Impacts of habitat fragmentation on microbats across an urban-rural landscape

It is well known that deforestation and habitat fragmentation, due to agriculture and urbanisation, modifies bat assemblages. Specifically, it has been found that bat diversity, abundance and foraging activity decrease as urban density increases and cover of remnant vegetation diminishes, although such effects are dependent upon functional identity of bat species. In many cases, remnant patches of vegetation are dispersed across complex, heterogeneous landscapes, whereby the landscape matrix is comprised of a complex suite of urban and agricultural habitats. Studies on other taxa, such as birds and invertebrates, have found that the configuration of the matrix often has a similar or greater influence on diversity within vegetation remnants than patch-scale attributes. However, the relative importance of patch and matrix characteristics on the diversity and activity of mammalian species in vegetation remnants is unknown. The objective of this study was to investigate the influence of habitat fragmentation on microbat diversity - specifically, 1) the variation in microbat assemblages across a modified woodland landscape and 2) the effects of landscape matrix on diversity and activity of microbats within woodlands remnants. A total of 47 sites were chosen for sampling between January and April of 2015, including woodlands of varying sizes, urban areas and agricultural land. Anabat II detectors were used to record foraging and non-foraging microbat activity. Microbat activity was not influenced by habitat fragmentation, yet the number of species was greatest in larger woodlands and agricultural areas. Small woodlands were found to house the least amount of species. It is likely that roosting and foraging resources were minimal in these woodlands. Urban density exceeding 55 % in the matrix surrounding a woodland patch adversely affected microbat diversity. Clutter-adapted species may have been deterred from visiting woodlands surrounded by high urban density due to light and noise pollution, or limited foraging resources. This arguably is the first study to examine the impact matrix condition has on microbat activity and diversity within fragmented woodland patches.