EAGER: The role of demographic stochasticity in community assembly

生态学中最大的谜题之一是解释为什么相似的物种可以在一个群落中共存；据推测，一个物种应该是更好的竞争者，并导致所有相似物种的灭绝。植物共存尤其难以解释，因为植物共享相对较少的有限资源，这应该会极大地限制可以共存的物种的数量。那么，一些植物群落怎么可能有数百个共存的物种呢？除了有限资源的数量外，至少有两个因素可能促进共存：土壤养分可获得性等条件在一个群落内可能不同(环境异质性)，以及由于随机机会(人口随机性)，个别植物的发芽率和死亡率可能不同。伯恩斯博士和她的合作者将在凯斯西储大学进行一项新颖的实验，以问：在创造允许多种植物共存的条件方面，环境异质性和人口随机性的相对重要性是什么？拟议的实验将操纵土壤环境的异质性，并将物种引入属于同一物种和密切相关物种的种群。这项实验将第一次能够清楚地区分环境异质性和人口随机性在确定在特定群落中哪些物种可以一起发现方面的相对重要性。伯恩斯和她的合作者与当地政府组织克利夫兰大都会公园密切合作，回答当地重要的管理问题，并确保科学家和土地管理人员之间的公开沟通。克利夫兰大都会公园是一系列约8000公顷的公园，环绕着大克利夫兰地区。克利夫兰大都会公园自然资源部致力于维护公园的健康和多样性。保持植物群落多样性对于大都会公园提供基本生态系统服务的能力至关重要，例如为克利夫兰地区提供清洁水。这个项目将加深我们对共存的理解，并将帮助管理者预防和控制生物入侵，维护植物群落的多样性。例如，如果更多的异质地点更有可能受到害虫物种的入侵，管理人员可以针对这些地区进行监测，以防止新的和潜在有害的生物入侵。

One of the great puzzles in ecology is explaining how similar species can coexist in a community; presumably, one species should be a better competitor and cause extinction of all similar species. Plant coexistence is especially difficult to explain, because plants share a relatively small number of limiting resources, which should greatly restrict the number of species that can coexist. So, how it is possible for some plant communities to have hundreds of coexisting species? At least two factors, in addition to the number of limiting resources, might promote coexistence: conditions such as soil nutrient availability might vary within a community (environmental heterogeneity) and individual plants might have different rates of germination and death due to random chance (demographic stochasticity). Dr. Burns and her collaborators will conduct a novel experiment at Case Western Reserve University to ask: what is the relative importance of environmental heterogeneity and demographic stochasticity in creating conditions that allow for many species of plants to coexist? The proposed experiment will manipulate heterogeneity of the soil environment and introduce species into populations belonging to the same species and a closely related species. This experiment will be able to clearly distinguish for the first time the relative importance of environmental heterogeneity and demographic stochasticity in determining which species can be found together in a particular community.Dr. Burns and her collaborators work closely with a local government organization, Cleveland Metroparks, to answer important local management questions and ensure open communication between scientists and land managers. Cleveland Metroparks is an ~8000 ha series of parks that ring the greater Cleveland area. The Cleveland Metroparks Natural Resources Division is committed to maintaining the health and diversity of the parks. Maintaining plant community diversity is essential for Metropark's ability to provide essential ecosystem services, such as providing clean water to the Cleveland area. This project will enhance our understanding of coexistence, and will help managers prevent and control biological invasions and maintain plant community diversity. For example, if more heterogeneous sites are more likely to be invaded by pest species, managers can target those areas for monitoring to prevent new and potentially detrimental biological invasions.