A barn used by lesser horseshoe bats (LHB) as a summer roost in a small Monmouthshire village was proposed for conversion into a new dwelling which would result in the loss of the roost. As compensation for the displacement of the bats, a large purpose-designed roost in an alternative nearby building was designed by DCE Ltd.
DCE Ltd designed this alternative roost in consultation with the Countryside Council of Wales, and relevant published and unpublished research, to provide optimal conditions for both roosting and breeding by lesser horseshoe bats. The interior of the roost is artificially heated to provide optimum temperatures for breeding, as well as temperature gradients which should encourage roosting throughout much of the year.
The new roosting building is large, and provides roosting opportunities for far more bats than were present in the original barn. In part, the thinking behind this takes into account the knowledge that there have been numerous other conversions in similar buildings in the surrounding area in recent years, and there are therefore quite likely to have been significant numbers of other displaced bats scattered at various locations around the village, some or all of which may also be roosting in sub-optimal conditions. The provision of a single large, optimally-designed roost should therefore potentially offer roosting opportunities for a significantly larger population than the one which was present in the original barn, as well as providing optimal conditions for breeding by a greater proportion of the local population. In 2010 at least 150 LHBs were present in the new roost including a number of juveniles, far more than the highest number ever recorded in the original barn and with clear evidence of breeding.