Island biogeography theory and the urban landscape: stopover site selection by the silver-haired bat (Lasionycteris noctivagans)

Many migratory bats require forested sites for roosting and foraging along
their migration path, but increased urbanization and intensive
agricultural practices may reduce the availability of stopover sites.
Urban forests may provide important stopover habitat, maintaining
landscape connectivity in regions where the majority of natural habitat
has been cleared for development. Island biogeography theory can be
applied to urbanized temperate forest biomes where small urban forests
represent islands separated from the larger “mainland” forest. We used
acoustic monitoring during the fall migration period to investigate the
use of urban forest habitat by the migratory species Lasionycteris
noctivagans (Le Conte 1831). We predicted that recorded activity would
have a positive relationship with forest patch area and shape and a
negative relationship with isolation from other forest patches, as
suggested by island biogeography theory. We observed greater activity at
larger forest patches, and although relationships for shape and isolation
were not statistically supported the observed patterns were consistent
with predictions. Our results demonstrate the need for more in-depth
research on the habitat requirements for both migratory and resident bat
species and the impact that ongoing urbanization has on local bat
populations.