Stronger Hurricanes and Climate Change in the Caribbean Sea: Threats to the Sustainability of Endangered Coral Species

An increasing sea surface temperature as a result of climate change has led to a higher frequency and strengthening of hurricanes across the northeastern Caribbean in recent decades, with increasing risks of impacts to endangered corals and to the sustainability of coral reefs. Category five Hurricanes Irma and María during 2017 caused unprecedented damage to coral reef ecosystems across northeastern Puerto Rico, including mechanical destruction, localized sediment bedload (horizontal sediment transport and abrasion), and burial by hurricane-generated rubble fields. Hurricanes inflicted significant site-, depth-, and life history trait-specific impacts to endangered corals, with substantial and widespread mechanical damage to branching species, moderate mechanical damage to foliose species, and moderate to high localized damage to small-sized encrusting and massive morphotypes due to sediment bedload and burial by rubble. There was a mean 35% decline in Acropora palmata live cover, 79% in A. cervicornis, 12% in Orbicella annularis, 7% in O. faveolata, 12% in O. franksi, and 96% in Dendrogyra cylindrus. Hurricane disturbances resulted in a major regime shift favoring dominance by macroalgae, algal turf, and cyanobacteria. Recovery from coral recruitment or fragment reattachment in A. palmata was significantly higher on more distant coral reefs, but there was none for massive endangered species. Stronger hurricanes under projected climate change may represent a major threat to the conservation of endangered coral species and reef sustainability which will require enhancing coral propagation and restoration strategies, and the integration of adaptive, ecosystem-based management approaches. Recommendations are discussed to enhance redundancy, rapid restoration responses, and conservation-oriented strategies.