Evaluating Benthic Macroinvertebrates As Bio-Indicators of Freshwater Habitat Quality in an Eastern Oregon Agro-Ecosystem
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AN ABSTRACT OF THE DISSERTATION OF Melissa A. Scherr for the degree of Doctor of Philosophy in Entomology presented on April 8, 2010. Title: Evaluating Benthic Macroinvertebrates as Bio-indicators of Freshwater Habitat Quality in an Eastern Oregon Agro-ecosystem. Abstract approved: Sujaya Rao David E. Wooster The effect of anthropogenic disturbance on river systems is gaining attention, and concerns about the state of freshwater natural resources are increasing globally, as are efforts to restore habitat that has been degraded by disturbance. In rivers, non-point source pollution affects the physical characteristics of the habitat and the endemic biotic assemblages. Aquatic macroinvertebrates are numerous and exhibit graded responses to various types of disturbance in the river, and may be used as indicators of habitat conditions. In this dissertation, macroinvertebrates were examined as bioindicators in the Umatilla River in eastern Oregon. The first study is a bioassessment of the impacts of agriculture on the benthic macroinvertebrate community in adjacent streams. The results of this study show that there are physical differences in habitat associated with adjacent land use, and the macroinvertebrate communities responded to these differences with changes in taxa richness and evenness. Indicator species analysis identified thirteen taxa which were indicative of habitat conditions associated with ideal habitat used as a reference condition, degraded habitat associated with agricultural land use, and transitional habitat associated with conservation/restoration management. The second study is a laboratory study in which the effects of temperature of a common mayfly nymph, Epeorus albertae (McDunnough) (Ephemeroptera: Heptageniidae) were evaluated. The study showed that not only the developmental rate of the nymphs was affected by temperature treatment (within a range of 18°C and 28°C), but the location of accumulated body tissues over time varied by temperature, with significant difference in the type of growth observed for insects held at the highest temperature. The third study examined the response of six indicator taxa to environmental variables as predictors of abundance in a non-parametric multiplicative regression. This study found that for all taxa examined, the two best predictors of abundance in the Umatilla River were turbidity and conductivity. Increased turbidity and conductivity are common effects of intensive agriculture in streams located in agro-ecosystems, but may potentially be mitigated by vegetative buffer strips and sustainable land use practices. Long term agricultural disturbance in the landscape has been shown to have lasting effects in the ecosystem which may be further exacerbated as global climate change increases dependence on freshwater resources. Understanding anthropogenic impacts on organismal communities and natural resources is vital to establishment of effective conservation, restoration, and maintenance of a healthy ecosystem. © Copyright by Melissa A. Scherr April 8, 2010 All Rights Reserved Evaluating Benthic Macroinvertebrates as Bio-indicators of Freshwater Habitat Quality in an Eastern Oregon Agro-ecosystem by Melissa A. Scherr A DISSERTATION submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented April 8, 2010 Commencement June 2010 Doctor of Philosophy dissertation of Melissa A. Scherr presented on April 8, 2010 APPROVED: Co-Major Professor, representing Entomology Co-Major Professor, representing Entomology Director of the Entomology Graduate Program Dean of the Graduate School I understand that my dissertation will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my dissertation to any reader upon request. Melissa A. Scherr, Author ACKNOWLEDGEMENTS This dissertation is possible because of the good fortune I have had in my associations at Oregon State University. I was first introduced to Dr. Sujaya Rao the junior year of my undergraduate education, and Dr. Rao has been a mentor to me ever since. She has been an example for dedication and perseverance not only in academia, but in my life as well. Sujaya has high expectations for her students, and as a result I was pressed to achieve more than would have been possible without her. Her interest in my success has opened the doors to many opportunities, and I would like to express my deepest appreciation and respect for her guidance and encouragement over the last several years. As a co-advisor, Dr. David Wooster has been an enthusiastic supporter from the conception of my interest researching aquatic bio-indicators, and has donated countless hours working with me in the river, in the laboratory, and at the word processor. Dr. Wooster has been instrumental in the formulation and execution of my research studies, lending his knowledge of river ecosystems and the ecology of the Umatilla River, and his patience with repeated manuscript draft editing. I can’t thank Dr. Wooster enough for his suggestions and assistance for the duration of my graduate career and for the hospitality extended to me numerous time during the months I have spent in Hermiston. I must also give credit to the remaining members of my graduate committee, Dr. Stan Gregory, Dr. Glenn Fisher and Dr. Joe Beatty, who have made time in their busy schedules to consult with me on my research plans, manuscripts and coursework several times over the last few years. The input they have provided has lent structure and focus to my research directions. Dr. Fisher especially has liberally bestowed his time and perspective as well as his infectious love for all things entomological, for which I am very grateful. In the last few years, the Entomology Program has grown to accommodate some of the most important associations of my time at Oregon State: my fellow graduate students. The impact of countless conversations about statistics, ecology, coursework, research and politics is immense and indefinable, and they have been integral in my personal and academic growth, and in the formation of my scientific perspective. I am fortunate to have been surrounded by such talented and commendable peers. Funding for my research was provided through many sources: the USEPA, Western SARE, Toshiba America, and the Agricultural Research Foundation. The majority of my funding was supplied by the National Science Foundation in two fellowships. The first was an NSF gK-12 fellowship, with Sujaya Rao as the P.I., and the second was through the Graduate Research Foundation. Many others must be acknowledged for contributions to my research and education: Dr. McCune for his assistance with multivariate statistics; Dr. Bill Gerth for his assistance identifying macroinvertebrates; Drs. Peter McEvoy and Jeff Miller for their enthusiasm as instructors and for their interest in my success; Dr. David Lytle for introducing me to the fascinating world of aquatic insects; Dr. John Rinehart for fostering my interest in invertebrate zoology as an undergraduate at Eastern Oregon University; and Mr. Bob Bohlen, formerly of West Valley High School in Spokane, Washington, who was responsible from the beginning for teaching me to love science. Finally, I would like to thank my family and friends for their profound support and encouragement throughout this process. CONTRIBUTION OF AUTHORS Dr. David Wooster assisted with study design, data collection and analysis, and provided editing for all manuscripts submitted as chapters in this dissertation. Dr. Sujaya Rao also assisted with study design, as well as manuscript preparation for chapters two, three, and four of this dissertation. TABLE OF CONTENTS Page Chapter 1: Introduction………………………………………………………… 1 Chapter 2: Agricultural land use and conservation easement effects on macroinvertebrate community structure in an arid-land river………… 8 Abstract……………………………………………………………….. 9 Introduction…………………………………………………………... 10 Methods………………………………………………………………. 12 Study Area……………………………………………………. 12 Study Design…………………………………………………. 14 Invertebrate Sampling………………………………………... 15 Environmental Data…….……………………………………. 17 Data Analysis………………………………………………… 18 Results……………………………………………………………… .. 21 Bioassessment……………………………………………… .. 21 Temporal Trajectory…………………………………………. 30 Discussion………………………………………………………….. .. 32 Land Use Impacts……………………………………………. 32 Easement Restoration………………………………………... 42 Data Analysis………………………………………………... 44 Conclusion…………………………………………………………... 45 Acknowledgements…………………………………………………. 47 Chapter 3: Effect of temperature on growth rate and behavior of Epeorus albertae (Ephemeroptera: Heptageniidae) nymphs………….......... 48 Abstract…………………………………………………………….. 49 Introduction…………………………………………………………. 50 TABLE OF CONTENTS (Continued) Methods……………………………………………………………. 54 Growth Rate Study………………………………….……… 54 Drift Behavior Study……………………………………….. 55 Data Analysis………………………………………………. 57 Results……………………………………………………………… 58 Growth Study...…..…………….……..……………………. 58 Drift Behavior Study..……………………………………… 63 Discussion……………………………………..…………………… 63 Growth Study…………………..…………………………… 63 Drift Behavior Study..………………………………………. 69 Acknowledgements………………………………………………… 71 Chapter 4: Macroinvertebrate response to interacting environmental gradients in the Umatilla River, Northeastern Oregon……..……… 72 Abstract…………………………………………………………..... 73 Introduction……………………………………………………….. 74 Materials and Methods……………………………………………. 76 Study Area………………………………………………… 76 Study Design………………………………………………