ABSTRACT Title of Document: HOW THE AVAILABILITY OF NUTRIENTS AND ENERGY INFLUENCE THE BIODIVERSITY OF CAVE ECOSYSTEMS Katie Schneider, Ph.D., 2009 Directed By: Dr. William F. Fagan, Professor, Department of Biology Resource constraints can affect species on multiple levels. In this dissertation, I combine laboratory experiments, an ecosystem-level manipulation experiment and statistical modeling to examine how resources maintain and constrain cave biodiversity and structure cave communities. Chapter I examines how N-limitation may drive morphological adaptations of cave arthropods. By analyzing free amino acid contents, I show that, in comparison to cave-transient millipedes, cave-obligates have decreased concentrations of essential, nonessential and N-rich amino acids, and amino acids associated with pigmentation and cuticular development. Chapter II tests the hypothesis that stoichiometric mismatches impose growth constraints on cave animals. Although results show that cave resource quality is similar to surface leaves, I do show that millipedes experience a strong mismatch to their food. Also, cave-obligate millipedes have lower %P and RNA/DNA (protein synthetic capacity) compared to cave- transient millipedes. Results from these chapters suggest that cave adaptations may reflect stoichiometric challenges of caves. Chapter III describes the manipulation experiment, wherein I removed all organic material from 12 caves, and, while excluding all natural subsidies, I added standardized quantities of leaf packs or rodent carcasses. For 23 months, I monitored the recipient communities to see how subsidies influence species abundance, diversity, and community dynamics. I observed 19,866 arthropods representing 102 morphospecies. Rat treatments supported greater abundances, but the treatments did not differ in richness. Multiple community-level analyses demonstrated that community composition differed drastically depending on treatment. Lastly, the communities changed directionally over time, diverging faster in caves receiving leaves. Chapter IV uses annual bioinventories of 65 caves to investigate occupancy patterns of terrestrial invertebrates. I estimated richness using classical estimators in concert with estimators that incorporate detection. I also used multispecies occupancy models to examine relationships between estimated richness and physical cave characteristics; demonstrating the importance of cave length, entrance geometry (a surrogate for energy input), and connectivity. The results show how inventory data, even if incomplete, can provide valuable information about the distribution of rare species. Resource availability can affect cave ecosystems on multiple levels. Here I illustrate how the biochemical composition, community dynamics, and occupancy patterns of cave species are influenced by resource constraints. HOW THE AVAILIBILITY OF NUTRIENTS AND ENERGY INFLUENCE THE BIODIVERSITY OF CAVE ECOSYSTEMS By Katie Schneider Dissertation submitted to the Faculty of the Graduate School of the University of Maryland, College Park, in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2009 Advisory Committee: Dr. William F. Fagan, Chair Dr. David C. Culver Dr. Daniel Gruner Dr. William Jeffery Dr. Barbara Thorne © Copyright by Katie Schneider 2009 Acknowledgements After a long six years, the list of people I have to thank is quite long. My family, friends, animals, labmates and therapist are largely responsible for the completion of this work; without their support, this work would not have been possible. My grandmothers, Nanny and Grandma, have looked upon me from Heaven and remain a source of comfort, warmth, and solace. My grandfather, Pop pop, who completed his formal schooling in his seventies but continues to learn new technology every day (currently in his 97th year), has been a tremendous source of inspiration and love. My parents, who have always stood by me, have gone above and beyond their call of duty. Dad, while I will miss helping out with the YLP, I look forward to living closer so that your visits will be more frequent. Thank you for all of the handwarmers, tactical equipment, and opportunities for law enforcement-related scholarships. Mom, though it may be hard to imagine, our relationship has become even stronger while I’ve been in graduate school. Whether you were hiking around helping me with fieldwork, or supporting me as I’ve faced the biggest personal challenges of my life, you are the best mother and role model any woman could ever have. Joe and Laurel, thank you for the sweet care packages and mix tapes while I faced my prelims, and the advice that I’ve needed through the years…while I’ll miss our annual Orioles games, we’ll only be 45 minutes from Yankee Stadium next year! Kris, my sister and BFF, thank you for always listening and never judging me. You and I are so similar in so many ways, and you understand me better than anyone. Ed, thanks for understanding my (our) little quirks and also understanding my scientific mind! Michelle, Willie, Tat, Vanessa, Patrice, Jess, and Holly: thank you for always being there for me, you are wonderful friends and I’m so lucky to have you. Athena and Apollo, I miss you guys. You always listened so patiently and knew when I needed a hug. Auggie, you are doing a great job holding down the fort and taking on the role of best dog ever. Mousecar de la Joya, say no to purple. Future Dog (Mickey): This is your year. I can’t wait. At school, my labmates have provided both emotional and statistical support, as well as assistance in the lab and in the field. Holly and Thomas, we’ve been through a lot, personally and professionally. Thank you for talking me down and talking me up so many times through the years. The Faganites: Castaldo, Evan, Elise, Paula, Christina, James, Justin, Heather, Sarah, Sara, Kären, Leslie, and Leslie, despite all the stressful times, I’ll still miss the fun times, mostly associated with brainstorming or problem solving in the white room, but also when Castaldo would tackle any one of you. To the newer students, I’m sorry I won’t be around to see all of your successes first-hand, but I look forward to hearing about them as they happen! My advisor, Bill Fagan, has helped me to frame my ideas in a larger ecological context. He has built a lab that is full of incredibly smart people doing very diverse projects, and thus, help was always somewhere to be found. Bill, a theoretical ecologist, is surprisingly good in the field – even though he did develop the framework of a modeling paper while standing in complete darkness with his headlamp illuminating a wall full of cave crickets. Thank you for providing me with many opportunities including the NCEAS workshop, several research assistantships, ii and even a trip to Antarctica. Thank you also your help in editing drafts of my dissertation. My committee, of course, has been instrumental to my progress. Mary Christman and Dan Gruner helped greatly with the statistical and community analyses. Mary, you were one of the major reasons why I wanted to come to Maryland. Though I was disappointed when you moved to Florida, I am glad that we have maintained our collaborative efforts despite the distance. Dan, thank you for being so easy to talk to and helpful in this process. Bill Jeffery, thank you for always providing me with opportunities to participate in biospeleological research, for allowing the use of your spectrophotometer, and for candidly talking with me during some of my more difficult times. Speaking of candid, Dave Culver: thank you for always being honest with me. You are the most straightforward person I know, and it’s taken me a long time to come to appreciate that as I do now. You were my inspiration for getting into this line of work, and I hope that I’ve made you proud. To the late Bob Denno, how I wish you were here to see how this project turned out, and of course, to provide some of your invaluable input into my findings. After all, the resource manipulation project developed after a conversation between us, and to be honest, it took me awhile to understand why you advised me to pick through carcasses for two years. I miss you, Bob. Barbara Thorne, thank you for standing in to be my Dean’s Representative. Your work has stood in my mind since the first time I heard your seminar, and I appreciate your input on my committee. Other faculty at UMD and AU have also been helpful, providing comments, conversations, and advice, including C. Tudge, G. Dively, S. MacAvoy, J.Shultz and S. Sukharev. Others have provided more specialized support: Sue Bertram (setting up the phosphorus analysis), Kaci Thompson (skull identifications) and Allen Ingling and Barry Nellenback (operating a two-ton incinerator). My collaborators on Chapters 1 and 2, Adam Kay and David Renault, have greatly strengthened these biochemistry papers because of their expertise. The DCBDC has also been a source of comfort and advice, when I can squeeze the time and money to join you. Undergraduate assistants, Karen, Jessica, Anna, Barry, Kat and Amar, thank you for all of your hard work on seemingly strange projects! Thank you to the taxonomists who willingly donated their time to identify cave specimens. Your expertise is a rare treasure and I appreciate your help. Individuals are thanked by name in the acknowledgements section of each chapter. My field work was incredibly physically intensive. Jason Gulley, you had no idea what you were getting into when I first told you about this project, and surprisingly, you didn’t leave when you found out what it would entail. I can’t thank you enough. Jeff Hajenga, you were someone that I could always count on and I’ve enjoyed spending so much time with you! Dave and Sandy Cowan, thank you for accompanying me in the field, offering me a warm place to sleep (with a heating blanket!), a place to shower, breakfast with waffles, and especially, making my fieldwork a time to catch up with friends.