中文摘要：

以内蒙古呼伦贝尔草原、科尔沁草原、锡林郭勒草原等为研究区域,借助群落分层取样方法,科学估测内蒙古典型草原的生物量碳分配情况,主要结论如下：1）我国内蒙古典型草原的平均生物量碳密度为400.56 g C/m^2,其中羊草-杂类草（585.18 g C/m^2）、冷蒿-其他小禾草（505.68 g C/m^2）以及克氏针茅群落（501.45 g C/m^2）具有较高的地下生物量碳密度。2）内蒙古典型草原拥有32.26×10^6hm^2的面积,贡献了112.76 Tg的生物量碳,其中地上生物量碳20.42 Tg,地下生物量碳92.34 Tg。3）根冠比（R∶S）分布上,内蒙古典型草原的平均根冠比数值为4.52,要大于一般草地类型。4）地下生物量碳（BGB）沿土壤深度的分布情况,糙隐子草、克氏针茅、羊草-杂类草、羊草-丛生禾草、大针茅、冰草等草本群落均属于＂指数型＂,即BGB沿深度分布符合指数函数,主要分布在0～10 cm土壤层;冷蒿-糙隐子草、冷蒿-其他小禾草、差巴嘎蒿群落等灌丛群落的BGB分布曲线为＂抛物线形＂,其地下生物量碳主要分布于20～40 cm土壤层,不符合指数函数但符合二次函数。

英文摘要：

Grasslands are one of the most widespread landscapes worldwide,covering approximately one-fifth of the world＇s land surface.China＇s grasslands cover only 6%-8% of total grassland area worldwide,but contain 9%-16% of the total carbon stored in the world＇s grasslands.Although some progress has been made in monitoring and understanding the factors affecting carbon partitioning,the role of species composition in carbon partitioning is still not fully understood.In this study,we evaluated the biomass distribution patterns and other vegetation indexes in several different steppes,including the Hulunbuir,Horqin,and Xilinguole Steppes.Unlike the random sampling method used in other studies,our study used a stratified sampling method to sample different communities in the typical steppes of northern China.The average biomass carbon density was 400.56 g C/m^2 in the typical temperate steppe.Among the different plant communities,Leymus chinensis-cluster（585.18 g C/m^2）,Artemisia frigida-others（505.68 g C/m^2） and Stipa krylovii（501.45 g C/m^2） had the highest belowground biomass（BGB）.The temperate typical steppe contributed 112.76 Tg biomass carbon with an area of 32.26×10^6hm^2,where the aboveground biomass was 20.42 Tg and the BGB was 92.34 Tg.The root∶shoot ratio in the temperate typical steppe was 4.52,which was higher than those of other grassland types.There were two types of BGB distribution： the exponential function type,in which the BGB was mainly distributed at a soil depth of 0-10 cm; and the quadratic function type.The BGB distribution showed the exponential function type in the Cleistogenes squarrosa,S.krylovii,L.chinensis-cluster,L.chinensis-forbs,S.grandis,and Agropyron cristatum communities.The BGB distribution showed the quadratic function type in the A.frigida-C.squarrosa,A.frigida-others,and A.halodendron communities.Evaluation of grassland biomass carbon storage in different grassland communities can clarify the dynamics of carbon storage.The results of this study provide a the