Microhabitat Preference of Egernia napoleonis in Undisturbed Jarrah Forest, and Availability and Introduction of Microhabitats to Encourage Colonization of Restored Forest



An animal's microhabitat requirements can impact its ability to colonize restored areas, particularly species requiring slow developing microhabitats, such as logs and woody debris piles. Introduction of these microhabitats may be required to facilitate colonization by some species. Restored bauxite mine-pits in the Jarrah (Eucalyptus marginata) forest of south-western Australia contain introduced log piles at densities of 1 ha−1. However, these have not facilitated colonization by Napoleon's skink (Egernia napoleonis), which rely on logs for habitat and are largely absent from restored sites. We radio-tracked 12 skinks in unmined forest to determine their microhabitat preferences and examined differences in vegetation structure, and microhabitat and food availability, between restored and unmined forests to identify reasons for their absence. Restored and unmined forests differed in canopy, mid- and understory cover and ground substrates, which were all potential barriers to colonization. Food availability was similar between restored and unmined forest, thus not a barrier to colonization. Skinks primarily utilized long logs, large woody debris piles, and large trees; microhabitats that were scarce or absent in restored sites and, therefore, potential barriers to colonization. Using this information, we introduced small woody debris piles into restored sites in close proximity to unmined areas containing skinks to facilitate skink colonization. This showed early signs of success and suggested that the lack of logs and woody debris were barriers to colonization. However, further monitoring is required to accurately determine the long-term value of woody debris piles in facilitating skink colonization.