Okbehlh LER Voshell, Jr., Ch Rman [Ik MSE Lol
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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° COLLECTIONe 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 ene °. 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.