热带森林植物功能群及其动态研究进展

热带森林极高的物种多样性和结构复杂性给生态学研究带来了很多挑战。植物功能群是对特定环境响应相似或对主要的生态过程具有相似作用的物种组合。应用植物功能群的方法是有效减少热带森林群落复杂性,并揭示其格局和过程的良好途径。在介绍植物功能群概念和划分途径的基础上,分析了热带森林植物功能群的时空动态规律。一般来讲,划分植物功能群通常有3种途径,并可通过5个步骤来完成。热带森林植物功能群的空间分布常受景观格局的制约,而环境异质性往往是影响不同植物功能群组配比例变化的直接原因。不同类型的植物功能群随演替过程发生显著的替代,而干扰体系和全球气候变化对功能群的动态过程具有重要的驱动作用。以功能群为基础的动态模型在模拟热带林群落动态和预测植被潜在分布等方面具有广阔的发展前景。探索有效的植物功能分类方法、构建完善的植物功能性状数据库、开发更为精确的功能群动态模型以及加强基于景观水平的植物功能群动态机制的认识等是未来热带森林植物功能群及其动态研究的重要方向。

Plant functional groups and their dynamics in tropical forests: a review

The high species richness and complex community structure of tropical forests pose great challenges to ecologists interested in the function and structure of tropical forests. Plant functional groups (PFGs) are defined as groups of species that either exhibit similar responses to environmental perturbations or have similar effects on major ecosystem processes. PFGs analysis is an effective approach to reduce the complexity of plant communities and to reveal general patterns and processes in tropical forests. In this paper, the concept of PFGs is briefly introduced, the approaches and procedures of aggregation for PFGs are described, and the spatiotemporal dynamics of PFGs in tropical forests are reviewed. PFGs are identified by the functional traits of plants in forest ecosystems. Important functional traits of plants in tropical forests include growth form, potential maximum height, wood density, seed size and dispersal syndrome, leaf size and habits (evergreen or deciduous), and buttress size etc. There are three approaches in aggregating plants into PFGs: intuitive, deductive, and quantitative. Five steps are needed to complete the aggregation process. PFGs replace each other in different successional stages and their relative proportions in the communities change significantly with the process of succession in tropical forest. The assemblages of the PFGs are usually confined by the landscape configuration and environmental heterogeneity. Dynamics of the PFGs are greatly influenced by disturbance regimes and global climate change. In tropical forests, the models based on PFGs have been developed to simulate community dynamics and to predict the potential distribution of vegetations. More detailed studies on PFGs dynamics in tropical forests are needed in the future, in aspects of effective aggregation of PFGs, solid database construction for major functional traits, improvement of modeling based on PFGs, and PFGs-based planning at the landscape level. The PFGs approaches in tropical forests may be extended to other complex forests (e.g. subtropical evergreen-leaved forests).