不同海拔高寒放牧草甸的生态系统呼吸与环境因子的关系

Relationships between ecosystem respiration and environmental factors of alpine grazing meadows along an altitudinal gradient(4300～4700m)

在全球变化的背景下,为了研究藏北高寒放牧草甸的生态系统呼吸和土壤呼吸特征,沿着3个海拔高度(4 300、4 500和4 700 m)观测了2010年7-9月白天的呼吸通量。同时,观测了同期的土壤温度、土壤水分含量、空气温度和相对湿度,在定性分析土壤水分含量和呼吸通量关系的基础上,将其分成低、中和高3个水平,在此基础上,分析生态系统呼吸、土壤呼吸与土壤温度、土壤水分含量、空气温度以及相对湿度的关系。结果表明,空气温度是决定生态系统呼吸和土壤呼吸变异的主导因子;生态系统呼吸、土壤呼吸以及裸地的土壤呼吸的Q10值分别为1.83～3.07、1.54～4.13和1.29～2.89;总体而言,生态系统呼吸和土壤呼吸Q10值随着海拔的升高和土壤水分含量的增加而增大。

The daytime ecosystem respiration and soil respiration from July to September in 2010 along an altitudinal gradient（4300~4700 m） were measured in order to study the character of ecosystem respiration and soil respiration under global change.Meanwhile,soil temperature,soil water content,air temperature and relative humidity were also measured.A qualitative analysis of soil water content and respiration flux was conducted.Then soil water content was divided into three levels.According to the three levels,the relationships between respiration flux and soil temperature,soil water content,air temperature and relative humidity were analyzed.Air temperature was the dominant factor controlling the variation of ecosystem respiration and soil respiration.The Q10 values of ecosystem respiration,soil respiration and soil heterotrophic respiration were 1.83~3.07,1.54~4.13 and 1.29~2.89,respectively.Overall,the Q10 increased with increasing altitude and soil water content.