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Seagrass restoration trials begin in Cornwall



A pioneering project attempting to restore climate change-fighting seagrass beds in Cornwall has got underway.

Cornwall Wildlife Trust has completed its first round of seagrass planting trials in the River Fal, thanks to funding from clothing brand Seasalt Cornwall. The ‘Seeding Change Together’ project is using technology never previously trialled in Cornwall before to study – and hopefully expand – the seagrass bed found at the Trust’s Fal-Ruan nature reserve.

Around 4,000 seeds were collected from stable and healthy meadows in the Fal Estuary at the end of last summer. Yet researchers were surprised that the seed pods collected yielded only a quarter of the seeds expected. Marine experts from the local nature charity are concerned that the summer’s prolonged periods of high temperatures may have affected the seeds’ development.

Seagrass meadow in the River Fal

Sophie Pipe, Seagrass Project Officer at Cornwall Wildlife Trust, said: “We experienced record-breaking heatwaves and droughts last summer, in addition to an incredibly mild start to autumn and sudden cold snaps this winter. These extreme conditions may have affected the seagrass meadows on site, but it’s an unknown as to what those short-term and long-term impacts will be. That’s why our research is so important.”

“We’re hoping to know more when the seedlings sprout in late spring or early summer this year. They could stay dormant for longer than we expect if there’s a temperature drop, or they could sprout early.

“Water quality is also something that may affect the health of the seagrass beds. We’re keen to study that in more detail on the site.”

The process of restoring the seagrass bed started last summer. Baseline surveys were carried out last July, prior to any activity taking place, to assess the size and health of the seagrass meadows.

Planting biodegradable hessian bags of seagrass seed mixture into the mudflats

A small group of volunteers – including employees from Seasalt Cornwall – have contributed over 120 hours to the project by collecting and planting seeds. The team used bodyboards on the mud to hold their weight when moving around the site, helping to minimise disturbance to these delicate plants.

Newly purchased testing equipment, funded by Seasalt Cornwall, is now helping scientists to understand how water quality is affecting the seagrass populations on-site. It is believed to be the first time these tests have been carried out at this location.

Marine biologists from Cornwall Wildlife Trust have tested a variety of methods aimed at identifying the most effective ways of restoring and growing seagrass. This includes placing seed mixtures into biodegradable hessian bags which are planted into the mudflats, as well as using cuttings of seagrass as an alternative to seed collection.

It is hoped the results will help the team upscale their efforts, with plans of planting an area 10x the size of the one used for the first round of trials.

Seagrass seeds

Sophie continues: “We are learning as we go! It is incredibly exciting to be doing practical studies of this kind for the first time in Cornwall. It’s not easy – seagrass restoration is an incredibly challenging task, one that experts all around the world have been working on and refining for decades now. There are still many unknowns, particularly for the species of seagrass that we’re focusing on which is only found high up estuaries.”

“Despite our trials being small-scale and low-cost, we have big ambitions to restore many of Cornwall’s lost seagrass meadows using the same methodology. It’s only thanks to Seasalt and this brilliant partnership that we’re on our way to making this a reality.”

Seagrass is a flowering marine plant that captures carbon from the environment up to 35 times faster than tropical rainforests, making it an important resource in the fight against climate change. It also provides a habitat for marine life such as juvenile fish and seahorses, cleans surrounding seawater and helps to stabilise the seabed to protect the coast from erosion.

Cornwall Wildlife Trust’s Fal-Ruan nature reserve is home to dwarf eelgrass, one of two species of seagrass found in Cornish waters. Despite appearing smaller and less impressive than common eelgrass, University of Exeter researchers have discovered dwarf eelgrass beds are twice as good at storing carbon than those found in more exposed coastal locations.

Seagrass supports thousands of marine animals, like this hermit crab

In the UK, approximately 92 percent of seagrass was lost in the last century. The huge decline has been caused by pollution, disease and coastal development. Additionally, damage from anchoring, moorings and dredging has impacted the country’s seagrass beds.

Seasalt Cornwall has committed to donating £150,000 as part of a three-year partnership. If successful, Cornwall Wildlife Trust hopes the project could lead to large-scale restoration and planting of seagrass in Cornwall’s estuaries.

Paul Hayes, CEO at Seasalt Cornwall, said: “Seeding Change Together is a vital project for the UK’s seagrass restoration efforts and we’re thrilled to be helping play a part in generating this essential research. Climate change isn’t a future problem – it’s here and now – and it’s alarming that extreme weather may be impacting the planting trials.

“We take our responsibility to protect the environment seriously and are committed to accelerating the transformation of our business to create positive change within our industry. It’s essential that we can protect these vital habitats so that we can influence the options we all have in the future. I can’t wait for Spring and to see the next phase of the project come together.”

Photo credit: Matt Slater, Seasalt Cornwall and Paul Naylor

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Mark Evans
Scuba Diver's Editorial Director Mark Evans has been in the diving industry for nearly 25 years, and has been diving since he was just 12 years old. nearly 40-odd years later and he is still addicted to the underwater world.
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