Quantitative population and community dynamics

在生态时间尺度上，物种的分布和丰度取决于当地物种的相互作用，如决定出生率和死亡率的竞争，以及在当地地点之间的分散。我的研究计划的重点是了解生态学中更大规模的模式是如何从决定丰度的基本过程中产生的：出生、死亡和运动。这是一个具有挑战性的问题，因为出生率、死亡率和迁移率取决于许多因素，并且在物种、地点和时间之间差异很大。我的提案描述了两个短期目标，以进一步推进我的长期研究计划：(1)空间同步性。生态学中最引人注目的大尺度模式之一是空间同步性：同一物种在空间上分离的种群数量都在增加或减少，数量一致，即使一些种群与其他种群相距数百甚至数千公里。像鸟类、昆虫和人类病原体这样不同的物种表现出空间同步性，这表明对同步性的解释在于一般原理，而不是系统特异性生物学。在我之前工作的基础上，我建议测试以前未经测试的假设，即空间同步性是如何从生物体从一个地方移动到另一个地方，以及从空间同步的天气波动中产生的。如果提出的假设成立，当前的许多想法将需要重新审视。(2)物种共存。从微生物到哺乳动物的竞争物种经常共存许多代。解释共存的机制通常是特定于系统的。为了确定一般原则，现代共存理论将这些系统特定机制的结果总结为可以在任何系统中量化的一组更小的抽象的“更高层次”机制。新的方法使量化这些高级机制成为可能。我建议测试关于环境波动和共存物种的数量如何调节高水平共存机制的强度的假设。很少有研究检验关于共存机制优势的假设。我建议用由快速生长的原生生物和细菌组成的实验室微观群落来解决这两个目标。这个系统允许我直接操纵空间同步性和物种共存的假设决定因素，这在大多数其他系统中是不可能的。实验室里的微观世界和自然系统一样，遵循着同样的基本规则。微观世界实验通过对假设的一般原理进行有力、直接的实验测试来补充实地研究。这些一般原则适用于加拿大和其他地方的物种。了解一般原则有助于我们保护和管理加拿大物种和生态系统的能力。除了有助于基本理解外，拟议的工作将为3名博士生，3名硕士生和13名本科生研究助理提供培训和研究经验。

On ecological timescales, the distribution and abundance of species depends on local species interactions like competition which determine birth and death rates, and dispersal among local sites. The focus of my research program is to understand how larger-scale patterns in ecology emerge from the fundamental processes that determine abundances: birth, death, and movement. This is a challenging problem because rates of birth, death, and movement depend on many factors and can vary greatly among species, locations, and times. My proposal describes two short-term objectives that further my long-term research program: (1) Spatial synchrony. One of the most striking large-scale patterns in ecology is spatial synchrony: spatially-separated populations of the same species all increasing, and decreasing, in abundance in concert, even though some populations are hundreds or even thousands of km from others. Species as different as birds, insects, and human pathogens exhibit spatial synchrony, suggesting that the explanation for synchrony lies in general principles rather than system-specific biology. Building on my previous work, I propose to test previously-untested hypotheses for how spatial synchrony arises from movement of organisms from place to place, and from spatially-synchronized weather fluctuations. If the proposed hypotheses hold, much current thinking will require revisiting. (2) Species coexistence. Competing species from microbes to mammals often coexist for many generations. The mechanisms explaining coexistence often are system-specific. To identify general principles, modern coexistence theory summarizes the consequences of these system-specific mechanisms in terms of a smaller set of abstract, "higher level" mechanisms that can be quantified in any system. New methods make it feasible to quantify these high-level mechanisms. I propose to test hypotheses about how environmental fluctuations, and the number of coexisting species, mediate the strength of high-level coexistence mechanisms. Few studies test hypotheses about the strengths of coexistence mechanisms. I propose to address both objectives with laboratory microcosm communities comprised of fast-growing protists and bacteria. This system allows me to directly manipulate the hypothesized determinants of spatial synchrony and species coexistence, manipulations that are impossible in most other systems. Laboratory microcosms play by the same fundamental rules as natural systems. Microcosm experiments complement field studies by allowing powerful, direct experimental tests of hypothesized general principles. Those general principles apply to species in Canada and elsewhere. Understanding general principles underpins our ability to conserve and manage Canadian species and ecosystems. Besides contributing to fundamental understanding, the proposed work will provide training and research experience for 3 Ph.D. students, 3 M.Sc. students, and 13 undergraduate research assistants.