Ecological Energetics of Wombats

Abstract

The three extant species of wombats are unique amongst mammals in being large, burrowing grazers that exhibit physiological and behavioural characteristics indicative of extreme energy conservatism. Previous energetics studies of wombats have been limited to their basal metabolism under laboratory conditions. In this study. the energetics and feeding ecology of free-living wombats of each species were examined by investigating field metabolic rates, water turnover rates - diets, food resources. ranging and behaviour. The three species differ markedly in the environments they inhabit; hairy-nosed wombats ('Lasiorhinus krefftii' and 'L. latifrons') are arid-adapted (dry Mediterranean or dry tropical climates) whereas common wombats 'Vombatus ursinus' are adapted to cool, mesic climates. Their habitats are characterised by seasonal or intermittent productivity, in which food quality and availability fluctuate strongly. Wombats in the semi-arid environments also face lack of free surface water for weeks or months. Where possible, data from each species and habitat were collected during '"good" and "poor" seasons. The species also differ markedly in their conservation status: two species are still reasonably abundant but the northern hairy-nosed-wombat is on the brink of extinction with a single free living population of about 60 individuals. Energetics information was collected for all three species, whereas common wombats were the focus of the dietary and ranging studies (time and resource constraint precluded extending these studies to all three species).