Mechanisms of community assembly in plant communities

我研究的首要目标是揭示自然系统中物种分布和丰度的现有变化的机械本质。我使用的领域和温室调查相结合，探讨如何竞争，捕食，扩散和适应环境条件的社区结构。* 生态系统模型经历了重大的发展和探索，以更好地了解过程的影响，特别是竞争，对群落内物种组织的模式。然而，最近的一项研究表明，这种模型很少能找到与竞争有关的确定性社区组装规则的重要证据（例如，性状分歧和负共现）。与此相结合，几种研究方法表明，多个过程可能会在社区内产生冲突的模式，而社区规模的空模型不会发现这些模式。 因此，人们非常担心目前可用的零模型工具是否能够解决我们希望它们解决的问题。此外，迄今为止，大多数研究还没有充分匹配零模型分析与实验操作和温室研究，以更好地将模式与过程联系起来。* 我们对竞争如何在社区内发挥作用的理解存在差距，这使上述问题更加复杂。例如，简单的竞争实验，确定成对的竞争层次结构相关的植物物种的最大尺寸不清楚地与类似的领域实验，并与潜在的大小差异，以推动生态位分化，从而避免竞争整合不良。最后，虽然存在促进自然系统内多样性的不传递性竞争的潜力，但竞争实验的简单性，特别是对植物物种的竞争实验，使得难以评估促进物种多样性的不传递性的潜力，特别是当竞争关系的评估通常依赖于有关物种确实在自然群落内竞争的证据不足时。我和我的学生将通过开发和改进零模型分析以及使用田间和温室实验来解决上述问题。这项工作将扩大我们的理解竞争，捕食和扩散，社区结构的相对贡献，并进一步了解竞争能力和丰富的自然社区中观察到的模式之间的联系。此外，了解不同机制的相对影响，可以增加（例如，分散，促进）或减少多样性（例如，竞争，捕食）将极大地为保护和恢复举措提供信息，并有助于管理入侵物种。

The overarching goal of my research is to uncover the mechanistic nature of existing variation in the distribution and abundance of species in natural systems. I use a combination of field and glasshouse investigations to explore how competition, predation, dispersal, and adaptation to environmental conditions contribute to community structure. ***Null models have undergone significant development and exploration to better understand the influence of processes, competition in particular, on patterns of species organization within communities. However, a recent review indicates that such models rarely find significant evidence of deterministic community assembly rules related to competition (e.g., trait divergence and negative co-occurrence). In combination with this, several avenues of research suggest that multiple processes may produce conflicting patterns within a community that are not picked up by community-scale null models. As such, there are significant concerns about whether the current collection of null modelling tools available can address the questions we wish them to. Furthermore, most research to date has not adequately matched null model analyses with experimental manipulation and glasshouse research to better link patterns with processes. ***The above issues are compounded by gaps in our understanding of how competition plays out within communities. For example, simple competition experiments that identify pair-wise competitive hierarchies related to plant species maximum size do not clearly align with analogous field experiments, and are poorly integrated with the potential for size differences to drive niche differentiation and thus the avoidance of competition. Finally, while the potential exists for intransitive competition to promote diversity within natural systems, the simple nature of competition experiments, particularly on plant species, makes it difficult to assess the potential for intransitivity to promote species diversity, particularly when assessments of competitive relationships generally rely on poor evidence that the species in question do in fact compete within natural communities.***My students and I will address the above issues by developing and refining null model analyses and through the use of field and glasshouse experiments. This work will expand our understanding of the relative contributions of competition, predation, and dispersal, to community structure and further our understanding of the link between competitive ability and patterns of abundance observed in natural communities. Additionally, understanding the relative impact of different mechanisms that can augment (e.g., dispersal, facilitation) or reduce diversity (e.g., competition, predation) will greatly inform conservation and restoration initiatives, and aid in the management of invasive species.********