Feature Article - Bats: Things that go bump in the night
Contributed by Forestry Tasmania
One of Australia’ s most unusual census operations is taking place in Tasmania’s State forests.
Rob Taylor, Principal Research Officer at Forestry Tasmania, is keeping track of populations of Tasmania’s 8 bat species to determine the impact of logging activity on the bats. This will assist long-term management of their habitat in wood production forests.
Each bat species has a unique echolocation call, which is used to navigate and to locate flying insects, their food source. Science has taken advantage of this to keep track of populations in Tasmania. The calls of each species were recorded using electronic equipment with microphones sensitive to ultrasonic sounds, which were then converted to audible sound and recorded onto tape.
This process has helped Dr Taylor to develop a tool to identify the echolocation calls of each species of Tasmanian bats offering an easy method of monitoring populations.
No Tasmanian bats are considered to be threatened and all species are widespread and found in most forest types. However, maintaining a suitable and long-term habitat is necessary to ensure populations remain secure in the future.
Bats require old trees for roost sites. In wood production forests, roost trees are retained in a variety of situations. These include stream reserves, wildlife habitat strips and clumps of trees retained specifically for this purpose in and around logged areas.
With the conversion of mature forest to regrowth, the ability of bats to use regrowth forest for foraging needed to be better understood by Forestry Tasmania.
Dr Taylor’s research found that because bats are able to fly up to 10 kilometres each night to forage, they are able to utilise regrowth forest for foraging by commuting from areas with hollows.
However, further research is needed to estimate the exact numbers of trees with hollows required to cater for the needs of future bat populations.