Hazel dormice are declining rapidly in the UK, largely due to loss of connected woodland habitat. They cannot cross open ground, making habitat fragmentation a critical welfare threat that prevents dispersal and genetic exchange.
Dormice in isolated woodland fragments face repeated failed hibernation attempts when insufficient autumn food prevents adequate fat accumulation. Starvation during or after hibernation is the primary cause of winter mortality. Genetic isolation in small populations reduces adaptability and immunity. The welfare of individual dormice in fragmented habitats is compromised by energy stress, failed reproduction, and increased disease susceptibility.