Degree Name

Master of Science (MS)

Semester of Degree Completion

2014

Thesis Director

Stephen J. Mullin

Abstract

Understanding the significance of trophic links has been of interest to ecologists for decades, likely because food web studies have the potential to reveal a considerable amount of information in the fields of ecosystem and community ecology. Despite the intrinsic benefits that come from elucidating food web structures, doing so is often problematic because of the complex and dynamic nature of ecological communities. The dietary ecology of small-bodied invertivorous snakes remains relatively understudied compared to other snake species. Many of these species are abundant throughout their range, making them ideal organisms for studying community-level questions. I employed a combination of stable isotope analyses as well as gut and fecal material analyses to quantify the trophic niche width of five species of invertivorous snakes (genera: Coluber, Diadophis, Opheodrys, and Storeria) occurring in central Illinois. I investigated seasonal differences in capture rates and quantified morphometric and isotopic differences among species. I used Bayesian mixing models to determine the potential sources of C13 and N15 in scale, red blood cell, and plasma tissue samples. The stable isotope data, supported by the gut and fecal analyses, revealed differences in the levels of dietary specialization within the community. High levels of trophic niche overlap were detected, however, indicating that snake dietary preferences are more likely a product of taxonomic affinity and species specific life-history, rather than interspecific competition. Further studies that involve a combination of techniques can provide a more comprehensive understanding of dietary ecology within snake communities.

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