Paving the way for Habitat Restoration: Can Artificial Rocks Restore Degraded Habitats of Endangered Reptiles?

The addition of artificial resources (nest boxes, shelter sites) to degraded habitats may help reverse the decline of species that rely on these structures. In south-eastern Australia, the endangered broad-headed snake (Hoplocephalus bungaroides) and its major prey, the velvet gecko (Oedura lesueurii), use exposed sandstone rocks for diurnal shelter sites. Removal of these sandstone “bush-rocks” for landscaping urban gardens has contributed to the decline of both species, and recent studies suggest that rock removal affects broad-headed snakes indirectly, via a decline in prey numbers. Thus, one way to restore degraded sandstone habitat is to provide artificial rocks for the snakes\u27 major prey, the velvet gecko. To investigate this possibility, we placed 128 square concrete pavers (19 cm wide, 5 cm thick) at three study sites in Morton National Park, where velvet geckos and broad-headed snakes are relatively common. We manipulated crevice width (4 vs 8 mm) and temperature of concrete pavers (shaded vs exposed) to determine how these factors influence retreat-site selection by velvet geckos. We monitored the usage of these artificial habitats by geckos and invertebrates over a 1-year period. During the cooler months most velvet geckos selected exposed pavers with narrow crevices. Larger geckos used wider crevices than did smaller conspecifics. Our results show that habitat restoration with appropriate-sized concrete pavers may be a feasible conservation technique for degraded rock outcrops. We recommend the use of large pavers (30–45 cm wide, 5–10 cm thick) with a variety of crevice sizes (up to 10 mm) to maximize the diversity of retreat-sites for broad-headed snakes and saxicolous lizards