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Snails guard Britain’s best habitats

03 November 2009

It’s easy to overlook the world’s smallest animals – insects, snails and other invertebrates – particularly when they live in marshlands and other wet places. Many of these species are now so threatened that they have been protected legally or made the subjects of special Action Plans to protect their habitats. But is it worth the effort?

Now, ecologists at Cardiff University have shown how conserving three of Britain’s rarest snails has had unexpected benefits. Sites set aside and managed for the snails turn out not only to be unique and special places that protect other species, but also have the best quality – for example, with the cleanest water.

The scientists think that, by acting as a stimulus to restrict chemical and fertiliser use on land around the protected sites, snail conservation has provided an incentive to protect water quality.

The Shining ram’s horn, the Little whirlpool ram’s horn and the Large-mouthed valve snail are three of Europe’s rarest snails, and live in drainage ditches on wet grasslands. Smaller than a little-finger nail, all three have declined dramatically over recent decades because of habitat loss or pollution. They are among approximately 900 species listed on the UK Biodiversity Action Plan, of which half are invertebrates.

Professor Steve Ormerod, of Cardiff University’s School of Biosciences, who led the work, said: "We are realising increasingly that species conservation gives us wider benefits because it helps us protect other features in the environment. This appears to be just as valid when we conserve even humble animals such as snails as it is for bigger and more charismatic ones"

Dr Isabelle Durance, another member of the Cardiff team, added: "For the last decade, there has been a major battle to halt the loss of biodiversity by 2010, but we’re failing. This evidence about the wider benefits and value of conserving rare invertebrates comes at a critical time to help focus new efforts."

1. A paper on the team’s research "Priority invertebrates as conservation surrogates", by S. J. Ormerod, Isabelle Durance, Aurelie Terrier, Alisa M. Swanson, is published in "Conservation Biology", the journal of the Society for Conservation Biology.

2. The Shining ram’s horn (Segmentina nitida), the Little whirlpool ram’s horn (Anisus vorticulus) and the Large-mouthed valve snail (Valvata macrostoma) are all listed in the UK Red Data Book of threatened species. Anisus vorticulus has been listed in Annex II of the EU Habitats Directive since 2003 (92/43/EEC). A picture of the Little whirlpool ram’s horn is available from the University press office.

3. The work was carried out on the the Arun Valley in West Sussex, Pevensey Levels in East Sussex, the Stour Valley in Kent, and Lewes Brooks in East Sussex

4. Information about the UK Biodiversity Action Plan can be found at:

Professor Steve Ormerod

School of Biosciences

Cardiff University

02920 875871

Stephen Rouse

Public Relations Office

Cardiff University

02920 875596