Identification of taxonomic and functional ichthyofaunal zones within the James River Basin, Virginia

• Main Author: Noel, Joseph L.
• Format: Others
• Published: VCU Scholars Compass 2018
• Subjects: Community Structure; Distribution; Freshwater Fish; Functional Trait; Taxonomy; Terrestrial and Aquatic Ecology
• Online Access: https://scholarscompass.vcu.edu/etd/5550; https://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=6638&context=etd

Environmental gradients structure ichthyofaunal communities longitudinally along river networks via the selective filtering of species’ traits. In many instances, these environmental influences have created distinct zones of co-occurring fish species. Zonation studies have most often been conducted with taxonomic data (species x site matrices), but the increasing availability of functional trait data creates an opportunity to build more rigorous understanding of species’ co-occurrence patterns. Notably, zonation studies that use taxonomic data may not reveal the same patterns as studies based on trait data. In this study, we tested for distinct ichthyofaunal zonation in James River Basin, VA using a combination of historical (1950-1987) and contemporary fish occurrence records (1986-2016) that were aggregated within 12-digit hydrologic units (HU). Zonation tests were performed separately for taxonomic data and functional trait data, using a combination of non-metric multidimensional scaling and k-means cluster analysis. We detected three distinct taxonomic zones and three functional trait zones within the James River Basin. In addition, through identifying that taxonomic dissimilarity between HUs was strongly correlated with functional dissimilarity, these zonation patterns were determined to not be significantly different.