Date of Award

January 2013

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Stephen C. Richter

Department Affiliation

Biological Sciences

Abstract

Headwater stream systems are productive habitats that are often at risk of human perturbation, and it is crucial that ecologists understand natural patterns and processes within these ecosystems. Using a multi-scale approach, I investigated factors influencing habitat associations of Ambystoma barbouri (streamside salamander) and Eurycea cirrigera (southern two-lined salamander) in a relatively undisturbed stream network in central Kentucky. I used likelihood ratio G-tests to identify associations between species and mesohabitat types (i.e., runs, riffles, and pools). I used second order Akaike's Information Criterion (AICc) model selection to predict patterns of presence and abundance throughout headwater reaches. Fine-scale abiotic habitat conditions influenced habitat associations and distribution patterns at larger spatial scales. Individual A. barbouri displayed strong negative associations to riffle habitat at both micro- and stream-reach scales shortly after hatching, likely as a result of passive in-stream dispersal in response to increased water velocity and turbulence. Ambystoma barbouri, in later stages of development, displayed evidence of active dispersal, resulting in stronger positive associations to run habitat and stronger negative associations to riffles. Habitat associations in late spring suggested interspecific interactions between A. barbouri and E. cirrigera, and further research is needed on the potential reversal of predatory roles between the two species as A. barbouri larvae develop. My results demonstrated the effectiveness of a multi-scale approach to investigating complex ecological processes of aquatic organisms and the utility of AICc in selecting biologically relevant predictive models of salamander presence and abundance in aquatic habitats.

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