Evaluating the protection status and exposure to warming of Caribbean reefs with high functional potential.

Over the past decades, climate change has emerged as a major threat to global biodiversity, negatively affecting the integrity and functioning of ecosystems and the benefits they provide to people. To mitigate these impacts, it is essential to identify climate refugia that support the persistence of the structure and function of reef ecosystems. Although most refugia analyses focus on thermal exposure to define priority areas, they often overlook other critical ecological and physical aspects of the ecosystems. We conducted the first assessment of climate refugia based on thermal exposure of a key attribute of coral reefs: their physical functionality. We used a previously published estimation of the potential for physical functionality of coral reefs in the Greater Caribbean. We used these estimates, thermal anomaly projections for 2049, and 10 Earth system models under two shared socioeconomic pathways (SSPs 3-7.0 and 5-8.5) to define priority reefs as those exhibiting high potential for physical functionality and having low exposure to climate change anomalies (refugia criteria). Forty-six percent of the priority reefs meeting the refugia criteria were unprotected. Several Caribbean countries had high potential to increase protection for functionally important reefs, including the Bahamas, Puerto Rico, the Turks and Caicos Islands, Panama, Cuba, Belize, Haiti, Honduras, Guatemala, and Jamaica. These findings provide a valuable tool for integrating the functional aspects of ecosystems when identifying priority conservation areas in the face of climate change.