The use of edge habitats by commuting and foraging bats
1998
Verboom, B.
Travelling routes and foraging areas of many bat species are mainly along edge habitats, such as treelines, hedgerows, forest edges, and canal banks. This thesis deals with the effects of density, configuration, and structural features of edge habitats on the occurrence of bats. Four hypothetical functions of edge habitats for bats were studied: foraging areas, shelter from wind, shelter from avian predators, and acoustical landmarks.Both wind and food abundance were found to affect the occurrence of foraging pipistrelle bats, Pipistrellus pipistrellus, near treelines. Feeding activity of pipistrelle bats was positively related to height, width and foliage density of treelines. The preference by pipistrelle bats of commuting routes leading from the roost to foraging areas was explained by the distribution of potentially good feeding sites at close distance from the roost.The results stress the importance of wind protected areas where bats can feed during windy conditions. Predator avoidance is argued to be a constraint on the movements of commuting bats at relatively high light levels, i.e. at dusk and dawn. Indications that vertical landscape elements play a role in the navigation by bats as acoustical landmarks come from a study where pond bats, Myotis dasycneme, commuting over canals gradually adapted their pulse emissions to the distance to the banks. Practical guidelines are provided to implement the results into the planning, conservation, and management of edge habitats for bats.
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