Foraging resource use by grey-headed flying-foxes in urban and non-urban Australia

Abstract

Urbanisation is a major threat to ecosystems globally, resulting in habitat loss and habitat fragmentation, reduced biodiversity, and/or species extinction. However, urban habitats also create opportunities for exploitation by adaptable species, and this often leads to unbalanced management actions that have little regard for species conservation. Better understanding of the underlying drivers of wildlife species urbanisation will assist wildlife managers in developing effective and balanced conservation-management strategies. The grey-headed flying-fox (Pteropus poliocephalus), is a large, highly mobile species, that is becoming increasingly dependent on urban areas. Flying-fox urbanisation has been hypothesised to be a result of loss of natural foraging habitat, an attraction to increased spatiotemporal stability of food resources in urban areas, and/or both. Yet, little is known about how P. poliocephalus utilise urban areas for foraging. This study aims to investigate foraging resource availability as a driver of the documented P. poliocephalus urbanisation. Foraging habitat use was assessed using a large satellite tracking dataset from 98 individuals between 2012-2017. These data were combined with vegetation type data, and published indices of P. poliocephalus habitat quality to assess foraging habitat preferences. Tracked individuals were overwhelmingly dependent on human-modified landscapes for foraging, particularly where they roosted in major-urban areas. To identify the specific food plant species that support P. poliocephalus in urban areas, paired GPS and accelerometer data were used to identify trees visited by foraging individuals roosting in Adelaide. Tracked individuals preferentially visited residential areas and road-side habitats. Individuals visited a relatively high diversity of food plant species in these habitats, and flowering/fruiting phenology records indicated collective year-round availability of food resources for P. poliocephalus. This study suggests that P. poliocephalus urbanisation is, at least in part, driven by spatiotemporal availability and stability of food resources.

Date of Award	2021
Original language	English