Reef Rescue Marine Monitoring Program Intertidal Seagrass FINAL REPORT For the Sampling Period 1st September 2008 – 31st May 2009 Len McKenzie & Richard Unsworth © The State of Queensland, Fisheries Queensland, 2009. This report should be cited as: McKenzie, L.J. and Unsworth, R.K.F. (2009) Reef Rescue Marine Monitoring Program: Intertidal Seagrass, Final Report 2008/2009. Fisheries Queensland, Cairns (127pp). Published through Fisheries Queensland, a service of the Department of Employment, Economic Development and Innovation (DEEDI);". 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 State of Queensland or the Minister for Primary Industries and Fisheries. While reasonable effort has been made to ensure that the contents of this publication are factually correct, the State 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. November 2009 Contents Acknowledgements ............................................................................................... xiv Executive summary .................................................................................................. 1 1. Introduction ........................................................................................................... 5 Background ............................................................................................................... 5 2. Methodolgy .......................................................................................................... 7 Inter-tidal seagrass monitoring ............................................................................... 7 Edge mapping .......................................................................................................... 7 Seagrass reproductive health (status) ................................................................ 10 Seagrass tissue nutrients ......................................................................................... 11 Sediment nutrients .................................................................................................. 12 Rhizosphere sediment herbicides ........................................................................ 13 Within seagrass canopy temperature ................................................................. 13 Seagrass canopy light ........................................................................................... 13 Reporting Approach .............................................................................................. 14 3. Results .................................................................................................................. 17 Cape York ........................................................................................................... 17 2008/2009 Summary .............................................................................................. 17 Background ........................................................................................................... 17 Seagrass cover and composition ....................................................................... 18 Seagrass tissue nutrients ....................................................................................... 21 Seagrass meadow edge mapping .................................................................... 22 Epiphytes and macro-algae ............................................................................... 23 Sediment nutrients ................................................................................................ 23 Sediment herbicides ............................................................................................. 24 Within meadow canopy temperature .............................................................. 24 Regional Climate .................................................................................................. 25 Wet Tropics ............................................................................................................... 27 2008/2009 Summary .............................................................................................. 27 Background ........................................................................................................... 28 Seagrass cover and composition ....................................................................... 29 Seagrass tissue nutrients ....................................................................................... 34 Seagrass meadow edge mapping .................................................................... 36 Epiphytes and macro-algae ............................................................................... 38 Sediment nutrients ................................................................................................ 39 Sediment herbicides ............................................................................................. 40 Within meadow canopy temperature .............................................................. 40 Within meadow canopy light availability ......................................................... 42 Regional Climate .................................................................................................. 45 Burdekin Dry Tropics ............................................................................................... 47 2008/2009 Summary .............................................................................................. 47 Background ........................................................................................................... 47 Seagrass cover and composition ....................................................................... 49 Seagrass tissue nutrients ....................................................................................... 52 Seagrass meadow edge mapping .................................................................... 54 Epiphytes and Macro-algae ............................................................................... 55 Sediment nutrients ................................................................................................ 56 Sediment herbicides ............................................................................................. 56 Within meadow canopy temperature .............................................................. 57 Within meadow canopy light availability ......................................................... 58 Regional Climate .................................................................................................. 60 Mackay Whitsunday .............................................................................................. 63 2008/2009 Summary .............................................................................................. 63 Background ........................................................................................................... 63 Seagrass cover and composition ....................................................................... 65 Seagrass tissue nutrients ....................................................................................... 69 Seagrass meadow edge mapping .................................................................... 71 Epiphytes and Macro-algae ............................................................................... 72 Sediment nutrients ................................................................................................ 73 Sediment herbicides ............................................................................................. 74 Within meadow canopy temperature .............................................................. 74 Regional Climate .................................................................................................. 76 Fitzroy ........................................................................................................................ 79 2008/2009 Summary .............................................................................................. 79 Background ........................................................................................................... 79 Seagrass cover and composition ....................................................................... 81 Seagrass tissue nutrients ....................................................................................... 85 ii Seagrass meadow edge mapping .................................................................... 87 Epiphytes and Macro-algae ............................................................................... 88 Sediment nutrients ................................................................................................ 90 Sediment herbicides ............................................................................................. 90 Within meadow canopy temperature .............................................................. 91 Regional Climate .................................................................................................. 92 Burnett Mary ...........................................................................................................