Effects of repeated low-intensity fire on reptile populations of a mixed eucalypt foothill forest in south-eastern Australia
Research Report No. 65
Authors: Marc Irvin, Martin Westbrooke and Mathew Gibson
Detailed ecological studies of Australian reptiles remain relatively rare, which impacts significantly on the community’s ability to develop appropriate strategies to conserve them. Most information related to the effects of fire on reptiles has been from studies in mallee woodlands, heathlands and northern Australian savanna forests, where reptilian diversity is high. Few studies have been undertaken in southern temperate areas.
Reptiles were studied in three of five Fire Effects Study Areas (FESAs) in the Wombat State Forest. The aim of this study was to determine the effects of repeated low-intensity prescribed fire on the forest ecosystem, including reptiles. Five burning treatments were replicated in each FESA: long-unburnt, short-rotation spring burnt, short-rotation autumn burnt, long-rotation spring burnt and long-rotation autumn burnt.
Research on reptiles was conducted over the period 1985–94 by various students from Ballarat University. During this period, eight species of skinks and one species of elapid snake were observed. However, only five species of skink were observed in sufficient numbers to make any judgment on the effects of the burning treatments.
Four standard herpetological survey techniques were used by the researchers: pitfall-driftline trapping, opportunistic searching, transect counts and stationary census counts. Of these, the stationary census counts technique proved to be the most successful method in the foothill forest environment.
The abundance of the Southern Water Skink (Eulamprus tympanum) remained relatively stable following both spring and autumn fires. This is likely to be due to the abundance and condition of its primary habitat—fallen logs and branches—which was not significantly affected. Conventry’s Skink (Pseudemoia conventryi) and Grass Skink (Pseudemoia entrecasteauxii) numbers were both significantly different between burning treatments.
Numbers of both species were significantly less in burnt treatments than in the long-unburnt control; the most notable were the frequently burnt spring treatments, 32 months after burning and the frequently burnt autumn treatments, 18–32 months after burning. These species were found to forage in the grass/herb and litter layers—the microhabitats most affected by burning.
McCoy’s Skink (Nannoscincus maccoyi) was most common after burning, but this was probably due to the removal of its normal habitat—the surface litter. McCoy’s Skink is a cryptic species and very difficult to find in unburnt areas. Garden Skink (Lampropholis guichenoti) inhabits moist gully areas; areas not frequently prone to low-intensity burning. This species was affected by the burning treatments only when a significant amount of the gully vegetation was burnt.
Fallen logs and unburnt litter are important refuges from fire. The small-scale mosaic of burnt and unburnt patches that generally result from low-intensity prescribed burning are crucial to local reptile survival and recolonisation.
Fire Research Report No. 65