Conventional wisdom on roosting behaviour of Australian flying foxes -- a critical review, and evaluation using new data

Abstract

1. Fruit bats (Family: Pteropodidae) are animals of great ecological and economic importance, yet their populations are threatened by ongoing habitat loss and human persecution. A lack of ecological knowledge for the vast majority of Pteropodid bat species presents additional challenges for their conservation and management. 2. In Australia, populations of flying-fox species (Genus: Pteropus) are declining and management approaches are highly contentious. Australian flying-fox roosts are exposed to management regimes involving habitat modification, either through human-wildlife conflict management policies, or vegetation restoration programs. Details on the fine-scale roosting ecology of flying-foxes are not sufficiently known to provide evidence-based guidance for these regimes and the impact on flying-foxes of these habitat modifications is poorly understood. 3. We seek to identify and test commonly held understandings about the roosting ecology of Australian flying-foxes to inform practical recommendations and guide and refine management practices at flying-fox roosts. 4. We identify 31 statements relevant to understanding of flying-fox roosting structure, and synthesise these in the context of existing literature. We then contribute contemporary data on the fine-scale roosting structure of flying-fox species in south-eastern Queensland and north-eastern New South Wales, presenting a 13-month dataset from 2,522 spatially referenced roost trees across eight sites. 5. We show evidence of sympatry and indirect competition between species, including spatial segregation of black and grey-headed flying-foxes within roosts and seasonal displacement of both species by little red flying-foxes. We demonstrate roost-specific annual trends in occupancy and abundance and provide updated demographic information including the spatial and temporal distributions of males and females within roosts. 6. Insights from our systematic and quantitative study will be important to guide evidence-based recommendations on restoration and management and will be crucial for the implementation of priority recovery actions for the preservation of these species into the future.

Ecological conditions experienced by bat reservoir hosts predict the intensity of Hendra virus excretion over space and time

“…Foremost, our findings emphasize that the ecological conditions experienced by reservoir hosts predict pronounced pulses of virus shedding and overall pathogen pressure. Across eastern Australia, habitats for the winter-flowering plants that drive flying fox nomadism have been reduced through land clearance, in turn driving nutritionally stressed bats into novel urban and agricultural environments outside their typical overwintering range (Eby et al, in review) [27,32,36,37]. Prior work has proposed, but not tested, that HeV shedding from flying foxes is driven by this process [23][24][25]63].…”

“…Connecting such data with changing ecology of wildlife further requires studies of abiotic and biotic correlates and host behavior and demography at similar or biologically meaningful spatial and temporal scales [7,14,82]. Here, the ecological conditions that predict HeV shedding from flying foxes were derived from behavioral data collected over approximately 25 years and from diverse sources [27,28,37] (Eby et al, in review). Although collecting this kind of ecological data will accordingly present logistical difficulties, the growth of national research networks, global community consortiums, and remote sensing, among other large-scale efforts, should facilitate similar approaches to link spatiotemporal data on both host ecology and infection [83].…”

“…We paired HeV prevalence data within our study region with long-term data on flying fox behavior. As described in full in Eby et al (in review), we used data held by Australian state governments, flying fox surveys conducted between 1998–2005 and 2012–2019, records held by local land managers and experienced observers, and direct observation by the authors to characterize the ecological conditions experienced by bat populations over time [27,28,37]. Roosts were classified as belonging to their historic winter range (and thus where bats rely on native winter dietary plants) or to newly established overwintering regions (and thus where native food is unavailable).…”

Spatial dynamics of pathogen transmission in communally roosting species: Impacts of changing habitats on bat‐virus dynamics

“…1). For details on how these stand structures were mapped, see details in Lunn et al (2021a) Because the focus of this study is on spatial structure and tree…”

“…attachment to individuals or a roosting substrate) and the structure of roosting substrates (e.g. size of caves and hollows or distribution of vegetation) (Dollin, Dollin & and the late Sakagami 1997;Lunn et al 2021a). Patterns of communal roosting are particularly important in the context of infectious diseases, as the rate of contacts will influence the propensity for infection and spread of pathogens.…”