Date of Graduation

7-2025

Document Type

Thesis

Degree Name

Bachelor of Science in Biology

Degree Level

Undergraduate

Department

Biological Sciences

Advisor/Mentor

Willson, J.D.

Abstract

Water conditions are changing globally due to climate change (Gleick, 1989). Headwater streams specifically are vulnerable to changes in hydrology, water quality, and physical characteristics from anthropogenic practices due to their small watersheds with shallow soils, yet they are often not a priority in conservation (Campbell et al., 2011; Abell et al., 2017). Within streams, plethodontid (i.e., lungless) salamanders, which are also sensitive to environmental changes, may be restricted in their distribution due to undefined stream characteristics and predation by fish (Welsh and Droege, 2002; Kuhajda et al., 2015). To better understand the pressures that influence stream salamander occupancy, I had two objectives: (1) examination of spatial distribution of the Oklahoma salamander (Eurycea tynerensis) in relation to stream size and physical characteristics within the Ozark highlands and (2) define these interactions within the context of flow characteristics in headwater streams. To achieve these objectives, I conducted visual surveys for E. tynerensis across varying flow regimes. I also recorded stream covariates and analyzed their relationship with salamander abundance using negative binomial regression, focusing on variables such as stream width, stream width variation, and substrate composition. Model selection was performed using an information-theoretic approach, with the final model including mean stream width and stream width variation as significant predictors of salamander abundance. I found that salamander abundance significantly decreased with increasing mean stream width, especially in streams smaller than 5.0-7.5 meters wide. Stream width variation was positively associated with higher salamander abundance, but substrate composition, canopy cover, and survey temperature were not significant predictors. These findings suggest that smaller, more variable watersheds may provide more suitable habitat for E. tynerensis, which has important implications for headwater stream management and conservation.

Keywords

Eurycea tynerensis; Salamander abundance; Salamander conservation; Aquatic; Headwater streams; Ozark Highlands

Download

Share

COinS