Rapid recovery of mammal fauna in the central Kimberley, northern Australia, following the removal of introduced herbivores

Abstract

Australia has lost more native mammal species than any other country in the past two centuries, and this record of loss looks likely to worsen over the next few decades. Small-to medium-sized mammals are declining in both distribution and density across large tracts of northern Australia's tropical savannas, including within protected areas. The most likely causes are a combination of changed fire patterns, the impacts of introduced herbivores and predation by feral cats. Here, in contrast to the prevailing trend across northern Australia, we report the recovery of native mammals in response to a large-scale (>40 000 ha) destocking experiment carried out at Mornington Wildlife Sanctuary in the central Kimberley, north-west Australia. Following the removal of introduced herbivores from 2004, the species richness and abundance of small native rodents and dasyurids increased significantly across all sampled habitats over the next 3 years.We discuss the implications of these results for guiding land management and applied research to help to reduce the impending risk of mammalian extinctions in northern Australia.

Response to commentary by Woinarski (Critical‐weight‐range marsupials in northern Australia are declining: a commentary on Fisher et al. (2014) ‘The current decline of tropical marsupials in Australia: is history repeating?’)

“…We agree with Woinarski (2014) that fire is likely to be a major agent of change in vegetation structure in northern Australia, and there is compelling evidence that changed fire schedules and grazing pressure affected the conservation status of mammals (e.g. Kutt & Woinarski, 2007;Legge et al, 2011). One reason is that fire and grazing increase habitat quality and hunting effectiveness of both foxes and cats, while decreasing habitat quality for many native mammals.…”

Occurrence of non-volant mammals on islands along the Kimberley coast of Western Australia

“…The Kimberley's three endemic non-volant mammal species (Petrogale burbidgei, Wyulda squamicaudata and Zyzomys woodwardi) are now largely restricted to the high rainfall north-west, and distributions of several other medium-sized mammals have also contracted to this area . However, as the threatening processes likely to be responsible for overall biodiversity loss in the southern and eastern Kimberley (Gibson and McKenzie 2012) now pervade the entire Kimberley, increasing concern has been expressed regarding the stability of its mammal populations (Lochman and Lochman 2003;Start et al 2007; Legge et al 2011). Moreover, the recent invasion of the introduced Cane Toad (Rhinella marina) into the east Kimberley is likely to pose an added threat to susceptible fauna, particularly carnivorous mammals, as it expands westwards across the region (How et al 2009;Shine 2010).…”

Critical‐weight‐range marsupials in northern Australia are declining: a commentary on Fisher et al. (2014) ‘The current decline of tropical marsupials in Australia: is history repeating?’

“…Pardon et al, 2003;Woinarski et al, 2004;Legge et al, 2008) and grazing (e.g. Woinarski & Ash, 2002;Kutt & Woinarski, 2007;Legge et al, 2011) on the abundance of marsupial species in northern Australia, including population viability modelling that predicted extinction under some fire regimes (Firth et al, 2010). Fisher et al (2014) provided one consistent data set on range decline in Australian marsupials.…”