Does Heterogeneity in Habitat Type, Size, and Arrangement Influence Patterns of Fish Biodiversity in the Neosho River, Kansas?

Habitat heterogeneity is a ubiquitous feature of stream and river ecosystems that can alter biodiversity and change the effectiveness of conservation policies.  Although much research invokes heterogeneity as an important ecological driver of biotic patterns, metrics that quantify heterogeneity differ, resulting in ambiguity in across-site comparisons of patterns and processes.  Using a suite of common metrics, we quantified patterns of habitat heterogeneity within and across dammed and undammed sites to test drivers of fish biodiversity.  Habitat type was mapped along 51 km of the Neosho River, Kansas at 10 sites.  Fish and environmental variables were collected within 168 individual habitat patches.  Habitat composition (pool= 6-19, run= 2-16, riffle= 3-9, glide= 0-18 total number of patches= 17-59), patch size (pool= 169.98-61, 268.27m², run= 143.31-12, 795.22m², riffle= 11.38-2.113.66m², glide= 105.70-7, 155.98m²) and arrangement of habitat patches varied across sites.  Based on a total sample of 30,000 fish from 43 species, fish biodiversity was significantly related to habitat heterogeneity.  Fish abundance and diversity was highest in riffles.  Species richness was related to percent riffle habitat and riffle density.  Because of high variability, consistent metrics of heterogeneity need to be applied across sites and systems to generalize patterns and drivers of biodiversity.