Effects Of Species Richness And Evenness On Litter Decomposition And N And P Release In Alpine Meadow Of The Tibetan Plateau

With the intensification of global climate change, frequent human activities and the increasing grazing intensity, biodiversity has changed, which could affect ecosystem function. As one of the important ecosystem functions, litter decomposition has a feedback on species composition and biodiversity and it restricts the return of nitrogen, phosphorus and other nutritional elements to the soil, therefore it plays a very important role in the balance of the substances in the soil. Many studies on litter decomposition have focused on species richness and composition, but less on species evenness. We selected5species (Anemone rivularis, Ligularia virgaurea, Elymus nutans, Thermopsis lanceolata and Kobresia capillifolia) in alpine meadow of the Tibetan Plateau, and investigated how species richness and evenness of leaf litter mixture affected decomposition and N P release. We set5levels of species richness (1,2,3,4,5) and2levels of species evenness, which included uneven mixture (proportion in the natural community for the studied species). The results showed:species richness had a significant effect on litter mass loss; species evenness also had a significant effect on litter decomposition, with faster mass loss in even mixtures than in uneven mixtures; species evenness had a significant effect on release of N and P, with net release faster in even mixtures than in uneven mixtures, and the N showed a decomposition pattern of enrichment-release, while P displayed a net release. The study suggests that variation of species composition and abundance, caused by alpine meadow degradation, will affect litter decomposition and N and P release, thereby grassland ecosystem functions.