Spatio‐temporal dynamics of the threatened elkhorn coral Acropora palmata: Implications for conservation

AIM: Species distribution models (SDMs) can be useful for predicting spatial dynamics. For species vulnerable to climate change, much attention has focused on predicting the future range of occurrence. However, predicted range changes provide little information about the potential impacts on population structure. Here, we develop and apply an SDM approach that incorporates population demography of a threatened coral species (U.S. Endangered Species Act) and aim to provide guidance for conservation efforts. We additionally use projected climate change scenarios to predict the potential future range of occurrence and spatial population structure. LOCATION: U.S. Virgin Islands, United States. METHODS: We applied process‐based dynamic range models to jointly model the spatio‐temporal population dynamics and spatial habitat suitability of the threatened elkhorn coral Acropora palmata in the U.S. Virgin Islands. The approach integrates information from multiple data sources under a hierarchical Bayesian framework. The models connect two components: (1) a niche model that correlates environmental predictors with demographic rates and (2) a size‐structured population model that describes local population dynamics and dispersal. RESULTS: The model predicts that, under scenarios of elevated sea surface temperature and significant wave height, (a) A. palmata will occur at only a small proportion of its potential habitat (water depth ≤ 20 m) and (b) population structure of the colony will shift from larger towards smaller size classes. MAIN CONCLUSIONS: For A. palmata, restricted geographic range and smaller colony sizes, as predicted by the models, would limit future population success. In general, the inclusion of demographic structure into a population range model provides critical information for conservation or restoration efforts in the context of climate change.