Abundance and habitat selection of foraging vespertilionid bats in Britain: a landscape-scale approach

Abstract

Abstract Large-scale surveys of the habitats required by foraging bats have seldom been attempted, despite a clear need for quantitative information in order to develop realistic conservation strategies. Accordingly, a standardized survey method was developed for a large-scale analysis of bat abundance and habitat selection in the whole of Britain. This was the first such survey of its kind undertaken anywhere. A random stratified sample of 1-km squares was surveyed by a network of volunteers walking fixed transects with bat detectors. They also collected information on the habitat features present in each 1-km square. Data from 910 squares were examined to test whether landscape and local habitat features influence bat activity. Significant regional differences were demonstrated between seven major land-class groups. Lowest bat activity levels occurred in upland, marginal upland and intensively farmed arable areas of the north. Habitat selection results are presented for two contrasting land-class groups. In both of these, woodland habitats and habitats associated with water were actively selected, whilst arable land, stone walls, scrub and parkland plus all grassland categories were avoided. Logistic regression models were used to identify habitats of critical importance within the two land-class groups. A variety of habitats were important in the pastural landscape but only one, semi-natural broadleaved woodland, was of critical importance in the arable landscape. The value of landscape-scale surveys for providing information on habitat use and a baseline from which to model’ the potential effects of changes in land use is discussed.