LATITUDINAL VARIATION IN THE DETERMINANTS OF COMMUNITY STRUCTURE

在不同的环境中，物种多样性水平自然不同。许多用来理解物种多样性如何在特定栖息地保持的理论都是建立在不同物种占据独特生态位的假设之上的。这意味着多个物种能够共同生活，只是因为每个物种以不同的方式与环境相互作用。然而，证据也表明，许多物种在与环境的相互作用方面几乎是相同的。为了解释共存物种的明显冗余性，中性生态学理论被认为是一种替代基于生态位的理论。它指出，并非每个物种都占据着自己的生态位，物种的多样性只是通过随机的机会慢慢消失而得以维持。该项目将进行观察研究和实地实验，以区分在北美西部湖泊中发现的豆娘组合结构的这两种替代理论。这项工作特别侧重于研究中性与基于生态位的过程的相对重要性如何随纬度在空间上变化。纬度可能起着重要的作用，因为北纬地区反复的冰川作用限制了当地群落的持续存在，从而限制了北方群落相对于南方群落生态位差异的进化能力。该研究将为理解物种共存机制的空间变化提供有价值的信息，对构建有效的生物多样性管理策略具有重要意义。生物多样性对人类的重要性从清洁的水到医学，再到娱乐和艺术。该项目将包括一系列关于生物多样性主题的正式和非正式教育活动，其中包括加强当地小学K-5年级的科学课程，开发以研究为基础的本科课程，以及创建一个公民科学项目，以鼓励公众参与并促进公众对生物多样性的了解。此外，本科生将从事科研事业的所有组成部分。

Levels of species diversity vary naturally among different environments. Much of the theory developed to understand how species diversity is maintained in particular habitats is built on the assumption that different species occupy unique niches. This means that multiple species can live together only because each species interacts with the environment in different ways. However, evidence also suggests that many species are nearly identical to one another in how they interact with the environment. Neutral ecological theory has been suggested as an alternative to niche-based theory in order to explain the apparent redundancy of coexisting species. It states that every species may not occupy its own niche and that diversity is maintained instead by species only slowly being lost by random chance. This project will conduct observational studies and field experiments to distinguish between these two alternative theories in structuring damselfly assemblages found in lakes throughout western North America. The work specifically focuses on examining how the relative importance of neutral versus niche-based processes may vary spatially with latitude. Latitude may play an important role because repeated glaciation at northern latitudes has limited the persistence of local communities there, and thus restricted the ability for niche differences to evolve in northern relative to southern communities. This research will provide valuable information for understanding how mechanisms allowing species coexistence may vary spatially, which is critical to constructing effective biodiversity management strategies. The importance of biological diversity to humanity ranges from clean water to medicine, to recreation and art. This project will incorporate a range of formal and informal education activities on the topic of biological diversity, that include enhancing the science curriculum for local K-5 elementary schools, developing an undergraduate research-based curriculum, and creating a citizen science project to encourage public participation and to contribute to public understanding of biodiversity. In addition, undergraduate students will be engaged in all components of the scientific research enterprise.