The importance of linear landscape elements for the pipistrelle Pipistrellus pipistrellus and the serotine bat Eptesicus serotinus

The relation between two species of bats, the pipistrelle (Pipistrellus pipistrellus (Schreber, 1774)) and the serotine (Eptesicus serotinus (Schreber, 1774)) and linear landscape elements such as hedgerows, tree lines and tree lanes was studied in an agricultural area in The Netherlands. The pipistrelle was observed almost entirely close to landscape elements, while serotines more frequently crossed fields and meadows. Serotine activity in these open areas was, however, negatively related to the distance to a landscape element and to windspeed. On a landscape scale the results indicate a more than proportional positive relation between the density of serotine bats and the density of linear landscape elements, whereas this relation was only proportional in the case of the pipistrelle. It is argued, that landscapes with a high density of linear elements have a surplus value for serotine bats. Three possible functions of linear elements for bats (orientation clues, foraging habitat and shelter from wind and/or predators) are discussed. Any of these may explain the results of this study.