呼伦湖地区草原植被特征及其动态变化

发布时间：2018-01-13 02:02

本文关键词：呼伦湖地区草原植被特征及其动态变化　出处：《中央民族大学》2017年硕士论文　论文类型：学位论文

【摘要】：呼伦贝尔草原属于我国北方草原的重要组成部分,并作为我国北方地区不可或缺的生态屏障。呼伦湖是内蒙古地区最大的淡水湖,对整个呼伦湖地区的生态系统平衡起到关键的作用。近年来,随着全球气候的变暖、以及过度放牧、过度打草等人类活动,使得呼伦湖地区草地退化日益严重,加之湖水的缩减,导致草地沙化、盐碱化、以及物种多样性减少。因此,开展呼伦湖地区草原植被的相关研究对于探讨我国北方地区草原生态系统动态变化规律具有重要的学术价值,同时对于整个呼伦贝尔草原的生态保护具有重要意义。本文对呼伦湖地区5种不同类型的典型草原植被以及植被组成结构进行了实地调查和观测研究;结合当地气候条件以及气象站数据,运用LI-6400型光合系统对不同草原植被优势种的光合特性进行了实地观测;通过遥感影像数据对研究区1991-2010年期间植被覆盖度变化进行分析研究。通过上述研究,得到如下研究结果:(1)研究区植被组成主要以禾本科、菊科为主,群落的组成相对复杂,植被多样性较高,其中以贝加尔针茅(Stipa baicalensis)草原和大针茅(Stipa grandis)草原植被丰富度相对较高,以多年生草本植物为主,呈现半干旱植被特征。(2)研究区所调查植被的区系地理成分研究表明,从科的角度来看,以世界分布为主;从属的角度来看,5种草原植被均以北温带分布为主;其中贝加尔针茅草原的分布类型最多,表明其物种组成结构相对复杂,适应能力较强。(3)根据植物多样性指数分析结果可知,5种类型草原植被中,贝加尔针茅草原和大针茅草原的物种丰富度相对较高,且多样性指数最大。(4)从地上生物量的研究表明,5种类型草原植被的地上生物量具有一定差异性。其中大针茅草原地上生物量最大,羊草(Leymus chinensis)草原和贝加尔针茅草原地上生物量相对较高,冷蒿(Artemisia frigida)草原地上生物量相对较低。(5)植被优势种光合特性研究表明,冷蒿的光合能力较强,暗呼吸速率较弱,其光合利用效率相对最高,对光的响应较为敏感;植物的光响应曲线观测和模拟研究表明,决定系数R2均已经达到0.97以上,说明模型从整体上对5种植物的拟合效果较好。(6)研究区植被动态变化研究结果显示,1991-2010年期间,不同植被覆盖度等级变化较为明显,水体面积逐渐减小。其中1991年,中高等覆盖度最高,达到35.95%;1995年,中等覆盖度最高,达到59.16%。水体面积由1991年的3270km2下降到2010年的2780km2,对当地植被产生一定影响,其生态环境趋于脆弱。
[Abstract]:An important part of Hulun Buir Grassland belong to the grasslands of northern China, and as the ecological barrier in northern China indispensable. Hulun Lake is the largest freshwater lake in Inner Mongolia, it's crucial to the balance of the entire ecosystem of Hulun Lake area. In recent years, with the global warming, and overgrazing, excessive grass and other human the activities of Hulun region grassland degradation is becoming increasingly serious, and the water cut, leading to grassland desertification, salinization, and species diversity reduced. Therefore, carrying out research on grassland vegetation in Hulun Lake has important academic value to explore the dynamic changes of grassland ecosystem in the northern area of our country, and has important significance for ecological the protection of the whole Hulun Buir Grassland. 5 different types of Hulun Lake area of typical grassland vegetation and vegetation composition structure The field investigation and observation research; combined with the local climate and weather station data, the use of LI-6400 photosynthetic system on Photosynthesis Characteristics of different grassland vegetation dominant species of light field observations; through remote sensing image data for the 1991-2010 period of vegetation coverage change were analyzed. Through the above research, the study are as follows results: (1) the vegetation of the study area is mainly composed of Gramineae, Compositae, community composition is relatively complex, vegetation diversity is higher, the Stipa baicalensis (Stipa baicalensis) grassland and Stipa grandis steppe vegetation richness (Stipa grandis) is relatively high, with perennial grasses, showing the characteristics of vegetation in semi-arid (2.) of floristic study area the vegetation survey shows that, from the point of view, the distribution in the world; subordinate perspective, 5 were divided by north temperate grassland vegetation The distribution types of cloth; stipabaicalensissteppe most, showed that the species composition is relatively complex structure, strong ability to adapt. (3) according to the plant diversity index analysis results, 5 types of grassland vegetation, species richness of Stipa baicalensis grassland and Stipa grandis grassland is relatively high, and biodiversity index (4 maximum.) from the study indicate that the aboveground biomass of the 5 types of grassland vegetation aboveground biomass had certain difference. The aboveground biomass of Stipa grandis steppe of Leymus chinensis (Leymus, chinensis) grassland and Baikal esparto aboveground biomass is relatively high (Artemisia FRIGIDA), Artemisia frigida grassland aboveground biomass relative low. (5) the vegetation dominant species photosynthetic characteristics of Artemisia frigida, photosynthetic ability, dark respiration rate is weak, the photosynthetic efficiency is highest, response to light is sensitive; plant response to light. Study and Simulation of line observations show that the coefficient of determination R2 has reached more than 0.97, indicating good model from the whole of the 5 species fit. (6) results in study area vegetation dynamic change research shows that during the period of 1991-2010, different vegetation coverage level changes are relatively obvious, the water area decreased gradually. In 1991, in the the higher coverage is the highest, reaching 35.95%; in 1995, the highest secondary coverage reached 59.16%., the water area decreased from 3270km2 in 1991 to 2780km2 in 2010, has a certain impact on the local vegetation, the ecological environment tends to be fragile.

【学位授予单位】：中央民族大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812

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