Macroinvertebrate community response to a restored stream in Lancaster County, PA

Big Spring Run (BSR), a tributary of the Conestoga River, is a heavily incised, agriculturally-impaired stream located in Lancaster County, PA. Specifically, BSR has been influenced by historic mill dams constructed in the 18^th century, prompting the restoration effort to remove such legacy sediments that were immobilized within the bank. During the summer of 2011, a 300 meter section of BSR was restored to reflect conditions prior to human impairment. The purpose of this study was to determine the impact of stream channel redesign and riparian buffer rehabilitation on structure. A BACI (Before/After/Control/Impact) sampling design was implemented to sample macroinvertebrates from three control reaches and one impact (restored) reach. Macroinvertebrates were collected using a Surber Sampler and returned to the laboratory for sorting and identification. All invertebrate samples to the generic (Genus) level and a Macroinvertebrate Aggregated Index for Streams (MAIS) were used to determine impact within all study reaches. Preliminary post-restoration analysis shows that there is not a significant difference between the pre- and post-restoration MAIS scores.