Light thresholds for seagrasses of the GBRWHA: a synthesis and guiding document

Collier, Catherine J., Chartrand, Katie, Honchin, Carol, Fletcher, Adam, and Rasheed, Michael (2016) Light thresholds for seagrasses of the GBRWHA: a synthesis and guiding document. Report. James Cook University, Cairns, Australia.

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[Extract]. Key Findings. This synthesis contains light thresholds for seagrass species in the Great Barrier Reef World Heritage Area (GBRWHA). The thresholds can be applied to ensure protection of seagrasses from activities that impact water quality and the light environment over the short-term, such as coastal and port developments. Thresholds for long-term maintenance of seagrasses are also proposed.

•The synthesis provides clear and consistent guidance on light thresholds to apply in managing potential water quality impacts to seagrass.

•All available information on biological light thresholds was tabulated and conservative management thresholds were identified to ensure seagrass protection.

•Acute management thresholds are suited to compliance guidelines for managing short-term impacts and these and are the focus of this synthesis. Long-term thresholds are suited to the setting of water quality guidelines for catchment management.

•The synthesis identified key areas where further information is required, including: ◦species for which almost no information on light thresholds exists; ◦location and population-specific thresholds particularly for the most at-risk species; ◦definitions of desired state to underpin the development of long-term light guidelines to meet them; ◦the effect of spectral quality on light thresholds; and, consideration of cumulative impacts (temperature, nutrients, sedimentary conditions) on acute and long-term light thresholds.

•Light management thresholds for acute impacts are presented for twelve species. Colonising species are the most sensitive to light reduction (i.e. lowest thresholds) and have the shortest time to impact while larger, persistent species have higher light thresholds and a longer time to impact.

•The recommended acute management thresholds are ready for application, as the conservative approach (higher light threshold, shortest time to impact) for species with low confidence should ensure protection to seagrass meadows at risk from acute light stress.

Item ID: 49809
Item Type: Report (Report)
ISBN: 978-1-925088-86-1
Additional Information:

Final Report.

Including knowledge gaps and future priorities.

Light thresholds for seagrasses of the GBR: a synthesis and guiding document is licensed by James Cook University for use under a Creative Commons Attribution 4.0 Australia licence. For licence conditions see:

Funders: National Environmental Science Programme (NESP)
Date Deposited: 15 Aug 2017 22:19
FoR Codes: 06 BIOLOGICAL SCIENCES > 0607 Plant Biology > 060701 Phycology (incl Marine Grasses) @ 50%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050206 Environmental Monitoring @ 40%
06 BIOLOGICAL SCIENCES > 0607 Plant Biology > 060705 Plant Physiology @ 10%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960802 Coastal and Estuarine Flora, Fauna and Biodiversity @ 40%
96 ENVIRONMENT > 9611 Physical and Chemical Conditions of Water > 961102 Physical and Chemical Conditions of Water in Coastal and Estuarine Environments @ 40%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 20%
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