Climate change is being blamed as a major contributor to flattening of the complex, multi-layered architecture of Caribbean coral reefs, which provide a natural defense against tropical storms and a home to hundreds of species of aquatic flora and fauna.

A study published in the Royal Society journal Biology Letters, authored in part by researchers from Simon Fraser University, states that the most complex type of reefs have been almost entirely wiped out across the entire Caribbean. Characterized by Table Corals of over 1 metre across and, and large Staghorn Corals, complex reefs act as a refuge for fish stocks, and hunting ground for larger, commercially fished species.

An analysis of 500 surveys of 200 reefs, conducted between 1969 and 2008, show that many have been replaced with the flattest types of rubble-strewn reef, which now cover approximately three quarters of the Caribbean’s reef area, up from about a fifth in the 1970s. Flatter reefs are less effective in protecting coastal settlements from storm swells and tidal surges, and are also less hospitable to biodiversity than healthy complex reefs, with repercussions for the fishing industry:

“Lack of … refuges for species with commercial importance, such as lobsters and large fishes may compromise the long-term sustainability of fisheries and fishing communities,” the report said.

Complex reefs also act as natural buffers, and their disappearance means that human coastal settlements are at increased risk from extreme weather events, such as more numerous and severe hurricanes, projected to occur due to climate change .

ACT’s biodiversity recommendations looked at the threats to ecosystems associated with climate change, and our upcoming report on Extreme Weather Events is due out in early September.