Abstract: Alpine meadow in China is degrading, seriously influencing species diversity and biomass production of vegetation. In this study, we chose a typical alpine meadow in QinghaiTibetan Plateau as a model system by establishing four treatments, including control (CK), 3-year warming (W), 2-year clipping (C), and 3-year warming + 2-year clipping (WC). The experiment followed a randomized block design consisting of five replications. We measured  species diversity (Margalef index, Shannon index, Simpson index and Pielou index) and belowground biomass of the vegetation in all treatments during the growing season of 2012 and 2013. The aim of this study was to assess the effects of warming and clipping on plant species diversity and  belowground biomass. The results showed that: (1) Species diversity was significantly higher in the middle growing season (from June to August) than in the early (May) and late (September) growing season. (2) The response of species diversity was not sensitive to 3-year warming and 2-year clipping, and species diversity was slightly increased in the W and C treatments while slightly decreased in the WC treatment. (3) Warming and clipping tended to increase vegetation belowground biomass and caused the variation of allocation pattern of belowground biomass across different soil layers. Clipping had significant effects on biomass in the 0-30 cm soil layer, whereas warming had significant effects on biomass in the 30-50 cm soil layer.

Key words: subalpine forest, soil respiration, dissolved organic matter, naphthalene, microbial biomass