内蒙古温带草原典型草地生态系统生产力对水分在不同时间尺度上的响应  

Response of Gross Primary Productivity to Water Availability at Different Temporal Scales in a Typical Steppe in Inner Mongolia Temperate Steppe

作　　者：郭群[1] 李胜功[1] 胡中民[1] 赵玮[1,2] 王敏[3] 

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [2]中国科学院大学,北京100049 [3]环境保护部环境与经济政策研究中心,北京100029

出　　处：《中国沙漠》2015年第3期616-623,共8页Journal of Desert Research

基　　金：国家自然科学基金项目(31400425;41301043);中国科学院地理科学与资源研究所青年人才项目(2013RC203);科技部科技支撑项目(2013BAC03B03);中国科学院青年创新促进会项目

摘　　要：水分是干旱、半干旱区草地生态系统生产力的主要限制因素,但水分如何影响生产力的季节内变异,以往研究相对不足。本研究以内蒙古温带典型草原为研究对象,基于多通道自动原位监测箱系统获得的生态系统日尺度总初级生产力(GPP)及遥感植被归一化指数估算年尺度的地上净初级生产力数据,在不同时间尺度上研究了水分对生产力的影响。结果表明:年降水量对该典型草原草地生态系统地上净初级生产力年际变异无显著影响,但土壤水分显著影响GPP的季节变异,土壤水分解释了GPP季节变异的22%;其他环境因子对生产力的季节变异也有一定影响;温度是生态系统处于干旱时GPP的主要限制因素,GPP随温度的升高而降低;而辐射是生态系统处于湿润时GPP的主要限制因素,GPP随辐射的升高而升高。本研究结果将有利于提升未来降水格局改变对草地生态系统生产力影响的认识。Water is a main driver to the productivity of grassland in arid and semi-arid area,however,we have quite limit knowledge about how water availability impacts the intra-annual variations of productivity.In this study,we quantified the effects of water availability on productivity at different temporal scales based on daily gross primary productivity(GPP)measured by a multichannel automated chamber system and annual aboveground net primary productivity(ANPP)evaluated by normalized difference vegetation index.Our results showed that there were no significant effects of annual precipitation on the inter-annual variations of ANPP.However,we found a similar seasonal dynamics of GPP with the soil water content,and soil water content remarkably affected GPP.Soil water content contributed to the 22%intra-annual variations of GPP.Our results also demonstrated that besides soil water,there were other environmental factors that affected the intra-annual variations of GPP.Air temperature determined the intra-annual variations of GPP when the soil water condition was relatively dry,and GPP decreased with increasing air temperature.Radiation was the dominant factor to affect the intra-annual variations of GPP when the soil water condition was relatively wet,and GPP increased with increasing radiation.The effects of other environmental factors on GPP may explain the weaker explanation power of annual precipitation to the inter-annual variations of productivity.Our results may help to thoroughly understand the effects of altering precipitation regimes on grassland productivity in the future.

关 键 词：温带草原 生产力 降水 

分 类 号：S812[农业科学—草业科学]