The role of plateau pika and plateall zokor in alpine meadow

As the key species, plateau pika and zokor play an important role in energy flow and nutrient circle of alpine meadow ecosystem in QinghaiTibetan Plateau. The negative effectiveness of plateau pika and zokor activities caused by extreme increase in number have been widely accepted by meadow managers but the positive effects of plateau pika and zokor activities on vegetation and soil should not be overlooked. Firstly, the population characteristics of plateau pika and zokor, which usually cause hazard in the QinghaiTibet Plateau, were briefly introduced, and then effects of two populations on vegetation and soil were discussed completely in this paper. This study proposed that plateau pika and zokor activities with the smaller density improved the community composition, plant diversity, biomass and seed dispersal; however, plateau pika and zokor activities with a higher density degraded vegetation and soil by increasing unpalatable plants and reducing plant height, cover and biomass, and accelerating soil erosion and reducing nutrients. The key problem of control plateau pika and zokor activity is to determine the causing hazard density and maintain the balance of alpine meadow ecosystem.