Home range and habitat use by Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) within a rainforest fragment in north Queensland

Abstract

Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi), one the largest arboreal mammals in Australia, has been poorly studied owing to its limited distributional range and secretive habits within tropical rainforests. This study investigated the way D. lumholtzi used its habitat within a rainforest fragment on the Atherton Tableland, North Queensland. Thirteen animals were fitted with radio-collars to determine their spatial and temporal use of habitat. Female D. lumholtzi used exclusive home ranges averaging 0.7 ha in area (90% harmonic mean), while males occupied larger home ranges of an average of approximately 2 ha, allowing for a density of 1.4–1.5 adult tree-kangaroos per hectare within the study area. The exception to this home- range size was one juvenile male presumably undergoing post-natal dispersal that used several forest fragments and other habitats, with a home range of 332 ha. Home ranges of males overlapped in part the ranges of several females. Home ranges of males tended to abut those of other males, and antagonistic encounters occurred at the boundaries of the home ranges. Males had a significantly larger body size than females (males 8.63 kg; females 7.05 kg). Social interactions between individuals, apart from antagonistic male–male encounters, were observed infrequently. Only 6% and 2.7% of fixes for females and males, respectively, included the presence of another animal in the same or adjacent tree at the time of location. Lumholtz’s tree-kangaroos were associated with a wide range of rainforest trees and a smaller number of vine species. However, in general, individual animals regularly associated with only a small suite (mean 3.5 species with >10% usage) of tree species present within their home range, and appeared to display individual preferences for certain species. Individual radio-tracked D. lumholtzi were visible only 9.4% of the time at night, and 20% of the time during the day. Males and females were as visible as each other, and both were seen significantly lower in the canopy and into the mid-storey during the night than during the day.