Wilder Humber Project Trials New Methods to Restore Seagrass Meadows

The Wilder Humber project is undertaking a multi-year effort to restore marine habitats in the Humber Estuary, with a focus on seagrass, saltmarsh, sand dunes, and native oysters. The programme aims to address habitat loss and support biodiversity through targeted restoration activities.

As part of the initiative, restoration trials compared different methods for re-establishing seagrass meadows. These trials evaluated Dispenser Injection Seeding (DIS), hessian seed bags, and core transplantation to determine the most effective approach for seagrass recovery in the estuary.

Historical data indicates that the Humber Estuary previously contained around 1,100 acres of seagrass, but this area declined to approximately 12 acres by the late 20th century. The Wilder Humber programme plans to restore nearly 40 hectares of protected habitats and reintroduce more than 500,000 native oysters as part of its broader conservation goals.

Trial results showed that DIS generated between 2.5 and 3 times more new seagrass patches than transplantation, and about 3.5 times more than unplanted control areas. Core transplantation achieved a survival rate exceeding 92% for transplanted patches, which also expanded by over 20 centimeters on average beyond their initial size.

What the numbers show

• DIS produced about 2.5–3 times more new patches than transplantation
• Core transplantation had over 92% survival of seagrass patches
• Historical seagrass coverage in Humber Estuary dropped from 1,100 to 12 acres

Donor sites used for core transplantation recovered within the first year, with no significant difference observed when compared to areas that were not harvested. This finding suggests that the method does not cause long-term harm to donor locations, supporting its use in ongoing restoration work.

Based on the outcomes of these trials, the project will implement a combined "patch-based" strategy that uses both DIS and core transplantation. According to the Yorkshire Wildlife Trust, this approach is intended to rebuild seagrass meadows more effectively by leveraging the strengths of both techniques.

The restoration of seagrass and other marine habitats in the Humber Estuary forms a central part of the Wilder Humber programme's objectives. The initiative is structured to deliver measurable improvements in habitat coverage and species reintroduction over its five-year duration.

Efforts to restore native oysters and other habitats are proceeding alongside the seagrass work. The overall programme is designed to enhance the ecological health of the estuary by restoring key habitats and supporting biodiversity through science-led interventions.

* This article is based on publicly available information at the time of writing.