Fish and habitat relations at multiple spatial scales in Cheyenne River Basin, South Dakota

Relations of reach and landscape scale factors to stream fish communities were investigated in Cheyenne River Basin. Fifty eight reaches were clustered into four primary habitat groups using bankful width and depth, slope, and substrate. Stream clusters had lower fish species richness and community similarity than river clusters. Nine fish species were stream specialists and eight were river specialists. Distance to mainstem river best predicted fish species richness and diversity. The ratio of impoundment area: watershed area best predicted fish community evenness. As the impoundment area: watershed area ratio and distance to mainstem river decreased, species evenness, richness, and diversity increased. A diversity of fish species were found in streams, yet river reaches had the highest richness and similarity scores indicating a stable source habitat for small stream assemblages. Thus, conserving habitat diversity, uninhibited access to habitats, and watershed hydrology will be beneficial for sustaining Great Plains fishes.