Semester
Fall
Date of Graduation
2025
Document Type
Thesis
Degree Type
MS
College
Davis College of Agriculture, Natural Resources and Design
Department
Wildlife and Fisheries Resources
Committee Chair
Caroline Chavez Arantes
Committee Co-Chair
Brent Murry
Committee Member
Luke Bower
Committee Member
Dustin Smith
Abstract
Understanding the environmental and spatial drivers of community composition is essential for conserving freshwater biodiversity. We examined how environmental gradients, land cover, and spatial structure influence fish beta diversity in wadeable streams across West Virginia, USA. We quantified total beta diversity and partitioned it into species replacement and richness difference components and used local contributions to beta diversity (LCBD) to identify compositionally unique sites. Community–environment relationships were evaluated with distance-based redundancy analysis (dbRDA), and a beta regression GLMM was used to test how elevation, slope, land cover, and stream order (factor) predicted LCBD while accounting for spatial structure (dbMEMs) and watershed identity. Species replacement and richness differences contributed comparably to total beta diversity and exceeded null expectations, indicating non-random assemblage structuring. Environmental gradients significantly explained variation in community composition, with elevation, slope, and land cover emerging as influential predictors. LCBD values varied substantially across the landscape and were highest in mid- to high-elevation watersheds. Dividing LCBD into quartiles revealed that sites in the upper quartile (>0.00230) were disproportionately unique relative to regional assemblages. The global beta regression model showed that elevation and slope positively predicted LCBD, while stream order exhibited nonlinear effects, and spatial predictors further improved model fit. These results demonstrate that beta diversity in Central Appalachian streams is shaped jointly by environmental sorting, land-cover heterogeneity, and spatial structure. Conservation strategies should therefore prioritize protecting elevational and land-cover gradients, as well as spatially structured watershed habitats, to maintain regional freshwater fish diversity.
Recommended Citation
Lowther Smith, Alanna Kaylee, "Effects of environmental and anthropogenic gradients on fish beta diversity in central Appalachian streams" (2025). Graduate Theses, Dissertations, and Problem Reports. 13154.
https://researchrepository.wvu.edu/etd/13154