Cooperative Fish and Wildlife Research Units Program: Missouri
Education, Research and Technical Assistance for Managing Our Natural Resources

Abstract Restoring large river sandbars may be needed as these habitats are important components of river ecosystems and provide essential habitat to terrestrial and aquatic organisms. However, anthropogenic alterations have caused these habitats and the biota dependent on them to decline. We quantified the factors influencing sandbar size and densities within the riparian zone and contributing tributaries of the Kansas River using aerial photographs and land use/land cover (LULC) data. We developed, a priori, linear regression models focused on altered LULC (i.e., cropland and urban cover) at the local, adjacent upstream river bend, and the segment (18-44 km upstream) scales and used an information theoretic approach to determine what alterations best predicted the size and density of sandbars. Variation in sandbar density was best explained by the global model focused on the segment scale, highlighting a complex relationship between sandbar size LULC within the riparian zone and contributing tributaries. Whereas five models explaining variation in the mean area of sandbars performed equally well. These models focused on cropland and urban cover at the segment and adjacent upstream bend scales and one was a global model focused on the segment scale. Agriculture was positively correlated with sandbar size in all of the top models it was included and urban cover was negatively correlated with sandbar size in all but one of the top models that included it. Our findings suggest that restoration efforts focused on upstream LULC may help to increase sandbar availability in Great Plains rivers.