19 0.19 0.04 0.53 8 0.14 0.2210 0.0316 -0.10 0.25 -0.02 -0.36 9 0.24 0.2905 0.0692 -0.24 0.32 -0.08 -1.16 10 0.48 0.3631 0.1729 0.24 0.41 0.10 1.46 11 0.24 0.4615 0.1099 0.10 0.53 0.05 . 0.75 12 0.14 0.598 0.0854 0.14 0.68 0.10 1.46 13 0.00 0.7777 0.0000 -0.10 0.85 -0.08 -1.21 14 0.10 0.9295 0.0885 0.10 1.02 0.10 1.46 15 0.00 1.1270 0.0000 9.00 1.13 0.00 0.00 N= 2] B= 0.6477 Uncorrected P (mg/A.S.) = 5.90 Correction factor (365/CP1) x 2.08 Annual P (mg/A.S.) = 72.28 * negative values not included in production summation (Benke and Wallace 1980). 189 Appendix 49. Calculation of production for Callibaetis floridanus in Pond 9 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) <(mg/A.S.) (loss x 15) 4 0.19 0.0122 0.0025 -0.10 0.02 -0.002 -0.02 2 0.29 0.0220 0.0063 0.05 0.03 0.001 0.02 3 0.24 0.0357 0.0085 0.00 0.05 0.00 0.00 4 0.24 0.0570 0.0136 0.14 0.07 0.01 0.15 5 0.10 0.0827 0.0079 0.05 0.10 0.005 0.07 6 0.05 0.1131 0.0054 -0.10 0.13 -0.01 -0.19 7 0.14 0.1563 0.0223 0.00 0.19 0.00 0.00 8 0.14 0.2210 0.0316 0.00 0.25 0.00 0.00 9 0.14 0.2905 0.0415 ~0.19 0.32 -0.06 -0.93 10 0.33 0.3631 0.1210 0.19 0.41 0.08 1.17 11 0.14 0.4615 0.0659 -0.10 0.53 -0.05 -0.75 12 0.24 0.598 0.1424 0.19 0.68 0.13 1.95 13 0.05 0.7777 0.0370 0.05 0.85 0.04 0.61 14 0.00 0.9295 0.0000 0.00 1.02 0.00 0.00 15 0.00 1.1270 0.0000 0.00 1.13 0.00 0.00 N= 2 B= 0.5057 Uncorrected P (mg/A.S.) = 3.96 Correction factor (365/CPI) x 2.08 Annual P (mg/A.S.) = 8.26 * negative values not included1n production summation (Benke and Wailace 1980). 190 Appendix 50. Calculation of production for Callibaetis floridanus in Pond 11 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 15) a 0.55 0.0122 0.0041 0.00 0.02 0.00 0.00 2 0.33 0.0220 0.0073 -0.19 0.03 -0.01 -0.08 3 0.52 0.0357 0.0187 0.24 0.05 0.01 0.16 4 0.29 0.0570 0.0163 0.05 0.07 0.003 0.05 5 0.24 0.0827 0.0197 -0.05 0.10 -0.005 -0.07 6 0.29 0.1131 0.0323 0.14 0.13 0.02 0.28 7 0.14 0.1563 0.0223 0.05 0.19 0.01 0.13 8 0.10 0.2210 0.0210 -0.10 0.25 -0.02 -0.36 9 0.19 0.2905 0.0553 -0.05 0.32 -0.02 -0.23 10 0.24 0.3631 0.0865 . -0.05 0.41 -0.02 -0.29 11 0.29 0.4615 0.1319 -0.05 0.53 -0.03 -0.38 12 0.33 0.598 0.1993 0.29 0.68 0.19 2.92 13 0.05 0.7777 0.0370 -0.14 0.85 -0.12 -1.82 14 0.19 0.9295 0.1770 0.19 1.02 0.19 2.92 15 0.00 1.1270 0.0000 0.00 1.13 0.00 0.00 N= 4 B= 0.8285 Uncorrected P (mg/A.S.) = 6.47 Correction factor (365/CPI) x 2.08 Annual P (mg/A.S.) = 73.47 * negative values not included1n production summation (Benke and Wallace 1980). 191 Appendix 51. Calculation of production for Anax junius in Pond 1 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Samole) (per Sample) (mg) (mg/Sample) (loss x 14) 4 1.00 0.01/72 0.02 0.53 0.03 0.01 0.20 2 0.47 0.0418 0.02 -0.06 0.06 -0.00 -0.05 3 0.53 0.0924 0.05 -0.12 0.14 -0.02 -0.23 4 0.65 0.2035 0.13 0.29 0.28 0.08 1.16 5 0.35 0.3931 0.14 -0.41 0.65 -0.27 -3.74 6 0.76 1.0732 0.82 0.47 1.77 0.83 11.65 7 0.29 2.9114 0.86 0.00 4.03 0.00 0.00 8 0.29 5.5749 1.64 0.00 7.26 0.00 0.00 9 0.29 9.4566 2.78 -0.06 13.42 -0.79 -11.04 10 0.35 19.0313 6.72 0.12 26.45 3.11 43.55 11 0.24 36.7716 8.65 0.06 50.25 2.95 41.36 12 0.18 68.6564 12.12 0.00 96.66 0.00 0.00 13 0.18 136.0913 24.02 0.18 182.18 32.15 450.16 14 0.00 243.8663 0.00 0.00 243.87 0.00 0.00 N= 5.59 B= 57.96 Uncorrected P (mg/A.S.) = 548.08 Correction factor (365/CPI) x 1.49 Annual P (mg/A.S.) = 816.64 * negative values not included In production summation (Benke and Wallace 1980). 192 Appendix 52. Calculation of production for Anax junius in Pond 2 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg> (mg/Sample>) (per Sample) (mg) (mg/Sample) (loss x 14) 4. 0.82 ~—60.0T%2 0.01 0.71 0.03 0.02 0.26 2 0.12 0.0418 0.00 -0.35 0.06 -0.02 -0.31 3 0.47 0.0924 0.04 0.35 0.14 0.05 0.68 4 0.12 0.2035 0.02 -0.29 0.28 -0.08 -1.16 5 0.41 0.3931 0.16 -0.06 0.65 -0.04 -0.53 é 0.47 1.0732 0.51 0.18 1.77 0.31 4.37 7 0.29 2.9114 0.86 0.24 4.03 0.95 13.27 8 0.06 5.5749 0.33 -0.06 7.26 -0.43 -5.98 9 0.12 9.4566 1.11 -0.12 13.42 -1.58 -22.11 10 0.24 19.0313 4.48 0.24 26.45 6.22 87.14 11 0.00 36.7716 0.00 , -0.29 50.25 -14.78 -206.88 12 0.29 68.6564 20.19 0.12 96.66 11.37 159.14 13 0.18 136.0913 24.02 0.06 182.18 10.73 150.22 14 0.12 243.8663 28.68 0.12 243 .87 28.68 401.50 N= 3.71 B= 80.42 Uncorrected P (mg/A.S.) = 816.59 Correction factor (365/CPI) x 1.49 Annual P (mg/A.S.) = 1216.73 * negative values not included in production summation (Benke and Wallace 1980). 193 Appendix 53. Calculation of production for Anax junius in Pond 4 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 14) TT 0.71 0.017%2 ~Q.07 0.18 0.03 0.005 0.07 2 0.53 0.0418 0.02 -0.06 0.06 -0.004 -0.05 3 0.59 0.0924 0.05 0.06 0.14 0.01 0.11 4 0.53 0.2035 0.11 0.18 0.28 0.05 0.70 5 0.35 0.3931 0.14 ~0.47 0.65 -0.31 -4.28 6 0.82 1.0732 0.88 0.71 1.77 1.25 17.47 7 0.12 2.9114 0.34 -0.06 4.03 -0.24 -3.32 8 0.18 5.5749 0.98 0.00 7.26 0.00 0.00 9 0.18 9.4566 1.67 ~0.06 13.42 -0.79 -11.046 10 0.24 19.0313 4.48 0.18 26.45 4.67 65.37 11 0.06 36.7716 2.16 0.06 50.25 2.95 41.36 12 0.00 68.6564 0.00 -0.12 96.66 -11.37 -159.14 13 0.12 136.0913 16.00 0.12 182.18 21.42 299.93 14 0.00 243.8663 0.00 0.00 243.87 0.00 0.00 N= 4.41 B= 26.86 Uncorrected P (mg/A.S.) = 425.01 Correction factor (365/CPI) x 1.49 Annual P (mg/A.S.) = 633.07 * negative values not tncluded in production summation (Benke and Wallace 1980). 194 Appendix 54. Calculation of production for Anax junius in Pond 6 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sampte) (loss x 14) 7 0.41 0.0772 0.01 0.12 0.03 0.003 0.04 2 0.29 0.0418 0.01 -0.06 0.06 -0.00 -0.05 3 0.35 0.0924 0.03 0.00 0.14 0.00 0.00 4 0.35 0.2035 0.07 0.12 0.28 0.03 0.47 5 0.24 0.3931 0.09 -0.24 0.65 -0.15 -2.14 6 0.47 1.0732 0.51 0.18 1.77 0.31 4.37 7 0.29 2.9114 0.86 0.24 4.03 0.95 13.27 8 0.06 5.5749 0.33 -0.18 7.26 -1.28 -17.94 9 0.24 9.4566 2.23 0.18 13.42 2.37 33.15 10 0.06 19.0313 1.12 0.00 26.45 0.00 0.00 11 0.06 36.7716 2.16 0.06 50.25 2.95 41.36 12 0.00 68.6564 0.00 -0.12 96.66 -11.37 -159.14 13 0.12 136.0913 16.00 0.12 182.18 21.42 299.93 14 0.00 243.8663 0.00 0.00 243.87 0.00 0.00 N= 2.94 B= 23.40 Uncorrected P (mg/A.S.) = 392.60 Correction factor (365/CPI) x 1.49 Annual P (mg/A.S.) = Ba4.97 * negative values not included tn production summation (Benke and Wallace 1980). 195 Appendix 55. Calculation of production for Anax junius in Pond 9 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 14) 1 0.76 —60.0T72 0.07 0.29 0.03 0.01 0.11 2 0.47 0.0418 0.02 0.06 0.06 0.00 0.05 3 0.41 0.0924 0.04 0.35 0.14 0.05 0.68 4 0.06 0.2035 0.01 -0.06 0.28 -0.02 -0.23 5 0.12 0.3931 0.05 -0.76 0.65 -0.50 “6.95 6 0.88 1.0732 0.95 0.65 1.77 1.14 16.01 7 0.24 2.9116 0.69 0.12 4.03 0.47 6.64 8 0.12 5.5749 0.66 0.12 7.26 0.85 11.95 9 0.00 9.4566 0.00 -0.18 13.42 -2.37 -33.15 10 0.18 19.0313 3.36 -0.12 26.45 -3.11 -43.55 11 0.29 36.7716 10.81 0.18 50.25 8.87 124.16 12 0.12 68.6564 8.07 0.12 96 .66 11.37 159.14 13 0.00 136.0913 0.00 0.00 182.18 0.00 0.00 14 0.00 243.8663 0,00 0.00 243.87 0.00 0.00 N= 3.65 B= 24.66 Uncorrected P (mg/A.S.) = 318.75 Correction factor (365/CPI) x 1.49 Annual P (mg/A.S.) = 414.93 * negative values not includedin production summation (Benke and Wallace 1980). 196 Appendix 56. Calculation of production for Anax junius in Pond 11 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample)> (per Sample) (mg) (mg/Sample) (loss x 14) 1 0.35 0.01/72 0.006 0.18 0.03 0.005 0.07 2 0.18 0.0418 0.01 0.06 0.06 0.004 0.05 3 0.12 0.0924 0.01 0.00 0.14 0.00 0.00 4 0.12 0.2035 0.02 -0.18 0.28 -0.05 -0.70 5 0.29 0.3931 0.12 -0.06 0.65 -0.04 -0.53 6 0.35 1.0732 0.38 0.12 1.77 0.21 2.91 7 0.24 2.9114 0.69 0.24 4.03 0.95 13.27 8 0.00 5.5749 0.00 -0.12 7.26 -0.85 -11.95 9 0.12 9.4566 1.11 0.00 13.42 0.00 0.00 10 0.12 19.0313 2.24 0.12 26.45 3.11 43.55 11 0.00 36.7716 0.00 0.00 50.25 0.00 0.00 12 0.00 68.6564 0.00 . -0.06 96.66 -5.68 -79.57 13 0.06 136.0913 8.00 0.06 182.18 10.71 149.97 14 0.00 243.8663 0.00 0.00 243.87 0.00 0.00 N= 7.96 B= T2.58 Uncorrected P (mg/A.S.) = 209.82 Correction factor (365/CPI) x 1.49 Annual P (mg/A.S.) = 310.63 * negative values not included In production summation (Benke and Wallace 1980). 197 Appendix 57. Calculation of production for Gomphus exilis in Pond 1 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 12) 1 0./6 0.0010 0.0008 -1.24 0.002 -0.002 -0.02 2 2.00 0.0023 0.0046 1.06 0.004 0.004 0.05 3 0.94 0.0056 0.0053 -0.06 0.008 -0.000 -0.01 4 1.00 0.0109 0.0109 0.29 0.015 0.005 0.05 5 0.71 0.0218 0.0154 -0.06 0.033 -0.002 -0.02 6 0.76 0.0514 0.0393 0.53 0.071 0.038 0.45 7 0.24 0.0990 0.0233 0.18 0.138 0.024 0.29 8 0.06 0.1911 0.0112 0.00 0.317 0.000 0.00 9 0.06 0.5255 0.0309 -0.24 0.850 -0.200 -2.40 10 0.29 1.3736 0.4040 0.00 2.281 0.000 0.00 11 0.29 3.7888 1.1143 0.29 6.868 2.020 24.24 12 0.00 12.4515 0.0000 0.00 12.451 0.000 0.00 N= 7.10 B= T.6599 Uncorrected P (mg/A.S.) = 25.08 Correction factor (365/CPI) x 1.11 Annual P (mg/A.S.) = 27.04 * negative values not included in production summation (Benke and Wallace 1980). 198 Appendix 58. Calculation of production for Gomphus exilis in Pond 2 Mean Mean Mean Indtv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 12) 1 0.41 0.0010 0.0004 -0.29 0.002 -0.0004 -0.01 2 0.71 0.0023 0.0016 -0.35 0.004 -0.001 -0.02 3 1.06 0.0056 0.0059 0.59 0.008 0.005 0.05 4 0.47 0.0109 0.0051 -0.18 0.015 -0.003 -0.03 5 0.65 0.0218 0.0141 0.24 0.033 0.008 0.09 6 0.41 0.0514 0.0212 -0.06 0.071 -0.004 -0.05 7 0.47 0.0990 0.0466 0.35 0.138 0.049 0.58 8 0.12 0.1911 0.0225 0.12 0.317 0.037 0.45 9 0.00 0.5255 0.0000 -0.12 0.850 -0.100 -1.20 10 0.12 1.3736 0.1615 -0.24 2.281 -0.537 -6.44 11 0.35 3.7888 1.3371 0.12 6.868 0.808 9.69 12 0.24 12.4515 2.9298 0.24 12.451 2.930 35.16 N= 5.00 B= 6.5459 Uncorrected P (mg/A.S.) = 46.03 Correction factor (365/CPI) x 1.11 Annual P (mg/A.S.) = 57.09 * negative values not included in production summation (Benke and Wallace 1980). 199 Appendix 59. Calculation of production for Gomphus exilis in Pond 4 Mean Mean Mean Indiv. ‘Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 12) 1 0.06 0.0070 0.00006 -0.94 0.002 -0.001 -0.02 2 1.00 0.0023 0.0023 0.00 0.004 0.000 0.00 3 1.00 0.0056 0.0056 0.29 0.008 0.002 0.03 4 0.71 0.0109 0.0077 -0.12 0.015 -0.002 -0.02 5 0.82 0.0218 0.0180 0.35 0.033 0.012 0.14 6 0.47 0.0514 0.0242 -0.65 0.071 -0.046 -0.55 7 1.12 0.0990 0.1106 -0.53 0.138 -0.073 -0.87 8 1.65 0.1911 0.3147 ‘ 1.18 0.317 0.373 4.47 9 0.47 0.5255 0.2473 0.24 0.850 0.200 2.40 10 0.24 1.3736 0.3232 0.06 2.281 0.134 1.61 11 0.18 3.7888 0.6687 0.00 6.868 0,000 0.00 12 0.18 12.4515 2.1977 0.18 12.451 2.198 26.37 N= 7.00 B= 3.9001 Uncorrected P (mg/A.S.) = 35.02 Correction factor (365/CPI) x 1.11 Annual P (mg/A.S.) = 38.85 * negative values not included in production summation (Benke and Wallace 1980). 200 Appendix 60. Calculation of production for Gomphus exilis in Pond 6 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 12) 4a 0.59 0.0010 0.0006 -0.88 0.002 -0.001 -0.02 2 1.47 0.0023 0.0034 0.94 0.004 0.003 0.04 3 0.53 0.0056 0.0030 -0.47 0.008 -0.004 -0.04 4 1.00 0.0109 0.0109 0.35 0.015 0.005 0.07 5 0.65 0.0218 0.0141 -0.41 0.033 -0.014 -0.17 6 1.06 0.0514 0.0544 0.29 0.071 0.021 0.25 7 0.76 0.0990 0.0757 0.29 0.138 0.040 0.49 8 0.47 0.1911 0.0899 0.35 0.317 0.112 1.34 9 0.12 0.5255 0.0618 0.12 0.850 0.100 1.20 10 0.00 1.3736 0.0000 -0.06 2.281 -0.134 -1.61 11 0.06 3.7888 0.2228 0.06 6.868 0.404 4.85 12 0.00 12.4515 0.0000 0.00 12.451 0.000 0.00 N= 6.71 B= 0.5366 Uncorrected P (mg/A.S.) = 8.23 Correction factor (365/CPI) x 1.11 Annual P (mg/A.S.) = 9.16 * negative values not includedin production summation (Benke and Wallace 1980}. 201 Appendix 61. Calculation of production for Gomphus exilis in Pond 9 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 12) 7 0.29 0.0070 0.0005 -0.35 0.002 -0.0005 -0.01 2 0.65 0.0023 0.0015 0.35 0.004 0.001 0.02 3 0.29 0.0056 0.0016 -0.18 0.008 ~0.001 -0.02 4 0.47 0.0109 0.0051 0.18 0.015 0.003 0.03 5 0.29 0.0218 0.0064 -0.18 0.033 -0.006 -0.07 6 0.47 0.0514 0.0242 0.18 0.071 0.013 0.15 7 0.29 0.0990 0.0291 -0.18 0.138 -0.024 -0.29 8 0.47 0.1911 0.0899 0.12 0.317 0.037 0.45 9 0.35 0.5255 0.1854 -0.18 0.850 -0.150 -1.80 10 0.53 1.3736 0.7272 . 0.18 2.281 0.403 4.83 11 0.35 3.7888 1.3371 0.24 6.868 1.616 19.39 12 0.12 12.4515 1.4643 0.12 12.451 1.464 17.57 N= 4.59 B= 3.35/00 Uncorrected P (mg/A.S.) = 42.44 Correction factor (365/CPI) x 1.11 Annual P (mg/A.S.) = 47.11 * negative values not includedin production summation (Benkeand Wallace 1980). 202 Appendix 62. Calculation of production for Gomphus exilis in Pond 11 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /Sample) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/Sample) (per Sample) (mg) (mg/Sample) (loss x 12) 1 0.42 0.0010 0.0004 -0.11 0.002 -0.0002 -0.00 2 0.53 0.0023 0.0012 -0.24 0.004 -0.001 -0.01 3 0.76 0.0056 0.0043 0.06 0.008 0.0005 0.01 4 0.71 0.0109 0.0077 0.06 0.015 0.001 0.01 5 0.65 0.0218 0.0141 -0.06 0.033 -0.002 -0.02 6 0.71 0.0514 0.0363 0.29 0.071 0.020 0.25 7 0.42 0.0990 0.0415 0.12 0.138 0.017 0.21 8 0.29 0.1911 0.0562 0.24 0.317 0.075 0.89 9 0.06 0.5255 0.0309 -0.24 0.850 -0.200 -2.40 10 0.29 1.3736 0.4040 -0.18 2.281 -0.403 -4.83 11 0.47 3.7888 1.7830 0.29 6.868 2.020 24.24 le 0.18 12.4515 2.1977 0.18 12.451 ~ 2.198 26.37 N= 5.48 B= 5.5770 Uncorrected P (mg/A.S.) = 51.98 Correction factor (365/CPI) x 1.11 Annual P (mg/A.S.) = 57.69 * negative values not includedin production summation (Benke and Wallace 1980). 203 Appendix 63. Calculation of production for Enallagma civile in Pond 1 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) a 0.52 0.0053 0.0020 0.14 0.01 0.001 0.01 2 0.38 0.0085 0.0032 0.19 0.01 0.002 0.02 3 0.19 0.0142 0.0027 -0.33 0.02 -0.01 -0.08 4 0.52 0.0329 0.0172 0.14 0.05 0.01 0.08 5 0.38 0.0864 0.0329 -0.05 0.14 ~0.01 -0.07 6 0.43 0.2116 0.0907 0.10 0.29 0.03 0.30 7 0.33 0.3879 0.1293 0.05 0.47 0.02 0.25 8 0.29 0.5765 0.1647 0.29 0.69 0.20 2.18 9 0.00 0.8373 0.0000 -0.38 1.09 -0.41 -4.55 10 0.38 1.4067 0.5359 0.19 1.91 0.36 4.00 11 0.19 2.5875 0.4929 0.19 2.59 0.49 5.42 N= q B= T4715 Uncorrected P (mg/A.S.) = 12.27 Correction factor (365/CPI) x 1.08 Annual P (mg/A.S.) = 13.25 * negative values not included in production summation (Benke and Wallace 1980). 204 Appendix 64. Calculation of production for Enallagma civile in Pond 2 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar cmg) (mg/A.S.) (per A.S.)} (mg) (mg/A.S.) (loss x 11) 7 ~—60L84 0.0038 0.0009 -0.38 0.01 -0.002 -0.02 2 0.62 0.0085 0.0053 0.29 0.01 0.003 0.03 3 0.33 0.0142 0.0047 -0.62 0.02 -0.01 -0.15 4 0.95 0.0329 0.0313 -0.52 0.05 -0.03 -0.31 5 1.48 0.0864 0.1275 0.33 0.14 0.05 0.50 6 1.14 0.2116 0.2418 0.57 0.29 0.16 1.80 7 0.57 0.3879 0.2217 0.29 0.47 0.14 1.49 8 0.29 0.5765 0.1647 0.19 0.69 0.13 1.46 9 0.10 0.8373 0.0797 0.10 1.09 0.10 1.14 10 0.00 1.4067 0.0000 -0.10 1.91 -0.18 -2.00 11 0.10 2.5875 0.2464 0.10 2.59 0.25 2.71 N= 6 B= T1241 Uncorrected P (mg/A.S.) = 9.12 Correction factor (365/CPI) x 1.08 Annual P (mg/A.S.) = 5.85 * negative values not includedin production summation (Benke and Wailace 1980). 205 Appendix 65. Calculation of production for Enallagma civile in Pond 4 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) | 0.67 0.0058 0.0025 0.29 0.01 0.002 0.02 2 0.38 0.0085 0.0032 0.29 0.01 0.003 0.03 3 0.10 0.0142 0.0014 -0.57 0.02 -0.01 -0.14 4 0.67 0.0329 0.0219 -1.10 0.05 -0.06 -0.64 5 1.76 0.0864 0.1522 0.76 0.14 0.10 1.13 6 1.00 0.2116 0.2116 0.29 0.29 0.08 0.90 7 0.71 0.3879 0.2771 0.29 0.47 0.14 1.49 8 0.43 0.5765 0.2471 0.10 0.69 0.07 0.73 9 0.33 0.8373 0.2791 0.10 41.09 0.10 1.14 10 0.24 1.4067 0.3349 0.10 1.91 0.18 2.00 11 0.14 2.5875 0.3696 0.14 2.59 0.37 4.07 N= 6 B= T.9007 Uncorrected P (mg/A.S.) = 41.50 Correction factor (365/CPI) x 1.08 Annual P (mg/A.S.) = 72.40 * negative values not included in production summation (Benke and Wallace 1980). 206 Appendix 66. Calculation of production for Enallagma civile in Pond 6 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) 1 0.52 0.0038 0.0020 0.48 0.01 0.003 0.03 2 0.05 0.0085 0.0004 -0.24 0.01 -0.003 -0.03 3 0.29 0.0142 0.0041 -1.24 0.02 -0.03 -0.29 4 1.52 0.0329 0.0501 -0.14 0.05 -0.01 -0.08 5 1.67 0.0864 0.1440 -0.19 0.14 -0.03 -0.28 6 1.86 0.2116 0.3930 1.29 0.29 0.37 4.05 7 0.57 0.3879 0.2217 0.10 0.47 0.05 0.50 8 0.48 0.5765 0.2745 0.19 0.69 0.13 1.46 9 0.29 0.8373 0.2392 0.05 1.09 0.05 0.57 10 0.24 1.4067 0.3349 . 0.19 1.91 0.36 4.00 11 0.05 2.5875 0.1232 0.05 2.59 0.12 1.36 N= 8 B= T7871 Uncorrected P (mg/A.S.) = 11.95 Correction factor (365/CPI) x 1.08 Annual P (mg/A.S.) = T2.97 * negative values not includedin production summation (Benke and Wallace 1980). 207 Appendix 67. Calculation of production for Enallagma civile in Pond 9 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) Closs x 11) 1 0.52 0.0058 0.0020 0.10 0.01 0.001 0.01 2 0.43 0.0085 0.0036 0.44 0.01 0.002 0.02 3 0.29 0.0142 0.0041 -0.38 0.02 -0.01 -0.09 4 0.67 0.0329 0.0219 -0.24 0.05 -0.01 -0.14 5 0.90 0.0864 0.0782 0.57 0.14 0.08 0.85 6 0.33 0.2116 0.0705 0.24 0.29 0.07 0.75 7 0.10 0.3879 0.0369 -0.10 0.47 -0.05 -0.50 8 0.19 0.5765 0.1098 0.05 0.69 0.03 0.36 9 0.14 0.8373 0.1196 0.14 1.09 0.16 1.71 10 0.00 1.4067 0.0000 -0.05 1.91 -0.09 -1.00 11 0.05 2.5875 0.1232 0.05 2.59 0.12 1.36 N= q B= 0.5699 Uncorrected P (mg/A.S.) = 5.05 Correction factor (365/CPI)} x 1.08 Annual P (mg/A.S.) = 5.25 * negative values not includedin production summation (Benke and Wallace 1980). 208 Appendix 68. Calculation of production for Enallagma civile in Pond 11 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) 1 0.335 0.0058 0.0073 -0.29 0.01 -0.002 -0.02 2 0.62 0.0085 0.0053 0.05 0.01 0.001 0.01 3 0.57 0.0142 0.0081 -0.62 0.02 -0.01 -0.15 4 1.19 0.0329 0.0392 0.05 0.05 0.00 0.03 5 1.14 0.0864 0.0987 0.67 0.14 0.09 0.99 6 0.48 0.2116 0.1008 0.29 0.29 0.08 0.90 7 0.19 0.3879 0.0739 -0.10 0.47 -0.05 -0.50 8 0.29 0.5765 0.1647 0.24 0.69 0.17 1.82 9 0.05 0.8373 0.0399 -0.10 1.09 -0.10 -1.14 10 0.14 1.4067 0.2010 0.05 1.91 0.09 1.00 11 0.10 2.5875 0.2464 0.10 2.59 0.25 2.71 N= 5 B= 0.9792 Uncorrected P (mg/A.S.) = 7.46 Correction factor (365/CPI) x 1.08 Annual P (mg/A.S.) = 8.05 * negative values not included in production summation (Benke and Wailace 1980). 209 Appendix 69. Calculation of production for Libellulidae in Pond 1 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) 8iomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) Closs x 11) 1 0.57 0.0050 0.0029 -0.67 0.01 -0.01 -0.06 2 1.24 0.0122 0.0151 0.43 0.02 0.01 0.09 3 0.81 0.0303 0.0245 0.14 0.04 0.01 0.06 4 0.67 0.0554 0.0369 -0.57 0.07 -0.04 -0.47 5 1.24 0.1000 0.1238 -0.29 0.15 -0.04 -0.46 6 1.52 0.2109 0.3214 0.14 0.29 0.04 0.46 7 1.38 0.4078 0.5632 0.38 0.55 0.21 2.31 8 1.00 0.7438 0.7438 0.57 0.99 0.57 6.22 9 0.43 1.3179 0.5648 0.43 1.78 0.76 8.40 10 0.00 2.4105 0.0000 0.00 3.19 0.00 0.00 11 0.00 4.2214 0.0000 0.00 4.22 0.00 0.00 N= 9 B= 2.3904 Uncorrected P (mg/A.S.) = 17.55 Correction factor (365/CPI) x 1.13 Annual P (mg/A.S.) = 19.83 * negative values not included In production summation (Benke and Wallace 1980). 210 Appendix 70. Calculation of production for Libellulidae in Pond 2 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) 1 0.535 0.0050 0.0017 -0.24 0.01 -0.002 -0,02 2 0.57 0.0122 0.0070 -0.10 0.02 -0.002 -0.02 3 0.67 0.0303 0.0202 -0.10 0.04 -0.004 -0.04 4 0.76 0.0554 0.0422 -0.48 0.07 -0.04 -0.39 5 1.264 0.1000 0.1238 0.33 0.15 0.05 0.53 6 0.90 0.2109 0.1908 -0.29 0.29 -0.08 -0.92 7 1.19 0.4078 0.4855 0.05 0.55 0.03 0.29 8 1.14 0.7438 0.8501 0.14 0.99 0.14 1.56 9 1.00 1.3179 1.3179 0.52 1.78 0.93 10.27 10 0.48 2.4105 1.1479 0.38 3.19 1.22 13.37 11 0.10 4.2214 0.4020 0.10 4&.22 0.40 4.42 N= 8 B= %.5890 Uncorrected P (mg/A.S.) = 30.44 Correction factor (365/CPI) x 1.13 Annual P (mg/A.S.) = 34.39 * negative values not included in production summation (Benke and Wallace 1980). 211 Appendix 71. Calculation of production for Libellulidae in Pond 4 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no. /A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) 1 0.24 0.0050 0.00712 -0.19 0.01 -0.001 -0.02 2 0.43 0.0122 0.0052 -0.19 0.02 -0.004 -0.04 3 0.62 0.0303 0.0188 -0.24 0.04 -0.01 -0.11 4 0.86 0.0554 0.0475 -0.24 0.07 -0.02 -0.19 5 1.10 0.1000 0.1095 0.05 0.15 0.01 0.08 6 1.05 0.2109 0.2209 -0.43 0.29 -0.13 -1.38 7 1.48 0.4078 0.6020 0.05 0.55 0.03 0.29 8 1.43 0.7438 1.0626 0.19 0.99 0.19 2.07 9 1.246 1.3179 1.6317 0.76 1.78 1.36 14.94 10 0.48 2.4105 1.1479 . 0.48 3.19 1.52 16.71 11 0.00 4.2214 0.0000 0.00 4.22 0.00 0.00 N= 9 B= G.B470 Uncorrected P (mg/A.S.) = 34.09 Correction factor (365/CPI) x 1.13 Annual P (mg/A.S.) = 30.50 * negative values not included in production summation (Benke and Wallace 1980). 212 Appendix 72. Calculation of production for Libellulidae in Pond 6 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg> (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) 4 0.10 0.0050 9.0005 -0.43 0.01 -0.003 -0.04 2 0.52 0.0122 0.0064 -0.05 0.02 -0.001 -0.01 3 0.57 0.0303 0.0173 -0.10 0.04 -0.004 -0.04 4 0.67 0.0554 0.0369 -0.43 0.07 -0.03 -0.35 5 1.10 0.1000 0.1095 -0.24 0.15 -0.03 -0.38 6 1.33 0.2109 0.2812 0.14 0.29 0.04 0.46 7 1.19 0.4078 0.4855 -0.19 0.55 -0.10 -1.15 8 1.38 0.7438 1.0272 0.19 0.99 0.19 2.07 9 1.19 1.3179 1.5689 -0.14 1.78 -0.25 -2.80 10 1.33 2.4105 3.2140 0.95 3.19 3.04 33.42 11 0.38 4.2214 1.6082 0.38 4.22 1.61 17.69 N= 10 B= 8.3555 Uncorrected P (mg/A.S.) = 53.64 Correction factor (365/CPI) x 1.13 Annual P (mg/A.S.) = 60.62 * negative values not included In production summation (Benke and Wallace 1980). 213 Appendix 73. Calculation of production for Libellulidae in Pond 9 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) 1 0.14 0.0050 0.0007 -0.10 0.01 -0.001 -0.01 2 0.24 0.0122 0.0029 -0.10 0.02 -0.002 -0.02 3 0.33 0.0303 0.0101 0.19 0.04 0.01 0.09 4 0.14 0.0554 0.0079 -0.10 0.07 -0.01 -0.08 5 0.24 0.1000 0.0238 0.10 0.15 0.01 0.15 6 0.14 0.2109 0.0301 0.05 0.29 0.01 0.15 7 0.10 0.4078 0.0388 -0.05 0.55 -0.03 -0.29 8 0.14 0.7438 0.1063 -0.05 0.99 -0.05 -0.52 9 0.19 1.3179 0.2510 0.19 1.78 0.34 3.73 10 0.00 2.4105 0.0000 -0.05 3.19 -0.15 -1.67 11 0.05 4.2214 0.2010 0.05 4.22 0.20 2.21 N= 2 B= 0.6727 Uncorrected P (mg/A.S.) = 6.34 Correction factor (365/CPI) x 1.13 Annual P (mg/A.S.) = 7.16 * negative values not included In production summation (Benke and Wallace 1980). 214 Appendix 74. Calculation of production for Libellulidae in Pond 11 Mean Mean Mean Indiv. Biomass Density Indiv. Standing Number Biomass Biomass Correction (no./A.S.) Biomass Stock Lost at Loss Loss Factor Instar (mg) (mg/A.S.) (per A.S.) (mg) (mg/A.S.) (loss x 11) 1 1.29 ~ 6.0050 0.0064 -0.29 0.01 -0.002 -0.02 2 1.57 0.0122 0.0192 0.10 0.02 0.002 0.02 3 1.48 0.0303 0.0447 -0.14 0.04 -0.01 -0.06 4 1.62 0.0554 0.0897 -1.43 0.07 -0.11 “1.17 5 3.05 0.1000 0.3048 1.05 0.15 0.15 1.67 6 2.00 0.2109 0.4218 0.43 0.29 0.13 1.38 7 1.57 0.4078 0.6408 -0.14 0.55 -0.08 -0.87 8 1.71 0.7438 1.2751 0.62 0.99 0.61 6.74 9 1.10 1.3179 1.4434 0.67 1.78 1.19 13.07 10 0.43 2.4105 1.0331 0.19 3.19 0.61 6.68 11 0.24 4.2214 1.0051 0.24 4.22 1.01 11.06 N= 16 B= 6.0641 Uncorrected P (mg/A.S.) = 40.63 Correction factor (365/CPI) x 4.13 Armual P (mg/A.S.) = 5.91 * negative values not includedin production summation (Benke and Wallace 1980). 215 Appendix 75. Soil chemistry data from experimental ponds. Analysis was conducted by Soil testing and plant analysis laboratory at Virginia Polytechnic Institute and State University. P, Phosphorus; K, Potassium; Ca, Calcium; Mg, Magnesium; Sol. Salts, Soluble Salts NO3,N, Nitrate Nitrogen; Mn, Manganese; Zn, Zinc; %OM, Percent Organic Mater. Pond PPM % pH P K Ca Mg Sol. NO3,N Mn 2n OM Salts February 1988 1 5.5 2 34 312 60 1 8 1.3 1.3 2.0 2 5.7 1 33 300 61 1 5 1.2 1.2 1.7 3 5.2 1 25 168 41 1 8 0.9 0.9 1.4 4 5.8 1 29 360 60 1 5 0.8 0.8 1.7 5 5.3 1 34 264 53 1 8 0.7 0.7 2.0 é 5.3 1 34 276 55 1 5 0.8 0.8 2.3 7 5.5 2 40 348 62 1 3 0.9 0.9 2.5 8 5.4 1 28 228 44 1 5 0.6 0.6 2.0 9 5.6 1 36 384 61 1 3 0.8 0.8 2.1 10 5.5 2 39 324 61 1 3 0.8 0.8 2.5 11 5.6 1 36 336 60 1 5 1.4 1.4 2.3 12 5.6 1 39 396 63 : 5 1.3 1.3 2.8 Mean 5.5 1.3 33.9 308.0 56.8 1.0 5.3 1.0 1.0 2.1 February 1989 1 5.9 1 39 528 54 1 3 8.6 1.3 2.5 2 5.8 1 39 492 55 1 3 7.6 1.2 2.6 3 5.8 1 31 384 41 1 3 9.1 1.2 2.0 4 6.1 1 37 588 59 1 3 7.2 1.2 2.3 5 6.0 1 36 492 53 1 3 7.7 1.2 2.0 6 5.2 1 36 564 54 26 5 5.6 1.3 2.3 7 5.6 1 36 468 50 1 3 7.6 1.3 2.5 8 6.0 1 36 528 54 1 5 5.5 1.2 2.0 9 5.9 1 37 564 56 1 3 6.8 1.4 2.7 10 5.8 1 39 528 57 1 3 6.6 2.0 2.3 11 5.9 1 36 516 53 1 3 6.1 1.2 2.3 12 5.8 1 37 576 54 1 3 7.4 1.3 2.5 Mean 5.8 1.0 36.6 519.0 53.3 3.1 3.3 7.1 1.3 2.3 April 1990 1 5.9 1 29 504 63 115 3 12.9 1.2 2.1 2 5.8 1 34 444 53 51 3 7.9 1.3 2.0 3 5.9 1 37 492 60 115 3 8.8 1.7 2.0 4 6.1 1 33 540 59 115 3 5.4 1.3 1.9 5 5.9 1 31 444 54 128 5 6.4 1.3 1.8 6 6.0 1 36 528 63 64 3 6.6 1.5 1.9 7 5.9 1 37 564 66 128 8 7.2 1.3 2.3 8 5.8 1 40 516 63 102 5 9.3 1.7 2.2 9 5.7 1 36 564 61 128 10 7.6 1.6 2.4 10 6.0 1 36 552 66 51 3 9.0 1.3 2.5 11 6.2 1 39 636 67 141 5 9.1 1.4 2.2 12 6.0 1 37 564 65 102 5 9.4 1.4 2.2 Mean 5.9 1.0 35.4 529.0 61.7 103.3 4.7 8.3 1.4 2.1 Sol. Salts range 0 - 422 considered"low" levels. 216 VITA I was born in Soda Springs, Idaho in 1960 and grew up on a farm there. In 1983, L graduated from Ricks College with an associates degree in natural science. In 1985, I graduated from Brigham Young University with a bachelors degree in Zoology, with a minor in Chemistry. I received a masters degree from Brigham Young University in 1987 in Zoology, with an emphasis in Entomology. My thesis research was on the residue profile of Diflubenzuron (an insect growth regulator insecticide) in forest foliage, forest litter, arthropods, and birds in West Virginia. In August 1987, I began studies at Virginia Polytechnic Institute and State University towards a Ph.D. degree in Entomology. My dissertation research was on the ecology of aquatic insects ina set of ponds located near Blackstone, Virginia. In addition to my research, I also worked on developing a program for long term ecological monitoring in the New River near Hinton, West Virginia. I have been a member of the Entomological Society of America since 1986, the Society of Environmental Toxicology and Chemistry since 1986, the North American Benthological Society since 1988, and the Phi Kappa Phi Honor Society since 1985. I received the Presidential Graduate Fellowship from Virginia Tech in 1987-1988 and the Dow-Elanco Graduate Scholarship in Entomology in 1991. Kot, Ubi Van D. Christman 217