The role of phylogenetic diversity on community assembly and ecosystem functioning: experimental tests using laboratory microcosms

过去几十年，人类活动不断升级，极大地改变了我们的生物圈，导致地球许多生态系统中生物多样性的广泛丧失。这种对生物多样性的侵蚀是否影响了生态群落由单个物种组成的方式？它会对自然和管理生态系统的功能，包括它们为人类提供的产品和服务（如食品、药品、水质、营养保留）产生任何影响吗？生态学家使用了多种方法，包括数学模型、实地和实验室实验以及观察，来回答这些重要的问题。虽然迄今为止进行的大量研究表明，生物多样性的变化可以带来重大的生态后果，但我们的知识相当不完整。特别是，我们目前对生物多样性效应的理解主要基于物种丰富度（即给定区域内的物种数量）或与物种丰富度相关的多样性指数。系统发育多样性是解释物种进化史的生物多样性的一个重要因素，它如何影响群落和生态系统的特性在很大程度上是未知的。在这个项目中，研究小组的目标是通过进行一系列以细菌作为模式生物的实验室实验来填补这一空白。该项目将从研究物种进化关系和物种间竞争强度之间的关系开始，这个问题在150年前由达尔文首次提出，但至今仍未得到解决。有了这些基本信息，关于物种之间的进化关系如何影响许多群落和生态系统过程和功能的几个假设将得到检验。这项研究将在被称为微观世界的小型人工生态系统中进行。除了科学贡献外，该项目还将通过培训研究生和本科生，特别是来自代表性不足的少数群体的学生，为教育推广做出贡献。少数民族学生将从佐治亚理工学院和艾格尼丝斯科特学院（亚特兰大大都会的一所小型文理女子学院）的工程/科学暑期本科研究项目中招募。

The past several decades have seen escalating human activities that have substantially transformed our biosphere, resulting in widespread loss of biodiversity in many of Earth's ecosystems. Does this erosion of biodiversity affect the way that ecological communities assemble from individual species? Will it have any impact on the functioning of natural and managed ecosystems, including products and services (e.g., food, medicine, water quality, nutrient retention) that they provide for humanity? Ecologists have used a multitude of approaches, including mathematical models, field and laboratory experiments, and observations, to answer these important questions. While the large body of research conducted so far has revealed that biodiversity change can carry significant ecological consequences, our knowledge is rather incomplete. In particular, our current understanding of biodiversity effects is largely based on species richness (that is, the number of species in a given area) or diversity indices associated with species richness. It is largely unknown how phylogenetic diversity, an important element of biodiversity that accounts for species' evolutionary histories, affects community and ecosystem properties. In this project, the research team aims to fill this void by conducting a series of laboratory experiments using bacteria as model organisms. The project will start by examining the relationship between species' evolutionary relationships and the strength of competition between species, an issue first addressed by Darwin 150 years ago and yet still unresolved. With this basic information in hand, several hypotheses will be tested on how evolutionary relationships among species affect a number of community and ecosystem processes and functions. The research will be conducted in small artificial ecosystems called microcosms. Besides scientific contributions, this project will also contribute to educational outreach by training graduate and undergraduate students, particularly those from underrepresented minority groups. Minority students will be recruited from the Summer Undergraduate Research Program in Engineering/Science at Georgia Institute of Technology and from Agnes Scott College (a small liberal arts women's college in metro Atlanta).