Hurricane Irma impact on biophysical and biochemical features of canopy vegetation in the Santa Fe River Basin, Florida

Abstract

Changes of biophysical and biochemical features in canopy cover over space and time can be used to elucidate watershed resilience to climate change or extreme weather. Geospatial technologies such as satellite remote sensing are helpful to identify such vegetation dynamics. This paper investigates the landfall impact of Hurricane Irma on canopy cover in the Santa Fe River Basin (Florida), which occurred in August 2017. Specifically, this study explores the effect of Hurricane Irma on vegetation dynamics via biophysical and biochemical features during the pre and post hurricane landfall. The geospatial analysis compares a suite of remote sensing spectral indices including enhanced vegetation index (EVI), leaf area index (LAI), fraction of photosynthetically active radiation (FPAR), evapotranspiration (ET), land surface temperature (LST), and global vegetation moisture index (GVMI). It is noticeable that paired spectral indices such as EVI-LST, GVMI-LST, LAI-LST, EVI-GVMI, EVI-LAI, LAI-FPAR, EVI-FPAR, and LAI-GVMI reflecting the dependent relationships between biophysical and biochemical features reveal varying level of logistic trends under Irma landfall impact. In addition, the evolution of these biophysical and biochemical features associated with the vegetation cover was analyzed in terms of the functional capacity over grassland, evergreen forested land, deciduous forested land, and agricultural land, to understand watershed response following Irma landfall. The functional capacity of the ecosystem reduced in terms of EVI and LAI over these four land-over patterns due to the landfall of Hurricane Irma. The interactions between agricultural land variation and flooding impact before and after the hurricane landfall further entail human impact on natural system in a food-water nexus.