Corals Most Important for Building Reefs are Now in Sharp DeclineNewsroom
ScienceDaily.com reports that staghorns, the very corals responsible for establishing today’s reefs, are now some of the most threatened coral species due to climate change and other human-made stressors.
A new study has found that the very corals responsible for establishing today’s reefs are now some of the most threatened coral species due to climate change and other human-made stressors.
Professor John Pandolfi from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at the University of Queensland (UQ) says the fast-growing, reef-building, branching Acropora, or ‘staghorn’, corals are responsible for the vast amount of modern reef growth. Although they have been around for at least 50 million years, these corals are now experiencing sharp declines in abundance worldwide.
“Acropora became a dominant reef builder about 1.8 million years ago,” Professor Pandolfi says. “And coral reefs have been so successful ever since then due in part to its ascendance–indeed, reefs grow most rapidly when staghorns are the dominant reef-building corals.”
The international study published last April examined global historical sea-level data, as well as global coral occurrence data–including fossil records–dating back to more than 60 million years ago.
The researchers found that while staghorns remained highly successful throughout rapidly changing environmental conditions in the past, their populations first began declining in Australia around the time of land-use changes with European colonisation. These patterns occur elsewhere, for example in the Caribbean Sea. More recently, these corals have suffered declines in abundance due to bleaching and disease, and have been almost completely wiped out across a number of reefs throughout the world.
Yet, staghorn corals currently remain one of the most prolific reef-builders, dominant on many reefs around the world and across all reef habitats: reef flats, crests and slopes, submerged reefs, and deeper reefs. They became successful because their colonies have the highest growth rates out of all corals, paired with an ability to regenerate when broken. Their presence is also a major factor in the ability of reefs to keep up with sea level rise–though they are sensitive to other environmental stresses, staghorns actually thrived under rapid sea level changes.