Dynamics of plant-herbivore-climate interactions in alpine and arctic communities

生态学家长期以来一直在争论各种因素如何决定捕食者（自上而下的力量）或资源（自下而上的力量）或非生物影响（例如天气和气候）在不同生态系统中何时何地占主导地位。能够更好地预测北部和高山环境对不同尺度干扰的反应，对于制定保护生物多样性、恢复退化栖息地和管理气候变化后果的可行战略至关重要。我的研究项目集中在了解北部高山和苔原环境中植物-草食动物-气候的相互作用。本研究项目的重点研究区域位于育空地区西南部的山脉，位于Kluane湖以东的红宝石山脉（61°N, 141°W）。该提案进一步发展了几个长期（自1995年以来）项目的研究主题，包括：(1)评估高山哺乳动物对气候年际变化的人口和行为反应，特别是季节性积雪；(2)确定资源可用性和捕食风险对草食动物种群（鼠兔、旱獭、地松鼠）行为和人口统计学的影响，作为检验营养开发模型预测的模型系统；(3)测定高寒植被在生理、人口和群落水平上对不同程度的自然和实验草食和气候年际变化的响应；(4)构建景观级过程（如雪、树线和灌丛动态等）对生物多样性影响的区域模型；5)通过长期监测、教育、推广以及科学和社区知识的整合，确保北部冻土带和高山环境可持续性的机制。

Ecologists have long debated how various factors determine when and where predators (top-down forces) or resources (bottom-up forces) or abiotic influences (e.g. weather and climate) will be predominant in different ecosystems. Being able to better predict the responses of northern and alpine environments to disturbance at different scales is essential for developing viable strategies for conserving biodiversity, restoring degraded habitats, and managing the consequences of climate change. My research program is focused on understanding plant-herbivore-climate interactions in northern alpine and tundra environments. The focal study areas for this research program are located in the mountains of the southwest Yukon, in the Ruby Ranges east of Kluane Lake (61° N, 141° W). This proposal further develops several research themes that are integrated into a long-term (since 1995) program, including (1) Evaluation of the demographic and behavioural responses of alpine mammals to inter-annual variation in climate, especially seasonal snow cover; (2) Determination of the effects of resource availability and predation risk on the behaviour and demography of herbivore populations (pikas, marmots, ground squirrels), as model system for testing the predictions of the trophic exploitation models; (3) Measurement of the responses of alpine vegetation to different levels of natural and experimental herbivory and interannual variation in climate, at physiological, demographic and community levels; (4) Construction of regional models to assess the influence of landscape-level processes (e.g. snow, treeline and shrubline dynamics, etc) on biodiversity; and 5) Mechanisms for ensuring sustainability of northern tundra and alpine environments, through long-term monitoring, education, outreach, and integration of scientific and community-based knowledge.