Illustrating principles of adaptive management by assessing stream health in a watershed impacted by hemlock woolly adelgid

Adaptive management involves making incremental adjustments in management policy to optimize the management strategy. Establishing baseline data is an important first step to this process. To give students in the Environmental Resource Management program at Penn State University practical experience with collecting baseline ecosystem data, I designed a field activity for students enrolled in the course ERM 413W: Case Studies in Ecosystem Management. Students collected riparian, water chemistry, and stream macroinvertebrate data from two locations in a central Pennsylvania watershed impacted by the invasive species, hemlock woolly adelgid (HWA). One area was heavily impacted by HWA and the other lightly impacted by HWA. The data indicated that riparian health differed between the two sites, but stream water quality was similar between sites despite the different levels of HWA infestation. The data collected by the students provides a baseline for future classes to compare their results against and assess how HWA infestation in this watershed, which is likely to intensify in coming years, is impacting stream health.