Effects of repeated low-intensity fire on the invertebrates of a mixed eucalypt foothill forest in south-eastern Australia
Research Report No. 61
Authors: Nick Collett and Fred Neumann
The effects of short- and long-rotation burning in spring and autumn on surface-active invertebrates were studied in mixed eucalypt foothill forest in west-central Victoria between 1985 and 1999. The prescribed fires were of low-intensity (<500 kW m–l). The 14-year study was based on many tens of thousands of arthropod specimens, representing 36 ordinal or lower level taxa contained in pitfall trap samples from a range of short- and long-term spring and autumn treatment areas and an unburnt control treatment area within the Blakeville Fire Effects Study Area in west-central Victoria.
There appears to be no effect of prescribed fires on surface-active invertebrates in the short and long term on spring burnt treatment areas, and in the short term on autumn-burnt treatment areas. However, significant increases in total taxa activity late in the study, primarily as a result of increases in activity of the groups: ‘total non-insects’, Acarina (mites) and Formicidae (ants) were observed in the longer term (over 14 years) on autumn-burnt treatment areas. Conversely, a decrease in activity of the Dermaptera (earwigs) was recorded, while the situation for the Collembola (springtails) and Diptera (flies) is less certain as changes in activity occurred on both the autumn burnt and the unburnt (control) treatment areas. However, as no significant change in activity was observed in the short term (i.e. in the period immediately before and after fire) for any of the aforementioned taxa, it cannot be stated for certain that the changes in activity following the second fire were due to fire or other environmental effects.
As this study was conducted to ordinal and sub-ordinal level only for most taxa, it is uncertain whether the results are applicable to a range of species within ordinal groups, or whether there is species-specific variation to the different fire treatments. Initial studies conducted to family and species level for Coleoptera (beetles) indicated some species groups underwent short-term changes in activity before soon returning to pre-fire levels. Further study is required to address this issue more fully for other ordinal/sub-ordinal groups.
Fire Research Report No. 61