School of Science

Seagrass restoration and the recovery of key ecosystem services

Occupying 0.3-0.8 million km² of coastal shoreline, seagrasses are critical marine ecosystems providing a myriad of key ecosystem services to our coastlines, such as, sediment stabilisation, carbon cycling and sequestration, coastal erosion buffers, habitat and fisheries provision, and trophic subsidies. Despite their recognised importance, seagrasses are among the most threatened ecosystems globally, with current loss rates amounting to 7% yr^-1. Following loss, seagrasses can take decades to recover, if at all, with restoration efforts being remarkably unsuccessful globally. Yet among this bleak scene, the meadow-forming seagrasses of Adelaide’s metropolitan coastline have shown unprecedented recovery since the early 2000’s, following mass losses due to poor water quality and sediment instability. This scale of recovery is unique, globally, but poorly understood. Nor do we understand how, or whether the ecosystem services that we associate with seagrasses have recovered, including the potential of seagrass restoration to recovery blue carbon functions. This project will address these knowledge gaps, focusing on two persistent seagrass ecosystems, Amphibolis antarctica and Posidonia sinuosa, which are 1) critical, widely distributed, marine assets in Australia; and 2) among the few species of seagrass in the world for which some successful restoration sites are available. In doing so, we will determine the processes leading to the recovery of meadows in Adelaide, and the socio-economic benefits subsequently derived.

This project aims to:

1. Understand the mechanism(s) of recovery of Posidonia sinuosa by reconstructing the recovery using an exception photographic dataset from the South Australian Department of Water (SA DEW), and relating this to existing datasets on sediment elevation changes, water depth, and nutrients; and
2. Assess if seagrass restoration results in the recovery of ecosystem services, using blue carbon as a representative ecosystem service. The research will identify the carbon stocks and sequestration rates in undisturbed, disturbed, and recovered seagrass meadows; determine the time-scale required before carbon stocks and sequestration rates begin to improve in recovering meadows; and assessing how meadow loss and restoration influences the ecosystem services which persistent seagrasses are known to provide.

Key Publications:

Tanner, J. E., & Theil, M. J. (2019). Adelaide Seagrass Rehabilitation Project: 2017-2019. https://www.naturalresources.sa.gov.au/files/sharedassets/adelaide_and_mt_lofty_ranges/coast_and_marine/adelaide-seagrass-rehabilitation-project-2017-19-rep.pdf

Lavery, P., Lafratta, A., Serrano, O., Masque, P., Jones, A., Fernandes, M., … Gillanders, B. (2019). Coastal Carbon Opportunities: Summary report on carbon storage and accumulation rates at three case study sites. Retrieved from www.goyderinstitute.org

Marbà, N., Arias-Ortiz, A., Masqué, P., Kendrick, G. A., Mazarrasa, I., Bastyan, G. R., … Duarte, C. M. (2015). Impact of seagrass loss and subsequent revegetation on carbon sequestration and stocks. Journal of Ecology, 103(2), 296–302. https://doi.org/10.1111/1365-2745.12370

Government of South Australia. (2019). Blue Carbon Strategy for South Australia. Retrieved from https://www.environment.sa.gov.au/files/sharedassets/public/climate-change/blue-carbon-strategy-for-south-australia.pdf

Funding agencies

South Australian Research and Development Institute (SARDI)
South Australian Department for Environment and Water (SA DEW)
Centre for Marine Ecosystem Services (CMER), Edith Cowan University
School of Science (SSCI), Edith Cowan University

Project duration

2020 - 2022

Supervisors/Researchers

Mr Jack Robinson
Professor Paul Lavery
Dr Oscar Serrano
Dr Milena Fernandes (Flinders University)