Collaborative Research: Maintaining High Species Diversity in Communities

摘要合作研究：在群落中保持高度的物种多样性生态系统经常包含进化上和生态上相似的物种。 然而，这种多样性实际上是通过直接促进共存的机制来维持的，还是从系统中缓慢消失的，这一点尚不清楚。 已经提出了许多机制，可以促进当地和区域尺度上的物种无限期共存。 只有当生命率（生存、生长、繁殖）随环境变化而变化时，以及当单个物种对相同的环境变化有不同的反应时，才存在这些共存机制。 另一种观点是，物种对环境的反应没有差异，并通过一个称为“生态漂移”的随机过程慢慢消失，在这个过程中，一个物种相对于另一个物种的种群规模取决于生存，生长和繁殖的不可预测性。 这一过程类似于“随机遗传漂变”，即由于遗传过程的不可预测性，在所谓的中性基因的相对丰度之间发生随机进化变化。这个项目将通过将共存机制纳入这些“中性”生态模型来阐述最近的生态漂移模型。 与中性模型一样，新理论的发展将利用决定物种多样性模式的生态机制与决定遗传多样性的进化过程之间的类比。 该研究的目标是开发一套预测，其中包括生态漂移和各种共存机制，在当地和区域尺度上运作。 这些预测将在统计上与当地和区域范围内的社区多样性的现有数据进行比较。 这项研究将为形成社区多样性的机制提供间接但非常实用的测试。

ABSTRACTCOLLABORATIVE RESEARCH: MAINTAINING HIGH SPECIES DIVERSITY IN COMMUNITIESEcosystems frequently contain species that are evolutionarily and ecologically similar. However, whether this diversity is actually maintained by mechanisms that directly promote coexistence or rather is lost very slowly from systems is unclear. Many mechanisms have been proposed that could promote the indefinite coexistence of species on both local and regional scales. These mechanisms of coexistence are only present when vital rates (survival, growth, reproduction) vary with the environment and when individual species have different responses to the same environment change. The alternative is that species do not differ in their responses to the environment and are slowly being lost through a random process called "ecological drift" in which the population size of one species relative to another is determined by the unpredictability inherent in survival, growth, and reproduction. This process is akin to "random genetic drift" in which random evolutionary changes among the relative abundances of so-called neutral genes occur due to unpredictability in the process of inheritance. This project will elaborate recent models of ecological drift by incorporating mechanisms of coexistence into these "neutral" ecological models. Like the neutral models, development of the new theory will take advantage of analogies between the ecological mechanisms that determine species diversity patterns and the evolutionary processes that determine genetic diversity. The goal of the research is to develop a set of predictions that incorporates both ecological drift and various coexistence mechanisms that operate on local and regional scales. These predictions will be statistically compared with existing data on community diversity across local and regional scales. The research will provide indirect but highly practical tests for mechanisms that shape community diversity.