Causes and consequences of spatio-temporal variation of species interactions at the community scale

物种之间的相互作用对生态系统的性质和人类群体的福祉都是关键。昆虫为农作物授粉可以提供食物，海胆捕食藻类可以防止沿海地区的藻类大量繁殖，捕食者的存在可以控制猎物的数量。然而，人们经常假设物种之间的相互作用是恒定的，或者换句话说，相同的两个物种在不同的背景下将以相同的方式相互作用。最近对实地观察的分析表明，情况并非如此；就像物种在其地理范围内的不同一样，相互作用也是如此。我的研究项目试图为这种变化提供解释，并在这一新知识的基础上，建立关于我们预期生态系统属性将如何在时间或空间中变化的预测。这个研究项目最重要的预测结果之一是，根据测量数据预测两个物种在给定环境中相互作用的可能性。我将使用相对较新的计算生态学领域的工具来解决这些问题，该领域建立在高性能模拟和统计方法的基础上，旨在分析极大的数据集。虽然我的研究活动是理论性的，但我将与经验科学家密切合作。这一合作将使我能够获得高质量的观测，并以不同系统的自然历史的可靠知识为后盾。这种密切的合作也将确保我将取得的理论进步，特别是我将开发的新工具和方法，植根于对自然系统有第一手知识的研究人员的问题和观察。特别是，我将确保我培训的所有学生都有机会花一些时间研究经验系统，这样他们就可以为弥合理论科学和经验科学之间的鸿沟做出贡献。除了为基础科学家提供新的机制和理论主张外，我预计我的工作将吸引管理者和利益相关者，因为它将提供一种预测生态群落结构的新方法。这将使我们能够更好地预测物种入侵和环境变化的影响，例如对需要保护的生态系统资产的影响。

Interactions between species are key both to the properties of ecosystems, and to the well-being of human populations. Pollination of agricultural crops by insects allows the provision of food, grazing of algae by sea urchins prevents algal blooms in coastal areas, and the presence of predators keep the population size of their preys in check. Yet, it has often been assumed that interactions between species are constant, or in other words, that the same two species will interact in the same ways in different contexts. Recent analysis of field observations show that this is not the case; much in the same way that species vary in their geographical range, so too do interactions. My research program seeks to provide explanations to this variation, and building on this new knowledge, to establish predictions about how we expect ecosystem properties to change in time or space. One of the most important predicted output of this research program is the ability to predict, based on measured data, the probability that two species will interact in a given environment. I will use tools from the relatively new field of computational ecology, which builds on high-performance simulations and statistical methods designed to analyse extremely large datasets, to address these questions. Although my research activities are theoretical, I will work in close association with empirical scientists. This collaboration will allow me to have access to high-quality observations backed by robust knowledge of the natural history of the different systems. This close collaborations will also ensure that the theoretical advances I will make, and in particular the new tools and methods I will develop, are grounded in the questions and observations of researchers with first-hand knowledge of natural systems. In particular, I will make sure that all the students I train have the opportunity to spend some time working on an empirical system, so that they can contribute to bridging the gap between theoretical and empirical science. In addition to providing new mechanisms and theoretical propositions for fundamental scientists to build upon, I expect that my work will appeal to managers and stakeholders, as it will provide a new way to forecast the structure of ecological communities. This will allow better predictions of the effects of species invasions and environmental changes, for example, on ecosystem properties in need of preservation.**