Biological Effectiveness of Instream Restoration

Elaine Langone Center, Terrace Room

Agriculture can negatively influence stream ecosystems through a variety of means including increased sedimentation, increased runoff of pesticides and nutrients, and contamination of local groundwater. Loss of water quality can decrease in-stream habitat availability resulting in a shift in fish and benthic macroinvertebrate assemblages. In recent years, many farmers have become more receptive to adopting environmentally friendly agricultural practices. A variety of best management practices have been used by farmers, including restricting livestock access to the stream, enlarging riparian buffers, and using less harmful pesticides and fertilizers in general or at more effective times. Efficacy of these management practices has not been well-studied enough to determine ecological benefits to stream species. In conjunction with the Conservation Districts in Montour, Northumberland, and Union counties, 11 local farmers and residents agreed to have 16 riparian habitat restoration projects constructed on streams that run through their property. To determine the biotic response to stream bank restoration, we conducted pre- and post-restoration sampling from 2015-2017. Stream assessments consisted of benthic macroinvertebrate sampling according to Pennsylvania Department of Environmental Protection protocol, backpack electrofishing a 100-m site to determine the amount of fish species present, and collection of standard water chemistry data for comparative analysis. We have found increase in aquatic species abundance post-restoration, likely due to decreases in sedimentation, increases in habitat availability, and less stormwater runoff. Our results suggest that simple streambank restoration projects and best management practice plans could improve the health our not only local watersheds, but also to the Susquehanna Watershed and even the Chesapeake Bay.