Assessment of the potential for competition between two sympatric herbivores - the northern hairy-nosed wombat, Lasiorhinus krefftii, and the eastern grey kangaroo, Macropus giganteus

Abstract

The northern hairy-nosed wombat, Lasiorhinus krefftii, is a critically endangered grazing herbivore, restricted to a single population of just 65 individuals in the savanna of central Queensland. Lasiorhinus krefftii shares its habitat with another grazing herbivore of similar body size, the eastern grey kangaroo, Macropus giganteus. This study investigated the potential for M. giganteus to compete with L. krefftii for food. Analysis of faecal residues demonstrated that both herbivores consumed grass almost exclusively, with the exception of small quantities of sedges and dicotyledons. Dietary overlap between M. giganteus and L. krefftii was high, both in the consumption of plant species (90%) and plant parts (99%), suggesting that there is potential for dietary competition. Using the distribution of faecal deposits for both herbivores, analysis of habitat usage by multiple linear regression techniques indicated that M. giganteus exhibits clear associations with some habitat features but proved inconclusive for L. krefftii because of their use of defecation in social marking. However, an examination of the population dynamics of M. giganteus suggested that the densities reported in this study, although highly seasonal, are sufficiently low that competition with L. krefftii for food is currently negligible.