【摘要】：近年來(lái),漓江流域植被退化不斷加劇,生態(tài)環(huán)境遭到嚴(yán)重破壞。因此,解決漓江流域植被恢復(fù)問(wèn)題迫在眉睫。本文以漓江江心洲為研究對(duì)象,考察了江心洲植物群落與土壤之間的關(guān)系,探討了漓江流域不同類(lèi)型江心洲的基本特征、植被演替規(guī)律及內(nèi)在驅(qū)動(dòng)力,研究了不同類(lèi)型江心洲植被生長(zhǎng)的主要影響因子,旨在為漓江江心洲近自然植被恢復(fù)和河流管理提供理論依據(jù)與技術(shù)參考。研究成果如下：(1)通過(guò)對(duì)江心洲環(huán)境影響因子的分析,篩選出植被生物量、相對(duì)高程差、坡度、礫石含量、土壤含水量、土壤有機(jī)質(zhì)含量、江心洲面積、土壤速效氮、土壤速效鉀和土壤PH值作為劃分江心洲類(lèi)型的指標(biāo)。運(yùn)用相關(guān)性分析和主成分分析法,精選出植被生物量、相對(duì)高程差、坡度、礫石含量、作為主導(dǎo)因子,進(jìn)行聚類(lèi)分析,將江心洲劃分為草本型江心洲、灌草型江心洲和喬灌草型江心洲3種不同類(lèi)型的江心洲。(2)18個(gè)漓江江心洲上共有植物86種,隸屬41科81屬,其中草本植物65種,灌木10種,喬木11種。江心洲草本植物優(yōu)勢(shì)種為狗牙根、苔草、活血丹等,灌木優(yōu)勢(shì)種為楓楊、水楊梅等,喬木優(yōu)勢(shì)種為楓楊和桑樹(shù)。三種類(lèi)型江心洲四周多樣性均呈現(xiàn)出洲尾側(cè)和遠(yuǎn)離主河道側(cè)植物群落多樣性大于洲頭及洲右側(cè)(主河道側(cè))的特性。三種類(lèi)型江心洲的土壤砂粒含量均大于60%,隨著江心洲演替階段的增加,砂粒含量、土壤容重和土壤含水量都呈現(xiàn)先減小后增大的趨勢(shì),土壤礫石含量呈減小的趨勢(shì)。土壤pH值呈逐漸減小的趨勢(shì),但均偏弱堿性,土壤有機(jī)質(zhì)、全氮、全磷、全鉀、速效磷呈先增后減的趨勢(shì),速效氮呈現(xiàn)先減后增的趨勢(shì),速效鉀呈現(xiàn)逐漸增大的趨勢(shì)。(3)通過(guò)對(duì)漓江流域江心洲植被演替的研究表明：草本型江心洲處于一年生和多年生草本植物優(yōu)勢(shì)種為主的正向演替階段,灌草型江心洲處于多年生草本、灌木和低矮喬木為主要優(yōu)勢(shì)種的正向演替階段,在江心洲植物群落演替的過(guò)程中群落的穩(wěn)定性由草本型的24.3減少到喬灌草型的18.64,呈增大趨勢(shì),物種的生態(tài)位寬度趨于平衡,草本植物由最初的耐旱、耐淹型變?yōu)橄碴�、潮濕�?群落多樣性、均勻度及豐富度均呈增加趨勢(shì)。江心洲植物群落演替過(guò)程為：草本型→灌草型→喬灌草型揭示演替規(guī)律。漓江流域江心洲植物群落演替的主要驅(qū)動(dòng)力為江心洲優(yōu)勢(shì)種植物的更替和優(yōu)勢(shì)種植物對(duì)惡劣的環(huán)境的適應(yīng)性。(4)洪水是江心洲的主要干擾因素,汛期前后植被科、屬、種及生物量均呈增加趨勢(shì),多樣性、優(yōu)勢(shì)度、均勻度汛期前后無(wú)明顯差異。洪水對(duì)草本型江心洲的土壤理化性質(zhì)影響最大,喬灌草型江心洲影響最小,其中草本型江心洲土壤容重、土壤有機(jī)質(zhì)、全氮、全磷和pH值汛期前后存在顯著差異,灌草型江心洲只有土壤含水量、土壤容重和PH值有變化,喬灌草型江心洲除了pH值以外其他均無(wú)明顯差異。(5)草本型江心洲的植被影響因子為洪水、土壤、地形及人為干擾,其植被恢復(fù)模式為優(yōu)勢(shì)種植物草種播撒及移栽搭配石籠護(hù)坡工程措施；灌草型江心洲的植被影響因子為洪水、速效鉀,速效磷、土壤有機(jī)質(zhì)、土壤全氮、相對(duì)高程差和人為干擾,其植被恢復(fù)模式為優(yōu)勢(shì)種植被移栽搭配石籠護(hù)坡工程措施；喬灌草型江心洲的植被影響因子為土壤有機(jī)質(zhì)、坡度、相對(duì)高程差和人為干擾,其植被恢復(fù)模式主要以自然恢復(fù)為主,植被補(bǔ)植和卵石干砌護(hù)岸措施,這為漓江江心洲生態(tài)修復(fù)過(guò)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.
【學(xué)位授予單位】：北京林業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：Q948
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本文編號(hào)：2209723