Ecological Stoichiometric Dynamics Of Plants And Soil Along A Successional Gradient In Subalpine Meadow Communities In Tibetan Plateau

Ecological stoichiometry is a discipline of studying element flow and balance between plants and the natural environment, playing an important role in ecological research nowadays.In the present thesis, we chose three successional stages in subalpine meadow communities:10 years after abandon (T10), T13 years after abandon and natural communities (T50), respectively. Based on the approach of space-for-time substitution and principles of succession and ecological stoichiometry, the ecological stoichiometry characteristics of soil and plants and their relationships with species richness and aboveground biomass were studied. Some main results were as following:(1) Total nitrogen in soil was highest in T13, and lowest in T10. However, total nitrogen in plants was highest in T50, and lowest in T13.In terms of total phosphorus, the highest content was found in T50 and the lowest in T13(2) In terms of organic matters in soil, the lowest was in T10 and the highest in T50. Meanwhile, with succession, soil organic matters content gradually increased.The highest pH of soil was found in T10, and the lowest in T50, which was in contrast with the pattern of organic matters.(3) In natural communities, soil total nitrogen, total phosphorus and soil N:P were significantly correlated with species richness. In T13, soil total phosphorus was significantly correlated with species richness, but not for soil total nitrogen or soil N:P. In T10, no significant relationships were found.(4) In terms of the relationships between soil N、P and aboveground biomass:in three successional stages, no significant relationships were found between aboveground biomass and soil total nitrogen, total phosphorus or soil N:P.