Ecology Colloquium Series - Coarse Woody Debris in Riparian Corridors of Central Pennsylvania: How Quantities, Characteristics and Dynamics Vary with Anthropogenic Disturbance
Tim Gould (Penn State)
Occurring in one of the most densely-populated regions of the continent, the wetlands, floodplains, and riparian corridors of North America’s Mid-Atlantic Region have been under constant and continuous pressure from humans since before the arrival of Europeans. Disturbances related to this pressure include extensive removal of coarse woody debris from channels and associated floodplains to facilitate recreation and protect infrastructure. Research in the Pacific Northwest demonstrates that debris is a crucial element of ecosystem architecture, but little has been done to quantify how anthropogenic actions alter debris loading. This project utilized field surveys to determine how debris quantity and quality differ among riparian sites in Central Pennsylvania that have been impacted by humans to a varying degree. Habitat quality assessments were developed to measure and classify disturbance level, allowing sites to be placed on a disturbance gradient. Counts and characterizations of debris, undertaken on a site-by-site basis, were compared to this gradient in an effort to uncover a consistent relationship between debris and disturbance. Monitoring debris dynamics and critical ecosystem functions (flow velocity, sedimentation rate) over the course of one year supplemented these core datasets. Results indicate that sites registering low disturbance scores contain more and larger debris, and that more and higher quality ecosystem functions occur at these sites. As growing numbers of designers and land managers begin to appreciate the value of debris and seek to restore it to the landscapes under their purview, data such as this will become increasingly important to ensure that the appropriate amount of debris is incorporated in a calculated and effective manner.