Anthropogenic landuse change has led to the deforestation and degradation of ecosystems globally. Human expansion has removed important habitat and resources for wildlife, causing an increase in habitat fragmentation, displaced wildlife, and an increased potential for human-wildlife interactions. These interactions carry a threat of zoonotic disease emergence, such as Hendra virus.
Hendra virus is a henipavirus found in Australia that spills over from Pteropus bats, known as flying foxes, to horses and humans. Most spillover events occur in winter months, when food resources for bats are reduced. We investigate the links between the loss of critical winter diet species and reduced food availability on bat roost dynamics for roosts near Brisbane, Australia.
We estimated changes in flying fox populations from quarterly observations of roost locations and count records by volunteers. Using the Queensland Herbarium’s Vegetation Management Regional Ecosystem mapping series, we measured the abundance and distribution of five critical winter diet species bi-annually since 1997 and assessed vegetation loss within a 50km radius of roosts.
Results/Conclusions
Vegetation abundance from 1997 to 2017 shows a serial loss of flying fox habitat throughout Queensland as well as a reduction of five critical winter diet species (E. robusta, E. tereticornis, E. siderophloia, M. quinquenervia, and B. integrifolia). Over 1,700,000 hectares of patches containing these species were lost, amounting to reductions between 1- 4% of their initial abundances. These formerly highly nomadic animals exhibited increased sedentary behavior, as evidenced by a growing number of roosts that are occupied year-round. These changes in the abundance and distribution of flying foxes reflect a change in foraging habits and food security, likely due to environmental and anthropogenic influences. Flying foxes serve as important pollinators for Eucalypt forests and native fruit trees and these patches are crucial for continuation of their ecosystem services.
Current flying fox distributions highlight potential areas of priority for preservation and restoration. Intense flowering events draw flying foxes out of urban areas away from horses and humans, potentially reducing viral transmission events. We identify remaining patches of habitat within foraging distance of continually occupied roosts that can be protected and detect areas of recently cleared winter habitat that could be strategically replanted.