Dendrogyra cylindrus: extinction risk assessment

This widely distributed coral species is conspicuous, but is uncommon to rare. It has low juvenile survivorship and is highly susceptible to bleaching, disease, and extensive reduction of coral reef habitat due to a combination of threats. The Florida Reef Tract subpopulation is functionally extinct at the northern edge of the species’ range, where a population decline of 93% and the loss of 86% of genotypes between 2014 and 2020 have been recorded after the appearance of a novel coral disease, the Stony Coral Tissue Loss Disease (SCTLD) in 2014. In the southern and central Caribbean, high rates of fragmentation contributing to clonality, extremely low recruitment and site-level extinctions have been reported for the species. Though information on global-level abundance and population trends is scarce, an 80% or higher decline in both the number of colonies and live cover has been reported in 60% of the countries where trends in abundance have been assessed. Based on this, a population reduction of >80% over the past three generations (i.e. 1990 to present) is inferred. Despite area-based protection in a large portion of the species’ range, most localized threats are ongoing and bleaching events are projected to increase in frequency due to climate change. Overall, the low adult abundance, high susceptibility to diseases, specially SCTLD, limited connectivity among subpopulations, and recruitment.