黄土高原森林次生演替过程中的群落构建

发布时间：2018-01-01 07:21

本文关键词：黄土高原森林次生演替过程中的群落构建　出处：《西北大学》2016年博士论文　论文类型：学位论文

【摘要】：群落构建过程对于解释物种共存和物种多样性的维持是至关重要的。大量研究已经基于生态位理论(niche theory)和中性理论(neutral Theory)研究了不同生态系统群落的构建机制,但是直到现在对群落构建和生物多样性的维持机理仍然没有统一的认识。演替是动态中的群落构建,提供了很好的机会来研究确定性过程和随机过程在群落物种组成过程中的作用。探索次生演替过程中的群落构建机制及其变化,分析环境因子对植物群落构建的影响,不仅有重要的理论意义,对退化生态系统的恢复与重建也具有重要的实践意义。本研究针对黄土高原森林区从一年生草本群落到顶极群落6个演替阶段的完整演替系列群落,基于多个维度的功能性状,结合群落属性、物种多样性、谱系多样性、功能多样性和环境因子的变异格局,通过构建零模型、群落性状梯度分析等方法,检验确定性过程和随机过程、以及环境过滤和相似性限制在各个演替阶段群落构建中的相对贡献,探讨在群落水平上功能性状对环境的响应,阐明环境因子对不同演替阶段群落构建过程的作用。结果表明,物种水平上扩散限制和其他随机过程在群落构建中占主要优势,而确定性过程(包括非生物环境过滤,竞争相互作用)决定了哪些属性、谱系组合出现在样地中。主要结论如下：(1)在黄土高原植被演替的过程中植物的进化历史已经在群落构建过程中植入了长期的进化印记。演替后期的群落更加谱系汇聚,群落间谱系周转较低；演替早期的群落谱系周转高,谱系发散。灌木阶段是谱系发散到汇聚的过渡阶段。从灌木到顶极群落的演替过程中,木本植物和草本植物表现出了不同的构建过程；木本植物的谱系结构总体表现为谱系汇聚,而草本植物表现出了发散或者随机。(2)黄土高原植被次生演替过程中群落属性之间同样存在资源投资上的权衡关系。演替早期的群落拥有快速获取和利用资源的功能属性,处在经济型谱的“快速投资-收益”端；随着演替的进行,后期群落的木本植物和常绿植物增加,植物把更多的资源投资在营养的储存和结构防御上,减少了对呼吸作用等功能的资源投入,多数物种处在经济型谱的“缓慢投资-收益”端,使得整个群落表现出了资源保存型策略。这体现了不同演替阶段群落根据其功能需求在群落内物种功能性状之间进行的资源权衡配置。这些结果也为未来从叶片经济型谱上升到植株、群落水平经济型谱的研究提供了良好的基础。(3)基于15种不同的功能属性,黄土高原植物整体能构成一个连续的植株经济型谱。这个经济型谱主要由各器官相关的结构和化学属性共同确定,能有规律地反映植物资源权衡策略从缓慢投资收益型到快速投资收益型物种转变的连续变化。而且,随着演替的进行,植物对最优属性组合的选择不同,器官在资源权衡上的不同,导致了不同演替阶段表现出不同的植株经济谱。(4)叶属性和其他属性间的依赖性在群落内和群落间表现出了不同的模式。总体来讲,群落间的依赖性要强于在群落内的依赖性。因此,在黄土高原植被演替过程中,群落中确实存在非中性的、与资源和环境相关的生态学过程(生物过滤、生境过滤),这些过程影响着物种器官间和器官内的功能权衡,从而影响群落的属性结构。(5)在黄土高原植被演替过程中,系统发育只控制了属性的α部分(群落内的变异),并不能控制属性的β部分(群落间的变异),说明系统发育对群落内物种属性的组成有明显的影响,而对群落间物种的周转影响不明显。属性生态位宽度无谱系信号的结果也表明,系统发育并不能控制物种属性在黄土高原的分布宽度。(6)在黄土高原森林的次生演替过程中,不同演替阶段、不同的属性表现出的构建模式不同。对于化学计量学属性(根、茎、叶的碳、氮、磷含量),沿着演替梯度会从演替早期群落属性的发散转变为后期属性的汇聚。说明随着演替的进行环境过滤对这些属性的过滤作用增强。随着演替年龄的增加,群落种子的属性和植株高度都表现出属性的发散,表明了竞争排斥(相似性限制)作用的增加。冗余分析的结果也显示,高的pH和硝态氮含量促进了早期群落化学计量学含量的发散；而高的氨氮含量促进了后期群落比叶面积、种子重量的发散。总之,在黄土高原森林的次生演替过程中,物种水平上扩散限制和其他随机过程在群落构建中占主要优势,而确定性过程(包括非生物环境过滤,竞争相互作用)决定了哪些属性、谱系组合出现在群落中。本研究有望提供暖温带森林演替过程中群落构建机制变化的新证据,对丰富群落构建理论有重要的理论意义,同时也可为该区植被的恢复重建提供重要的理论依据。
[Abstract]:During the construction of community is crucial for maintaining interpretation of species coexistence and species diversity. A large number of studies have been based on Niche Theory and neutral theory (niche theory) (neutral Theory) was constructed to study the mechanism of different ecosystem community, but until now the community building and maintaining mechanism of biodiversity is still no unified understanding is a dynamic construction in succession. The community, provides a good opportunity to study the process of deterministic and stochastic process which function in the process of community species. Explore the mechanism and the change in the process of secondary succession in community construction, analysis of the effects of environmental factors on the construction of plant communities, not only has important theoretical significance, restoration and reconstruction the degraded ecosystem also has important practical significance. This research aimed at the loess plateau forest area from herb community to climax community succession 6 Complete succession stage, the functional traits of multiple dimensions based on the combination of community property, species diversity, phylogenetic diversity, functional diversity and variation pattern of environmental factors, through the construction of zero model, community character gradient analysis method, test process and deterministic stochastic process, as well as environmental filtering and similar restrictions the relative contribution in the construction of communities in different succession stages, to explore the functional traits at the community level response to environment, clarify the environmental factors during the construction of communities in different successional stages. The results showed that the species level diffusion limited and other stochastic process is dominant in the community construction, and deterministic process (including non biological environmental filtering, competitive interaction) determines which attributes, pedigree combinations in the plots. The main conclusions are as follows: (1) in the Loess Plateau Vegetation Succession in the process The evolution of history has been in the community in the process of constructing the implantation of the long-term evolution of late successional communities. Mark more spectrum aggregation, low turnover among communities lineages of early successional communities; lineage turnover high lineage divergence. The shrub stage is the transitional stage of lineage divergence to convergence. From shrubs to climax community succession process woody plants and herbaceous plants showed different construction process; hierarchical structure overall performance for woody plants and herbaceous plant lineages together, showing divergent or random. (2) have the same tradeoff between resource investment between the community property of Vegetation Secondary Succession in the Loess Plateau. The early successional community has the function of quick attribute access to and use of resources, in the economic spectrum "quick investment return"; with the succession, evergreen woody plants and plant communities in the late Increase investment in plants to put more resources and storage structure on defense to reduce nutrition, respiration and other functions of the resources, most species are in the economic spectrum "slow investment income", so that the whole community showed the resource conservation strategy. This reflects the communities in different successional stages according to its function demand in the community between species traits of resource allocation trade-offs. These results also for the future from the leaf economic spectrum up to the plant, provides a good foundation of community level economic spectrum. (3) 15 different functional properties based on the Loess Plateau, the whole plant can form a continuous plant economic spectrum. The economic spectrum is mainly composed of various organs related to the structure and chemical properties determined, can regularly reflect the plant resource balancing strategy investment return type from slow to fast return on investment The continuous variation of species change type. Moreover, with the succession, plant selection on the optimal combination of attributes of different organs in different resource trade-offs, resulting in different successional stages of economic plants showed different spectra. (4) the dependence of leaf attribute and other attributes between communities and between communities show different models. Generally speaking, the dependence between communities than in the communities dependent. Therefore, in the process of vegetation succession in the Loess Plateau, the existence of community non neutral, ecological processes associated with resources and environment (biological filtration, filtration process, these habitats) affect the species and organs the organ function balance, thus affecting the property structure of the community. (5) in the succession of vegetation in Loess Plateau, the system development can only control the properties of alpha part (variation in the community), and can not control the beta (part of community property The variation between), showing that there was a significant impact on the composition of species in the community property system development, and the effects on community species turnover is not obvious. The niche width of non pedigree signal attribute results show that the system can not control the development and distribution of species attributes in the width of the Loess Plateau (6) in the secondary succession. The process of loess plateau forest in different successional stages, different properties exhibit various construction models. The chemometrics (root, stem, leaf properties of carbon, nitrogen, phosphorus), along the succession gradient will change from the divergence of early successional communities attribute for later attributes together. With the succession of environmental filtering filtering effect on these properties increased. With the increase of successional age, community seed attributes and plant height showed that the properties of the divergence of competitive exclusion (similar restrictions). The increase of action redundant points The analysis results also showed that high pH nitrate content and promote the early divergence community content and chemometrics; high ammonia nitrogen content to promote the late community specific leaf area, the divergence of the seed weight. In short, in the process of secondary succession forest in the Loess Plateau, the level of species diffusion restrictions and other stochastic processes accounted for the major the advantage in the community construction, and deterministic process (including non biological environmental filtering, competitive interactions) determines which attributes, pedigree combinations in the community. This study is expected to provide new evidence to construct the mechanism of changes of communities in warm temperate forest succession process, to enrich the community construction has an important theoretical significance in theory, provide a theoretical basis for the important also for the restoration and reconstruction of vegetation in this area.

【学位授予单位】：西北大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q948

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