Habitat and Imperilment of the Candy Darter Etheostoma osburni in the New River Drainage, USA By Corey Garland Dunn Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN FISH AND WILDIFE CONSERVATION Paul L. Angermeier, Chair C. Andrew Dolloff Emmanuel A. Frimpong 17 November 2017 Blacksburg, Virginia, United States Keywords: Endemic, Habitat Suitability, Range Dynamics, Stream Fish © Corey G. Dunn, 2017 Habitat and Imperilment of the Candy Darter Etheostoma osburni in the New River Drainage, USA Corey Garland Dunn ACADEMIC ABSTRACT The streams of the southeastern United States are both hotspots for biodiversity and centers of imperilment. The specific spatiotemporal scales at which stressors impact biota are often unknown, partly due to inadequate knowledge about many species’ life-histories. I conducted two complementary studies to investigate the habitat associations of an imperiled highland stream fish, the Candy Darter Etheostoma osburni. In Chapter 2, I asked (1) does micro-habitat suitability correlate with the “robustness” (i.e., viability) of four distinct populations? In Chapter 3, I expanded the extent of investigation, and asked (2) which environmental factors, expressed at what spatial scales, best explain in-stream conditions, and (3) do stream segments where Candy Darters persist have cooler temperatures and less fine-sediment than segments where the species is extirpated or historically went undetected? Chapter 2 revealed Candy Darters demonstrate ontogenetic habitat shifts, with age-0 individuals selecting slower water velocities than adults. Despite, clear habitat selection for multiple habitat variables, suitability attributed to fine-sediment avoidance most strongly correlated with population robustness across streams. Chapter 3 indicated Candy Darters are extirpated from most areas in Virginia and southern West Virginia. Land use and natural catchment features, including geology, elevation, and stream geomorphology, predominantly explained instream conditions. Populations persist in segments with cool stream temperatures and low embeddedness year- round. To recover Candy Darters, managers will need to remedy pervasive land-use threats and restore stream habitat, while operating within the impending context of warming air and water temperatures and the existential threat of the introduced Variegate Darter E. variatum. Habitat and Imperilment of the Candy Darter Etheostoma osburni in the New River Drainage, USA Corey Garland Dunn PUBLIC ABSTRACT The Candy Darter is a small colorful stream fish only found in the New River Valley of Virginia and West Virginia. It was historically recorded throughout much of its range, but the species has since seemingly disappeared from many historical locations. Biologists, who are tasked with conserving declining species, know very little about the Candy Darter, which makes it difficult to determine the reasons for its decline. My goal was to clarify the habitats and streams used by the Candy Darter. In Chapter 2, my team recorded the habitats that Candy Darters preferred in four different streams where the species is either abundant (two streams), rare (1 stream), or has disappeared (1 stream). I determined individuals consistently avoid areas with high levels of fine sediment. I also discovered the streams where the species still exists had lower levels of fine sediment, indicating that high levels of fine-sediment may diminish habitat quality for individuals and eventually impact populations. In Chapter 3, I asked whether the conclusions from Chapter 2 were valid for most streams where Candy Darters have ever been recorded. In addition to less fine-sediment, I suspected the streams where Candy Darters still exist, would have cooler stream temperatures than the streams where they have disappeared. I surveyed 42 locations for Candy Darters and recorded stream temperatures and fine-sediment levels at each location. I confirmed that, on average, the streams where Candy Darters still exist have much cooler stream temperatures and fewer fine-sediments. Stream temperatures and fine- sediment levels could be explained by surrounding environmental conditions including geology, altitude, stream size, and the amount of pasture beside and upstream of each location. These findings are consistent with many other studies that have found non-natural land covers, including pasture, lead to higher amounts of fine-sediment washing into streams and create warmer stream temperatures. The decline of the Candy Darter is similar to the declines of dozens of other fish species throughout the southeastern United States. To restore Candy Darters, biologists will need to work with landowners to improve conditions adjacent to streams, while combatting other threats, such as warming air temperatures and non-native species. DEDICATION To my 10th-grade biology teacher, Mrs. Dunn iv ACKNOWLEDGEMENTS This research progressed from an initial solo snorkeling trip to Big Stony Creek after feeling inspired in my undergraduate Fisheries Techniques course to defending this thesis, with several missteps, rabbit holes, and campfires in between. As a PhD student, I now look back with a somewhat seasoned perspective at the special opportunity that I was given as a master’s student – a chance to identify and craft a thesis topic. Naturally, there were several people who helped me along the way. First, I thank my major adviser, Dr. Paul Angermeier, who when helping brainstorm potential research projects, encouraged me to “find a good story” and “go where the fish are.” Time will tell if I succeed in the former, but I definitely accomplished the latter. Of all the lessons learned in graduate school, the most import lesson is not to be afraid to think deeply about complex issues. This is Paul’s expertise, and I’m grateful to have learned from the best. Next, I thank my committee members, Drs. Andy Dolloff and Emmanuel Frimpong – both of whom provided guidance as I developed my project, made time for me despite busy schedules, and were patient with me during this exceptionally long and circuitous process. As a new graduate student, who was also new to Natural Resources, I leaned heavily on my lab-mates. Jane Argentina and Amy Villamagna were my first mentors in this field. Jamie Roberts helped me work through conceptual models, whereas Greg Anderson helped me work through the statistical variety. I was happy and fortunate that my path and the international paths of Tiz Mogollón Gómez and Ryan Liang all converged in Blacksburg, Virginia. This research took me all over the New River Valley, and I thank the scientists who lent their time to provide direction throughout my travels. My primary contacts were Bryn Tracy (NCDEQ) in North Carolina, and Dan Cincotta (WVDNR) and Stuart Welsh (WV University) in West Virginia. I am especially grateful to Mike Pinder (VDGIF), who encouraged this research from its infancy as a hypothetical undergraduate research project. I thank all the members of my research team – many of whom have since completed graduate degrees and continue to have a presence in our field. Team members included Matt Bierlein, Joe Cline, David Crain, Daniel Dodge, Laura Heironimus, Pat Kroboth, Josh Light, Luke Longanecker, Phil Pegalow, Jordan Richard, and Chris Rowe. Finally, I thank my current major adviser, Dr. Craig Paukert (Univ. Missouri), who graciously allowed me to dedicate time towards wrapping up my master’s research back east. v ATTRIBUTION I have or intend to publish two chapters (2 and 3) of this thesis as stand-alone manuscripts. Consequently, there will be some redundancy between these two chapters. Both manuscripts were joint efforts between Dr. Paul Angermeier and myself. Dr. Angermeier secured funding and significantly contributed to these chapters’ conceptual underpinnings, study designs, and refinement through diligent editing of draft manuscripts. Accordingly, the narratives of Chapters 2 and 3 are first-person plural. Both chapters are also formatted according to journal specifications. Chapter 2, Dunn and Angermeier (2016), was published in the Transactions of the American Fisheries Society, and Chapter 3, Dunn and Angermeier (In review), has been submitted to Freshwater Biology. The narrative of the remainder of this thesis uses first-person singular, and complies with the editorial conventions of the American Fisheries Society. References Dunn, C.G. and Angermeier, P.L. 2016. Development of habitat suitability indices for the Candy Darter, with cross-scale validation across representative populations. Transactions of the American Fisheries Society, 145:1266–1281. Dunn, C.G. and Angermeier, P.L. In review. Pathway to imperilment: extirpation of a highland fish explained by fine-sediment, stream temperature, and landscape context. vi TABLE OF CONTENTS ACADEMIC ABSTRACT ............................................................................................................. ii PUBLIC ABSTRACT ...................................................................................................................iii DEDICATION............................................................................................................................... iv ACKNOWLEDGEMENTS............................................................................................................ v ATTRIBUTION............................................................................................................................