RZS NSW News

Safe Space: Identifying multi-threat refuges for mammals in semi-arid landscapes

Australia’s arid and semi-arid mammals are diverse, unique and facing the highest rates of species decline and extinction globally. In the semi-arid mallee one-third of the historic mammal assemblage is regionally extinct. Many of these species are important ecosystem-engineers whose foraging diggings contribute to soil-health and habitat complexity. One such species, the greater bilby (Macrotis lagotis) is a generalist, digging omnivore that was widespread in Australia’s arid and semi-arid regions but is now restricted to 20% of its former range. The decline of the greater bilby is mainly due to the interacting threats of predation by the feral cat (Felis catus) and European red fox (Vulpes vulpes), grazing and habitat disturbance by introduced herbivores, and inappropriate fire regimes. Bilbies are opportunistic forages that are adapted to exploit the changing resources associated with environmental disturbance. However frequent, severe or large fires that burn considerate areas of vegetation may threaten bilby populations and amplify vulnerability to feral predator predation and further disturbance.

Fenced exclosures free of feral predators and invasive herbivores are an important tool for reintroducing threatened species across their former range. The greater bilby has been reintroduced to ten fenced exclosures across the mainland, including Scotia Wildlife Sanctuary (Scotia) in the mallee country of south-west NSW, which is owned and managed by the Australian Wildlife Conservancy (AWC). These havens provide a unique opportunity to understand how bilbies, and other mammals, respond to fire patterns in the absence of other threats. 

This project aims to understand how bilby survival, habitat use, and movement is shaped by fire mosaics in semi-arid mallee. This research will be conducted in relation to the planned burn program conducted by the AWC Operations Team at Scotia to mitigate the spread of wildfires and promote pyrodiversity.  A combination of animal-borne telemetry, remote cameras and drone-operated remote sensing will be used to map the fine-scale habitat structure and resource availabilty changes associated with bilby activity and resource selection. These findings will provide new knowledge on bilby habitat use in relation to fire mosaics in an understudied area of their former range. More broadly, this research will reveal practical ways for using fire to benefit populations of threatened species – including critical populations within fenced exclosures.

Samantha Girvan, The University of Melbourne

Sam is a first year PhD candidate with the Biodiversity Dynamics Research Group (biodynamos) at the University of Melbourne. As an ecologist, Sam has previously worked in research, monitoring and environmental restoration programs across Australia. Sam is passionate about collaborative research that informs adaptive conservation management for threatened species. Her research projects aims to broaden our understanding of bilby ecology and contribute to the conservation of bilbies and other threatened arid and semi-arid mammals.