In a unique partnership, many of the landowners on Purbeck, including the National Trust, Dorset County Council, Dorset Wildlife Trust, MOD, RSPB, and other conservation bodies such as English Nature and the Dorset Bat Group have joined together to try to find out how bats use the landscape within the Purbeck area so that measures can be put in place to safeguard roosts, flight lines and feeding areas.
Financial support from SITA Trust, through the Landfill Tax Credit Scheme, and partners of the project are funding a three year PhD student from the University of Bristol, who will be tagging the bats and using radio receivers to record their flight patterns, which can range as far as 30 miles in one night, to locate their night roosts and feeding areas.
The UK population of greater horseshoe bats has been estimated by one survey at 4,000 individuals with only 200 breeding females believed to be in Dorset, which is the eastern edge of its range in the UK. However, it is a time of range expansion and the greater horseshoe bat offers a model of how an animal on the edge of its range can move once it has been given room to move.
Greater horseshoe bats can live to be 30 years old and do not start breeding until three or four. They gather to breed in warm roof voids of old stable blocks or large houses and hibernate close to their summer roosts in cellars or underground quarries. Several partners including The National Trust and Dorset Wildlife Trust have recently restored some of the disused quarries on Purbeck, at Acton, and part of the study will focus on the bats' use of these abandoned quarries.
The bats feed entirely on insects, especially moths and beetles. They navigate across large areas of countryside at night, often following hedgerows and woodland edges. As the bats are no respecter of landowner boundaries, this project is unique in that it involves all the main landowners on Purbeck, as well as private landowners and allows the project to study the bats across a wide area.
Jon Flanders, PhD student and main researcher for the project, said: "We are already beginning to build up a picture of where the bats are feeding and what routes they are using. Through the research we have also discovered how one of our roosts holds double the number of greater horseshoe bats we had recorded there before making it an even more important roost than we previously thought."
Angela Peters, National Trust ecologist on Purbeck, said: "This unique collaboration of landowners in Purbeck will allow us for the first time to track the greater horseshoe and other bats as they forage for food and travel between roosts. We are involving local people who are interested in learning more about these wonderful creatures by enlisting their help to track their flights during the evenings using bat detectors. Several bat evenings to educate the public about bats and the project have also been held locally. The results of this three year project will be invaluable in helping us get a clear view on how we can prioritise our management of our habitats and agricultural practices. This will ensure the continued survival of the rare bats of Purbeck."
From early September, the project will be monitoring the annual bat swarming, a social behaviour phenonemenon/mating strategy which takes place every autumn. One of the questions that the project will be looking to find answers for is the reason bats return to their winter roosts to swarm when they don't use those sites as roosts during the summer and autumn. Co-ordinated counts will be taking place at various quarries in Purbeck and bat detectors and selected trapping will be used to determine species.
The project will officially be launched on 8 September at Corfe Castle (6:00pm) and will be followed by an evening bat walk around Corfe Castle.