Adaptation to climatic conditions is a major ecological and evolutionary driver. Long-term study of European badger population dynamics in Oxfordshire reveals that rainfall and temperature patterns affect food (principally earthworm) availability, energy expended in thermoregulation, and activity patterns, with badgers able to seek refuge in their setts. Cubs prove especially vulnerable to harsh weather conditions, where drought and food shortages exacerbate the severity of pandemic juvenile coccidial parasite infections. Crucially, weather variability, rather than just warming trends, stresses badgers, by destabilising their bioclimatic niche. Summer droughts cause mortality, even driving genetic selection; and while milder winters generally benefit badgers, less time spent in torpor leads to more road casualties. Similar effects also operate over a wide spatial scale in Ireland, impacting regional badger densities and bodyweights. That even an adaptable, generalist musteloid is so variously susceptible to weather conditions highlights how climate change places many species and ecosystems at risk.
