Are Flying-Foxes Coming to Town? Urbanisation of the Spectacled Flying-Fox (Pteropus conspicillatus) in Australia

Abstract

Urbanisation of wildlife populations is a process with significant conservation and management implications. While urban areas can provide habitat for wildlife, some urbanised species eventually come into conflict with humans. Understanding the process and drivers of wildlife urbanisation is fundamental to developing effective management responses to this phenomenon. In Australia, flying-foxes (Pteropodidae) are a common feature of urban environments, sometimes roosting in groups of tens of thousands of individuals. Flying-foxes appear to be becoming increasingly urbanised and are coming into increased contact and conflict with humans. Flying-fox management is now a highly contentious issue. In this study we used monitoring data collected over a 15 year period (1998–2012) to examine the spatial and temporal patterns of association of spectacled flying-fox (Pteropus conspicillatus) roost sites (camps) with urban areas. We asked whether spectacled flying-foxes are becoming more urbanised and test the hypothesis that such changes are associated with anthropogenic changes to landscape structure. Our results indicate that spectacled flying-foxes were more likely to roost near humans than might be expected by chance, that over the period of the study the proportion of the flying-foxes in urban-associated camps increased, as did the number of urban camps. Increased urbanisation of spectacled flying-foxes was not related to changes in landscape structure or to the encroachment of urban areas on camps. Overall, camps tended to be found in areas that were more fragmented, closer to human habitation and with more urban land cover than the surrounding landscape. This suggests that urbanisation is a behavioural response rather than driven by habitat loss.

Climate Change Could Increase the Geographic Extent of Hendra Virus Spillover Risk

“…Sources of uncertainty may be related to: (1) the type of presence only data used limits the number of analytical methods that can be used and hampers the identification of limiting factors; (2) the effects of climate on HeV spillover act at several different levels of ecological organisation and are not well understood, for instance temperature, humidity and ground vegetation might also limit the available pathways for HeV transmission to horses (Martin et al 2017), and temperature can regulate the flowering status of native plants (Hudson et al 2010), the main source of food for flying foxes; (3) flying fox species distributions do not depend entirely on climate (Tidemann et al 1999; Vardon et al 2001), but are greatly affected by native plant phenology (Giles et al 2016), and have an apparently innate preference for fragmented and urbanised landscapes (Tait et al 2014); (4) the predicted distributions of flying foxes in response to climate change do not account for other organisms’ shifting distributions that affect bats’ distributions. Other organisms shifting distributions might give rise to novel and unpredictable interactions and effects on bats’ distributions (Eby et al 1999; Eby and Law 2008; Giles et al 2016); and (5) climate change could also affect horse behaviour and susceptibility to diseases.…”

“…Possible improvements to our models to make them more specific might involve: (1) including a model of bat distribution that better accounts for the effect of urbanisation (Tait et al 2014); (2) including other biological interactions that are crucial for bat species (Giles et al 2016) that can be transferred to climate change scenarios; and (3) establishing direct links between climatic factors and the levels of HeV infection in bats. Such an analysis would likely result in smaller areas and populations predicted to be at risk.…”

Changing resource landscapes and spillover of henipaviruses

“…However, abundant evidence demonstrates that altered resource landscapes are changing the movement behaviors of pteropodids. Migratory E. helvum and Epomophorus wahlbergii have formed colonies in African cities that now persist year round, mirroring the behavior of several flying fox species in Australia and Asia . In Australia, periods of resource scarcity driven by habitat loss may drive flying foxes to seek alternative food sources in urbanized areas, where they form sedentary subpopulations .…”

Physiological biomarkers of Hendra virus infection in Australian Flying-foxes (Pteropus spp.)

“…Flying-foxes roosting in urban and peri-urban areas result in conflict between humans and bats, primarily due to the impact on amenity due to noise, odour and faeces (Tait et al 2014). Currently in Australia, the emergence and transmission of zoonotic diseases in flying-foxes primarily Hendra virus and Australian bat lyssavirus, and the risk of transmission, is of great concern to people living in close proximity to flying-fox roosting and feeding habitats.…”

“…The resultant debate between flying-fox conservation as an important part of the ecosystem and the demands for control is a contentious and politicised issue (Tait et al 2014). Requests for removal of flying-fox colonies from both urban and rural areas are currently being considered by local government authorities.…”