Date of Award

Spring 5-9-2026

Document Type

Thesis

Degree Name

Master of Science in Fisheries and Wildlife Science

Department

Biological Sciences

College

College of Science, Technology, Engineering, & Mathematics

Committee Chair

Kyler Hecke, PhD

Second Committee Member

Zach Moran, PhD

Third Committee Member

Kendall Moles, PhD

Program Director

Tom Nupp, PhD

Dean of Graduate College

Michael Bradley, PhD

Abstract

Freshwater mussel communities in small tributary streams are poorly documented in Arkansas, limiting the understanding of how diversity is structured across river networks. To address this data gap, we surveyed 147 sites across five previously unsurveyed watersheds in the South-Central Plains Ecoregion (SCPE). We sampled 5,473 individuals representing 17 species, including four Arkansas Species of Greatest Conservation Need (SGCN). We evaluated patterns in community variation utilizing β-diversity based on both presence-absence and abundance data. Overall turnover (βsor and Bray) was partitioned into replacement (βsim and BrayBal) and nestedness (βsne and BrayGra) components. Replacement and nestedness each drove turnover in two watersheds, while Moro Creek was equally driven by both. Variance partitioning using distance-based redundancy analyses (dbRDA) with spatial data (AEM) and environmental variables revealed that drivers of β-diversity varied significantly, with models explaining 0–91% of the variance. While some components were explained purely by environmental or spatial factors, most exhibited shared explanation, suggesting that community structure in these tributaries reflects both localized habitat conditions and broader network connectivity. Beyond broad community patterns, we identified 40 mussel beds (>10 mussels/m2 ) across 28 sites. Subsampling of 4,936 individuals revealed evidence of recruitment for all species, including three SGCNs: Little Spectaclecase, Tapered Pondhorn, and Texas v Lilliput. Statistical analyses using PERMANOVAs and non-metric multidimensional scaling (NMDS) revealed distinct physical habitat associations. In Moro Creek, significant habitat differences were observed between headwater and mainstem beds (F1,18 = 3.82, R 2 = 0.175, p = 0.002). Key environmental drivers of bed composition included substrate (cobble and sand), canopy cover, bank angle, and stream width. These results underscore the ecological importance of tributary networks and provide critical baseline data for conservation strategies that prioritize protecting unique assemblages, maintaining dispersal pathways, and managing specific habitat features to sustain these imperiled faunal groups.

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Available for download on Friday, October 23, 2026

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