Understanding and Restoring Seagrass

Seagrass

Seagrass bed with snakelock anemone. Photo credit Matt Slater Cornwall Wildlife Trust

Seagrass is a flowering plant that only grows in seawater and thrives as brilliant underwater meadows of green grass. Seagrass meadows are a natural solution to a range of issues: they clean our coastal waters and help to keep our ocean healthy and climate stable. Seagrass also provides a home and nursery for hundreds of species, including commercial fish, helping support the livelihoods of many Cornish residents. Seagrass is critically important for the long-term capture and storage of coastal blue carbon, and globally seagrass stores an estimated 10-18% of all ocean carbon.

Understanding Seagrass

Over recent years, Cornwall Council have commissioned projects to investigate seagrass to understand its true potential to help tackle the climate and ecological emergencies.

Mapping of Mount’s Bay seagrass beds by Cornwall Council uncovered a revelation no one could have predicted. Surveys revealed a new area the size of 290 rugby pitches: it is one of the largest beds ever found in the UK. The bed is larger than all known seagrass beds in Cornwall combined and equates to 3.4% of known seagrass areas within the UK. These findings have reignited interest across Cornwall for the potential discovery of new seagrass beds using echo-sound technology.

A study by the University of Exeter found a total area of 172 rugby pitches of seagrass in the Fal & Helford estuaries: one of the most healthy and productive seagrass beds in the UK - this will aid Cornwall in its ambitions to become carbon neutral by 2030.

While exciting new discoveries are promising, these seagrass beds face many risks, also highlighted by this research. The main risks link to water quality, boating activities and climate change. The authorities in the Fal and Helford are working hard to reduce the pressures on seagrass beds and boat owners can help by following best practice and thinking carefully about where they anchor.

Falmouth Seagrass Restoration Project

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Exciting plans are underway to restore seagrass meadows within the Fal and Helford Special Area of Conservation (SAC). These important underwater habitats support high levels of marine biodiversity, provide a vital carbon store, protect coastlines and offer serene spaces for recreation and wellbeing.

Seagrass in the Fal

Within the SAC, there are around 100 hectares – or approximately 1.1km2 – of Zostera marina, also known as common eelgrass. While much of this remains intact, some areas are degraded and require active restoration to reach their full potential.

The Project

This restoration effort is part of a multiyear collaboration between Cornwall Council Ocean Conservation Trust’s Blue Meadows project, the University of Exeter, Falmouth Harbour and Falmouth Marine Conservation Group. Each partner brings its own expertise to the collaboration, from ecological monitoring and habitat restoration techniques to community engagement and local marine stewardship.

Restoring

Seagrass restoration technique, photo credit Ocean Conservation Trust

Restoration work is scheduled to begin within the next year, once we have completed public consultation to build the project with our communities and obtain funding for the Project. The restoration work will use a combination of Ocean Conservation Trust’s innovative HMS OCToPUS seagrass seeding device and cultivated adult seagrass plants grown in hessian pillows. This two-pronged approach is great for restoring seagrass habitats at scale, with this project setting an ambitious goal to restore 10 hectares of seagrass over the next three years. The restoration sites have been carefully selected and are already supported by Blue Meadows Sensitive Habitat Marker Buoys, maintained by Falmouth Harbour, which designate Voluntary No Anchor Zones to reduce threats to these sensitive seabed habitats.

Monitoring

In preparation, the coming months will see partners undertaking detailed site monitoring, seed collection and community outreach. The project also provides a valuable opportunity for scientific research, with the University of Exeter facilitating data collection and analysis to assess the restoration success and ecological impacts. This research will offer important insights into carbon sequestration, species abundance, and the expansion of seagrass meadows, contributing to broader seagrass knowledge and future restoration efforts.

Connecting

Snorkelling in Falmouth, photo credit Your Shore Network and Cornwall Wildlife Trust

Community engagement will play a central role throughout. By connecting people with their local marine environment, the initiative aims to foster long-term stewardship of seagrass meadows. Community seagrass monitoring programmes and citizen science initiatives will develop as part of the project, ensuring that Falmouth’s community remain at it’s heart. Public awareness campaigns will also continue to highlight the importance of these habitats and promote sustainable behaviours throughout the wider SAC.