October 2008 Synthesis of evidence to support the Scientific Consensus Statement on Water Quality in the Great Barrier Reef Prepared by: Jon Brodie, Jim Binney, Katharina Fabricius, Iain Gordon, Ove Hoegh-Guldberg, Heather Hunter, Peter O’Reagain, Richard Pearson, Mick Quirk, Peter Thorburn, Jane Waterhouse, Ian Webster and Scott Wilkinson This document was prepared by an independent panel of scientists with expertise in Great Barrier Reef Water Quality. This document does not represent government policy. © The State of Queensland (Department of the Premier and Cabinet) 2008. Published by the Reef Water Quality Protection Plan Secretariat, August 2009, 100 George Street, Brisbane Qld, 4000. The Queensland Government supports and encourages the dissemination and exchange of information. However, copyright protects this document. 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Copies of this publication can be obtained by contacting (07) 3225 8050 or at www.reefplan.qld.gov.au Contents Background 1 The taskforce 2 Introduction 3 Part A: Review the 2003 statement and update it by reviewing available scientific evidence 4 1 Review scientific evidence for a decline in the quality of water that discharges from the catchments into the GBR 4 2 Review scientific evidence for the presence, nature and extent of land-derived contaminants in GBR waters 9 3 Review scientific evidence for causal relationships between water quality change and ecosystem health 18 4 Review existing scientific evidence for a decline in the quality of water in GBR catchment waterways leading to reduced instream ecosystem health 24 5 Review scientific evidence for the effectiveness of current or proposed management intervention in solving the problem 28 6 Discussing the implications of confounding influences including climate change and major land use change 35 Part B: Evaluate current research and advise on capabilities, gaps and priority research needs 37 1 Assess water quality impacts 38 2 Quantify acceptable levels of pollution 40 3 Locate and quantify the sources of pollution 41 4 Identifying management practices to reduce pollution from key sources 44 5 Assess the effectiveness of actions to reduce pollution 46 References 48 iii Synthesis of evidence to support the Scientific Consensus Statement on Water Quality in the Great Barrier Reef Background A consensus statement of the current Tasks understanding of Great Barrier Reef Review the 2002 statement and update it by: (GBR) water quality science was prepared to underpin the future direction 1. Reviewing scientific evidence for: of the Reef Water Quality Protection Plan • a decline in the quality of water that (Reef Plan) actions and to guide future discharges from the catchments into investment in Reef Plan activities. the Great Barrier Reef • a decline in the quality of water in Terms of Reference GBR catchment waterways leading to The Terms of Reference for the reduced instream ecosystem health statement, prepared by the Reef Water • the presence, nature and extent of land- Quality Partnership (RWQP) Support derived contaminants in Reef waters Team and Reef Plan Secretariat, and • causal relationships between water quality reviewed by the RWQP Scientific Advisory change and ecosystem health Panel, are provided below. • the effectiveness of current or proposed management intervention in Purpose solving the problem and the social and To review the Summary Statement of economic impediments to uptake. the Reef Science Panel regarding water quality in and adjacent to the Great 2. Evaluating current research, and Barrier Reef, in a contemporary context. advising on capabilities, gaps and This statement, which was produced by priority research needs, to: technical experts in 2002, supported the • assess water quality impacts development of the Reef Plan. Given that • quantify acceptable levels of pollution it was nearing the halfway mark of the • locate and quantify the sources 10-year plan, it was considered timely to of pollution review and, where appropriate, update the statement to support the reinvigoration of • reduce pollution from key sources Reef Plan and guide future investment in • assess the effectiveness of actions to Reef Plan priority activities. reduce pollution. 3. Discussing the implications of confounding influences, including climate change. The wording of the above Terms of Reference has been slightly modified by the Taskforce, in consultation with the Reef Plan Secretariat. 1 Synthesis of evidence to support the Scientific Consensus Statement on Water Quality in the Great Barrier Reef The taskforce A taskforce has been convened to prepare the consensus statement and includes the contributors listed in the table below. Contributor Title Organisation Expertise Jon Brodie Principal Research Officer, Australian Centre for Tropical Water quality and agricultural (Lead author) Water Quality Freshwater Research science – catchment to reef Jim Binney Senior Consultant Marsden Jacob Associates Resource economics Dr Katharina Principal Research Scientist, Australian Institute of Marine Coral reef ecology Fabricius Coral Reef Ecology Science Professor Theme Leader, Healthy CSIRO Sustainable Terrestrial ecology and social Iain Gordon Terrestrial Ecosystems Ecosystems interactions Professor Ove Director, Centre for Marine Coral reef ecology and University of Queensland Hoegh-Guldberg Studies climate change Principal Scientist, Natural Department of Natural Biogeochemistry of land Dr Heather Hunter Resource Sciences Resource and Water and water systems Department of Primary Dr Peter O’Reagain Principal Scientist Agricultural science – grazing Industries and Fisheries Professor Director, School James Cook University Tropical ecology Richard Pearson of Tropical Biology Contracted to Meat and Dr Mick Quirk Senior Consultant Agricultural science – grazing Livestock Australia Principal Research Scientist, CSIRO Sustainable Agricultural and environmental Dr Peter Thorburn Tropical Production Systems Ecosystems science – cropping Science Coordinator, Water quality science – Jane Waterhouse CSIRO GBR Projects catchment to reef Catchment and marine Research Scientist, Catchment Dr Ian Webster CSIRO Land and Water hydrodynamics and and Aquatic Systems biogeochemistry Additional contributors Research Scientist, Catchment Catchment hydrology and Dr Scott Wilkinson CSIRO Land and Water and Aquatic Systems material fluxes Apologies have been received from the following individuals Definitions that were approached to participate: The following terms are defined for the purposes of this Tim Wrigley (Canegrowers – cane management practices) discussion paper: Brigid Nelson (DPI&F – grazing management practices) Contaminant – any material that can be detected in water at Miles Furnas (AIMS – marine water quality and oceanography) above ‘natural’ concentrations. Malcolm McCulloch (ANU – marine water quality and climate change). Pollutant – when a contaminant is at concentrations known to cause environmental harm. 2 Introduction The establishment of the Reef Water This package will constitute Quality Protection Plan (Reef Plan – Commonwealth Government investment Anon, 2003) by the Australian and over the next five years for addressing Queensland governments was supported GBR water quality improvement targets. by a body of evidence showing a There is a need to focus investment decline in water quality on the GBR. in GBR water quality in a way that Efforts to review this evidence included demonstrates a tangible return on Williams (2002), Williams et al. (2002) investment for government agencies, and the Great Barrier Reef Protection regional National Resource Management Interdepartmental Committee Science (NRM) bodies and industry groups over Panel (2003). The latter document was the life of the Reef Rescue policy. a comprehensive review of the evidence Since 2003, there have been significant available at the time, prepared by a advances in the knowledge to support taskforce of experts led by Dr Jo Baker. implementation of the Reef Plan. It is As the Reef Plan approached its five-year timely to synthesise this knowledge (half-way) mark there was recognition of and reach consensus on current the need to improve the effectiveness of understanding of the system to support its delivery, particularly through improved the reinvigoration of Reef Plan and partnership arrangements and a clear guide future investment in Reef Plan focus on land management actions. In priority activities. This discussion paper November 2007, the Labor party released provides a synthesis of current knowledge an election policy document proposing against a set of Terms of Reference funding of $200 million over five years defined by the Reef Water Quality for a Reef Rescue program ‘to tackle Partnership Scientific Advisory Panel climate change and improve water quality and the Reef Plan Secretariat. It reviews in the Great Barrier Reef’. This package the Summary Statement of the Reef includes substantial funding ($146 million) Science Panel regarding water quality in for a Water Quality Grants Scheme, and adjacent to the Great Barrier Reef and supporting monitoring, reporting in a contemporary