Global Trajectories of the Long-Term Decline of Coral Reef Ecosystems

TLDR

Coral reef degradation began centuries ago, yet no global summary of its magnitude exists, and reefs will not survive without immediate large‑scale protection from human exploitation. We compiled records extending back thousands of years on the status and trends of seven major guilds of carnivores, herbivores, and architectural species from 14 regions. Large animals declined before small animals and architectural species, with Atlantic reefs declining earlier than those in the Red Sea and Australia, yet decline trajectories were similar worldwide, and all reefs were substantially degraded long before coral disease and bleaching outbreaks.

Abstract

Degradation of coral reef ecosystems began centuries ago, but there is no global summary of the magnitude of change. We compiled records, extending back thousands of years, of the status and trends of seven major guilds of carnivores, herbivores, and architectural species from 14 regions. Large animals declined before small animals and architectural species, and Atlantic reefs declined before reefs in the Red Sea and Australia, but the trajectories of decline were markedly similar worldwide. All reefs were substantially degraded long before outbreaks of coral disease and bleaching. Regardless of these new threats, reefs will not survive without immediate protection from human exploitation over large spatial scales.