An experiment to test key hypotheses of the drivers of reptile distribution in subalpine ski resorts

Abstract

Summary1. Alpine and subalpine ecosystems support many endemic species. These ecosystems areincreasingly under threat from human-induced disturbances such as habitat loss and fragmenta-tion as a consequence of ski resort development and expansion. However, limited peer-reviewedresearch has investigated the impacts of ski-related disturbances on wildlife, particularly onreptiles.2. To address this knowledge gap, we conducted reptile surveys to determine the patterns ofreptile distribution and abundance in Australian ski resorts. Then, using a factorial experi-mental design, we investigated 1) the influence of temperature and predation in drivingobserved distribution s and 2) how a common ski resort management practice – mowing ofmodified ski slopes – affected thermal regimes and rates of predatio n of reptiles on ski runs.3. We found that the removal of vegetation structural complexity through mowing resultedin significantly higher rates of predation on plasticine models, as well as significantly alteredthermal regimes.4. Crucially, mown ski runs had higher maximum ground temperatures that frequentlyexceeded the recorded critical maximum body temperatures of the target species of lizards.Thus, mowing has the potential to render these areas unsuitable for thermoregulatorypurposes for a large proportion of the potential activity period of reptiles.5. Together, modifications of the thermal environment and elevated rates of predationappear to explain the avoidance of ski runs by reptiles. To facilitate the persistence of reptilesin disturbed subalpine environments, management plans must focus on implementing strate-gies that reduce the impact of human activities that alter temperature regimes and predationrates on lizards.6. Synthesis and Applications. We suggest that the retention of structural comp lexity on skiruns (e.g. through the cessation of mowing during peak reptile activity periods) and/or reveg-etation with native plant communities will concurrently provide refuge from predators andbuffer against extreme temperatures, making ski runs more hospitable to reptiles. Based onour findings, we emphasize that effective management strategies targeting subalpine biodiver-sity con servation require an understanding of the drivers that determine species distributionsin these landscapes.