高山草甸垂穗披碱草人工草地群落特征及稳定性研究

通过对江河源区人工草地建成后植被恢复效果、生长动态、植物群落特征、环境因子及其演替的分析表明：植物生长季节，垂穗披碱草人工、半人工草地地上生物量和高度的增长趋势符合“慢（初期）-快（中期）-慢（后期）”的S型规律，植被盖度的增长趋势符合“快（初期）-慢（中期）-慢（后期）”的规律。人工草地建植后第二年，物种多样性指数、生物量、优势种群特征、草场质量和土壤特征因不同草地类型而有所变化。人工草地在建成后4年内植物群落由“生产稳定性”急剧向“生态稳定性”转化，呈现出明显的退化态势，退化原因与毒杂草侵入和有效养分逐步匮缺有关。加强高寒地区人工草地建成以后的后期管理如灭杂、灭鼠、施肥和禁止放牧等，对防止人工草地退化，提高利用效率，保证垂穗披碱草人工草地生产稳定性与生态稳定性之间的平衡极为重要。

The Community Characteristics and Stability of the Elymus nutans Artificial Grassland in Alpine Meadow

The restoring effects,growing dynamics,plant community characteristics,environmental factors and succession were analyzed,respectively, after the construction of Elymus nutans artificial grassland in the source region of Yangtze and Yellow rivers.The results were as follows.The increasing trends of the aboveground biomass and the height of the E.nutans artificial and semi-artificial grassland showed S type(slow-fast-slow) while that of the vegetation community has the pattern of "fast-slow-slow".The species diversity index,biomass,dominant population,grassland quality and soil features depended on the types of grassland.The artificial grassland degraded from "productivity stability" to "ecological stability" quickly during the 4 years since they were constructed.The degradation was correlated with invasion of poisonous forbs and deficiency of soil available nutrients.The means of management after the construction of artificial grassland,such as weed control,mice control,fertilizing and grazing release,was very important to holdback the degenerative succession,to increase the utilized efficiency,to maintain the balance of the E.nutans artificial grassland between the "productivity stability" and "ecological stability".