Bat communities in a fragmented forest landscape on the south-west slopes of New South Wales, Australia

Abstract

Ultrasonic detectors were used to compare bat activity and species richness at replicated continuous and isolated forests, large and small remnants, corridors and open areas on the south-west slopes of New South Wales, Australia. The habitat matrix in this area consists primarily of agricultural land interspersed with indigenous forest remnants and pine plantations. Ten taxa of bat were recorded, with the fewest in corridors. A multivariate analysis revealed that a gradient in forest area, habitat diversity and structural complexity was the most consistent predictor of activity for four taxa ( C. morio, Nyctophilus spp., V. regulus and F. tasmaniensis), suggesting that these are sensitive to the effects of forest fragmentation. Six species ( N. australis, M. planiceps l.p., C. gouldii, M. schreibersii, V. darlingtoni, V. vulturnus) appeared tolerant of fragmentation and were not sensitive to isolation effects. Most tolerant species were active over open areas and probably used resources in the agricultural mosaic. Typically they were fast flying, low manoeuvrability species which are predicted to forage in uncluttered habitats. Although total activity in small remnants and corridors was as great as that in large forests continuous with a 690 000 ha national park, feeding activity was greatest in continuous forests, suggesting that larger forests with high habitat diversity offered more foraging opportunities. Despite providing fewer feeding opportunities, remnants represent an important conservation resource for bats because activity is concentrated here and they provide potential roost sites. Activity of each species in open areas was not significantly lower than that in corridors (non-riparian), suggesting that corridors were not used regularly by bats to move through the landscape. More detailed studies of the movements of species identified as sensitive to fragmentation would help to explain how fragmentation affects these species and thus what measures are required to improve their conservation.