关键词: 碳稳定同位素, 氮稳定同位素, 青藏高原, 高寒草甸生态系统, 碳氮循环

Abstract: 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 (δ¹³C and δ¹⁵N) of plants and soils in alpine meadow, such as altitude, moisture, fertilization, grassland degradation, and temperature. The values of plant δ¹³C were positively correlated with altitude, and negatively correlated with atmospheric pressure, grassland degradation and temperature. The relationship between plant δ¹³C and precipitation was non-linear. The values of soil δ¹³C were positively correlated with altitude and grassland degradation. The values of plant δ¹⁵N were positively correlated with soil moisture and fertilization, and negatively correlated with grassland degradation. Secondly, we reviewed the current application and progresses of ¹³C and ¹⁵N 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 ¹³C and ¹⁵N isotopes application in researches on soil organic carbon and soil respiration in the alpine meadow, transitions of vegetation type, and climate change, soil N₂O trace, exploration of vegetation degradation, identification of the origin of Tibetan medicine and animal food, etc. ¹³C and ¹⁵N isotopes could be widely used and play important roles in researches on the alpine ecosystems.

Key words: ¹³C isotope, ¹⁵N isotope, Qinghai-Tibet Plateau, alpine meadow ecosystem, nutrient cycle