Threats to the barbastelle bat Barastella barbastellus are poorly understood, but its low population density and slow population growth make it particularly vulnerable to factors such as: (1) Further loss and fragmentation of ancient deciduous woodland habitat;
(2) Loss, destruction and disturbance of roosts or potential roosts in buildings, trees and underground sites;
(3) reduction in numbers of insect prey due to habitat simplification acting through factors such as fertiliser use and intensive grazing.
Barbastella barastellus is considered as "Vulnerable" by the IUCN Red List. The species is listed on "Appendix II" of the Bonn Convention (and its Agreement on the Conservation of Bats in Europe, 1994), "Appendix II" of the Bern Convention (and its appropriate Recommendations) and Annexes II and IV of the EC Habitats and Species Directive.