The evolutionary ecology of geographic ranges in western North American Mimulus

对物种分布范围的生态和进化控制的理解落后于在快速环境变化时代预测未来分布范围的需要。主要问题包括：a)地理范围边缘何时何地与生态位的界限一致；b)为什么生态位进化可能在范围边缘失败；c)广布物种和特有物种的范围限制过程如何不同；d)范围将如何响应气候变化而移动。缺乏答案阻碍了有关稀有物种和外围种群的管理决策。这在加拿大尤其重要，因为许多濒危物种已经到达了它们的北部极限。这项研究计划的总体目标是发展对物种地理范围的生态、进化和保护的综合理解。近期研究目标和计划如下：(1)量化不同范围边缘和不同范围物种的限制生态因子的相对重要性。我们将进行环境操作和种子导入，以评估非生物，生物和扩散限制的强度。我们还将比较广布物种和狭义特有物种的生理生态位宽度。(2)研究范围边缘和范围大小不同的物种生态位进化的制约因素。我们将进行人工选择，以确定边缘种群是否缺乏遗传变异以扩大范围。为了验证淹没基因流导致范围边缘适应不良的假设，我们将从范围内部模拟不同程度的基因流。我们还将研究分布广泛和稀有物种范围内的生态位进化模式。(3)气候变化驱动差移的精细化预报试验方法。我们将使用上述实验结果来帮助参数化分布模型，以评估扩散限制、生理可塑性、生物相互作用和进化变化对潜在范围移动的影响。通过本研究培养的高素质人才包括4名博士、2名硕士和若干名本科生。

Understanding of the ecological and evolutionary controls over species' ranges lags behind the need to forecast future ranges in an era of rapid environmental change. Major questions include a) when and where geographic range edges are concordant with limits to the ecological niche, b) why niche evolution might fail at range margins, c) how range-limiting processes differ for widespread and endemic species, and d) how ranges will move in response to climate change. A lack of answers hinders management decisions concerning rare species and peripheral populations. This is of particular relevance in Canada, where many species at risk reach their northern limits. The overall goal of this research program is to develop a synthetic understanding of the ecology, evolution and conservation of species' geographic ranges. Near-term research objectives and plans are as follows: (1) Quantify the relative importance of limiting ecological factors across different range edges and for species with contrasting range sizes. We will conduct environmental manipulations and seed introductions to assess the strength of abiotic, biotic, and dispersal limitations. We will also compare physiological niche breadth of widespread and narrowly endemic species. (2) Examine constraints on niche evolution at range margins and for species with contrasting range sizes. We will conduct artificial selection to determine if edge populations lack genetic variation for range expansion. To test the hypothesis that swamping gene flow causes maladaptation at the range edge, we will simulate varying degrees of gene flow from the range interior. We will also examine patterns of niche evolution across the ranges of widespread and rare species. (3) Test methods for refining forecasts of range shifts driven by climate change. We will use experimental results from the above to help parameterize distribution models that evaluate the effects of dispersal limitation, physiological plasticity, biotic interactions, and evolutionary change on potential range shifts. Highly qualified personnel to be trained through this research include four PhD, two MS, and several undergraduate students.