Trends in Dominican Republic coral reef biodiversity 2015–2022

Abstract

In 2015, we initiated a country-wide coral reef ecosystem-monitoring program in the Dominican Republic (DR) to establish biodiversity baselines against which trends in the most important components of coral reef ecosystem’s structure and function could be tracked. Replicate transects were set at a 10 m depth at each of the 12 coral reef sites within 6 DR regions in 2015, 2017, 2019, and 2022. We quantified the species-level abundances of adult and juvenile corals, reef fishes, sea urchins, lionfishes, and algal functional groups. Country-wide, coral cover and reef fishes have declined. The steepest declines occurred for reefs that had been among the best in the Caribbean in 2015. However, by 2022, adult and juvenile coral, parrotfish, and other herbivores had declined, and macroalgae had increased. The declines in north-shore coral abundance corresponded with the observed disturbances from coral bleaching, hurricanes, and disease. The capacity of reefs to recover from such disturbances has been compromised by abundant and increasing macroalgae that have likely contributed to north-shore declines in juvenile corals. Country-wide, the abundance of all reef fish species has declined below those of other regions of the Caribbean. Improved management of fishing pressure on coral reefs would likely yield positive results.