Ecosystem Responses to the Interacting Forces of Bridge Improvements and Beavers
Principal Investigator:
Benjamin Simpson, Penobscot Nation, [email protected]
Co-Principal Investigators:
Kyle Hubbard, University of Maine
Joseph Zydlewski, USGS Maine Cooperative Fish and Wildlife Unit
Christina Murphy, USGS Maine Cooperative Fish and Wildlife Unit
Beavers alter entire ecosystems to suit their needs, while simultaneously providing environmental stability, resilience, and biodiversity to the surrounding area. These ecosystem services result from the inundation of water itself, tied exclusively to the dams which beavers create. Many species, both floral and faunal as well as terrestrial and aquatic, depend on the presence of beaver wetland resources to survive. Specifically, beaver ponds themselves act as premier habitat for young-of-year fish, providing cover from predators, an abundance of food, and thermal refuge, leading to greater juvenile survival and fitness. We believe this bridge construction may impact the amount of water held in this area, which may cause changes in the stability, resiliency, and biodiversity of the local ecosystem.
To assess the effectiveness of this construction effort, we will track environment conditions (temperature and spatial patterns of water inundation) before and after construction. To assess fish communities, we will electrofish and net fish in conjunction with environmental DNA surveys. This will be coupled with macroinvertebrate surveys. In addition, we will be tracking beaver movements using satellite tags and have set camera traps to monitor how terrestrial fauna use dam structures before and after construction. We expect to see an increased presence of migratory and resident fish species in waters above currently dammed areas after habitat connectivity is improved. Many animals may immediately change their movements or behavior near the bridges and the roadway due to construction disturbance but could return to baseline soon thereafter.
Presentations:
Hubbard, K., Murphy, C., Simpson, B., and Zydlewski, J. 2025. Effects of road crossing construction on the aquatic community of a beaver-influenced landscape. 155th Annual Meeting of American Fisheries Society, San Antonio TX., August 11.
Hubbard, K., Murphy, C., Simpson, B., and Zydlewski, J. 2026. Effects of road crossing construction on the aquatic community of a beaver-influenced landscape. Atlantic Salmon Ecosystems Forum, Bangor ME., January 13.