Australian seagrass habitats: condition and threats
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The primary objective of this ACEAS Working Group is to bring together numerous data sets that currently exist in relation to seagrass distribution in order to improve and update the spatial detail and accuracy of the 2000 and 2008 estimate of seagrass distribution currently available on OzCoasts. Where sufficient data is available we will use the expertise of the group and available data to estimate temporal changes in seagrass distribution in several focal areas that represent different climatic zones (tropical, sub-tropical, temperate). Once the coastal habitats have been assessed, the land uses in the coastal catchments will also be assessed using existing studies and data bases available to members of the group. Due to the likely variation in quality of information available, we will use existing tools, such as “Coastal Eutrophication Risk Assessment Tool” (soon to be published on OzCoasts), and will undertake two levels of analysis.
1) Statistical modelling, relating seagrass presence/absence and the OzCoasts indicators. This is analogous to the approach of van der Heide et al. (2009). This will only be possible once the group has brought together existing data relating to seagrass distribution and nutrient/sediment loads delivered by coastal catchments (ambient water quality may provide a surrogate). The group will also use this statistical approach and the newly created data base to explore if it is possible to predict additional information in regard to seagrass habitats, including maximum depth and percent cover.
2) For specific locations, where appropriate temporal information exists, the group will also apply a systems model approach (e.g. the seagrass survival model being developed in New South Wales and van der Heide et al., 2007 and 2011). This analysis technique will use the physiological and ecological expertise of the workshop participants to investigate controlling variables and the different spatial and temporal scales on which they operate and apply the model to define critical thresholds for seagrass viability, loss and recovery.
The outputs from this working group will build on products produced by the National Land and Water Audit in 2000 and updated in 2008 (Mount and Bricher, 2008).
An additional output of the working group will be a recommendation to TERN on future monitoring technology deployments that will enhance the ability for accurate assessment of seagrass condition to be undertaken in the future. This will include recommendations on monitoring information that will enhance the accuracy of statistical models developed by the working group.
Mount, R.E. and P.J. Bricher (2008) “Estuarine, Coastal and Marine (ECM) National Habitat Map Series Project Report February” Spatial Science Group, School of Geography and Environmental Studies, University of Tasmania. Report to the Department of Climate Change and the National Land and Water Resources Audit, Canberra, ACT.
van der Heide, T. van Nes, E. H., Geerling, G.W., Smolders, A. J. P., Bouma, T. J. and M. M. van Katwijk (2007) Positive Feedbacks in Seagrass Ecosystems: Implications for Success in Conservation and Restoration. Ecosystems 10: 1311–1322.
van der Heide, T., Peeters, E.T.H.M., Hermus, D. C. R., van Katwijk, M.M., Roelofs, J. G. M. and A. J. P. Smolders (2009) Predicting habitat suitability in temperate seagrass ecosystems. Limnol. Oceanogr. 54(6): 2018–2024.
van der Heide, T., van Nes, E. H., van Katwijk, M.M, Olff1, H. and A. J. P. Smolders (2011) Positive Feedbacks in Seagrass Ecosystems – Evidence from Large-Scale Empirical Data. Plos One. 6(1), e16504.
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Products and Outcomes
Kate O'Brien presented a paper on November 5, 2013 at the 22nd Biennial conference of the Coastal and Estuarine Research Foundation "Towards resilient coasts and estuaries: science for sustainable solutions"
Three critical scales to manage for seagrass resilience: physiology morphology and landscape. Authors: Katherine O'Brien, Michelle Waycott, Gary Kendrick, Angus Ferguson, Paul Maxwell, Peter Scanes, Len McKenzie, James Udy, Kieryn Kilminster, Kathryn McMahon, Jimena Samper-Villarreal, William C. Dennison
Paul Maxwell presented a paper on behalf of the group at the Australian Marine Sciences Associations Golden Jubilee conference held at the Gold Coast in July 2013. His presentation can be viewed below.
Download their final report here [2MB]
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Workshop 1 Report (28-30 May 2012)
Representatives from national science organisations, State Government Departments and research institutions from all Australian states came together in Brisbane for a 3 day workshop to investigate the information available to assess the current condition of seagrass habitats in Australia and their major threats.
The workshop provided an important opportunity to identify disparate data sets from different regions which can be brought together to provide a more holistic picture of our knowledge of seagrass habitats around the Australian coast. We have been able to identify many regions around the Australian coastline where no data had previously been recorded at the national level (2008 map), but where either a member of the group has data to that can provide information on the seagrass habitat in this region or has access to data.
The group has identified the need for a national seagrass data set that holds key information on seagrass habitat condition and primary drivers of change, as well as a link to various state and research organisation databases that hold more detailed original data sets. As a first step the group will be focusing on finalising the framework for the database and importing data from various participants.
Two review papers have been identified: firstly conceptualising the seagrass habitats of Australia and the major threats to these different habitats, and secondly identifying the challenges of modelling the drivers of change in coastal habitats. These will provide the background for the final outputs that are planned using the compiled datasets of seagrass area and change over time:
||Synthesis paper on the trajectory of seagrass change in Australia
||Improved web based products, including an interactive map with case studies and conceptual diagrams showing key pressures on seagrass habitats in different bio-regions of Australia.
||Development of a national predictive model that will predict presence or absence of seagrass based on key drivers.
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Workshop 2 Report (19-22 March 2013)
The second workshop of this group brought together many projects that participants had worked on since the first workshop.
||We developed the conceptual understanding of how seagrass resilience is influenced by environmental and anthropogenic impacts that occur at different spatial and temporal scales to a stage where it is now ready for publication. This conceptual understanding has, in addition, been put into a framework to assist environmental managers and provide direction for appropriate monitoring and management of seagrass.
||In the workshop we made further progress obtaining and entering data into a database that was developed after the first workshop to enable the national assessment of seagrass condition and
||A framework for assessing the risk of seagrass loss along various parts of the Australian coast was initiated and will be further developed after the workshop.
||Progress has been made on an assessment of the key processes important for maintaining seagrass habitats in the different bio-regions of Australia (Tropical and sub-tropical Northern Australia, Temperate SE Australia, Temperate SW Australia). An assessment was made of current condition and threats (using the risk framework developed during the workshop) and likely impacts on the resilience of Australian seagrass in the face of land use change (including urban expansion and changes in farming practices) and climate change. This will be made available through a scientific publication as well as updates to the Ozcoast and National Estuarine Network websites.
A SONG that summaries the key threats to seagrass was developed and produced during the workshop as a way to communicate to community members the importance of seagrass, and disturbances that need to be managed if we want to keep these valuable habitats in the future.
Summarised outputs from both workshops will be made available to national initiatives currently attempting to quantify the ability of seagrass to act as marine sinks for carbon dioxide (Blue Carbon Cluster).
A report of the workshop can also be found on the Integration and Application Network site at the Center for Environmental Science at the University of Maryland.
Back row (left to right): Bill Dennison (Uni of Maryland), Kate O'Brien (Uni of Queensland), Gary Kendrick (The UWA Oceans Institute and School of Plant Biology, Uni of Western Australia), Angus Ferguson (Consultant), Mitchell Lyons (Uni of Queensland), Kathryn McMahon (Edith Cowan Uni)
Front row (left to right): Len McKenzie (James Cook Uni), Lynda Radke (Geoscience Australia), James Udy (Healthywaterways, Qld), Paul Maxwell (Griffith Uni), Kieryn Kilminster (WA Department of Water), Michelle Waycott (University of Adelaide), Vanessa Lucieer (Uni of Tasmania), Peter Scanes (NSW Dept. of Environment, Climate Change & Water).
(absent: Jonathan Hodge, CSIRO ACEF, TERN)
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