Marsupial response to matrix conversion: Results of a large-scale long-term ‘natural experiment’ in Australia

Abstract

We quantified changes in forest-dependent mammal populations when the habitat in which they live remains intact but the surrounding matrix is converted from open grazed land to closed pine plantation forest. This situation is increasingly common as plantations are often established on formerly cultivated or grazed land.We conducted a large-scale (30km2), long-term (14years) fully controlled and replicated (111 sites) ‘natural experiment’ in south-eastern Australia. The study focused on the effects of changes occurring in the matrix on mammals which inhabit patches of native Eucalyptus woodland.We found that none of the five target species in our study (two macropods, two possums and a glider) responded negatively to pine plantation establishment. For three species (the sugar glider Petaurus breviceps, the red necked wallaby Macropus rufogriseus and the swamp wallaby Wallabia bicolor) the response to plantation establishment was positive (i.e., increase in colonisation/patch use in sites surrounded by pine plantations) whereas the two possums (the common ringtail possum Pseudocheirus peregrinus and the common brushtail possum Trichosurus vulpecula) were positively affected by the amount of native tree cover surrounding sites, rather than pine plantation establishment.We foresee two strong implications of our work for the conservation of mammal species in agricultural areas subject to multiple land-use changes: 1) Our results suggest that converting agricultural land to pine plantations will not affect our target mammalian species negatively; rather, it may facilitate colonisation of remnant patches of native vegetation by some species. 2) Our findings underscore the critical importance of preserving remnant native vegetation within plantations, as it may decrease the risk of local extinction for some species or facilitate the colonisation of new sites for others. Thus, retention of patches of remnant native vegetation should be part of the design of future plantations.