Long-term monitoring update to condition of the Great Barrier Reef

The AIMS Long-term Monitoring Program has released an update on the condition of the Great Barrier Reef (GBR) based on survey data gathered across the entire GBR over the last 32 years. The update, which assesses data captured up to February 2017, describes a system under considerable pressure.

Following on from an AIMS publication in 2012, which described a 27-year decline in coral cover on the Reef, and last year’s update, today’s update shows that average hard coral cover (the most common indicator of reef health) across the entire system declined further during 2016, but the magnitude and trajectory of change varied between the Northern, Central and Southern regions.

Click here to read the full update.

“The Great Barrier Reef is a large, dynamic and important ecosystem, so it is essential that we continually monitor its condition and trends, and update our understanding of the reef’s current health in a broader context”, says Dr Britta Schaffelke, Program Leader for the AIMS ‘Healthy and Resilient GBR’ Program.

“These data show that the impacts of disturbances such as coral bleaching, crown-of-thorns starfish and cyclones vary along the length of the Reef. The decline in coral cover due to severe disturbances over the past two years is quite concerning.”

Dr Hugh Sweatman, AIMS Research Scientist and head of the monitoring team explains, “Our most recent data show that in the Northern region, coral cover is less than half of what is was in 2011, which is unprecedented for the region in the last 30+ years.

“This decline is largely due to severe coral bleaching event that caused significant mortality in 2016, in combination with 2 severe cyclones and continued crown-of-thorns outbreaks.

“The Central region was experiencing a general increase in coral cover until bleaching reduced this in 2016. Coral cover in the Southern region continues to increase from low levels in 2009.”

 

Trends in mean hard coral cover across the Northern, Central and Southern regions of the Great Barrier Reef over the past 32 years. Read the full report for further detail.

The update includes information taken from the extensive surveys taken over 2016 and into early 2017, but does not include data after the 2017 severe bleaching event, or Tropical Cyclone Debbie. This information will be included in future updates.

Long-term outlook for the Great Barrier Reef

The researchers highlight that it is difficult to predict the recovery of the Great Barrier Reef. “Despite the fact that we have over 30 years of information from the Program, we are only now starting to have data gathered over a sufficiently long period of time to allow us to understand the reef recovery process under a changing climate,” says Dr Schaffelke.

“Recent analysis of this long-term data set shows that recovery can be severely hampered by impacts associated with climate change, particularly increasing sea temperatures.”

A recent AIMS study indicated that recovery after a major heat-stress event in 2002 on the GBR was slowed, compared to previous recovery periods, and that affected reefs suffered high rates of coral disease. A separate AIMS study on the effects of cyclones concluded that, while recovery can be strong on some reefs, the projected increases in intensity of cyclones as a result of climate change could make it more difficult for reefs to recuperate.

Read the update in full here.

AIMS’ Long-term Monitoring Program is the longest, most comprehensive source of information on the health of corals for the Great Barrier Reef.

For more information:

Dr Hugh Sweatman

Senior Research Scientist,

Leader of AIMS Long-term Monitoring Program

Tel: +61 (7) 4753 4470

h.sweatman@aims.gov.au