Evolutionary ecology of species distributions

没有任何物种随处可见。理解为什么不涉及生态学的核心问题(栖息地的使用是否受到气候的限制？与其他物种的互动？缺乏扩散？)和进化(为什么不是所有物种的分布都通过适应不断扩大？)。这些问题还与重要的保护问题直接相关，包括栖息地碎片化、入侵和气候变化导致的范围转移。射程极限的理论模型远远超过了对其预测的稳健测试，阻碍了理论在现实世界中的实际应用。*理论对边缘种群的生态和进化作用做出了截然不同的预测，这取决于限制它们的环境梯度。我的长期目标是测试控制物种范围限制的生态和进化过程中的全球模式，特别是物种相互作用的作用。我的短期目标是测试：在生态梯度(例如气候、物种相互作用)中产生范围限制的全球模式；在稳定和收缩范围边缘适应的普遍性和后果；以及物种相互作用的生态和进化重要性是否随着生物多样性的增加而增加。*我建议在三个互补的空间尺度上进行实验。对生物、非生物和遗传因素范围的实验操作将测试它们在草药海拔范围内的相对重要性。这对生物多样性的分布有广泛的影响，但还没有针对任何物种确定。我将使用实验性的细菌进化来测试空间和时间的变异性是否可以像集合种群模型所预测的那样创造范围边缘。通过增加斑块灭绝或隔离来进行人为的范围收缩，将检验它们对扩散演化的预测效果。在收缩极限下的扩散进化可能决定遗传多样性在射程转移期间保持得多好。最后，从北极到赤道的实验，包括我实验室的一项实验，最近证实了物种相互作用强度向低纬度/海拔方向增加。我将扩大我的实验，以评估互动强度的增加是否与生物多样性的增加有关，以及更强的互动是否会产生更多的选择。这些关系旨在解释生物多样性的全球格局，但尚未在全球范围内进行测试。*大多数濒临灭绝的加拿大物种是边缘种群，加拿大是所有国家中纬度梯度最大的国家之一。边缘种群对物种持久性的重要性，边缘种群如何对环境变化做出反应，以及纬度梯度的起源和含义是加拿大典型的保护问题。

No species occurs everywhere. Understanding why not involves questions at the heart of ecology (is habitat use limited by climate? interactions with other species? lack of dispersal?), and evolution (why aren't all species distributions constantly expanding via adaptation?). These questions are also directly related to important conservation problems, including habitat fragmentation, invasions, and climate-change induced range shifts. Theoretical models for range limits far exceed robust tests of their predictions, preventing realistic application of theory to real-world conservation. ***Theory makes contrasting predictions about the ecological and evolutionary role of edge populations depending on the environmental gradient that limits them. My long-term goal is to test for global patterns in the ecological and*evolutionary processes governing species range limits, particularly the role of species interactions. My short-term goals are to test: for global patterns in the ecological gradients (e.g. climate, species interactions) that generate range limits; the prevalence and consequences of adaptation at stable and contracting range edges; and whether the ecological and evolutionary importance of species interactions increases alongside biodiversity. ***I propose experiments at three complementary spatial scales. Experimental manipulations of biotic, abiotic, and genetic factors range will test their relative importance across a herb's elevational range. This has broad implications for the distribution of biodiversity, but has not been established for any species. I will use experimental bacteria evolution across to test whether spatial and temporal variability can create range edges, as predicted by metapopulation models. Artificial range contractions via increasing patch extinction or isolation will test their predicted effect on dispersal evolution. Dispersal evolution at contracting limits could determine how well genetic diversity is maintained during range shifts. Finally, arctic-to-equator experiments, including one from my lab, have recently confirmed that species interaction intensity increases toward low latitudes/elevations. I will expand my experiment to assess whether increased interaction intensity is associated with increased biodiversity, and whether stronger interactions generate increasing selection. These relationships are proposed to explain global patterns in biodiversity but have not been tested at a global scale.***Most Canadian species at risk are edge populations, and Canada has one of the largest latitudinal gradients of any country. The importance of edge populations to species persistence, how edge populations respond to environmental change, and the origin and implications of latitudinal gradients are quintessential Canadian conservation questions.