SYDNEY, Sept. 24 (Xinhua) -- Crown-of-thorns starfish (COTS), notorious coral predators blamed for damaging Australia's Great Barrier Reef, may have a positive role in maintaining coral diversity when their populations are kept at low levels, new research has found.
The study challenges the perception of COTS as purely destructive, suggesting that controlled populations can have a positive impact on coral prevalence and diversity, according to a statement released Thursday by Australia's University of Sydney (USYD).
The research, published in Ecology and Evolution, tracked coral feeding scars and surviving tissue after COTS predation in protected areas of the Great Barrier Reef with healthy fish populations.
Native to the Great Barrier Reef, coral-eating COTS have caused widespread coral destruction, with four major outbreaks recorded about every 15 years since the 1960s. Declining populations of COTS predators, including tritons and reef fishes, may increase the risk of outbreaks, the study showed.
Researchers found living coral tissue remained after almost 75 percent of the COTS feeding events examined. The findings suggest that at low densities, COTS support coral biodiversity by preventing dominant coral species from monopolizing reef space, allowing slower-growing species to persist.
The researchers stressed that the findings do not diminish the damage caused by devastating COTS outbreaks, but highlight the ecological benefits of low-density COTS populations in a healthy marine ecosystem.
"It's important to distinguish between COTS populations performing their natural role as coral predators and outbreaks causing sustained reef decline," said the study's lead author Shawna Foo from the USYD School of Life and Environmental Sciences.
The research could also inform future culling practices, with researchers saying the goal should not necessarily be to eliminate COTS entirely once an outbreak is suppressed. ■
