We need urgent action to stop Britain’s Medicinal Leeches from going extinct. Our collaborative recovery project brings together a consortium of organisations to begin conservation work at the leech’s three main remaining locations. We're also engaging thousands of people to protect this spectacular but misunderstood species.

Medicinal leech.

The elusive Medicinal Leech Hirudo medicinalis, the UK’s largest leech, is an iconic freshwater animal with striking vivid orange and yellow markings. It is found in ponds and ditches, where it commonly feed on frogs and provides an important part of the food web. The Medicinal Leech is also entangled in British medical history. During Medieval times, leeches were common and often used as a medicinal cure. Even today, leeches are essential for medicine and are still used to increase blood circulation.

The decline of Britain's Medicinal Leech

The number of Medicinal Leeches in Britain has declined spectacularly. Once found in high abundance at hundreds of sites, there are now only four main populations left: in Kent, Hampshire, Dorset and Cumbria. In England, this unusual species has been pushed to the edge of extinction. Its decline was initiated by the historical medical trade, when millions of leeches were exported abroad. More recently, changes in land use, wetland drainage and loss of grazing that have contributed to its rapid declines.

Medicinal Leeches are now a global conservation priority, and are listed under a raft of international legislation, including: Appendix III of the Bern Convention, Appendix II of the Convention on International Trade in Endangered Species (CITES), Annex V of the Habitats Directive and the IUCN Red List.

Large pond with trees behind and grass in the fore.

How can we save the remaining Medicinal Leeches?

1 Collate knowledge and data

We’re conducting a literature review and mapping of the Medicinal Leech’s distribution, This will help us to document and understand the decline of England’s Medicinal Leeches.

The data will be made available online through the Freshwater Habitats Trust website, to inform future conservation activities.

2 Establish eDNA monitoring

This cutting-edge new survey method will make surveying for Medicinal Leech easier. It will include widespread volunteer engagement through the surveys at 25 sites across England.

We’re aiming to create an established form of eDNA monitoring for the species. This will provide a more accurate assessment of Medicinal Leech distribution and pond occupation.

3 Collaborate with zoos

Individuals from the four main remaining populations in three zoos will act as a living biobank. This will provide a genetic safety net in the form of a living gene bank in case of wild extinctions. It will also ensure long-term support for reintroduction projects, to broaden their distribution and increase species resilience.

4 Raise the profile of the Medicinal Leech

We have planned three zoo displays and six events to engage thousands of people with their conservation.

Zoo-based ark populations will provide outreach opportunities, including displays and interpretative information. This will engage visitors in the conservation and ecology of this unique leech.

5 Run a collaborative workshop

In phase two of the project we aim to bring people together to help us to define and initiate national level conservation actions, engaging partners, land managers and key volunteers.

6 Establish a comprehensive Conservation Action Plan

This will ensure we can work in partnership to deliver long-term conservation actions on all three main English populations.