SYDNEY, Aug. 18 (Xinhua) -- Researchers in Australia have used more than 30 years of data to develop a new framework to more accurately measure the impact of climate change-induced events on the Great Barrier Reef.
The framework quantifies reef degradation over time and provides other researchers a "health check" tool to assess reef health. It can be used to measure the impact of severe disturbances, including coral bleaching, cyclones and floods, on reefs, according to a statement released Tuesday by Australia's University of Sydney (USYD).
Researchers analyzed data dating back to 1995, focusing on coral cover and algal buildup. High coral cover indicates a reef able to sustain healthy marine life populations, and high levels of algae point to poor reef health.
Rather than relying on absolute coral cover, which varies widely among reef systems, the research team compared each reef against its own historical data collected since the late 1980s.
"A reef with 30 percent coral cover might be considered healthy in one location but indicate substantial decline in another," said USYD PhD candidate Kate Whitton, lead author of the study published in Marine Environmental Research.
The study created three ecological categories for reefs -- healthy, coping and struggling. The framework could help scientists identify imperiled reefs and recommend timely interventions to aid recovery, Whitton said.
It found reefs generally transitioned into a "coping" state when coral cover declined below about 65 percent of their historical maximum, while declines below 35 percent were associated with a "struggling" state, marked by increased algae and major losses of reef-building corals.
The researchers also found complex coral forms were more vulnerable to disturbances than simple, round corals, leaving reefs flatter, with fewer shelters for fish and less protection from storm waves, making it harder for organisms to thrive and corals to regrow. ■