NESP MaC Project 1.8 - Including sediment processes in restoration strategies for Australian seagrass ecosystems, 2021-2022 (UNSW)

This record provides an overview of the NESP Marine and Coastal Hub small-scale study - "A national framework for improving seagrass restoration". For specific data outputs from this project, please see child records associated with this metadata.

Seagrasses provide resources and ecosystem services critical to the health of coastal ecosystems and human populations. They increase water clarity, stabilise sediments and reduce coastal erosion, sequester carbon, and provide habitat and food to marine animals, including commercially important fish and invertebrates. Across Australia, the loss of &gt;275,000 ha of seagrass meadows and associated ecosystem services—valued at AU$ 5.3 billion—has contributed to the long-term degradation of estuarine and coastal marine ecosystems. Restoration of seagrass is critical for improving the health and function of these ecosystems and sustaining coastal communities and industries that depend on them, yet restoration projects to date typically occur at small scales, driven by local priorities and with variable success.

This project addressed this problem by bringing together scientists and key stakeholders to collate knowledge on seagrass ecology and restoration, and generated a framework to scaling-up restoration nationally. A national workshop with experts identified a shortlist of drivers key to restoration success, including sediment dynamics, microbial communities, hydrodynamics, and species interactions. It highlighted the importance of incorporating seagrass genetics and life histories into site and donor material selection to improve long-term resilience. New technologies such as eDNA, automation, and AI were also assessed for their potential to improve monitoring and reduce costs, while standardised methodologies and molecular tools were recommended to track microbial indicators and site suitability. A key insight from the workshop was the central role of sediment processes in feedback loops that determine seagrass health—providing a foundation for more effective, scalable restoration strategies.

On-ground case studies were conducted in Western Australia and New South Wales to test the proposed restoration framework in collaboration with Indigenous and community partners: sediment quality assessment and manipulation (Gamay Rangers, UNSW); seed and seedling capture using sediment-filled hessian tubes (Malgana Rangers, UWA); and large-scale seed collection for seed-based restoration through the 'Seeds for Snapper' initiative (OzFish and UWA). These trials demonstrated the effectiveness of community-led restoration and reinforced the potential of seed-based methods for scaling up seagrass recovery.

Outputs
• Effect of sediment quality and manipulation on seagrass transplant success [field data]
• Locations and health of beachcast fragments of Posidonia in Botany Bay [field data]
• Effect of engineering hydrodynamics (by use of hessian socks) on seagrass transplant success [field data]
• Final project report [written]

Tags: National Environmental Science Program (NESP) Marine and Coastal Hub, climate adaptation, ecosystem function, restoration, threatened species
Organization: Australian Ocean Data Network