内蒙古草甸草原生物量碳分配格局

以中国北方草甸草原为研究对象,借助GIS等工具手段,在草地群落类型实测数据基础上,对内蒙古草甸草原的地上/地下生物量分配开展定量研究,主要结论如下:1)内蒙古草甸草原的生物量碳密度为660.43 g C/m²,其中地榆群落(460.63 g C/m²)具有最高的地上生物量碳密度,地榆群落(787.10 g C/m²)和五花草塘群落(776.22 g C/m²)具有最高的地下生物量碳密度,其他群落间则不存在显著性差异(P>0.05);2)温带草甸草原以16.60×10⁶ hm²的面积,贡献了111.20 Tg的生物量碳,其中地上生物量碳为27.57 Tg,地下生物量碳为83.63 Tg,根冠比(R∶S)为3.03;3)地下生物量沿土壤深度的分布可分为两种类型:线叶菊、芨芨草、野大麦、地榆、贝加尔针茅、苔草以及五花草塘群落属于“指数型”,其地下生物量主要分布在0~10 cm土壤层,且符合指数函数,该类型占据草原群落的主要部分;拂子茅、小叶锦鸡儿以及芦苇群落属于“抛物线”形,其地下生物量主要分布在0~10 cm和20~40 cm土壤层,该类别群落主要为灌木或半灌木,分布曲线不符合指数函数而符合二次函数。

Biomass allocation patterns in the temperate meadow steppe in Inner Mongolia

Grasslands are one of the most widespread landscapes worldwide,covering approximately one-fifth of the world’s land surface.Although China’s grasslands cover only 6% -8% of the world’s total grassland area,they store 9%-16% of the total carbon in the world’s grasslands.Many studies have focused on monito-ring and understanding the factors affecting carbon partitioning;however,the role of species composition in carbon partitioning is still not fully understood.In this study,we evaluated the biomass distribution patterns and other indexes of vegetation in the meadow steppe of northern China,based on geographic information sys-tems (GIS)tools and field data for different community types.The results showed that the average biomass carbon density was 566.35 g C/m2 in the temperate meadow steppe.Among the different plant communities, Sanguisorba officinalis with 460.63 g C/m2 had the highest aboveground biomass (AGB),while a tessellated meadow had the highest belowground biomass (BGB).However,there were no significant differences in BGB among other types of plant communities (P >0.05).The temperate meadow steppe contributed 111.20 Tg bio-mass carbon within an area of 12.90×10 6 hm2 ,where the AGB was 27.57 Tg and the BGB was 83.63 Tg.The root∶shoot in the temperate meadow steppe was 3.03.There were two types of BGB distribution:the expo-nential function type,in which BGB was mainly distributed in the first 0-10 cm soil depth,and the quadratic function type,in which the BGB was mainly distributed at soil depths of 0-10 cm and 20-40 cm.The BGB distribution was the exponential function type in the Filifolium sibiricum ,Achnatherum splendens ,Hordeum agriocrithon ,S .officinalis ,Stipa baicalensis ,Carex tristachya ,and the tessellated meadow communities, indicating that this type of BGB distribution was a characteristic of grassland communities.The Calamagrostis epigeios ,Caragana microphylla ,and Phragmites australis communities showed a BGB distribution that fit-ted the quadratic function,rather than the exponential function.Evaluation of grassland biomass carbon stor-age by different grassland communities is meaningful for understanding carbon storage dynamics.The results of this study provide a theoretical basis for developing management strategies and designing research on natural grasslands in northern China.