Fish assemblage patterns as a tool to aid conservation in the Olifants River catchment (East), South Africa

Abstract

South Africa has committed to address freshwater conservation at the catchment scale, using a combination of landscapelevel and species-level features as surrogates of freshwater biodiversity. To support this work, we examined fishes in the Olifants River catchment, where multiple anthropogenic pressures affect streams. Patterns in fish assemblage data across 88 sites were analysed and related to landscape environmental variables using statistical techniques of multivariate ordination, cluster analysis, and regression tree analysis. We identified 6 distinct fish assemblage types, which were separated by altitude and human influence, primarily dry-land cropping and dams. In the upper reaches of the catchment, we identified a faunal shift from Barbus neefi , which occurred in less impacted sites, to B. anoplus and Tilapia sparrmanii , which were favored in cropland and mixed cropland/urban settings, respectively.

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