摘要
在全球变化的背景下,内蒙古草原生态系统的降水量可能增加或者减少.迄今,降水量的改变对该区域草地生态系统碳交换的影响我们还知之甚少.为此,本研究通过完全控水防雨棚,开展了降水梯度实验,探究该生态系统碳交换(ecosystem carbon exchange)随降水量变化的响应轨迹.结果表明:随着生长季降水量从100mm增加到500mm,净生态系统碳交换(net ecosystem exchange,NEE)、生态系统呼吸(ecosystem respiration,ER)和生态系统总生产力(gross ecosystem productivity,GEP)均显著提高,这些过程均表现为明显的非线性响应.NEE、ER和GEP的饱和点对应的降水量分别为350mm,200mm和275mm.从响应率的变化斜率看,降水量减少(<275mm的处理)的效应显著强于降水量增加(>275mm的处理)的效应.变异来源分析说明,随着降水量的改变,群落生物量是草原生态系统碳交换的首要影响因素,可以解释NEE、ER和GEP变异的30.89%、41.90%和40.60%,而土壤含水量和土壤温度只能解释NEE、ER和GEP变异的11.51%、7.78%和9.28%.上述结果为我们理解和预测未来降水变化对内蒙古温带典型草原生态系统碳交换的影响提供了依据.
Under the global change context,the amount of precipitation in Inner Mongolian grassland ecosystem is predicted to increase or decrease. However, the potential impacts of these changes on ecosystem carbon exchanges remain poorly under- stood. To address this issue, a precipitation manipulation experiment was conducted by using fully-controlled rainout shelters in Inner Mongolian grassland ecosystem. The results showed that,with the increase of precipitation amount from lOOmm to 500mm, net ecosystem exchange （NEE） ,ecosystem respiration （ER） and gross ecosystem productivity （GEP） all increased significant- ly, but followed a nonlinear trajectory. The saturation points for NEE, ER and GEP were observed at the precipitation levels of 350mm, 200mm and 275mm, respectively. Based on the slopes of response rate of NEE, ER and GEP to decreased and increased precipitation amount, precipitation reduction had stronger impacts on three parameters related to precipitation increase. Variation partioning analysis indicated that community biomass production was the primary factor influencing ecosystem carbon exchan- ges. Community biomass alone can explain 30. 89% ,41.90% and 40. 60% of variation in NEE ,ER and GEP,respectively. Soil moisture and soil temperature jointly can only explain 11.51% ,7. 28% and 9. 28% of variation in NEE,ER and GEP,respec- tively. These results have implications for better understanding and predicting the impacts of precipitation changes on ecosystem carbon exchanges in typical steppe ecosystems in Inner Mongolia.
作者
朱建军
张彬
严月
潘庆民
ZHU Jian-jun ZHANG Bin YAN Yue PAN Qing-min(State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P. R. C. School of Ecological and Environmental Science, Inner Mongolian Agricultural University, Huhhot 010018, P. R. C School of Life Sciences, Jiangxi Normal University, Nanchang 330022, P. R. C.)
出处
《西南民族大学学报（自然科学版）》
CAS
2016年第5期516-524,共9页
Journal of Southwest Minzu University(Natural Science Edition)
基金
国家自然科学基金项目(30970496)
关键词
全球变化
碳通量
降水格局
非线性响应
global change
ecosystem carbon fluxes
precipitation regime
nonlinear response
