- Title:
-
Effects of Repeated Low-intensity Fire on Insectivorous Bat Populations of a Mixed Eucalypt Foothill Forest in South-eastern Australia
- Date:
- December 2003
- Organisations
- DSE
- Location:
- Victoria, Australia
Overview
Seven species of bat were recorded in the Wombat Fire Effects Study Areas (FESAs). Only the three southern-most FESAs were surveyed. Bats are the most species-rich mammal group in the forest and are therefore an important fauna group. Bats feed mainly in the middle and overstorey vegetation and are therefore most likely to be affected by changes in forest structure. Bats are also one of the most difficult groups to study.This study employed a wide range of bat survey techniques, including searches of mines, natural hollows and nest boxes, trip lines, vertical trip lines, mist nets, frame nets, harp traps, Skye ultrasonic detectors, Anabat II bat detectors and radio telemetry. This report is the summary of ten separate studies undertaken by staff and students from Ballarat University.
Five burning treatments were replicated in each FESA in this study: long-unburnt, short-rotation spring and short-rotation autumn burning, long-rotation spring and long-rotation autumn burning.
Bat activity was found to be significantly affected by air temperature and seasonal conditions. Therefore, comparison between fire treatments had to be made either by accounting for differences in the conditions at the time of surveying or by contemporaneous measurement.
Bat activity was related almost linearly with air temperature, with activity ceasing below 9oC. Insect activity was also correlated to air temperature; as a result it is inferred that bat activity is closely related to airborne invertebrate activity.
Tree cavities, varying from hollows to fissures, were found to be important as roost sites for bats. Different species may have different requirements for roost sites, but further research is needed to determine the range and nature of these roost sites and the effect of repeated fires on them.
No significant difference in bat activity was found in any of the fire treatments at the Blakeville and Musk Creek FESAs. This suggests that the value of habitat for bats was relatively equal for all burning treatments. This study found that bats travel at least 1–5 km, therefore the size of the treatment areas in this study is probably too small to draw firm conclusions about the impact of repeated low-intensity fire on bat populations.
