Species Distributions in a Changing Estuary: Predictions under Future Climate Change, Sea-Level Rise, and Watershed Restoration

Predicting future changes in species distributions due to climate change and sea-level rise are critical for informing adaptive management of large-scale estuarine ecosystem restorations. In this study, we used binomial generalized additive models (GAMs) to predict suitable habitat for 24 species groups under current conditions and projected conditions for 2060 in Florida Bay, a large and shallow estuary subject to one of the largest hydrological restoration efforts in the world, the Comprehensive Everglades Restoration Plan (CERP). Overall, potential sea-level rise due to climate change had a large influence in the system, driving the biggest reduction in habitat suitability in both magnitude and spatial extent. In contrast, the impacts of increased freshwater flows (and localized changes in salinity and salinity variation) from restoration influenced a greater number of species, but are predicted to have a relatively smaller influence on future habitat suitability for the majority of species in Florida Bay. The broadest positive changes in occurrence probabilities were found for spotted seatrout, pink shrimp, hardhead halfbeak, scaled sardine, common snook, and great barracuda. Negative changes occurred in numerous small-bodied species such as hardhead silverside, goldspotted killifish, rainwater killifish, and bay anchovy, as well as larger-bodied Crevalle jack, gray snapper, and white mullet. The model results predicted winners and losers, thereby providing an opportunity to ensure management strategies are designed appropriately to best achieve the desired results for the future of the Florida Bay ecosystem.