Date of Award

Spring 5-8-2025

Degree Type

Thesis

Degree Name

Master of Science - Biology

Department

Biology

First Advisor

Carmen G. Montaña

Second Advisor

Reuber Antoniazzi

Third Advisor

Brent Burt

Fourth Advisor

Joshuah Perkin

Abstract

Freshwater ecosystems in East Texas contain a rich freshwater biodiversity, with the Neches and Sabine River basins supporting some of the greatest freshwater fish diversity in the state. Given the heterogeneity of habitats and species diversity, these rivers serve as excellent natural systems for examining the ecological processes shaping biodiversity patterns and species distributions. In 2023-2024, 60 streams in the Neches and Sabine River basins were surveyed across three seasons to investigate the patterns and ecological drivers of taxonomic (TDβ), functional (FDβ), and phylogenetic β-diversity (PDβ) facets of freshwater fish assemblages. Additionally, I created two ecological niche models for a Species of Greatest Conservation Need (SGCN), Spotted Sucker Minytrema melanops, to compare model accuracy and inform conservation efforts of the species in these basins. The results of this study revealed that β-diversity facets of fish assemblages were correlated yet influenced by different combinations of regional and local factors (e.g., stream order, wetted width, different land cover types). The ecological niche model created using random forest algorithms outperformed the maximum entropy approach, and factors related to channel morphology (e.g., stream order, slope) and land cover type (e.g., agriculture) were important predictors of species occurrence.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Available for download on Saturday, May 09, 2026

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