Samantha Yabsley
- PhD Student, Lab of Animal Ecology, Hawkesbury Institute for the Environment, University of Western Sydney
- Topic: The impacts of extreme heat events on Australian flying-foxes
- Research Umbrella: Flying-foxes and extreme heat events
- Supervisors: Prof Justin Welbergen, Dr Jessica Meade, A/Prof Christopher Turbill
- Contact: Samantha Yabsley
Bio
I completed my Bachelor of Science (Zoology) at Western Sydney University in 2016. During my studies I had the privilege of undertaking an internship through Hawkesbury Institute for the Environment, whereby I worked closely with Dr Anastasia Dalziell and Prof Justin Welbergen, studying the vocal mimicry of the Superb Lyrebird in the Blue Mountains.
I completed my Master of Research on the drivers of flying-fox urbanisation with the Animal Ecology Lab at Western Sydney University in 2021, and began my PhD project on the impacts of extreme heat on Australian flying-foxes in September 2022. I am interested in the field of movement ecology and all things wildlife conservation.
I completed my Bachelor of Science (Zoology) at Western Sydney University in 2016. During my studies I had the privilege of undertaking an internship through Hawkesbury Institute for the Environment, whereby I worked closely with Dr Anastasia Dalziell and Prof Justin Welbergen, studying the vocal mimicry of the Superb Lyrebird in the Blue Mountains.
I completed my Master of Research on the drivers of flying-fox urbanisation with the Animal Ecology Lab at Western Sydney University in 2021, and began my PhD project on the impacts of extreme heat on Australian flying-foxes in September 2022. I am interested in the field of movement ecology and all things wildlife conservation.
Research
Extreme weather events including extreme heat events are predicted to increase in frequency and severity over coming years under current climate change models (Easterling et al., 2000; Katz & Brown, 1992). However, little is known about how extreme heat events impact biodiversity (Hughes, 2003). In Australia, extreme heat events can kill flying-foxes at near-biblical scales (Welbergen et al., 2008). Flying-foxes are large (Welbergen, 2010) and highly mobile species (Welbergen et al., 2020). They are gregarious, and roost colonially in exposed canopy tree branches during the day (Welbergen, 2005), and these behaviours expose them to the effects of extreme weather (Welbergen, et al., 2008), including extreme heat events. Flying-foxes have thermoregulatory mechanisms that allow them to cope with a great range of environmental conditions (see Ochoa-Acuna & Kunz, 1999); however, when exposed to temperatures exceeding 42°C, their thermoregulatory behaviours begin to fail and many may die from hyperthermia, with deaths sometimes numbering in the tens of thousands (Welbergen et al., 2008; Mo et al., 2021). Dependent young and lactating mothers appear to be particularly sensitive to the effects of extreme heat events, which is of concern for the persistence of the species (Welbergen et al., 2008). In addition, different flying-fox species appear to have different levels of sensitivity to extreme heat events, with species inhabiting more tropical regions (black flying-foxes P. alecto; spectacled flying-foxes P. conspicillatus) appearing to be more sensitive than those occurring in more temperate (grey-headed flying-fox, P. poliocephalus) and inland regions (little-red flying-fox, P. scapulatus) (Welbergen et al., 2008).
Two out of the four mainland species of flying-fox in Australia are listed as vulnerable to extinction (Eby et al., 2021; Roberts et al., 2020), due to diminishing natural foraging and roosting habitat (Mickleburgh et al., 1992), direct killing in response to fruit crop depredation (Aziz et al., 2016), flying-fox urbanisation (Meade et al., 2021; Yabsley et al., 2021; Yabsley et al., 2022), and harassment and disturbance of roosts (Roberts et al., 2021), and exposure to extreme heat events compounds the threats they already face (Eby et al., 2021; Roberts et al., 2020). Flying-foxes provide critical ecosystem services, engaging in long-distance seed dispersal and pollination, helping to maintain the health and genetic diversity of forest ecosystems for a broad range of flora and fauna (e.g., Fujita & Tuttle, 1991; Aziz et al., 2021). Thus, gaining further understanding of the vulnerability of flying-foxes to extreme heat events, predicting the long-term persistence of the species under future climate change scenarios, and testing whether roost microclimate manipulation can help mitigate the effects, are of critical importance to the conservation of these threatened and ecologically important species.
The overarching aim of this research is to develop a comprehensive understanding of the vulnerability of flying-foxes to extreme heat events, and provide a much-needed evidence base for management and conservation. The specific proposed research objectives are to:
Extreme weather events including extreme heat events are predicted to increase in frequency and severity over coming years under current climate change models (Easterling et al., 2000; Katz & Brown, 1992). However, little is known about how extreme heat events impact biodiversity (Hughes, 2003). In Australia, extreme heat events can kill flying-foxes at near-biblical scales (Welbergen et al., 2008). Flying-foxes are large (Welbergen, 2010) and highly mobile species (Welbergen et al., 2020). They are gregarious, and roost colonially in exposed canopy tree branches during the day (Welbergen, 2005), and these behaviours expose them to the effects of extreme weather (Welbergen, et al., 2008), including extreme heat events. Flying-foxes have thermoregulatory mechanisms that allow them to cope with a great range of environmental conditions (see Ochoa-Acuna & Kunz, 1999); however, when exposed to temperatures exceeding 42°C, their thermoregulatory behaviours begin to fail and many may die from hyperthermia, with deaths sometimes numbering in the tens of thousands (Welbergen et al., 2008; Mo et al., 2021). Dependent young and lactating mothers appear to be particularly sensitive to the effects of extreme heat events, which is of concern for the persistence of the species (Welbergen et al., 2008). In addition, different flying-fox species appear to have different levels of sensitivity to extreme heat events, with species inhabiting more tropical regions (black flying-foxes P. alecto; spectacled flying-foxes P. conspicillatus) appearing to be more sensitive than those occurring in more temperate (grey-headed flying-fox, P. poliocephalus) and inland regions (little-red flying-fox, P. scapulatus) (Welbergen et al., 2008).
Two out of the four mainland species of flying-fox in Australia are listed as vulnerable to extinction (Eby et al., 2021; Roberts et al., 2020), due to diminishing natural foraging and roosting habitat (Mickleburgh et al., 1992), direct killing in response to fruit crop depredation (Aziz et al., 2016), flying-fox urbanisation (Meade et al., 2021; Yabsley et al., 2021; Yabsley et al., 2022), and harassment and disturbance of roosts (Roberts et al., 2021), and exposure to extreme heat events compounds the threats they already face (Eby et al., 2021; Roberts et al., 2020). Flying-foxes provide critical ecosystem services, engaging in long-distance seed dispersal and pollination, helping to maintain the health and genetic diversity of forest ecosystems for a broad range of flora and fauna (e.g., Fujita & Tuttle, 1991; Aziz et al., 2021). Thus, gaining further understanding of the vulnerability of flying-foxes to extreme heat events, predicting the long-term persistence of the species under future climate change scenarios, and testing whether roost microclimate manipulation can help mitigate the effects, are of critical importance to the conservation of these threatened and ecologically important species.
The overarching aim of this research is to develop a comprehensive understanding of the vulnerability of flying-foxes to extreme heat events, and provide a much-needed evidence base for management and conservation. The specific proposed research objectives are to:
- Determine species-specific microclimatic and microhabitat profiles of roosts to determine the levels of exposure of Australian flying-foxes to extreme heat events.
- Determine the ecophysiological drivers of sensitivity of Australian flying-fox species to extreme heat events.
- Determine the implications of extreme heat events for the long-term persistence of flying-foxes and other wildlife.
- Test the efficacy of roost microclimate manipulation for mitigating the impacts of extreme heat events on flying-foxes.
Academic Publications
YABSLEY, S. H., MEADE, J., HIBBURT, T., MARTIN, J. M., BOARDMAN, W. S. J., NICOLLE, D., WALKER, M., TURBILL, C & WELBERGEN, J. A. (2022). Variety is the spice of life: flying-foxes exploit a variety of native and exotic food plants in an urban landscape mosaic. Frontiers in Ecology and Evolution, 10:907966
YABSLEY, S. H., MEADE, J., MARTIN, J. M., & WELBERGEN, J. A. (2021). Human-modified landscapes provide key foraging areas for a threatened flying mammal: The grey-headed flying-fox. Plos One, 16: e0259395.