GIS AND REMOTE SENSING TO EXAMINE MANGROVE RESILIENCY ON FLORIDA BAY ISLANDS AFTER HURRICANE IRMA

Hurricane Irma hit south Florida on September 10, 2017 as a category 4 storm, significantly impacting Everglades National Park, including Florida Bay. Fieldwork had previously been conducted in 2014 on four islands in Florida Bay to investigate sea level rise and island resiliency. To examine the impacts of Hurricane Irma on the vegetation of the four islands, high-resolution multispectral satellite imagery was obtained and analyzed to determine the health of the vegetation after the storm. Imagery was obtained before, about a month after, a year after, and approximately two years after the storm to examine the lasting impact of Hurricane Irma on the islands’ mangrove population. The images were manually interpreted within GIS to quantify the landmass variance of the islands through digitization, and the near-infrared spectral band was used to calculate a normalized difference vegetation index (NDVI) to identify live green vegetation on the islands. The results of the manual interpretation indicated that all four islands decreased in vegetated area by 2-9% one year after Irma, with the two islands closest to the eye of the hurricane having the greatest percentage loss. Most changes occurred to the interiors of the islands, however two of the islands experienced a loss of vegetation along their eastern perimeters. Within Everglades National Park, mangroves serve as natural buffers against coastal storms, so determining the vitality of these mangroves and other vegetation is important to understanding the long-lasting impacts of Hurricane Irma on south Florida, and the role that storms in general play in the resiliency of the Florida Bay islands.