[Carbon and nitrogen stable isotopes technology in the researches on alpine meadow ecosystem in Qinghai-Tibet Plateau: Progress and prospect].

Carbon and nitrogen stable isotopic technique has been widely used in research of glassland ecosystems. Here, we summarized studies using carbon and nitrogen stable isotopes in the alpine meadow ecosystem on the Qinghai-Tibet Plateau. Firstly, we reviewed the environmental factors which influenced carbon and nitrogen isotope composition (δC and δN) of plants and soils in alpine meadow, such as altitude, moisture, fertilization, grassland degradation, and temperature. The values of plant δC were positively correlated with altitude, and negatively correlated with atmospheric pressure, grassland degradation and temperature. The relationship between plant δC and precipitation was non-linear. The values of soil δC were positively correlated with altitude and grassland degradation. The values of plant δN were positively correlated with soil moisture and fertilization, and negatively correlated with grassland degradation. Secondly, we reviewed the current application and progresses of C and N in the identification of plant photosynthetic type, water use, nutrient transport along food chain and carbon and nitrogen cycle in the alpine meadow. Finally, we prospected the C and N isotopes application in researches on soil organic carbon and soil respiration in the alpine meadow, transitions of vegetation type, and climate change, soil NO trace, exploration of vegetation degradation, identification of the origin of Tibetan medicine and animal food, . C and N isotopes could be widely used and play important roles in researches on the alpine ecosystems.