The Environment Agency is warning that unless action is taken the Letcombe Brook in Oxfordshire could soon lose its population of white clawed crayfish (Austropotamobius pallipes), the UK’s only native variety.
One of the few remaining places where the white clawed crayfish can still be found, the brook’s source is two springs, one in Letcombe Basset and one in Letcombe Regis – hence its name. It then runs for twelve kilometres through the Oxfordshire countryside, passing through numerous villages and towns including Wantage and Grove, before joining with the Childrey Brook north of East Hanney.
And whilst a recent Environment Agency survey has confirmed a good population of white clawed crayfish in the brook, they are warning that steps must be taken to reduce man’s impact on this vital chalk stream habitat, or this community, like so many others, will disappear.
Once widespread and numerous, the white clawed crayfish has been in decline for a number of years and is now moving towards extinction having been wiped out in many parts of the country – predominantly as a result of human activities.
Pollution of rivers, over-abstraction of water which reduces flows and increases sediment build-up, and unsympathetic engineering of rivers which destroys swathes of vital vegetation have all had a significant impact.
The introduction of the American signal crayfish into UK rivers in the 1970s has also hit its British cousin hard.
Bigger, greedier and more aggressive than their relatives, they quickly established themselves as the dominant species, taking over territory and food supplies. The signal crayfish also carries a fungal disease to which they are resistant, but which is fatal to the white clawed variety.
So far the brook seems to have been spared the terrors of the American crayfish, but even so, the situation for its native inhabitants is finely balanced.
With habitat being lost, polluted or under attack from ruthless, diseased invaders, white clawed crayfish populations are now diminishing, which is why preserving the colony in the Letcombe Brook should be a priority for the local human community says Pedro Collins, conservation officer for the Environment Agency.
“The native British crayfish is very much the underdog in its battle for survival and nationally its suffering badly. But they’re plucky little blighters and won’t go down without a struggle. The odds are heavily stacked against them though, so wherever we find pockets of resistance we need to do all we can to help.”
The Environment Agency is working with a number of partners to improve the habitat in the Letcombe Brook, and is planning several initiatives specifically for its crayfish, including installing artificial burrows in the banks and creating refuges to help them escape from predators.
The partners also jointly fund a part-time officer, Sally Wallington to help raise awareness of the value of the brook and its need for sensitive management. Sally is able to provide free advice to those living or working adjacent to the brook on how they can minimise their impact on this important habitat.
Ensuring development is controlled is also a key objective. “This really is vital,” says Sally. “If development alongside the brook is allowed to happen without proper consideration the impact on its ecology could be disastrous.”
She continued: “The white clawed crayfish has a number of challenges to contend with. The best thing I can do to help is to achieve support from all sections of the community to protect the brook as a whole.
“The entire brook is important ecologically, but the presence of white clawed crayfish makes it even more special. If the collective will is to cherish, nuture and protect the brook, then they’ll be safe; if not, they’ll inevitably die out. And that would be a tragedy.”
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The following organisations are working in partnership to preserve the Letcombe Brook: the Environment Agency, Wantage Joint Environmental Trust, Grove Joint Environmental Trust, Vale of White Horse District Council
For more information on the Letcombe Brook and how groups and individuals can help preserve it, contact Sally Wallington on 01235-771447, or e-mail letcombebrook@hotmail.com
