Effects of fire on northern bettong (Bettongia tropica) foraging behaviour

Abstract

An examination of movement paths, foraging patterns and habitat use of an endangered mycophagous marsupial, the northern bettong (<i>Bettongia tropica</i>), was undertaken in fire-prone forest in north-eastern Australia before and after experimentally induced fires. Fungal biomass remaining at bettong foraging points was similar across the study area prior to burning, but increased significantly on burnt ground during the period after fire. After burning, significantly more bettongs chose to forage in burnt habitat and those that did experienced higher probabilities of truffle recovery. Using data from spool-and-line tracking, observed movement patterns of bettongs were compared with those expected from a simple null model of animal movement (a correlated random walk). Analysis of mean-squared displacement revealed that 22% of observations fell beyond the model's 95% prediction interval. Further analysis revealed the reasons for the model's inadequacy: bettongs exhibited area-restricted search behaviour by taking significantly more frequent and more acute turns immediately prior to and following recovery of hypogeous fungi (truffles), and by taking significantly more frequent and more acute turns following any other foraging activity. In general ecological terms, the results indicate a flexible response by the northern bettong to habitat alteration and increased food availability brought about by low intensity fires.