The influence of disturbance on community structure and plant diversity of alpine meadow

The main purpose of this study was to examine the effects of disturbance nutrient addition, enclosure,(middle and heavy) grazing on community structure, plant diversity, and functional group. The results showed that nutrientaddition leads to a decrease in species diversity; middle grazing increases the complexity of plant community and plant diversity, supporting the hypothesis of intermediate disturbance; heavy grazing, because of it serious influence on plant community, results in a low richness and diversity index; while enclosure, the light disturbance, with the community dominated by few species, have lower diversity too. The five diversity indices (species number, richness index, ShannonWiener index, Simpson index and evenness index) changes in an increasing order, as follows: nutrient addition enclosure heavy grazing middle grazing.However,the dominance shows a reverse trend. The plant species within four disturbance communities were classified into functional groups based on the differences in life form. Although the four communities had the similar functional groups,which all was composed of perennial grasses, perennial forbs and sedges, the proportion of each group in different community and the species diversity within the functional groups are quite different. This result suggests that the type of disturbance had different effect on species compositions, diversity patterns and ecosystem functioning in alpine meadow pasture. 