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".