Refuge sites used by the scincid lizard Tiliqua rugosa

Abstract

We examined microhabitat use by the Australian scincid lizard Tiliqua rugosa (the sleepy lizard) in chenopod shrubland. Thirty radiotagged lizards were followed during their spring period of activity (September-November 2000). Characteristics of refuges used by the lizards were compared with the perennial woody plants in 10 10 m x 10 m randomly located quadrats at each of the three sites in the study area. We found that sleepy lizards used multiple refuge sites. Perennial woody bushes constituted an important habitat component for both active and inactive lizards. Use of refuge sites by the lizards was non-random. They used large bushes with foliage in contact with the ground ('dome shaped'), and they sheltered under thorny bushes more frequently than expected if choice was random. Bushes that were used repeatedly tended to be larger and were more likely to be dome-shaped. Under these large and dome-shaped bushes, daytime temperatures were lower than under smaller bushes. Refuge use was modified as the season progressed, with lizards using larger bushes and a greater proportion of dome-shaped bushes later in the season. We suggest that sleepy lizards are modifying their refuge site use as ambient temperatures increase, based on microclimatic needs, implying an ability to discriminate among bushes.