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Scientists agree on land use impacts on Reef - Consensus Statement led by TropWATER researchers

land use effects on the GBR.pngResearchers from TropWATER at James Cook University have led a group of multidisciplinary scientists in the preparation of the latest scientific consensus on land use impacts on Great Barrier Reef water quality and ecosystem condition.

“Our overarching consensus is that key Great Barrier Reef ecosystems are showing declining trends in condition due to continuing poor water quality, cumulative impacts of climate change and increasing intensity of extreme events” Mr Jon Brodie from TropWATER James Cook University said.

Mr Brodie led the group of 12 scientists from from JCU, AIMS, CSIRO, CQUniversity, the Queensland Government and C2O Consulting in the development of the overarching consensus statement.

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The group comprised Jon Brodie, Jane Waterhouse, Stephen Lewis, Len McKenzie and Michelle Devlin from TropWATERJCU; Britta Schaffelke and Katharina Fabricius from AIMS; Frederieke Kroon and Peter Thorburn from CSIRO; John Rolfe from CQUniversity; Johanna Johnson from C2O Consulting; and Michael Warne from the Department of Science Information Technology Innovation and the Arts.

The multidisciplinary team gathered a large amount of scientific knowledge of water quality issues in the Great Barrier Reef to support the development of the Reef Water Quality Protection Plan 2013 (Reef Plan) to reach consensus on the current understanding of the system.

The consensus statement was released at the Great Barrier Reef Ministerial Forum and is available on line at

The evidence base is synthesised in a series of five supporting chapters, which involved contributions from 40 scientists from 16 organisations including research institutions, Queensland and Australian government agencies and private consultancies.

The following conclusions are based on those detailed reviews:

  • The decline of marine water quality associated with terrestrial runoff from the adjacent catchments is a major cause of the current poor state of many of the key marine ecosystems of the Great Barrier Reef.
  • The greatest water quality risks to the Great Barrier Reef are from nitrogen discharge, associated with crown-of-thorns starfish outbreaks and their destructive effects on coral reefs, and fine sediment discharge, which reduces the light available to seagrass ecosystems and inshore coral reefs. Pesticides pose a risk to freshwater and some inshore and coastal habitats.
  • Recent extreme weather– heavy rainfall, floods and tropical cyclones – have severely impacted marine water quality and Great Barrier Reef ecosystems. Climate change is predicted to increase the intensity of extreme weather events.
  • The main source of excess nutrients, fine sediments and pesticides from Great Barrier Reef catchments is diffuse source pollution from agriculture.
  • Improved land and agricultural management practices are proven to reduce the runoff of suspended sediment, nutrients and pesticides at the paddock scale.


The work has been supported by the Queensland Government’s Reef Plan Secretariat in the Department of the Premier and Cabinet.

For further information please contact Jon Brodie on 0407 127 030.

Issued: July 10, 2013

JCU Media Liaison, Jim O’Brien 07 4781 4822 or 0418 892449


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