城市化梯度上杂草多样性格局成因与群落分异机制

Urban ruderal is one of the three types of urban vegetation and has short life cycle, strong plasticity and high sensitivity to environmental variation. During fast urbanization in recent years in China, its γ-diversity at regional scale has showed a significant decreasing with increasing urbanization intensity, while its β-diversity between communities at local scale has showed a significant increasing trend. This study will focus on the wastelands in Shanghai, which is a typical habitat for urban ruderal. Along urbanization gradients, the rural communities on wastelands will be investigated for species composition, habitats and seed banks. With combination of plant transplanting experiment and environment controlling experiment, the key factors that determining the variation pattern of biodiversity along urbanization gradients will be revealed for the whole life history of ruderal. Meanwhile, the relative roles of region process and local process on explaining the community assemblage along urbanization gradients will be distinguished from taxon-based, phylogenetics-based and traits-based analysis. In addition, the community dynamics of urban ruderal will be monitored to reveal the seasonal variation and annual replacement of species and indicate the community differentiation process at temporal scale and the underline mechanisms. The study has important theoretical and practical significance for understanding the causes of diversity variation and community differentiation during urbanization, improving the study framework of urban vegetation, and guiding the management and conservation of urban biodiversity.

随着我国近年快速城市化进程，作为城市植被三大类型之一的杂草群落，由于其生活史周期短、可塑性强、敏感性高的特征，在城市化梯度上呈现出区域水平上γ多样性减少、局域水平上群落β多样性增加的现象。本项目以上海城市杂草典型生境之一的废弃地为研究对象，在城市化梯度上开展群落学调查、生境测定和种子库调查，实施野外移植试验和室内控制实验，从杂草不同生活史阶段剖析生物多样性在城市化梯度上变化格局的主导因素，同时从物种、谱系和功能性状三个维度辨析局域与区域过程在城市杂草群落空间分异过程中的作用；结合对固定监测样地的追踪调查，探明杂草群落的季相变化及年际更替动态，揭示杂草群落在时间尺度上分异过程及成因。研究对于阐明城市化过程中植物多样性变化与群落分异的成因、完善城市植被研究体系、指导城市生物多样性保育与管理具有理论和现实意义。

随着我国近年快速城市化进程，作为城市植被三大类型之一的杂草群落，由于其生活史周期短、可塑性强、敏感性高的特征，在城市化梯度上呈现出区域水平上γ多样性减少、局域水平上群落β多样性增加的现象。本项目以上海城市杂草典型生境之一的废弃地为研究对象，在城市化梯度上开展群落学调查、生境测定和种子库调查，实施野外移植试验和室内控制实验，从杂草不同生活史阶段剖析生物多样性在城市化梯度上变化格局的主导因素，同时从物种、谱系和功能性状三个维度辨析局域与区域过程在城市杂草群落空间分异过程中的作用；结合对固定监测样地的追踪调查，探明杂草群落的季相变化及年际更替动态，揭示杂草群落在时间尺度上分异过程及成因。研究对于阐明城市化过程中植物多样性变化与群落分异的成因、完善城市植被研究体系、指导城市生物多样性保育与管理具有理论和现实意义。