Variety is the spice of life: flying-foxes exploit a variety of native and exotic food plants in an urban landscape mosaic

Generally, urbanization is a major threat to biodiversity; however, urban
areas also provide habitats that some species can exploit. Flying-foxes
(Pteropus spp.) are becoming increasingly urbanized; which is thought to
be a result of increased availability and temporal stability of urban food
resources, diminished natural food resources, or both. Previous research
has shown that urban-roosting grey-headed flying-foxes (Pteropus
poliocephalus) preferentially forage in human-modified landscapes.
However, which land-use areas and food plants support its presence in
urban areas is unknown. We tracked nine P. poliocephalus roosting in
Adelaide, South Australia, between December 2019 and May 2020, using
global positioning systems (GPS), to investigate how individuals used the
urban landscape mosaic for feeding. The most frequently visited land-use
category was “residential” (40% of fixes) followed by “road-side,”
“reserves” and “primary production” (13–14% each). However, “reserves”
were visited four times more frequently than expected from their areal
availability, followed by the “residential” and “road-side” categories
that were visited approximately twice more than expected each; in
contrast, the “primary production” category was visited approximately five
times less than expected. These results suggest that while residential
areas provide most foraging resources supporting Adelaide’s flying-fox
population, reserves contain foraging resources that are particularly
attractive to P. poliocephalus. Primary production land was relatively
less utilized, presumably because it contains few food resources.
Throughout, flying-foxes visited an eclectic mixture of diet plants (49
unique species), with a majority of feeding fixes (63%) to locally
indigenous Australian native species; however, in residential areas 53% of
feeding visits were to non-locally indigenous species, vs only 13% in
reserves. Flowering and fruiting phenology records of the food plants
visited further indicated that non-locally indigenous species increase the
temporal availability of foraging resources for P. poliocephalus in urban
Adelaide. Our findings demonstrate the importance of residential areas for
urban-roosting P. poliocephalus, and suggest that the anthropogenic
mixture of food resources available in the urban landscape mosaic supports
the species’ year-round presence in urban areas. Our results further
highlight the importance of conserving natural habitats within the urban
landscape mosaic, and stress the need for accounting for wildlife
responses to urban greening initiatives.