THE EFFECTS OF FIRE ON THE FRILLNECK LIZARD (CHLAMYDOSAURUS-KINGII) IN NORTHERN AUSTRALIA

A population of frillneck lizards, Chlamydosaurus kingii, was monitore d by radio telemetry and mark-recapture techniques between April 1991 and April 1994, as part of a landscape-scale fire experiment, in Kakad u National. Park, Northern Territory. The study aimed to investigate b oth the short- and longer-term effects of fire on a lizard species in a tropical savanna where fires are frequent and often annual. Frillnec k lizards are able to survive fires that occur in the first few months of the dry season by remaining perched in trees. A high level of mort ality (29%) occurred during late dry-season fires, along with changes in their behavioural response to fire: sheltering in either larger tre es or hollow termite mounds. Food is more accessible after fires due t o the removal of ground vegetation This is reflected in greater volume and diversity of prey in stomach contents after fires. This increase is more pronounced after late dry-season fires, possibly due to increa sed accessibility of prey caused by more complete vegetation removal. Frillneck lizards show an overall preference for trees with a dense ca nopy cover located in an area with a low density of grass. Fire has an effect on this relationship. Frillneck lizards in habitat unburnt for a number of years tend to perch, in trees with a smaller canopy, wher eas lizards in annually burnt habitat perch in trees with a dense cano py. Volume and composition of Lizard stomach contents was broadly simi lar among fire treatments over a 2 year period, although termites were more predominant in stomach contents of lizards in unburnt habitat. W et-season body condition is lower in lizards from unburnt habitat, alt hough the reason for this is unclear. These results demonstrate the im portance of different fire intensities and regimes on the ecology of a lizard species in a tropical savanna.