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Title:Impacts of introduced crayfish on Ash Meadows aquatic communities: Ash Meadows National Wildlife Refuge, Nevada
Author(s):Kilburn, Stephanie
Advisor(s):Taylor, Christopher A.
Department / Program:Natural Res & Env Sci
Discipline:Natural Res & Env Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):invasive species
introduced crayfish
desert springs
endemic species
community structure
trophic position
Abstract:The single greatest concentration of endemic life in the United States, and second greatest in North America, can be found 90 miles northwest of Las Vegas, Nevada in Ash Meadows National Wildlife Refuge. This area is threatened by numerous non-native, introduced species, most notably the Red Swamp Crayfish (Procambarus clarkii). The interactions are of concern to the Refuge because of the presence of the federally protected endemic life, specifically pupfish (Cyprinodon nevadensis mionectes and Cyprinodon nevadensis pectoralis) and the federally threatened Ash Meadows naucorid (Ambrysus amargosus). Crayfishes may be potential predators and/or competitors for resources. I investigated the potential impacts P. clarkii poses to the sensitive aquatic systems and more specifically its food web. Within the Refuge, three springs lacking crayfish were compared to three springs which contained crayfish. I coupled habitat assessments, invertebrate community assessment and fish abundance and condition with stable isotope analysis and gut content analysis or crayfishes to better understand the interactions which the invasive P. clarkii has with the endemic system. Invertebrate communities, specifically snail populations, are less diverse in those springs with crayfish. Fish condition and abundance showed no significant trends between treatments. Stable isotope analysis indicated significant overlap at the same consumer level between crayfish, pupfish and even invertebrate grazers and predators in some seasons, but trophic position analysis showed no significant relationship to treatment. Gut contents revealed that crayfish shifted to a more animal based diet in the winter months, and animal material (specifically fish parts or snails) occurred in over a third of the stomachs examined. Results from this study highlighted the direct and indirect effects which this invasive crayfish poses to Ash Meadows aquatic communities and the need for future management techniques to include continued efforts to eradicate crayfish from the springs.
Issue Date:2013-02-03
URI:http://hdl.handle.net/2142/42342
Rights Information:Copyright 2012 Stephanie L Kilburn
Date Available in IDEALS:2013-02-03
Date Deposited:2012-12


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