Human Modifications to Salt Marshes in the Northeastern U.S.

This presentation by Erin Peck and Julie Walker was given as part of the NE CASC Webinar Series.
Description: With climate change and increased coastal land alteration, salt marshes globally are becoming increasingly degraded. Salt marshes in the Northeast are particularly vulnerable given the history of intensive alteration such as ditching and tidal restrictions since European colonization. Such alterations reduce the accretionary potential of salt marshes in this region, in turn reducing their ability to keep up with accelerating relative sea level rise. This ultimately leads to reductions in marsh area and loss of ecosystem function, including flood protection, carbon burial, habitat provision, and nutrient filtration. Through collaboration between multiple government, academic, and non-profit organizations, we are investigating the following questions: (1) What are the spatial patterns of salt marsh vulnerability to relative sea level rise across the Northeast? (2) And how is this vulnerability linked to specific salt marsh modifications (e.g., ditching, and tidal restrictions)? This webinar will discuss how we have addressed these questions by combining the Unvegetated to Vegetated Ratio (UVVR) salt marsh vulnerability metric (computed using Landsat imagery) with mapped tidal restrictions (e.g., culverts, bridges, tide gates, dikes) and ditches for the Northeastern coast of the United States. We hypothesize that estimated salt marsh lifespans, a mass balance between relative sea level rise and sediment budget (estimated using UVVR), will be shortened where salt marsh modifications are most intense. Our results will be used to drive science-based decision making through prioritization of salt marsh restoration.