Abstract
Ecological niche models (ENMs) are used to assess the abiotic preferences of species by linking their occurrences to the environmental conditions in which they live. We developed a fossil‐informed ENM framework that integrates mid‐Holocene and modern occurrences to test niche stability and reconstruct abiotic niche characteristics for four critical reef‐building Caribbean coral species (elkhorn coral [ Acropora palmata ], staghorn coral [ Acropora cervicornis ], boulder brain coral [ Colpophyllia natans ], and mustard hill coral [ Porites astreoides ]). Given evidence of niche stability, we used fossil‐improved niche estimates to predict area and location of habitat for future climate scenarios in 2050 and 2100. We built species distribution models with environmental predictors and compared models trained with modern‐only versus combined fossil and modern occurrences to evaluate differences in niche breadth, model performance, and projected habitat distributions under future climate scenarios. Including mid‐Holocene fossil data in ENMs broadened niche estimates, resulting in a larger area of predicted habitat than models based solely on modern data (up to 114,559 km 2 more in 2100). Although our models showed that suitable habitats existed for most corals in 2100, the amount declined dramatically (45–100% decrease in area from the present day), there was a significant restriction of lower latitude habitat suitability, and marine protected areas did not overlap the majority of predicted future suitable habitat (8–20% overlap by 2100). Fossil‐informed models expanded niche estimates in environmental space and incorporated environmental conditions not represented in modern data, resulting in broader projections of future habitat. Our results suggest that actions to reduce emissions and expand protected areas in the northern Caribbean are imperative to prevent significant degradation and that using fossil occurrences in niche estimation can improve the reliability of conservation forecasting, an approach that is transferable across taxa and regions.