Habitat Use by Bats (Chiroptera) Assessed by Means of a Broad-Band Acoustic Method

Abstract

1. Bat foraging activity was quantified by using a broad-band acoustic method on transects in 10 land use types in south-west England. From multivariate analysis of parameters of bat echolocation calls, 83% of bat passes could be identified to species level with quantified degrees of certainty. The remaining 17% could be identified to species group. 2. Total bat activity was positively correlated with air temperature, and once adjusted for temperature, was significantly higher over rivers and lakes than over other land use types. 3. Bats that use frequency-modulated echolocation calls (mainly Myotis spp., but some Plecotus auritus) were recorded in nine of 10 land use types, but never in villages. Rivers and lakes supported high levels of activity of these species. Bats classified as 45 kHz and 55 kHz phonic types of Pipistrellus pipistrellus had different habitat requirements; 45 kHz P. pipistrellus fed in many habitats, while 55 kHz P. pipistrellus fed mainly over rivers and lakes. Bats classified as Nyctalus noctula, Nyctalus leisleri and Eptesicus serotinus were most active in open habitats and over rivers and lakes. 4. Total bat activity was equally high in woodland interiors and along woodland edges, but bats were relatively more active in sheltered sections of transects than in exposed sections. 5. Plans for land management should take into account the habitat needs of bats. For most bat species in Britain, rivers and lakes are of primary importance. Management plans should aim to maintain physical diversity and features used by insects in freshwater habitats, woodlands and pasture.