Mechanisms of community assembly in plant communities

我的研究的首要目标是揭示自然系统中物种分布和丰富性的现有变化的机械本质。我使用实地和温室调查相结合的方法来探索竞争、捕食、扩散和对环境条件的适应如何对群落结构做出贡献。为了更好地理解过程，特别是竞争对群落内物种组织模式的影响，Null模型经历了重大的发展和探索。然而，最近的一项综述表明，这些模型很少找到与竞争相关的确定性社区集会规则的重要证据(例如，特征差异和负共现)。结合这一点，几个研究途径表明，多个过程可能会在社区内产生冲突的模式，而社区规模的零模型不会拾取这些模式。因此，目前可用的一系列零建模工具是否能够解决我们希望它们解决的问题，这一点令人严重关切。此外，到目前为止，大多数研究都没有将零模型分析与实验操作和温室研究充分匹配，以更好地将模式与过程联系起来。*由于我们对社区内的竞争如何进行的理解存在差距，上述问题变得更加复杂。例如，确定与植物物种最大大小相关的成对竞争等级的简单竞争实验与类似的田间实验没有明显的一致，并且与大小差异驱动生态位分化从而避免竞争的可能性结合得很差。最后，虽然自然系统中存在潜在的非传递性竞争来促进多样性，但竞争实验的简单性质，特别是对植物物种的竞争实验，使得评估不可传递性促进物种多样性的潜力变得困难，特别是当对竞争关系的评估通常依赖于有问题的物种确实在自然群落中竞争的糟糕证据时。*我的学生和我将通过开发和完善无效模型分析以及通过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对竞争、捕食和扩散对群落结构的相对贡献的理解，并进一步理解在自然群落中观察到的竞争能力和丰度模式之间的联系。此外，了解可增加(例如，扩散、促进)或减少多样性(例如，竞争、捕食)的不同机制的相对影响，将极大地为保护和恢复倡议提供信息，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.********