Determinism and stochasticity in the spatial-temporal continuum of ecological communities: the case of tropical mountains

Ecological communities are assembled in a spatial-temporal continuum. However, we still have a poor understanding of the relative importance of different mechanisms structuring community composition (i.e., beta-diversity) in space and time. In this study, we start by introducing a conceptual model that capitalizes upon the core-occasional species concept to predict that the assembly process in tropical mountains is driven by the deterministic turnover of core species in space via habitat sorting, but the turnover of occasional species through time via stochastic events of colonization and local extinctions. We then propose a general analytical framework that allows assessing these predictions by partitioning the total variance of a species-by-site-by-time matrix (i.e., total beta-diversity) among its purely spatial (variation in space independent of time), purely temporal (variation in time independent of space), and spatiotemporal (i.e., variation across different sites across differen...生态群落的构建发生于时空连续体之中。然而，我们对塑造群落组成（即β多样性，beta-diversity）的各类机制在空间与时间维度上的相对重要性仍知之甚少。本研究首先引入依托核心-偶见物种概念的概念模型，提出如下预测：热带山地的群落组装过程，在空间维度上由核心物种通过生境筛选产生的确定性周转所驱动，而偶见物种的时间周转则由定植与局部灭绝等随机事件主导。随后我们提出一套通用分析框架，可通过拆分物种-样地-时间矩阵（即总β多样性，total beta-diversity）的总方差来验证上述预测，拆分维度涵盖纯空间（不依赖时间的空间变异）、纯时间（不依赖空间的时间变异）以及时空维度（即不同样地间跨……）