Abstract
Climate change is exerting significant impacts on ecosystems worldwide, with alpine regions being particularly vulnerable. Alpine fauna is relatively poorly understood, particularly in terrain which is difficult for humans to survey. Knowledge of alpine species is further limited by a paucity of survey techniques that are widely applicable in this environment. Drones have potential as a low-impact tool for surveying fauna in remote alpine terrain. New Zealand's diverse alpine lizards are an ideal system for exploring novel survey techniques. We build on previous research demonstrating the potential of drones for surveying alpine lizards by evaluating (1) how closely a drone can approach different alpine lizard species in scree, talus, and tussock-grassland habitats and (2) the effectiveness of drone surveys compared to traditional systematic visual searches for these species and habitats. The drone (model: DJI Mavic Air 2) was able to approach within 0.1-2.5 m of a lizard (mean = 0.77 m) before triggering a flight response. Systematic visual searches outperformed drone surveys in all habitats accessible to human observers. However, drones were relatively effective in talus habitats, demonstrating their potential utility in inaccessible rocky alpine habitats. Improvements to drone technology may further enhance the utility of drone-based surveys in ecological research.