Seagrass indicators, distribution and thresholds of potential concern ... Status and Trends of Seagrass Habitats in the Great Barrier Reef World ... While reasonable effort has been made to ensure that the contents of this publication ...... The conceptual diagram symbols are courtesy of the Integration and Application Network.
Status and Trends of Seagrass Habitats in the Great Barrier Reef World Heritage Area
Rob Coles, Len McKenzie, Michael Rasheed, Jane Mellors, Helen Taylor, Kara Dew, Skye McKenna, Tonia Sankey, Alex Carter and Alana Grech Queensland Department of Primary Industries and Fisheries Northern Fisheries Centre, Cairns
Supported by the Australian Government’s Marine and Tropical Sciences Research Facility Project 1.1.3 Condition, trend and risk in coastal habitats: Seagrass indicators, distribution and thresholds of potential concern
© Queensland Department of Primary Industries and Fisheries. PR07-3258 ISBN 978 0 7345 0381 7 This report should be cited as: Coles, R. G., McKenzie, L. J., Rasheed, M. A., Mellors, J. E., Taylor, H., Dew, K. McKenna, S., Sankey. T. L., Carter A. B. and Grech A. (2007). Status and Trends of Seagrass Habitats in the Great Barrier Reef World Heritage Area. Report to the Marine and Tropical Sciences Research Facility. Reef and Rainforest Research Centre Limited, Cairns (122 pp.). Made available for download by the Reef and Rainforest Research Centre Limited for the Australian Government’s Marine and Tropical Sciences Research Facility. The Marine and Tropical Sciences Research Facility (MTSRF) is part of the Australian Government’s Commonwealth Environment Research Facilities programme. The MTSRF is represented in North Queensland by the Reef and Rainforest Research Centre Limited (RRRC). The aim of the MTSRF is to ensure the health of North Queensland’s public environmental assets – particularly the Great Barrier Reef and its catchments, tropical rainforests including the Wet Tropics World Heritage Area, and the Torres Strait – through the generation and transfer of world class research and knowledge sharing. This publication is copyright. The Copyright Act 1968 permits fair dealing for study, research, information or educational purposes subject to inclusion of a sufficient acknowledgement of the source. The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment and Water Resources. While reasonable effort has been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. This report is available for download from the Reef and Rainforest Research Centre Limited website: http://www.rrrc.org.au/mtsrf/theme_1/project_1_1_3.html June 2007
Status and Trends of Seagrass Habitats in the Great Barrier Reef World Heritage Area
Contents List of Figures...........................................................................................................................iii List of Tables ...........................................................................................................................vii List of Maps .............................................................................................................................vii Acknowledgements ................................................................................................................viii 1.
PURPOSE OF THIS REPORT.......................................................................................... 1
2.
INTRODUCTION............................................................................................................... 2 Tropical Seagrasses.......................................................................................................... 3 Seagrasses of the Indo Pacific ...................................................................................3 Seagrasses of the Great Barrier Reef World Heritage Area.......................................3 Tropical Seagrass Biology................................................................................................. 7 Growth........................................................................................................................7 Reproduction ..............................................................................................................8 Seasonality.................................................................................................................8 Fisheries...................................................................................................................10 Ecosystem Values ....................................................................................................11 Key Elements of the Biophysical Setting......................................................................... 11 Light and Depth ........................................................................................................11 Temperature.............................................................................................................12 Tide and Water Movement .......................................................................................12 Nutrients ...................................................................................................................12 Salinity......................................................................................................................13 Resilience.................................................................................................................13 Anthropogenic Impacts.................................................................................................... 14 Management Framework for the Protection of Seagrasses ............................................ 15
3. SEAGRASS STATUS AND TRENDS IN THE GBRWHA ................................................. 16 Monitoring Strategy ......................................................................................................... 16 Seagrass Habitats ....................................................................................................16 Assessing Seagrasses at Risk for Priority Monitoring ..............................................17 Climate .....................................................................................................................20 Associated Macrofauna............................................................................................20 Fisheries Data ..........................................................................................................20 Reporting Approach ........................................................................................................ 21 Cape York ....................................................................................................................... 23 Background ..............................................................................................................23 Conceptual Summary ...............................................................................................26 Summary of Monitoring Data....................................................................................29 Climate .....................................................................................................................30 Associated Macro-fauna...........................................................................................31 Fisheries...................................................................................................................31 Regional Summary ...................................................................................................32 Information Gaps ......................................................................................................32 Wet Tropics ..................................................................................................................... 33 Background ..............................................................................................................33 Conceptual Summary ...............................................................................................35 Summary of Monitoring Data....................................................................................38 Climate and Seagrass Change ................................................................................45
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Associated Macro-fauna...........................................................................................47 Fisheries...................................................................................................................48 Regional Summary ...................................................................................................49 Information Gaps ......................................................................................................50 Burdekin Dry Tropics....................................................................................................... 51 Background ..............................................................................................................51 Conceptual Summary ...............................................................................................53 Summary of Monitoring Data....................................................................................55 Climate .....................................................................................................................59 Associated Macro-fauna...........................................................................................60 Fisheries...................................................................................................................61 Regional Summary ...................................................................................................62 Information Gaps ......................................................................................................62 Mackay – Whitsunday ..................................................................................................... 63 Background ..............................................................................................................63 Conceptual Summary ...............................................................................................65 Summary of Monitoring Data....................................................................................67 Climate and Seagrass Change ................................................................................70 Associated Macro-fauna...........................................................................................71 Fisheries...................................................................................................................73 Regional Summary ...................................................................................................74 Information Gaps ......................................................................................................74 Fitzroy.............................................................................................................................. 75 Background ..............................................................................................................75 Conceptual Summary ...............................................................................................78 Summary of Monitoring Data....................................................................................80 Climate and Seagrass Change ................................................................................83 Associated Macro-fauna...........................................................................................84 Fisheries...................................................................................................................84 Regional Summary ...................................................................................................84 Information Gaps ......................................................................................................85 Burnett Mary.................................................................................................................... 86 Background ..............................................................................................................86 Conceptual Summary ...............................................................................................88 Summary of Monitoring Data....................................................................................90 Climate and Seagrass Change ................................................................................91 Associated Macro-fauna...........................................................................................92 Fisheries...................................................................................................................92 Regional Summary ...................................................................................................92 Information Gaps ......................................................................................................93 4.
DISCUSSION .................................................................................................................. 94 General............................................................................................................................ 94 Trends ......................................................................................................................95 Natural Resource Management Regions .................................................................96 Pressures .................................................................................................................96 Protection .................................................................................................................97 Gaps in Knowledge ..................................................................................................98
5.
CONCLUSIONS............................................................................................................ 100
6.
REFERENCES.............................................................................................................. 101
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Status and Trends of Seagrass Habitats in the Great Barrier Reef World Heritage Area
List of Figures Figure 1. General conceptual model of seagrass habitats in north east Australia .................6 Figure 2. Conceptual diagram of controls and key processes limiting growth between seasons of intertidal Halophila ovalis .......................................................................................9 Figure 3. Key to symbols used for conceptual diagrams.......................................................22 Figure 4. Conceptual diagram of estuary habitat in the Cape York region............................26 Figure 5. Conceptual diagram of coastal habitat (
