【作者】 乌仁其其格；

【导师】 武晓东；

【作者基本信息】 内蒙古农业大学 ， 草业科学， 2009， 博士

【摘要】 本研究以呼伦贝尔草甸草原羊草+杂类草群落和贝加尔针茅+羊草群落为研究对象,于2007-2008年通过野外调查和室内分析,对不同退化程度下植物群落组成与结构特征、土壤的理化特征、土壤微生物类群数量定量分析研究,并对植被与土壤因子进行主成分和典型相关分析,对所获得的植被与土壤因子的指标体系模糊综合评价,获得了能表示不同退化程度的差异性系数—指示度。结论如下:1.随着草地退化程度的增加,群落物种组成逐渐单一,数量逐渐减少,物种重要值变化明显,群落科属组成发生明显变化,多年生植物逐渐减少;群落盖度、群落高度、地上现存量、地表凋落物和地下生物量显著降低;植物α多样性各指数显著降低,植物群落的β多样性指数逐渐增大,群落相似性系数逐渐变小。2.土壤理化性质和微生物类群数量在0～10cm变化显著。土壤粗粒和容重显著提高,土壤含水量显著降低。土壤有机物和全氮含量轻度退化区显著高于中度和重度退化区。速效养分变化显著,pH值变化不明显;细菌和放线菌的数量显著降低,真菌的数量显著增加。3.草甸草原羊草+杂类草群落和贝加尔针茅群落不同退化程度下植物与土壤因子之间相关不一致。4.根据植被与土壤相结合为指标体系的模糊综合评价得出的指示度分别为;羊草+杂类草群落中度退化区为0.7426、重度退化区为0.5611;贝加尔针茅+羊草群落中度退化区为0.7702、重度退化区为0.5980。更多还原

【Abstract】 The characteristics of community and structure, The physical and chemical characteristics of soil, the amount of microbes of soil in the Leymus chinensis +forb community and Stipa baicalensis + Leymus chinensis community under the different degeneration scale were investigated in 2007 and 2008. The data obtained from the experiment were analyzed with the principal components, the canonical correlation and fuzzy comprehensive evaluation method, which obtain coefficient of different degradation scale known as indication. The results were shown as follows:1. The composition of community species was gradually unitary, quantity reduced, the important value of species and the composition of Family-Genus varied obviously, and the perennial plants gradually reduced with grassland degeneration. The coverage, height, above-ground biomass, surface litter and the underground biomass of grassland community reduced obviously with grassland degeneration. The indexes ofα-diversity of community decreased obviously, the index ofβ-diversity of community increased gradually, and the similarity coefficient of community in the different degeneration scale was a declining trend with grassland degeneration.2. The physical and chemical characteristics of soil in the 0～10cm soil layer were obviously changed. The soil coarse particle and bulk density were significantly increased. Soil moisture content was significantly decreased. The soil organic matter content and the soil total nitrogen content were significantly higher in light degradation (LD) than in heavy degradation (HD) and moderate degradation (MD). The available nutrient varied significantly, but the pH had no significant change. The amount of bacterium and ray fungi reduced obviously, and the amount of fungus increased obviously.3. There were no consistent correlation between vegetation and soil factor under different degeneration scale at Leymus chinensis +forb community and Stipa baicalensis + Leymus chinensis community.4. The indication of MD and HD, according to the fuzzy comprehensive evaluation of vegetation and soil, at Leymus chinensis +forb community, were 0.7426 and 0.5611, respectively, and at Stipa baicalensis + Leymus chinensis community, were 0.7702 and 0.59804, respectively.更多还原