title: Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical.
abstract: Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia) on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent) and red foxes (in the south). Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall), our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south.
authors.affiliation: Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lawes
authors.affiliation: School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Diana O
authors.initials: DO
authors.lastname: Fisher
authors.affiliation: School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia.
authors.forename: Chris N
authors.initials: CN
authors.lastname: Johnson
authors.affiliation: School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Blomberg
authors.affiliation: School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia; Flora and Fauna Division, Northern Territory Department of Land Resource Management, PO Box 496, Darwin, Northern Territory, Australia.
authors.forename: Anke S K
authors.initials: AS
authors.lastname: Frank
authors.affiliation: Biodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft für Naturforschung, Frankfurt, Germany.
authors.forename: Susanne A
authors.initials: SA
authors.lastname: Fritz
authors.affiliation: School of Environment, Griffith University, Nathan Campus, Sydney, Queensland, Australia.
authors.forename: Hamish
authors.initials: H
authors.lastname: McCallum
authors.affiliation: Centre for Climate Change and Tropical Biology, School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.
authors.forename: Jeremy
authors.initials: J
authors.lastname: VanDerWal
authors.affiliation: CSIRO-Land and Water-Australian Tropical Sciences Precinct, PMB PO, Aitkenvale, Queensland, Australia.
authors.forename: Brett N
authors.initials: BN
authors.lastname: Abbott
authors.affiliation: Australian Wildlife Conservancy, PO Box 8070, Subiaco East, Perth, Western Australia, Australia; National Environmental Research Program Northern Australia Hub, Charles Darwin University, Darwin, Northern TerritoryT, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Legge
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Mike
authors.initials: M
authors.lastname: Letnic
authors.affiliation: TropWATER, James Cook University, Townsville, Queensland, Australia.
authors.forename: Colette R
authors.initials: CR
authors.lastname: Thomas
authors.affiliation: School of Earth and Environmental Sciences, Terrestrial Ecosystems Research Network, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Nikki
authors.initials: N
authors.lastname: Thurgate
authors.affiliation: Flora and Fauna Division, Northern Territory Department of Land Resource Management, PO Box 496, Darwin, Northern Territory, Australia; National Environmental Research Program Northern Australia Hub, Charles Darwin University, Darwin, Northern TerritoryT, Australia.
authors.forename: Alaric
authors.initials: A
authors.lastname: Fisher
authors.affiliation: James Hutton Institute, Invergowrie Dundee, Scotland, United Kingdom.
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Gordon
authors.affiliation: ARCUE, School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Alex
authors.initials: A
authors.lastname: Kutt
mesh_terms: D000818:Animals; D001315:Australia; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D020387:Food Chain; D005589:Foxes; D008394:Marsupialia; D011157:Population Dynamics; D011235:Predatory Behavior; D012377:Rodentia; D013021:South Australia