Caribbean coral reefs: Past, present, and insights into the future

Abstract

Coral reefs are considered one of the more widely distributed "animal forests" in the tropical oceans. Notwithstanding, their status has been deteriorating in the last decades, and the Caribbean Sea is not an exception to this pattern. In this region, the joint effects of hurricanes, diseases, species introductions, and human activities (tourism, fisheries, and habitat loss) have caused severe decreases in coral cover, affecting the performance of the entire ecosystem. In this contribution, we began by reviewing the history of the reef coral faunas at genus level since the Eocene, under the perspective of functional diversity. The data show that, although regional origination and extinction modified the taxa composition, there has been a remarkable homogeneity in the number of functional groups present over time. However, the number of species per group has decreased and the lower redundancy makes current assemblage more fragile to perturbations. Finally, the recent status of Caribbean reefs is discussed, and models of random extinction and of loss of the most threatened species are applied. The results evidenced that, in both cases, at regional scale, no functional group may disappear, but reef systems in Cuba and the Lesser Antilles are the most susceptible to suffer direct damage by the loss of species. In particular, the main worry for the present and the future of the coral reefs of the Caribbean Sea may be the loss of the key reef builders (including Acropora, Orbicella), which are responsible for the construction of the reef structural framework, and consequently the drivers of many ecological processes and ecosystem services.