Evolutionary ecology of species distributions

没有一个物种会在所有地方出现。理解为什么不涉及到生态学的核心问题（栖息地的使用是否受到气候的限制？）与其他物种的相互作用？缺乏扩散？)和进化（为什么不是所有物种的分布都通过适应而不断扩大？）这些问题也与重要的保护问题直接相关，包括栖息地破碎化、入侵和气候变化引起的范围转移。范围限制的理论模型远远超出了对其预测的可靠测试，阻碍了理论在现实世界中的实际应用。根据限制边缘种群的环境梯度，理论对边缘种群的生态和进化作用做出了对比预测。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：产生范围限制的生态梯度（如气候、物种相互作用）的全球模式；在稳定和收缩的范围边缘适应的普遍性和后果；物种相互作用的生态和进化重要性是否会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。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具有广泛的影响，但尚未对任何物种建立。我将使用实验细菌进化来测试空间和时间的变化是否可以创造范围边缘，正如元种群模型所预测的那样。通过增加斑块灭绝或隔离来人工缩小范围将检验它们对扩散进化的预测效果。在收缩极限上的扩散进化可以决定遗传多样性在范围变化过程中的维持程度。最后，北极到赤道的实验，包括我实验室的一个实验，最近证实了物种相互作用的强度向低纬度/海拔方向增加。我将扩大我的实验，以评估增加的相互作用强度是否与增加的生物多样性有关，以及更强的相互作用是否会产生更多的选择。这些关系被提出用来解释生物多样性的全球格局，但尚未在全球范围内得到检验。大多数处于危险中的加拿大物种都是边缘种群，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，边缘种群对环境变化的反应，以及纬度梯度的起源和影响是加拿大保护的典型问题。

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 andevolutionary 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.