All UK bat species and their roosts are protected by law, but development activity remains one of the most significant causes of roost loss and bat mortality. Effective ecological assessment is the primary safeguard.
Bats disturbed during hibernation use critical fat reserves that may not be replaced before spring emergence, causing starvation. Maternal roost disturbance in summer causes mothers to abandon pups. Roost destruction during active occupation kills animals directly. Bats excluded from roosts outside the permitted season may be unable to find alternative roosts in time to survive winter. The welfare impact of illegal roost destruction extends beyond the immediate deaths to the disruption of multi-generational roost sites used for decades.