漓江江心洲植被演替及其修复机制研究

发布时间：2018-08-28 14:57

【摘要】：近年来,漓江流域植被退化不断加剧,生态环境遭到严重破坏。因此,解决漓江流域植被恢复问题迫在眉睫。本文以漓江江心洲为研究对象,考察了江心洲植物群落与土壤之间的关系,探讨了漓江流域不同类型江心洲的基本特征、植被演替规律及内在驱动力,研究了不同类型江心洲植被生长的主要影响因子,旨在为漓江江心洲近自然植被恢复和河流管理提供理论依据与技术参考。研究成果如下：(1)通过对江心洲环境影响因子的分析,筛选出植被生物量、相对高程差、坡度、砾石含量、土壤含水量、土壤有机质含量、江心洲面积、土壤速效氮、土壤速效钾和土壤PH值作为划分江心洲类型的指标。运用相关性分析和主成分分析法,精选出植被生物量、相对高程差、坡度、砾石含量、作为主导因子,进行聚类分析,将江心洲划分为草本型江心洲、灌草型江心洲和乔灌草型江心洲3种不同类型的江心洲。(2)18个漓江江心洲上共有植物86种,隶属41科81属,其中草本植物65种,灌木10种,乔木11种。江心洲草本植物优势种为狗牙根、苔草、活血丹等,灌木优势种为枫杨、水杨梅等,乔木优势种为枫杨和桑树。三种类型江心洲四周多样性均呈现出洲尾侧和远离主河道侧植物群落多样性大于洲头及洲右侧(主河道侧)的特性。三种类型江心洲的土壤砂粒含量均大于60%,随着江心洲演替阶段的增加,砂粒含量、土壤容重和土壤含水量都呈现先减小后增大的趋势,土壤砾石含量呈减小的趋势。土壤pH值呈逐渐减小的趋势,但均偏弱碱性,土壤有机质、全氮、全磷、全钾、速效磷呈先增后减的趋势,速效氮呈现先减后增的趋势,速效钾呈现逐渐增大的趋势。(3)通过对漓江流域江心洲植被演替的研究表明：草本型江心洲处于一年生和多年生草本植物优势种为主的正向演替阶段,灌草型江心洲处于多年生草本、灌木和低矮乔木为主要优势种的正向演替阶段,在江心洲植物群落演替的过程中群落的稳定性由草本型的24.3减少到乔灌草型的18.64,呈增大趋势,物种的生态位宽度趋于平衡,草本植物由最初的耐旱、耐淹型变为喜阴、潮湿型,群落多样性、均匀度及丰富度均呈增加趋势。江心洲植物群落演替过程为：草本型→灌草型→乔灌草型揭示演替规律。漓江流域江心洲植物群落演替的主要驱动力为江心洲优势种植物的更替和优势种植物对恶劣的环境的适应性。(4)洪水是江心洲的主要干扰因素,汛期前后植被科、属、种及生物量均呈增加趋势,多样性、优势度、均匀度汛期前后无明显差异。洪水对草本型江心洲的土壤理化性质影响最大,乔灌草型江心洲影响最小,其中草本型江心洲土壤容重、土壤有机质、全氮、全磷和pH值汛期前后存在显著差异,灌草型江心洲只有土壤含水量、土壤容重和PH值有变化,乔灌草型江心洲除了pH值以外其他均无明显差异。(5)草本型江心洲的植被影响因子为洪水、土壤、地形及人为干扰,其植被恢复模式为优势种植物草种播撒及移栽搭配石笼护坡工程措施；灌草型江心洲的植被影响因子为洪水、速效钾,速效磷、土壤有机质、土壤全氮、相对高程差和人为干扰,其植被恢复模式为优势种植被移栽搭配石笼护坡工程措施；乔灌草型江心洲的植被影响因子为土壤有机质、坡度、相对高程差和人为干扰,其植被恢复模式主要以自然恢复为主,植被补植和卵石干砌护岸措施,这为漓江江心洲生态修复过程中的生物工程措施的配置提供了成熟可行的范式。
[Abstract]:In recent years, vegetation degradation in the Lijiang River Basin has been aggravated and the ecological environment has been seriously damaged. Therefore, it is urgent to solve the problem of vegetation restoration in the Lijiang River Basin. The results are as follows: (1) Through the analysis of environmental impact factors, the biomass of vegetation, relative elevation difference and slope were screened out. Degree, gravel content, soil water content, soil organic matter content, Jiangxinzhou area, soil available nitrogen, soil available potassium and soil PH value were used as the indexes to classify Jiangxinzhou type. Jiangxinzhou is divided into three types of Jiangxinzhou: herbaceous Jiangxinzhou, shrub-grass Jiangxinzhou and arbor-shrub-grass Jiangxinzhou. (2) There are 86 species of plants belonging to 41 families and 81 genera in 18 Lijiang Jiangxinzhou, including 65 herbaceous plants, 10 shrubs and 11 arbors. The dominant arbor species are Maple Poplar and Mulberry. The plant community diversity of the three types of Jiangxinzhou is higher than that of the mainland and the right side of the mainland. Soil pH value decreased gradually, but soil organic matter, total nitrogen, total phosphorus, total potassium, available phosphorus increased first and then decreased, available nitrogen decreased first and then increased, and available potassium increased gradually. (3) The study on the vegetation succession of Jiangxinzhou in the Lijiang River Valley shows that the herbaceous Jiangxinzhou is in the positive succession stage of dominant annual and perennial herbaceous species, while the shrub-grass Jiangxinzhou is in the positive succession stage of perennial herbaceous species, shrubs and low-dwarf trees as dominant species, and is in the plant community of Jiangxinzhou. The stability of the community decreased from 24.3 of herbaceous type to 18.64 of arbor-shrub-herbaceous type, showing an increasing trend. The niche breadth of the species tended to be balanced. The herbaceous species changed from drought-tolerant and drought-tolerant to shade-loving, moist type. The diversity, evenness and richness of the community showed an increasing trend. The main driving forces of plant community succession in Jiangxinzhou of Lijiang River Basin are the replacement of dominant plants and the adaptability of dominant plants to harsh environment. (4) Flood is the main disturbance factor of Jiangxinzhou. Vegetation families, genera, species and biomass increase before and after flood season. Flood had the greatest influence on soil physical and chemical properties of herbaceous Jiangxinzhou, while arbor-shrub-grass Jiangxinzhou had the smallest influence. Soil bulk density, soil organic matter, total nitrogen, total phosphorus and pH value of herbaceous Jiangxinzhou were significantly different before and after flood season. Soil bulk density and PH value changed, and there was no significant difference except pH value in arbor-shrub-grass type of Jiangxinzhou. (5) Flood, soil, topography and human disturbance were the main factors affecting the vegetation in herbaceous type of Jiangxinzhou, and the vegetation restoration model was dominated plant grass sowing and transplanting with stone cage slope protection measures. Flood, available potassium, available phosphorus, soil organic matter, soil total nitrogen, relative elevation difference and human disturbance are the main factors affecting vegetation restoration in the arbor-shrub-grass type of Jiangxin River. The measures of natural restoration, vegetation replantation and dry cobblestone revetment provide a mature and feasible paradigm for the allocation of bioengineering measures in the ecological restoration process of the Lijiang River.
【学位授予单位】：北京林业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q948
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本文编号：2209723