江河源区高山嵩草草甸覆被变化对植物群落特征及多样性的影响
Effects of Vegetation Cover Change of Alpine Kobersia Meadow on Plant Community Structure and Diversity in Source Region of the Yangtze and Yellow River

王文颖 ¹ 王启基 ² 景增春 ² 李世雄 ¹ 史惠兰 ¹

文摘	本研究是在青海省达日县青珍乡进行的，分析了高山嵩苹草句不同退化演替阶段覆被变化与植物群落特征、多样性关系。研究结果表明：轻度退化草地、中度退化草地、重度退化草地物种数分别占研究区物种数的58．93％、73．2l％、66、07％。原生植被的优势种高山嵩草随退化程度的加剧而逐渐减少，其优势度分别为27．13％、12．37％、1．82％。物种多样性指数依次为中度退化演替阶段（3．41）〉重度退化演替阶段（3．39）〉轻度退化演替阶段（2．99）；均匀度指数依次为重度退化演替阶段（O．94）〉中度退化演替阶段（0．92）〉轻度退化演替阶段（0．86）。地上生物量中度退化草地最大，轻度退化草地居中，重度退化草地最低。随着退化程度的加剧。禾草类和莎草类植物的生物量减少，而杂类草增加。轻度退化草地地下生物量明显高于退化草地。相关分析表明。植被盖度与土壤含水量之间呈极显著的正相关关系（P〈0．01）。
其他语种文摘	The effect of vegetation cover change on plant community structure and species diversity of alpine Kobersia meadow was studied in Qinzheng of Gande County of Qinghai Province. The results showed that the species number is 33 on light degraded grassland, and dominant species is Kobresia pygmaea and subdominant species are PotentiUa nivea, Saussurea superba and Festuca ovina. The species number is 41 on medium degraded grassland, and dominant species is Kobresia pygmaea and subdominant species are Oxytropis melanocalyx Ligularia virgaurea and Stipa aliena. On severely degraded grassland, the species number is 37, dominant species are Aster alpinum and Ligularia virgaurea, and subdominant species are Artemisia annua, K. humilis and Morina chinensis. The percentage of Species number oc.cupying total species number of study site on light, medium and severely degraded grassland are 58. 93%,73. 21% and 66. 07%, respectively. Dominance of Kobersia pygmaea decreased with the degradation of grassland. The rate of dominance is 27.13 %, 12.37% and 1.82% for light, medium and severely degraded grassland, respectively. Along grassland degradation series, Kobresia pygmaea that reproduce by clone in an alpine environment disappears gradually while the species such as Ligularia virgaurea, Aster alpinum, Leontopodium nanum and Elymus nutans that reproduce by seeds develop rapidly due to change of soil micro-environment. Species diversity ranked as medium degraded grassland （3.41）〉 severely degraded grassland （3.39）〉 light degraded grassland （2.99）. Evenness index ranked as severely degraded grassland （0.94）〉 medium degraded grassland （0.92）〉 light degraded grassland （0.86）. Aboveground biomass in medium degraded grassland ranked at the top, followed by light degraded grassland and severely degraded grassland. Grass and sedge biomass decreased and herb biomass increased with grassland degradation. Belowground biomass in light degraded grassland is higher than in severely degraded grassland. Soil water content in 0 ~ 20 cm profile in light degraded grassland is significant higher than that in severely degraded grassland （p 〈 0.01 ）. Correlation analysis showed that there is a significant positive correlation between vegetation cover and soil water content. Soil waterretaining capacity increases with the increase of vegetation coverage.
来源	资源科学 ,2006,28(2):118-124 【核心库】
关键词	江河源区 ; 覆被变化 ; 植物群落特征 ; 物种多样性
地址	1. 青海师范大学生命科学系, 西宁, 810008 2. 中国科学院西北高原生物研究所, 西宁, 810001
语种	中文
文献类型	研究性论文
ISSN	1007-7588
学科	林业;畜牧、动物医学、狩猎、蚕、蜂
基金	国家“十五”科技攻关重大项目
文献收藏号	CSCD:2332292