Researchers from the University of Queensland have mapped both the loss of branching corals and changes in coral community structure in Australia’s Palm Islands region over the past century and found the region may be in worse shape than previously thought, a new study published in the Proceedings of the National Academy of Sciences reports.
While scientists have long been concerned about reef health across the world, this is the first time researchers have conducted in depth analysis of this area. They found that corals in the region are extremely sensitive to environmental change, which suggests the reef needs to be closely monitored in order to preserve future ecosystem health.
This new information is important because it demonstrates how high-resolution uranium-thorium dating, as well as both modern and palaeoecological techniques, can improve our understanding of coral mortality and help plan for long recovery periods. Such studies have not been possible in the past because the limited baseline information of ecological dynamics before the 1980’s made it hard to understand recent ecosystem trends.
“Hard coral cover on the Great Barrier Reef is on a trajectory of decline,” said lead author Tara Clark, a researcher at The University of Queensland, according to Phys.org. “Yet, little is known about past coral mortality before long-term monitoring began around the 1980s to give us a long-term picture of what has happened since European colonization of the coast.”
During their research, the team discovered that ecologically important branching Acropora corals have declined as of late and are far behind the expected recovery timeline. Further study of this trend revealed that Acropora coral death in reefs in the Palm Islands occurred at the same time as major disturbance events like beaching and flooding. In fact, 2014 surveys showed low Acropora cover — less than five percent — across all sites.
The new findings, in combination with past studies, also reveal that the inshore Great Barrier reef had already degraded before any long-term monitoring began. This puts a new timeline on the region and suggests the site is likely worse off than the past estimate showed. The team hopes their new study will bring light to this issue and help increase human action to preserve the area.