Assessing Biological Condition of Restored Streams in an Agriculturally Impaired Chesapeake Bay Sub-Watershed

ABSTRACT Intensive agricultural practices can be detrimental to aquatic biological conditions; however, restoration such as removing livestock and creating in-stream habitat can strengthen biotic communities. Smith Creek, a sub-watershed of the Chesapeake Bay, was designated a showcase watershed in 2010 by the United States Department of Agriculture to demonstrate the efficacy of widespread restoration. Our study sought to follow up on these efforts by assessing the individual and combined impacts of restoration, habitat, and land cover on aquatic macroinvertebrate communities in Smith Creek. We predicted that longer-restored sites, sites with less surrounding pasture, and streams with larger substrate size would have the highest stream condition. At 14 properties that were restored between zero and 20 years ago, we conducted kick-net surveys for macroinvertebrates and measured in-stream habitat characteristics. We calculated the Chesapeake Basin-wide Index of Biotic Integrity (Chessie B-IBI) and the Virginia Stream Condition Index (VSCI) to indicate biological condition and calculated land cover within 10 and 100 meters (m) of the stream on the property. Time since restoration was a significant predictor of both indices. The Chessie B-IBI was best predicted by time since restoration and substrate size together. Our results suggest that the restoration initiative may help improve stream conditions given enough time, but additional efforts are needed to establish causal effects of restoration.