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

Abstract

Alpine and subalpine ecosystems support many endemic species. These ecosystems are increasingly under threat from human-induced disturbances such as habitat loss and fragmentation as a consequence of ski resort development and expansion. However, limited peer-reviewed research has investigated the impacts of ski-related disturbances on wildlife, particularly on reptiles. To address this knowledge gap, we conducted reptile surveys to determine the patterns of reptile distribution and abundance in Australian ski resorts. Then, using a factorial experimental design, we investigated 1) the influence of temperature and predation in driving observed distributions and 2) how a common ski resort management practice - mowing of modified ski slopes - affected thermal regimes and rates of predation of reptiles on ski runs. We found that the removal of vegetation structural complexity through mowing resulted in significantly higher rates of predation on plasticine models, as well as significantly altered thermal regimes. Crucially, mown ski runs had higher maximum ground temperatures that frequently exceeded the recorded critical maximum body temperatures of the target species of lizards. Thus, mowing has the potential to render these areas unsuitable for thermoregulatory purposes for a large proportion of the potential activity period of reptiles. Together, modifications of the thermal environment and elevated rates of predation appear to explain the avoidance of ski runs by reptiles. To facilitate the persistence of reptiles in disturbed subalpine environments, management plans must focus on implementing strategies that reduce the impact of human activities that alter temperature regimes and predation rates on lizards. Synthesis and Applications. We suggest that the retention of structural complexity on ski runs (e.g. through the cessation of mowing during peak reptile activity periods) and/or revegetation with native plant communities will concurrently provide refuge from predators and buffer against extreme temperatures, making ski runs more hospitable to reptiles. Based on our findings, we emphasize that effective management strategies targeting subalpine biodiversity conservation require an understanding of the drivers that determine species distributions in these landscapes. Show more