My course project for Observing the Earth From Space assessed changes in vegetation at Sherwood Island State Park, Westport, CT, over the time period 1974-2005. False-color infrared aerial photos were georeferenced and, following a site visit, supervised classification was used to divide the marsh into botanically distinct zones. The Sherwood Island salt marsh declined in area by 21% over the three decades studied, amounting to a net loss of 4.4 hectares of vegetated area. The most affected vegetation class was the ecologically critical Spartina patens-dominated high marsh, which declined in areal coverage by 75%, accounting for 90% of the loss in total vegetated area.
These results, which contribute to an understanding of the nature of marsh drowning in Long Island Sound, are contextualized with a discussion of previous research at Sherwood Island and other data regarding anthropogenic stress on salt marshes. This study illustrated the potential value of freely available aerial photos in assessing vegetation change in coastal wetlands. My new project will be to extend this research to other salt marshes in Connecticut.