A GIS Analysis of the Effects of Watershed Land-Use and Riparian Integrity on Stream Fish Communities in the Red River Basin

Because streams are an integrated component of a broader landscape, vegetation disturbances in the watershed can have profound effects on stream-fish communities. To test whether there is any correlation between vegetation disturbance and fish community composition, we compared: 1.) total quantity of disturbance in the local watershed and 2.) riparian zone integrity 3km upstream from each sampling site. Fish species composition is determined from historical records collected throughout the western tributaries of the Red River of the North in North Dakota, USA. By unifying archival datasets and temporally appropriate multi-scalar landscape data, we investigated the relationships between percent composition of fish guilds, local riparian integrity, and HUC-12 land use. Riparian integrity was analyzed and pooled to a 50m distance class from the stream edge (PCA proportion of variance = 88.82). PCA component loadings and biplots indicated positive correlations of riparian integrity with generalist and benthic insectivores and negative correlations with generalist and tolerant species (proportion of variance = 29.02). Ongoing land cover analyses currently reveal a strong positive correlation between agricultural land use and omnivorous species (α=0.05, Pearson’s r=0.2351). Our model relies on remote sensing to identify streams with sedimentation risk and may enable targeted management without extensive field surveys.