Ms Ishtar kenny1
1University Of Adelaide, adelaide, Australia
Seagrass meadows and oyster reefs often co-occur within temperate oceans, where their interactions can create positive feedback effects that promote each habitat’s establishment and resilience. Restoration efforts to repair the loss of these habitats typically occur in isolation, yet the creation of oyster reefs is regularly associated with neighbouring seagrass recovery, suggesting their co-restoration may benefit habitat connectivity. In this presentation, I’ll discuss research on the co-restoration of oyster reefs and seagrass occurring in South Australia.
Along the South Australian coastline, Australia’s largest oyster reef restoration project is recovering native Ostrea angasi reefs, once prevalent in the Great Southern Reef. These oyster reefs can reduce hydrodynamic energy and sediment movement leeward of the reefs, which may assist in recovering the seagrass meadows that have suffered large declines in shallow coastal waters (<10m), where hydrodynamic activity prevents new recruitment. My research considers the effect of the restored oyster reefs on the recruitment of the dominant seagrass species Posidonia australis and Amphibolis antarctica, using sand-filled hessian bags for their attachment. To test the role of oyster reefs in dampening hydrodynamic energy to facilitate seagrass recruits, we placed the hessian bags wayward (wave-exposed side), leeward, and completely external (control), to the reef and monitored recruitment. Early results suggest improved survival wayward of the oyster reefs may be occurring, with more sediment deposition being observed near the reefs compared to the control sites. As oyster reef restoration projects are on the rise in Australia and abroad, concurrently restoring seagrass may provide a cost-effective means to its much-needed recovery.
Presentation Slides – Ishtar Kenny
