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The native white-clawed crayfish, once a familiar sight in rivers and streams across England, is now under threat.

Pollution and habitat destruction, together with the menace of the larger North American signal crayfish, are depleting its numbers.
So Leeds City Council and Environment Agency have launched the Ark Project to give it a safe refuge.

Kerry Fieldhouse, species conservation officer, says this may be the last hope for the creature.

Some were rescued four years ago and put into the upper lake and now there is a five-year project to protect them there.

"We haven't yet introduced them on a massive scale," said Kerry, "as we are trying to get the lake up to optimum condition. It will be a Noah's Ark site.

"We hope to introduce some at the end of this summer and also next summer.

"We know they exist in the Gorge and people say they have seen them in Waterloo Lake. Anglers used to pull them out all the time and one man found one in a Coca Cola can. It had gone in there to moult its shell."

Crayfish are at risk from predatory fish and so pike and carp are being moved from the upper lake to other sites.

An interpretation board next to the upper lake describes the Ark Project.

It urges the public to report any sightings of the crayfish to the Environment Agency and to wash boots and fishing tackle to help limit the spread of disease.

It points out that crayfish eat plant material at night and break down plant and animal matter, returning nutrients to the eco-system.

Leaf litter offers protection for hiding and feeding, and old walls and other stonework have crevices and gaps which provide refuges and over-wintering sites.

Kerry is interested in all forms of wildlife in Roundhay Park and has launched a project to identify bat species.

She encourages volunteers to use bat sensors which pick up sounds that are beyond human hearing.

"We have identified the common pipistrelle and soprano pipistrelle over Waterloo Lake," she said. "Pipistrelle don't fly very high.

"They might be small and cute but they are very feisty and don't want to be in captivity."