The biogeographical patterns of species richness and abundance distribution in stream diatoms are driven by climate and water chemistry

In this inter-continental study of stream diatoms, we asked three important but still unresolved ecological questions: 1) What factors drive the biogeography of species richness and species abundance distribution (SAD); 2) Are climate-related hypotheses, which have dominated the research on the latitudinal and altitudinal diversity gradients, adequate in explaining spatial biotic variability; and 3) Is the SAD response to the environment independent of richness? We tested a number of climatic theories and hypotheses (i.e., the species-energy and the metabolic theory; and the energy variability and the climatic tolerance hypothesis) but found no support for any of these concepts as the relationships of richness with explanatory variables were non-existent, weak or unexpected. Instead, we demonstrated that diatom richness and SAD evenness generally increased with temperature seasonality and at mid- to high total phosphorus concentrations. The spatial patterns of diatom richness and the SA...

本项针对溪流硅藻的跨洲际研究，提出了三个尚未解决的重要生态学核心问题：1. 哪些因素驱动物种丰富度与物种多度分布（Species Abundance Distribution, SAD）的生物地理格局；2. 主导纬度与海拔多样性梯度研究的气候相关假说，是否足以解释空间生物变异；3. 物种多度分布对环境的响应是否独立于物种丰富度？我们检验了多项气候相关理论与假说，即物种能量理论、代谢理论、能量变异性理论与气候耐受假说，但未发现上述任一理论得到支持——因物种丰富度与解释变量之间既无显著关联、关联强度极弱，亦或呈现出与预期相悖的结果。与之相反，本研究证实，硅藻物种丰富度与物种多度分布均匀度通常随温度季节性波动增强而升高，且在总磷浓度处于中高水平时呈上升趋势。硅藻物种丰富度与物种多度分布的空间格局及……