Habitat, Distribution, and Diet of the Tennessee Bottlebrush Crayfish (Barbicambarus Simmonsi)
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HABITAT, DISTRIBUTION, AND DIET OF THE TENNESSEE BOTTLEBRUSH CRAYFISH (BARBICAMBARUS SIMMONSI) BY ANDREW JOSEPH STITES THESIS Submitted in partial fulfillment of the requirements for the degree of Master of Science in Natural Resources and Environmental Sciences in the Graduate College of the University of Illinois at Urbana-Champaign, 2014 Urbana, Illinois Master’s Committee: Adjunct Assistant Professor Christopher A. Taylor Associate Professor Cory Suski Adjunct Assistant Professor Michael Dreslik ABSTRACT In order to effectively manage and conserve species, it is essential to have a basic understanding of their ecology. Unfortunately, such information is unavailable for most crayfish species, including the two members of the genus Barbicambarus. To obtain ecological data I conducted surveys for Barbicambarus simmonsi within the Shoal Creek drainage in Lawrence County, Tennessee and Lauderdale County, Alabama from Summer 2013-Spring 2014. The objectives of the first part of my study were to determine distribution, habitat use, and site occupancy of the Tennessee Bottlebrush Crayfish, Barbicambarus simmonsi. The distribution was increased from 3 to 14 sites across Shoal Creek. Habitat use modeling did not yield significant results, but observations indicate large flat boulders as utilized habitat. Flow was the most important covariate when determining site occupancy, but this should be interpreted with some caution, as it does not match field observations. The objectives of the second part of my study were to determine trophic position and diet of B. simmonsi and B. cornutus using stable isotope analysis and gut content analysis, and determine if there was correlation between carapace length and trophic position for each species. Crayfish for the analysis were collected during the fall of 2012 and the spring of 2013. My results indicate both species occupy a higher trophic position compared to other sympatric crayfish species. I also noted a significant positive correlation between trophic position and body size. My data suggest Barbicambarus species function as a predator within the stream and there is some niche separation between them and other crayfish species. ii ACKNOWLEDGEMENTS I would like to thank my advisor, Dr. Christopher Taylor for all of his guidance and support throughout my graduate and undergraduate studies. The knowledge he has passed on has been invaluable to my education and development as a biologist. I would also like to thank my committee members; Dr. Cory Suski and Dr. Michael Dreslik, whose advice and input has been essential in my development as a scientist and as a scientific writer. Also, thank you to Dr. Michael Dreslik and Dr. Bill Peterman for their help with my statistical analyses. I am grateful for everyone who helped me in the field, without whom I would have been incapable of getting any sampling done. Special thanks to Eddie Gordon and his family for providing me with a canoe to conduct my sampling and volunteering countless hours of his valuable time to help in the field. Also, special thanks to Jeff Garner and his family and the Tennessee Department of Environment and Conservation for providing housing during my field trips down in Tennessee and Alabama. Finally, I would like to thank my family and friends for their constant encouragement and support. iii TABLE OF CONTENTS CHAPTER 1: GENERAL INTRODUCTION ....................................................................1 LITERATURE CITED ........................................................................................................4 CHAPTER 2: DISTRIBUTION AND HABITAT REQUIREMENTS OF BARBICAMBARUS SIMMONSI ..........................................................................................7 INTRODUCTION ...............................................................................................................7 METHODS ..........................................................................................................................8 RESULTS ..........................................................................................................................12 DISCUSSION ....................................................................................................................14 TABLES AND FIGURES .................................................................................................19 LITERATURE CITED ......................................................................................................32 CHAPTER 3: TROPHIC ECOLOGY OF BARBICAMBARUS SPECIES........................36 INTRODUCTION .............................................................................................................36 METHODS ........................................................................................................................38 RESULTS ..........................................................................................................................41 DISCUSSION ....................................................................................................................44 TABLES AND FIGURES .................................................................................................48 LITERATURE CITED ......................................................................................................68 CHAPTER 4: SUMMARY................................................................................................72 APPENDIX A: OCCUPANCY MODELING SUPPLEMENTARY MATERIAL ..........73 APPENDIX B: CRAYFISH SAMPLING SUPPLEMENTARY MATERIAL ................77 iv CHAPTER 1: GENERAL INTRODUCTION Since its inception in the 1980s, the term biodiversity has accrued a variety of definitions (Meinard et al. 2014). The widely accepted definition is that biodiversity encompasses all biological variation, ranging from large-scale biomes and ecosystems down to the level of species, genes, and behaviors (Purvis and Hector 2000). At times species richness is used as a general indicator of biodiversity in an area (Fleishman et al. 2006). Because species richness and ecosystem function are linked (Hooper et al. 2005), knowledge of both is essential for effective conservation practices. Conservation of biodiversity and ecosystem function is often hindered when basic ecological data is lacking for particular species and is exacerbated when knowledge is lacking for keystone species (Taylor et al. 2007). Freshwater ecosystems are perhaps the most endangered ecosystem in the world, mainly due to anthropogenic effects (Dudgeon et al. 2006; Martinuzzi et al. 2014). Human water practices have led to severe degradation of freshwater systems by pollution and habitat loss, which in turn have had negative effects on biodiversity (Martinuzzi et al. 2014). Aquatic ecosystems are biologically invaluable because they support 10% of the world’s species (Carrizo et al. 2013). Nowhere is the endangerment of freshwater systems more pronounced than in biologically rich regions of the world with high levels of human population centralization and growth, with one example being the southeastern United States (Martinuzzi et al. 2014). The endangerment of southeastern freshwater systems is alarming, as the area is a known hotspot for aquatic biodiversity for fishes, crayfishes, mussels, and amphibians (Taylor et al. 2007; Martinuzzi et al. 2014). Although the conservation status of fish for the southeastern United States is regularly assessed (Deacon et al. 1979; Williams et al. 1989; Warren et al. 2000), the 1 status of crayfish is not, and ecological data is lacking for crayfish in general (Taylor et al. 2007; Moore et al. 2013) Among aquatic invertebrates, crayfish are a diverse group often comprising a large amount of the biomass in aquatic systems and having large impacts on the ecosystem (Momot 1995; Taylor and Soucek 2010). Crayfish are considered a keystone species because of their capacity to affect vegetation and invertebrate communities through predation and their ability alter habitat through substrate disturbance (Momot 1995; Geiger and Alcorlo 2005). Nearly two- thirds of the 600+ crayfish species occur in North America (Taylor et al. 2007), and about 3.4 new species are described each year (Moore et al. 2013). Of the 410 North American species, approximately two-thirds, mostly endemic species, occur in the southeast United States (Taylor et al. 2007). Endemic species typically have small ranges and are at higher risk to threats such as habitat loss or invasive species (Jones and Bergey 2007). Thus, it is imperative to conserve crayfish, a unique biotic resource, by broadening our knowledge of basic crayfish ecology. The genus Barbicambarus is a unique genus in the eastern United States consisting of only two species. The first record of Barbicambarus cornutus was by Faxon in 1884 from the Green River and the species ranges within the Barren and upper Green river systems in Kentucky and Tennessee (Hobbs 1974). The first record of Barbicambarus simmonsi was by Taylor and Schuster in 2010 from Shoal Creek in Tennessee and Alabama. Crayfish within Barbicambarus are characterized by having antennae densely covered in long setae, a larger than average body size, and a strongly dorsoventrally flattened carapace (Taylor and Schuster 2010). Little is known about the ecology of Barbicambarus species other than anecdotal observations on habitat found in their initial descriptions. Moore et al. (2013), describe how basic life history and ecological knowledge of populations and species are essential