An ambitious project to restore seagrass meadows has been launched by UK conservationists working to rebuild the Thames Estuary ecosystem.

To help protect and reverse recent declines of the habitat, conservationists from the Zoological Society of London (ZSL) are for the first time planting tiny seeds from dwarf eelgrass across three sites in Kent, including Seasalter, Whitstable, and Elmley Nature Reserve.

Seagrass, the only flowering plant to grow in seawater is found gently swaying in shallow waters on coastlines across the world. Forming biodiversity-boosting underwater meadows, it plays an essential role within marine ecosystems, offering food and shelter for sea birds and fish, including seahorses and sharks.

However, research has shown that least 44% of seagrass has been lost from the UK coastline since 1936.

Thea Cox, conservation project manager at ZSL said, “Seagrass seeds may be small but each one is vital to recover this extraordinary habitat.

"Seagrass meadows provide essential nursery grounds for fish, food for birds, and habitat for a range of invertebrates – meaning they play a vital role in the health of marine habitats. Many seagrass species also help absorb and store carbon within their tissues and the sediment – meaning they can also play an important role in tackling climate change.

"Almost half of seagrass in the UK has been lost in the last 90 years – with 39% of that loss having happened since the 1980s. However, with evidence-based conservation action, we have the chance to reduce the pressures on this incredible habitat and restore lush green meadows at scale.”

Through the use of a modified sealant gun, the team are able to carefully inject precise amounts of a mud and seed mixture into the ground at the trial sites. They will continue to monitor sites over the coming months as the eelgrass grows.

This follows on from work in 2023, trialing the transplant of adult dwarf eelgrass plants. Learnings from other seagrass restoration projects across the UK and Europe and from the Kent trials, will help inform scaling-up restoration efforts in the Thames estuary.

Thea added, “The reason we’ve seen such drastic declines in seagrass cover in the UK is likely a combination of factors – such as reduced water quality and caused by pollution, physical disturbance of meadows and industrial development.

"Restoration work is just one part of the picture to create more and healthier seagrass beds – we also need action to address the threats, thereby protecting existing meadows as well as creating the conditions to maximise the chances of restoration success at scale.”

In addition to support for restoration projects, ZSL is calling on decision-makers to safeguard seagrass habitats through mapping and monitoring and take steps to minimise pressures on sites where possible.

The seagrass restoration trials are part of a larger ZSL-led project, Restoring the Thamescape, which aims to restore coastal habitats in the Thames. The Kent work is made possible through collaboration with organisations including the Fieldwork Company, University of Groningen, Project Seagrass, and Office Francais de la Biodiversite, with funding from Garfield Weston, Orsted and Marshall Wace TOPS (ESG) Foundation.