DISSERTATION RESEARCH: Community assembly across regional diversity and latitudinal gradients

人类依赖生物多样性提供无数的商品和服务，因此，我们必须了解调节空间和时间多样性的过程。例如，人们早就认识到，物种的数量通常会向赤道方向增加，科学家们历来认为这种纬向多样性梯度？环境因素的变化或物种相互作用方式的变化造成的。因此，对这一主题的研究探索了多样性和纬度如何与几乎所有可以想象到的东西相关。这一系列研究忽略了一个简单的替代解释：随机过程。特别是，一个新个体的偶然到来或一个小种群的随机灭绝可能会对碰巧生活在某个地方的物种产生巨大的影响。一些科学家现在认为，这种随机事件的影响可能会因纬度和多样性而异。因此，这项研究的目标是确定这些随机过程与更可预测的过程在确定物种发生地点方面的重要性。这将通过收集自然水生群落的数据，并在北美的几个地点和纬度进行户外实验来实现。该项目还为本科生和高中生提供了几个积极参与生态研究的机会。两名本科生将被带去进行跨洲抽样旅行，并将在与这项研究相关的独立项目中接受指导。这项实验工作包括几名来自圣路易斯高中的学生，他们不仅直接与研究人员在这个项目上合作，还接触到了华盛顿大学的其他项目。最后，该项目的一个方面是收集跨纬度梯度的多个地点和年份的自然群落数据。在空间和时间上复制标准化采样方法的如此庞大的数据集相对罕见，但对于了解大规模的生物多样性模式是绝对必要的。这个项目产生的数据将通过华盛顿大学S泰森研究中心被添加到一个公开可用的数据库中，任何感兴趣的人都可以访问。

Humans depend on biodiversity for countless goods and services, and it is thus essential that we understand the processes that regulate diversity in space and time. For example, it has long been recognized that the number of species generally increases towards the equator, and scientists have historically assumed that this ?latitudinal diversity gradient? results from variation in environmental factors or changes in how species interact with each other. Consequently, research on this topic has explored how diversity and latitude relate to nearly everything imaginable. This body of work has ignored a simple alternative explanation: random processes. In particular, the accidental arrival of a new individual or the random extinction of a small population can make a big difference in what species happen to live in a certain place. Some scientists now believe that the effect of such random events may vary with latitude and diversity. The goal of this research, therefore, is to determine how important these random versus more predictable processes are in determining where species occur. This will be achieved by collecting data from natural aquatic communities and conducting outdoor experiments across a several sites and latitudes in North America. This project also provides several opportunities for undergraduate and high school students to become actively involved in ecological research. Two undergraduate students will be taken on cross-continental sampling trips and will be mentored on independent projects that relate to this research. The experimental work incorporates several students from St Louis high schools, who not only work directly with the researchers on this project, but also get exposure to other projects at Washington University. Finally, one aspect of this project is collecting data for natural communities over multiple sites and years across a latitudinal gradient. Such large data sets with standardized sampling methods replicated in space and time are relatively rare, yet are absolutely necessary to understand large-scale patterns of biodiversity. The data generated from this project will be added to a publicly available database through Washington University?s Tyson Research Center, giving access to anyone interested.