Suchergebnisse

Free-ranging koalas (Phascolarctos cinereus) were monitored by means of radio-relocation in the area of Blair Athol Coal Mine and surrounding properties. Daytime tree use, home range and diet of these koalas was determined in spring and autumn, as was the leaf moisture composition of potential fodder species. Koalas used on average 93 (male koalas) and 56 (female koalas) trees during the period of observation, occupying home ranges of 135 and 101 ha respectively. Mean sightings per tree were 1.19 for both males and females and home-range sizes were not significantly different between sexes or seasons. Koalas were observed returning to previously used daytime roosting trees infrequently (<12%). Although koalas were observed roosting in trees of the species that they ate, proportional species representation in the diet of these koalas during spring and autumn did not accurately reflect concurrent observations of their daytime tree-roosting behaviour. Koalas were observed to utilise non-fodder species for daytime roosting, and patterns of daytime tree use and diet selection varied between individuals inhabiting adjacent communities within the site. Leaf moisture of tree species represented in koala diets was greater in autumn than spring.

Faecal pellets were collected under trees used by free-ranging koalas in
south-western, central and south-eastern Queensland to determine the spatial
and temporal distribution of pellets with respect to the activity of koalas.
Deposition of faecal pellets by koalas was analysed according to the time of
day at which the tree was occupied. For free-ranging koalas, 47% of
daily faecal pellet output was recovered using a collection mat of 8 ×
8 m placed under a day-roost tree. The best predictor of pellet production was
the presence of a koala in a tree between 1800 hours and midnight. For other
periods, there was no relationship between period of tree occupancy and faecal
pellet recovery. There was a significant relationship between the average
length of tree occupancy and the time of day that a koala entered a tree.

North Stradbroke Island lies 4 km off the coast of Queensland, Australia. It is home to one of the only naturally occurring island populations of koalas and it is mined for mineral sands. We analysed the diet and day use tree selections of koalas and recorded the tree species composition of revegetated and undisturbed landscapes at this location. We used faecal cuticle examination to compare the diet of koalas that used reconstructed landscapes with that of koalas that used undisturbed areas. Reconstructed landscapes that were composed of more than 95% diet and/or roost tree species had evidence of use by koalas. Eucalyptus robusta was the most commonly eaten and utilised species and there was no difference in general diet composition between koalas that used the revegetated landscape and those inhabiting undisturbed areas. Other species that were used for roosting and forage included E. racemosa, E. pilularis, Lophostemon confertus and Melaleuca quinquinerva. We observed individual differences and seasonal variation in the diet composition of radio-tracked koalas. These results suggest either flexibility in the diet choices of koalas, or individual preferences within groups of koalas. Our results also indicate that post-mining landscapes can provide habitat that will be used by koalas, which should encourage further efforts into habitat re-creation for native species.