EFFECTS OF 2 SPRING PRESCRIBED FIRES ON EPIGEAL COLEOPTERA IN DRY SCLEROPHYLL EUCALYPT FOREST IN VICTORIA, AUSTRALIA

The cumulative effects of two low-intensity prescribed fires, applied within 3 years during spring (15 October 1985 and 3 November 1988), were assessed on families and species of surface-active Coleoptera (beetles) in litter of dry sclerophyll mixed eucalypt forest over a 5.7 year period between 26 March 1985 and 26 November 1990. The study was based on 13 925 adult specimens, representing 31 families and 105 species, of which 70 species (66.7% of total) are undescribed. The most commonly trapped 'major' families were the predominantly predatory Staphylinidae and the decomposer/fungus feeding Nitidulidae and Leiodidae. The specimens were contained in 2240 pitfall trap samples collected from a burnt and an unburnt ('control') site adjacent to each other within a 30.7 ha study area. The two fires had no discernible cumulative effect on the activity of the Nitidulidae, the Leiodidae, the pool of 28 rarely trapped 'minor' families and the totals of decomposers/fungus feeders. However, short bursts in activity occurred among the first three of these taxa/groups during periods between the two fires. In contrast, activity of the Staphylinidae, the most abundant of all taxa trapped, declined significantly after the second fire relative to pre-first fire levels. This trend accounted for the observed reductions in activity of total Coleoptera, of total predators and of the proportions of Coleoptera in total arthropods. Family and species richness of the Coleoptera remained unchanged following the fires. An undescribed fungus-feeding lathridiid (Aridius sp.) incurred a short upsurge in activity after the second fire. As only activity (and not diversity and taxon richness) of the Staphylinidae was affected by the fires, it is expected that they will return to pre-fire activity levels when the forest recovers in the absence of further fires. Two short-rotation low-intensity spring fires can therefore be applied in the forest type studied without causing unacceptable adverse impacts on litter-frequenting Coleoptera.