A 10-year demographic study of a small mammal community in the Australian Alps

Abstract

This paper describes a 10-year study of the community of two species of small rodents (Mastacomys fuscus, Rattus fuscipes) and one species of dasyurid marsupial (Antechinus swainsonii) in the subalpine zone of the Australian Alps. Each species exhibited differing life-histories with respect to population numbers, intra- and interannual fluctuations in numbers, reproduction, proportion of young in the population, winter survival, immigration and longevity. Of the two species of rodents, M. fuscus had the lowest population numbers, was the least fecund, had the highest rate of survival, and the smallest fluctuations in numbers. A. swainsonii was the least numerous species, and the winter die-off of males and the high fecundity of females resulted in much greater fluctuations in numbers than for either rodent. For all species, there were interannual variations in most demographic parameters, suggesting considerable flexibility in response to annual variations in the environment. None of the three species is known to hibernate, nor is there any evidence of cyclicity, as shown by some species of subarctic and arctic small mammals. Comparisons are made with subalpine small mammals in other parts of the world and the influence of the subalpine environment in determining population numbers is considered.