CAREER: Life on the Edge: The Effects of Climate, Competition and History on Range Limits

为什么椰子树从未在佛罗里达北部发现，而圣诞树（如香脂冷杉）从未在宾夕法尼亚州南部生长？这些物种对霜冻和干旱等气候压力的耐受性不同，因此将它们的分布限制在一个被称为物种“范围”的地区。尽管经过了一个世纪的研究，科学家们才刚刚开始了解包括气候在内的哪些因素会影响这些范围的边界。为了解决我们认识上的这些基本差距，研究者将利用观测数据、实验和数学模型来研究华盛顿州雷尼尔山上五种树种的当前和未来分布范围。该项目将评估与其他树种的竞争如何与气候相互作用，以限制每种树种的生存范围；确定目标树种的分布是否反映了过去而不是现在的气候；并确定目标树种的范围能以多快的速度变化，以应对太平洋西北地区预测的快速气候变化。拟议研究的更广泛影响有三个方面。研究物种是经济上有价值的木材物种，在华盛顿西部的森林中占主导地位，提供生态系统服务，如供水、濒危物种栖息地和碳储存。因此，从这项研究中获得的信息将对保护生物学家、土地管理者和政策制定者规划气候变化有价值。研究人员将为华盛顿大学（每年有2000名本科生）的生物学入门课程和高中课程开发气候变化课程。雷尼尔山国家公园的一个公民科学项目将提高公众对气候变化如何影响自然世界的认识。

Why are coconut trees never found north of Florida while Christmas trees (i.e. balsam firs) never grow south of Pennsylvania? These species differ in their tolerance of climatic stressors like frost and drought, thereby limiting their distributions to an area termed the species "range". Despite a century of study, scientists are only beginning to understand which factors, including climate, influence the boundaries of these ranges. To address these fundamental gaps in our understanding, the investigator will utilize observational data, experiments and mathematical models to study current and future ranges of five tree species on Mt. Rainier, Washington. The project will assess how competition with other tree species interacts with climate to limit ranges for each tree species; determine whether the distributions of target tree species reflect past as opposed to current climates; and determine how quickly ranges of target tree species can shift in response to the rapid rates of climate change predicted for the Pacific Northwest.The broader impacts of the proposed research are threefold. The study species are economically valuable timber species, and dominate western Washington forests that provide ecosystem services such as water supply, habitat for endangered species and storage of carbon. Thus, the information gained from this research will be valuable to conservation biologists, land managers and policy makers planning for climate change. The investigator will develop a climate change curriculum for an introductory biology class at University of Washington (reaching 2000 undergraduates per year) and a high school course. A citizen science program at Mt. Rainier National Park will increase the general public's awareness of how climate change impacts the natural world.