Bat roosts are legally protected in the UK; understanding the welfare of colonial bats in roosts — including temperature, humidity, and roost fidelity requirements — informs conservation practice.
The welfare of bat colonies depends critically on roost microclimate stability. Maternity colonies of bats use specific roost sites because they meet the precise temperature and humidity requirements for successful pup development. Development work that disturbs roosts even without direct killing displaces colonies from sites with irreplaceable thermal characteristics, causing reproductive failure and eventual population decline. Conservation of roost sites is therefore not merely about individual animals but about the long-term viability of local populations.