The countless abandoned mining adits – passages which once provided access to the mines – may seem inhospitable at first glance. But this is only the case for plants, which are unable to survive without light. However, as there are comparatively few natural caves in the nature park, they serve as welcome hiding places for some species of animal. One characteristic in particular makes the underground passages im-portant for amphibians, moths and butterflies, and – above all – bats: they have a constant climate and are unaffected by frost. This makes them an ideal habitat in winter. It is therefore crucial to make sure that the adit entrances are still accessible to these animals when sealing them.
In undisturbed parts of the adits, bats hide away in crevices or hang upside down from the roof to hiber-nate. During this process, their body temperature drops to that of their surroundings. All their bodily functions are heavily reduced. This allows the animals to survive for up to five months on the fat reserves stored in their bodies. If they are repeatedly disturbed, the bats will use up their reserves too quickly and will not have enough energy to wake up. The result is then that the bats will die.