Landscape Influences on Stream Habitats and Biological Assemblages

<em>Abstract.</em>—The Topeka shiner <em>Notropis topeka </em>is a small cyprinid listed as endangered in 1999 due to an 80% reduction in its former range across six Great Plains states. Conservation and recovery plans require information on structural indices of existing populations, distribution, and habitat relations at several spatial scales. We examined physical habitat associations of Topeka shiners at the valley segment and reach scales, and associations with fish species using stepwise logistic regression. Fish and habitat data were collected at 52 sites. Habitat features at the valley segment scale were acquired using data from a geographic information system. At the valley segment scale, Topeka shiners were associated with stream condition variables (stream size, groundwater potential, channel slope, streamflow, network position) and land-cover variables (% pasture, % trees). At the reach scale, Topeka shiners were associated with low grazing and small trees in riparian zones, low bank height, less submerged vegetation, and coarse substrates. Topeka shiners were associated with five fishes that inhabit small, intermittent, warmwater streams. Evidence of greater abundance of Topeka shiner populations in our region compared to other regions may be a result of the natural character of the streams and associated wetlands, which can influence the habitat variables associated with Topeka shiners at both scales. We identified management strategies that would be effective at conserving habitat of Topeka shiners at large and local scales.