1Division of WildUfe and Ecology, CSIRQ, P.O. Box 84, Lyneham, Australian Capital Territory, Australia 2602.
Australia has at least 70 bat species and these constitute one-quarter of Australia’s mammals. In the tropics this ratio increases to one-third, and in southeastern coastal forests it is up to 40%.
Some rainforest tree species appear to be dependent upon flying foxes to disperse their fruits and ensure their long-term survival. A “raiders versus residents” model of seed dispersal, shown in Spectacled Flying Foxes Pteropus conspicillatus, is important in increasing the success of seedling survival because the residents force the raiders to leave their territories which causes seeds to be dropped distant from the parent tree. However, colonies of Spectacled Flying Foxes appear to have declined in number and size over the last decade, probably due to their status as unprotected fauna in Queensland.
There is evidence from tropical American forests for the concept of “pivotal” tree species, the conservation of which appears to be deterministic in the conservation of rainforest and fruit bats as a mutualistic system. Pivotal tree species in Australian rainforests must be identified urgently and preserved.
Until the present data for bat distribution are centralized, then analysed to search for shortcomings and to target data-deficient areas for survey, insectivorous bats will always be neglected in forest conservation arguments. There is evidence that aged trees with roost hollows are a limiting resource for many species. Gould’s Long-eared bat Nyctophilus gouldi is an indicator of forest quality, since it only roosts in unlogged gullies and within them, only in trees of 80 cm diameter. Since hollows in eucalypt trees may take 100 years to form, a short logging rotation time of 20–40 years will have a detrimental effect upon many species of forest bats. From a forest bat conservation point of view it is vital to acknowledge the importance of retaining at least some mature forest trees during logging operations. There is an awareness of many conservation problems for forest bats but there is much difficulty in finding solutions. These difficulties are compounded by the size of Australia and a lack of scientific expertise in this area.