STUDY OF HISTORICAL CHANGES IN WATER-WARD EXTENT OF SALT MARSHES IN NEW YORK CITY’S SPRING CREEK, IDLEWILD, AND PELHAM BAY PARKS

Recent work conducted by a collaboration between New York City Parks & Recreation (NYC Parks) and Brooklyn College, CUNY, has revealed an overall salt marsh loss of approximately 20% between 1974 and 2012, although individual marshes show great variability in the amounts of loss. This research was conducted on the urban fringing marshes using 1974 and 2012 aerial photos. To determine more detailed historical analysis of marsh change, a trends analysis is being conducted on selected marshes, Spring Creek Park and Idlewild Park (Queens, NY), and Pelham Bay Park (Bronx, NY), using 1999 aerial photos. This will allow us to determine relative rates of loss (or gain) between 1974 and 1999 and between 1999 and 2012. The spatial analysis uses ArcGIS and involves careful georeferencing and various steps in the GIS analysis in order to reduce error and make meaningful conclusions to help determine the cause(s) of these changes. The results of the 1999 trends analysis will be presented. This research will help NYC Parks better manage the numerous remnant marshes formed after the last glacial retreat. As they are located in a highly urban environment, these marshes serve a role in coastal protection, naturally filter wastes and pollutants, provide habitat for wildlife and aesthetic enjoyment for visitors.