Funded by the Growing Greener Program through the Pennsylvania Department of Environmental Protection, the Academy of Natural Sciences of Drexel University studied 17 streams within the lower Delaware River Basin to determine the effectiveness of a variety of past restoration projects implemented 4-20 years ago. Most of these projects, if monitored at all, were assessed within a few years of implementation, but ecosystems take more time to respond to environmental changes. Because of this, there is a lack data that accurately reflects whether these projects are having their intended effects of improving ecosystem integrity. To provide this data, ANSDU scientists surveyed and compared the macroinvertebrate and habitat parameters upstream of, and within, these restoration projects in 2016-2018. Macroinvertebrate communities are responsive indicators of changing water quality, and are assessed to calculate an Index of Biological Integrity (IBI) score. The effectiveness of a restoration project would be illustrated in a better IBI score found within these projects than upstream of them. Specific priorities, such as site selection and types of restoration projects to study, were identified by working closely with managers, practitioners, and county conservation districts throughout southeast PA to ensure the application of study findings for future restoration initiatives.
Results/Conclusions
Preliminary results showed that roughly thirty five percent of restoration projects showed a positive difference between sampling reaches, indicating a restorative success, while fourteen percent displayed a negative difference, showing that the restoration area became worse than the upstream reach. Fifty-one percent of sites displayed no difference between the two reaches. Revisiting past restoration projects provides an opportunity to comprehensively assess the ecological outcomes of restoration projects. By identifying whether projects were ecologically “successful” and comparing conditions within “successful” project reaches to reaches just upstream of the projects, results from this study can provide insight in how to better target future actions that will have the greatest chance of improving stream ecosystem integrity, how to best show these changes, and how to apply financial investments in restoration more effectively for future monitoring.