The reasons for the decline of this species include the loss and degradation of suitable habitat resulting from a number of factors including inappropriate management and pesticide use, which may decrease prey availability. Many bats are particularly susceptible to disturbance; destruction and/ or disturbance of summer and winter roosts is likely to have contributed to the decline (8).
The Natterer's bat has not been given priority status under the UK Biodiversity Action Plan. There has therefore been little co-ordinated monitoring and conservation work targeted at this species, but the National Bat Monitoring Programme does count Natterer's colonies (4). Suggested measures that should be taken include population monitoring and mapping, with careful monitoring of barn conversions (2), research into the detailed habitat requirements of this species in order to inform management, promotion of woodland restoration and creation providing connectivity between sites, and protection of important swarming and hibernation sites (8).Under the Wildlife and Countryside Act, 1981 it is an offence to intentionally kill, injure or take a bat, or to damage, destroy or obstruct access to roosts (5).