Habitat use of obligate alpine geckos from southern New Zealand

Animals that inhabit the alpine zone often persist in isolated and fragmented populations and possess a range of behaviours and adaptations that enable them to survive in these harsh environments. These characteristics can make them particularly susceptible to escalating anthropogenic threats, including climate change. New Zealand has a diverse lizard fauna, of which approximately 25% of species inhabit the alpine zone. The cryptic nature of many alpine lizards makes them difficult to find and study, limiting effective conservation management. We investigated the habitat use of the orange-spotted gecko (Mokopirirakau “Roys Peak”), a cryptic species found between 1150 and 1800 m a.s.l. in central and western Otago. We measured attributes of 30 plots based on gecko sightings and shed skins and 30 plots that we randomly allocated across the searched area. We evaluated gecko habitat use relative to availability by recording rock size, rock thickness, slope, percent cover of rock and shrubs, and plant community composition at both locations where geckos or skin were observed and random sites in the search area. We also trialled a novel method of tracking movements of these animals using fluorescent powder for understanding microhabitat use. We found that orange-spotted geckos select habitats with larger rocks and a greater proportion of rock cover. We did not identify a difference in the use of various vegetation types or communities, which likely reflects the greater importance of rock characteristics in determining gecko habitat selection. Tracking gecko movements using fluorescent powder offered novel information about the habitat use of this species, including evidence of geckos using novel microhabitats such as small subterranean holes and tunnels. Our findings revealed key characteristics of habitats selected by orange-spotted geckos, extending our understanding of their ecology and contributing towards addressing the deficiency of knowledge about alpine lizard species that we hope will ultimately lead to improved conservation management.