The Role of Phylogenetic Relatedness and Diversity on Community Assembly and Ecosystem Functioning: Experimental Tests Using Laboratory Protist Microcosms

人类活动，如退耕还林、过度开发利用自然资源、环境污染以及不断增加的温室气体排放到大气中，造成了巨大的生物多样性损失。由于担心生物多样性的减少可能会降低自然和管理的生态系统为人类提供产品和服务的能力，生态学家研究了生物多样性与生态系统功能(如作物生产)之间的关系。这些研究极大地提高了我们对生物多样性丧失后果的认识。然而，这些研究大多集中在物种多样性，即一个生态群落中的物种数量，而对生物多样性的其他组成部分的关注相对较少。因此，我们对物种多样性以外的生物多样性成分丧失的后果的认识存在很大差距。该项目将探索系统发育多样性(PD)的能力，这是生物多样性的一个组成部分，说明物种进化关系，预测生态群落的结构和生态系统的功能。该项目还将为博士后研究员以及研究生和本科生提供高质量的研究培训，特别是那些来自代表性不足群体的学生。利用淡水纤毛原生动物作为模式生物，拟议的实验将在四个特定领域增进知识。首先，它将在系统发育的背景下将重要的生态特征与物种生态位和适合度差异联系起来。其次，它将通过检验新的假说来研究系统发生多样性(PD)-生态系统功能关系的潜在机制，这些新假说认为PD-生态系统功能关系取决于PD如何转化为物种生态位和适应度差异。第三，它将通过将PD与物种生态位和适应度差异联系起来，研究物种库中的PD在调节群落聚集的历史偶然性中的作用。第四，它将通过检验入侵者的成功和影响来对达尔文的归化假说进行严格的检验，新的假说来自于最近对现有经验研究的荟萃分析。总之，这项拟议的研究将系统发育生态学与当代物种共存理论结合在一起，以更机械地理解PD在群落组装和生态系统功能中的作用。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Human activities, such as the conversion of forests into agricultural land, overexploitation of natural resources, environmental pollution, and the ever-increasing release of greenhouse gases into the atmosphere have resulted in tremendous biodiversity loss. Concerned over the possibility that the decline in biodiversity may reduce the ability of natural and managed ecosystems to provide products and services for humanity, ecologists have studied relationships between biodiversity and ecosystem functions (e.g., crop production). These studies have significantly improved our knowledge on the consequences of biodiversity loss. Nevertheless, the majority of these studies have focused on species diversity, that is, the number of species in an ecological community, and relatively little attention has been paid to other components of biodiversity. As a result, there is a significant gap in our knowledge on the consequences of the loss of biodiversity components other than species diversity. This project will explore the ability of phylogenetic diversity (PD), a component of biodiversity that accounts for species evolutionary relationships, for predicting the structure of ecological communities and the functions of ecosystems. This project will also provide high-quality research training for a postdoctoral fellow, and graduate and undergraduate students, particularly those from underrepresented groups. Using freshwater ciliated protists as model organisms, the proposed experiments will advance knowledge in four specific areas. First, it will link ecologically important traits and species niche and fitness differences in a phylogenetic context. Second, it will investigate mechanisms underlying phylogenetic diversity (PD)-ecosystem function relationships by testing the novel hypotheses that PD-ecosystem function relationships depend on how PD translates into species niche and fitness differences. Third, it will examine the role of the PD of the species pool in modulating the historical contingency of community assembly by linking PD with species niche and fitness differences. Fourth, it will provide a rigorous test of Darwin's naturalization hypothesis by examining both invader success and impact, with novel hypotheses informed by recent meta-analysis of existing empirical studies. Together, the proposed research marries phylogenetic ecology with contemporary species coexistence theory to gain a more mechanistic understanding of the role of PD for community assembly and ecosystem functioning.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.