Ketton artificial bat cave

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Objective

Built in response to the condition of the old mine (and in anticipation of conditions very likely to be imposed), an artificial bat cave is intended to provide an alternative long-term safe haven for bats.

Context

Grange Top Quarry provides the adjacent Ketton Cement Works with raw materials for the production of cement. In 2000, Castel Cement asked a permission for the extension of the Ketton quarry. This was gained in 2002, and a condition of the consent was that a Habitat Management Scheme should be prepared and habitat management carried out in accordance with the scheme. One of the measures to be covered by the scheme was to ensure no loss or damage to existing populations of statutorily protected species.

Ecological studies showed that the location was favourable for the development of bat colonies. Bats currently use an old stone mine near to the working area. A 150m standoff from the underground extent of this mine for normal production blasting is observed to ensure that the bat conservation interest is not unduly affected by blasting vibration. This existing bat cave was already in a poor condition: there were a number of unsupported blocks in the roof of the mine and accumulated rock fall material close to the mine entrance. A specially designed grille has been installed at the entrance that allows bats in but keeps humans out, as the mine is considered too dangerous for further entry.

Solutions

Paul Bradley, ecologist, in conjunction with Dr Ralph Stebbings, the well-known bat ecologist, developed the design concept for a new cave. The artificial cave has been designed to provide a wide range of hibernation conditions in terms of crevice size, temperature, and humidity and it is likely that bats will vary their use of different parts of the cave once they become established.

Linking the new cave into the surrounding landscape is vital to encourage bats to use the site for hibernation and roosting. Construction of the new bat cave was only made technically possible by the combined efforts of quarry managers, quarrymen and contractors.

Results

The cave has been constructed from a hard, high silica limestone to ensure its long-term durability. Construction of the new cave took six months to fully complete and required careful thought and attention to detail throughout. It is now amongst the world’s largest purpose-built bat caves. Completed in 2000 it will be a continuing feature of the local landscape into the next millennium.