植物个体资源竞争与群体结构特性分析  

A general model for plant resource competition and population structures

作　　者：曾晓东[1,2] 宋翔 高小斐[1,2] Xiaodong Zeng;Xiang Song;Xiaofei Gao(International Center for Climate and Environment Sciences,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大气物理研究所国际气候与环境科学中心,北京100029 [2]中国科学院大学,北京100049

出　　处：《科学通报》2023年第21期2836-2848,共13页Chinese Science Bulletin

基　　金：国家重点研发计划(2017YFA0604804);中国科学院前沿科学重点研究计划(QYZDY-SSW-DQC002);国家自然科学基金(42275177)资助。

摘　　要：资源竞争是形成不同尺度生态结构最重要的驱动因素.植物生态系统资源竞争的自组织过程具有3个显著特点,即群体具有中等数目的个体数、个体差异巨大、个体间仅具有复杂的近程相互作用.本文从生态系统资源竞争与群体结构的一般性问题出发,建立可显式描述植物个体间资源竞争的生态动力学模型,并依据资源竞争的数学特性,按照完全非对称性竞争和完全对称性竞争两种极端形式,分别设计数值模拟试验,并与无竞争试验对比,分析不同竞争形式、不同群体竞争度下个体资源分配及群体结构特征的共性和差异.结果表明,随着竞争度上升,两种竞争形式下的生态系统结构特征(不同高度的顶层冠层覆盖度)均偏离无竞争情况对应的分布,表现为高大冠层比重减少,而低矮冠层比重增加,顶层冠层平均高度下降,不同于经典竞争模型的结论.在完全非对称性竞争情况下,个体差异明显上升,如中等高度个体的平均竞争度以及低矮个体的平均死亡率迅速增加,植被覆盖区域顶层冠层覆盖度曲线半高宽逐渐增大,顶层冠层高度标准差增加,但高大冠层占模拟区域的覆盖度逐渐趋于稳定.而在完全对称性竞争情况下,个体差异明显低于完全非对称性竞争情况,所有高度的平均竞争度和平均死亡率均上升,顶层冠层覆盖度曲线逐渐向低高度方向偏移,高大冠层占模拟区域的覆盖度也逐渐降低.本文提出了一个研究群体结构随竞争度变化的理论框架,可为生态系统复杂资源竞争研究提供重要的数学理论基础,并应用于地球系统模式的陆表过程模式及植被动力学模式的多尺度建模框架设计.Resource competition is one of the major driving forces shaping ecological patterns at various scales.Competition exists as the total supply of essential resources is less than the total demand of different individuals in an ecosystem;thus,the growth of some or all individuals is reduced due to the limitation of these resources,and hence,various ecological patterns form.The self-organization processes of ecosystem resource competition show three distinct characteristics;i.e.,a population has a moderate number of individuals,with each being different,and there are only local interactions among individuals within the system.A dynamic ecological model with an explicit description of competitive interactions among neighboring individual trees is constructed in this work to investigate the general features of resource competition and population structures.Despite the complex characteristics of the process through which plant size impacts competition for various resources,two simple mathematical schemes are developed to represent the two extreme cases,i.e.,a completely asymmetric competition case in which the most competitive individuals obtain all the resources and a completely symmetric competition case in which resources are equally allocated among all individuals.Numerical simulations applying these two schemes are performed and compared with the control experiments in which competition is ignored and all individuals can acquire the maximum available resources.The properties of individual and population variables,such as the degree of competition and mortality rates among individuals and the distribution of the top canopy at different heights,are analyzed.The similarities and differences are compared among different competition modes and different degrees of population competition.The set of completely asymmetric competition simulations shows larger variances among individuals,such as the rapid increase in the degrees of competition for individuals with moderate heights and mortality rates for small individuals,and

关 键 词：资源竞争 群体结构 个体差异 自组织 生态动力学建模 

分 类 号：Q948.1[生物学—植物学]