Analysis of factors implicated in the recent decline of Australia's mammal fauna

Abstract

Aim To assess whether eight factors thought to be involved in the extinction process can explain the pattern of recent decline in Australia's mammal fauna. Location Australia. Methods We compiled the first comprehensive lists of mammal species extant at the time of European settlement in each of Australia's 76 mainland regions, and assigned a current conservation status to each species in each region to derive an index of faunal attrition. We then sought to explain the observed region‐to‐region variation in attrition (the dependent variable) by building a series of models using variables representing the eight factors. Results A strong geographically based pattern of attrition emerged, with faunal losses being greatest in arid regions and least in areas of high rainfall. The Akaike information criterion showed support for one model that explained 93% of the region‐to‐region variation in attrition. Its six variables all made independent contributions towards explaining the observed variation. Two were environmental variables, namely mean annual rainfall (a surrogate for regional productivity) and environmental change (a measure of post‐European disturbance). The other four were faunal variables, namely phylogenetic similarity, body‐weight distribution, area (as a surrogate for extent of occurrence), and proportion of species that usually shelter on the ground (rather than in rock piles, burrows or trees). Main conclusions In combination with historical evidence, the analysis provides an explicit basis for setting priorities among regions and species. It also shows that the long‐term recovery of populations of many species of Australian mammals will require introduced predator suppression as well as extensive habitat management that includes controlling feral herbivores. Specifically, habitat management should restore aspects of productivity relevant to the types of species at risk and ensure the continual availability of suitable refuges from physiological stressors.

Bats and Water: Anthropogenic Alterations Threaten Global Bat Populations

“…Anthropogenic activities such as extraction and diversion of water have had adverse impacts on rivers in the arid-zone of Australia (Walker 1985;Kingsford and Thomas 1995). High natural variation in water availability coupled with anthropogenic activities and climate change has the potential to catastrophically affect arid-species that depend on water availability (Roshier et al 2001;McKenzie et al 2007;Saunders et al 2013).…”

There is a critical weight range for Australia's declining tropical mammals

“…These models are analogous to ordinary logistic regression models, but instead of a binary response a multinomial response can be specified. The variables included in each model were: (1) ln(body mass) and ln(body mass) 2 (to allow for a unimodal relationship); (2) ln(mean annual rainfall) (given that rainfall is well known to explain substantial variance in the probability of range contraction of mammals; McKenzie et al, 2007); (3) 'southernness' (i.e. tropical versus subtropical) and its interaction with each of ln(body mass) and ln(body mass) 2 , such that the relationship between body mass and decline could vary between northern and southern marsupials.…”

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

“…Burbidge and McKenzie 1989;Johnson 2006;McKenzie et al 2007). These losses have been most pronounced in the arid and semi-arid areas of central Australia, and appear to be size-dependent, with the most severely affected group comprising mediumsized mammals (i.e.…”