SYDNEY - Australia hailed "solid" progress on water quality at the Great Barrier Reef Wednesday but admitted that overall conditions were now "poor" as it battles UNESCO threats to downgrade its heritage status.
Environment Minister Mark Butler released a report card showing that the reef's health had slumped since 2009 due to cyclones and floods, despite progress on reducing agricultural runoff.
"Extreme weather events significantly impacted the overall condition of the marine environment which declined from moderate to poor overall,' the report said.
It said key reef ecosystems were showing "declining trends in condition due to continuing poor water quality, cumulative impacts of climate change and increasing frequency and intensity of extreme events".
Despite reductions in nitrogen (seven percent), pesticides (15 percent), sediment (six percent) and pollutants key to outbreaks of devastating crown-of-thorns starfish (13 percent), the report said the reef was in strife.
Major flooding in 2010-2011 followed by powerful cyclone Yasi had badly damaged the world's largest coral reef, degrading water quality and depleting overall cover by 15 percent.
"Full recovery will take decades," the report said.
A major longitudinal study of the reef's health, published last year, revealed that coral cover had more than halved due to storms, predatory starfish outbreaks and bleaching linked to climate change over the past 27 years.
UNESCO has threatened to downgrade the reef's world heritage status to declare it at-risk in 2014 without significant action on rampant coastal and resources development seen as a threat to its survival.
Butler unveiled lofty targets for improving water quality over the next five years, aiming for at least a 50 percent reduction on 2009 levels of nitrogen pollutants linked to crown-of-thorns starfish outbreaks, 20 percent for sediment runoff and 60 percent for pesticides.
"In spite of solid improvement, data tells us that poor water quality is continuing to have a detrimental effect on reef health," Butler said.
"To secure the resilience of the Great Barrier Reef it is critical that we build on the momentum of the previous reef plan with a focus on improving water quality and land management practices through ambitious but achievable targets."