Coastal dry tropical forests in Florida and the Caribbean in peril: A review

Abstract

Coastal dry tropical forests (CDTFs) are important yet vulnerable ecosystems. In this paper, we highlight the special conservation issues facing CDTFs by focusing on one variant of the type, those that occupy limestone substrate in the northeastern Caribbean. Our analysis draws largely from the coastal terrestrial broadleaf forests of the northern Bahamas, the Florida Keys, and southwestern Puerto Rico. Based on the surveys of storm surge recorded during major hurricanes during the last 50 years, we define CDTFs as coastal terrestrial broadleaf forests on ground surfaces elevated up to 5 m above sea level and occurring within 5 km of the coast. These forests are not only threatened by land-use change from urbanization but also climate-driven sea level rise (SLR) and hurricanes, which have degraded them and reduced their extent. CDTFs are distinguished from other dry tropical forests by the occasional influence of marine water incursion during periodic storms, requiring species common to these forests to have some level of salt tolerance despite experiencing well-drained, fresh water conditions during most of their life span. With precipitation being the sole freshwater source for most CDTFs, SLR and the resulting salinization in the rooting zone subjects these forests to increasingly stressful conditions. Hence, even a modest rise in sea level can push numerous imperiled and endangered species and coastal terrestrial broadleaf communities to the edge of their tolerance, causing a decline in extent or their complete disappearance. Outside of protected areas, rapid urbanization has fragmented these forests and reduced their extent, which in turn have modified the interaction between rising seas and forest function. This work emphasizes the need for refined risk assessments to be completed and for conservation measures to be enforced so that resources can be directed appropriately to prevent further loss of CDTFs.

Abstract in Spanish is available with online material.