The ecology and management of the squirrel glider (Petaurus norfolcensis) in a fragmented landscape, central Queensland

The squirrel glider Petaurus norfolcensis is an arboreal gliding marsupial, exposed to ongoing pressure from vegetation clearing, and subsequent habitat fragmentation throughout its geographic range. This thesis describes an investigation into the ecology of the squirrel glider in the Mackay region, Queensland. The study extended the regional knowledge of this species through five different investigations: i) examination of squirrel glider distribution across 16 sites of various remnant size and the influence of habitat parameters on distributions ii) description of aspects of the population ecology iii) a description of the species diet within the Mackay region iv) a novel behavioural study of the use of wooden poles, that might allow gliders to traverse treeless areas between remnant habitat, and v) examination of natural and artificial hollow use. This study filled a gap in the understanding of the distribution of squirrel gliders. A total of 211 captures of 92 individual squirrel gliders was made during 15,120 trap nights, from 12 of 16 study sites. There was no significant difference in the number of gliders among remnant sizes, and genetic analysis suggests genetic diversity was similar among populations. Remnant habitat in all size classes and corridors contained gliders. Important habitat features required by the squirrel glider identified by SIMPER analysis included an abundance of bluegum, poplar gum, ironbark, bloodwood, acacia and grass tree. These appear to be important food resources as the flowering periods of these species provide a continuum of nectar and pollen through autumn, winter and spring, when little else is in blossom. In addition, bluegum and poplar gum are bark shedders and this characteristic potentially provides habitat for insects, which are consumed by gliders. There seems to be a single reproductive period between autumn to mid-winter (April to July), allowing late lactation to coincide with a greater abundance of dietary resources in summer months. The mean home range used by tracked gliders was 6 ha, with several den trees utilised within core areas. Results from faecal analyses and feeding observations indicate the major dietary components important to the squirrel glider were invertebrates, blossom and sap. The importance of invertebrates and blossom are known for this species, however observations of sap feeding (between 20 40% of feeding observations) were greater than previously reported. Of the five tree species from which sap was obtained, four of these had not previously been documented to provide a sap resource to the squirrel glider. This finding extends knowledge of food resources utilised by this species. Radio-tracking identified stags to be an important den resource. Living trees with smooth gum bark, half bark and ironbark were also used to den. Ground surveys revealed many tree species commonly supported hollows when 30 cm DBH, and were commonly used to den by squirrel gliders, although on average den trees were about 40 cm DBH. Stags, poplar gum, ironbark and bloodwood showed a high tendency to develop hollows with >50% of trees surveyed being hollow-bearing when around 35 40 cm DBH. It appears bluegum needs to be >50 cm DBH to form hollows. Nest boxes were installed at 16 sites and checked every 6 months for 3 years in order to further understand usage and management issues associated with them. A total of 5.6% of nest boxes displayed squirrel glider use, mainly in winter, and occupancy increased over the duration of the study. Boxes had been installed between 1.5 and 3 years at survey sites before a glider was captured in a nest box. Box use was highest at sites estimated to have low hollow-availability. Gliders were detected using a power pole corridor con-structed across a clearing to connect two areas of remnant glider habitat. Gliders readily climbed the poles they were released on, and 14 animals were observed to glide successfully to another pole on 38 occasions. Several gliders were trapped in both remnants and in traps placed on poles. On seven occasions, hair-tubes placed on poles contained glider hair. Three gliders were seen to use poles to move between remnants four times and to den in refuges attached to poles. Although this study was limited, the observations suggest that installing gliding poles may assist gliders to traverse open areas between remnants. Maintaining landscape connectivity between large and small remnants of suitable habitat, will be important for squirrel glider populations in fragmented landscapes. The habitat map produced for the study area can guide on-ground work required to re-establish corridors. Installing poles for gliding may assist gliding marsupials to traverse open areas between remnants, and should be used as a management technique to reconnect fragmented habitat where appropriate. Protecting hollow-bearing trees, especially stags, is essential for this species. Installation of nest boxes may assist this species in areas with low numbers of natural hollows. However, nest box design needs to be improved to withstand climatic conditions in the study area.