CHARACTERISTICS OF ARBOREAL MARSUPIAL HABITAT IN THE SEMIARID WOODLANDS OF NORTHERN QUEENSLAND

The distribution of the koala, Phascolarctos cinereus, and the common brushtail possum, Trichosurus vulpecula, within the Prairie-Torrens Cr eek Alluvials province of the Desert Upland region of northwestern Que ensland was examined. The optimum habitat for each species as indicate d by the occurrence of faecal pellet groups was found to be that assoc iated with creek-lines. However, other land types were also used by ea ch species to varying degrees. The relationship between various habita t variables and pellet group counts was investigated using Multiple re gression and a Generalised linear model. Proximity to creek-bed, Total basal area of trees, Species richness and Acacia basal area (negative ) best explained the occurrence of koalas. Proximity to creek-bed, Aca cia basal area (negative), Total basal area of trees, Free water (nega tive) best explained the occurrence of brushtail possums. In contrast to studies of arboreal species in the moist south-eastern forests of A ustralia no relationship was found between foliar nutrient concentrati ons and the occurrence of koalas or brushtail possums. However, a sign ificant relationship was found between leaf water concentration and th e occurrence of koalas. It is suggested that water availability is the paramount factor defining preferred arboreal habitat in arid and semi -arid woodlands.