AUTHORS: Stephanie Webster, South Dakota State University; Jacob Zona, South Dakota State University; Tait Ronningen, US Fish& Wildlife Service; Chris Cheek, South Dakota State University
ABSTRACT: Barriers to aquatic connectivity can be present in many forms, (e.g. dams, culverts, and velocity). Most research on barriers to fish passage has focused on large barriers, however small barriers (e.g. culverts, road-stream crossings) are more common across the landscape and can lead to a cumulative impact on the connectivity of aquatic systems. Previous studies have focused on economically valuable and anadromous fishes and more research focusing on the impacts on resident small-bodied fishes is needed. The objectives of this study are 1) Assess connectivity in Bureau of Land Management priority watersheds in Montana & Wyoming by inventorying road-stream crossings and 2) Contribute inventory data to SARP to prioritize passage projects with the most potential for conserving species of conservation concern. We will inventory potential barriers by identifying small structures in selected HUC10 watersheds that contain species of conservation concern, annual rates >3 CFS, and >40% BLM land using aerial imagery. We will assess barrier severity using the protocol developed under the Southeast Aquatic Resources Partnership. Survey efforts will allow prioritization of barrier remediation projects that provide the greatest connectivity gain for species of conservation concern. We will evaluate the impact of network connectivity on fish communities by using databases from state, private, and federal organizations. We will analyze this data using the spatial stream network modeling function in R to account for spatial autocorrelation that is inherent in most terrestrial-based models. We expect to find that many of the identified barriers will be minor to moderate in severity and that decreased network connectivity will result in homogenized fish communities. The significance of this research is to provide an understanding that network connectivity has important management implications and provide managers with information about which barriers would be most efficient for remediation efforts.
