高寒草原不同植物群落地上-地下生物量碳分布格局

高寒草原具有独特的自然生境和生物资源,对高寒草原开展系统研究对于减缓气候变化与草原恢复具有重要实践意义。以往研究主要针对高寒草原生物量碳开展整体评估,缺乏对不同群落类型间的定量比较。本文分析了高寒草原10种主要典型植物群落地上-地下生物量碳分布格局以及对总生物量碳的贡献差异。结果表明:高寒草原面积为167.33×10^6hm^2,总生物量碳为1.53 Pg(1 Pg=1015g),其中地上生物量碳0.19 Pg,地下生物量碳1.34 Pg;紫花针茅、青藏苔草和紫花针茅-小蒿草群落面积大,生物量碳密度高,为高寒草原贡献了69.3%的生物量碳。高寒草原平均生物量碳密度为690.80 g C·m^-2,其中紫花针茅群落(196.14 g C·m^-2)和蔷薇群落(177.93 g C·m^-2)具有最高的地上生物量碳密度(AGC);蔷薇(1491.18 g C·m^-2)和紫花针茅-小蒿草群落(1306.51 g C·m^-2)则具有最高的地下生物量碳密度(BGC),且显著高于其他群落类型(P<0.05)。不同群落的BGC在土壤中的垂直分布格局存在较大差异,驼绒藜、盐爪爪、金露梅、紫花针茅、青藏苔草、紫花针茅-小蒿草、蔷薇、固沙草、砂生槐等群落的BGC主要集中在表层土壤(0~10 cm),分布曲线呈指数函数,而华扁穗草群落的BGC则集中在40~60 cm土壤层,分布曲线呈二次函数关系。对草原植物群落的地上-地下生物量碳开展评估,可以提高生物量碳的估算精度,为草原生态管理提供更有力的数据支持。

Above-and below-ground biomass carbon allocation pattern of different plant communities in the alpine grassland of China

Alpine grassland has unique natural habitats and biological resources.A comprehensive study of alpine grassland would be beneficial to climate change mitigation and grassland restoration.The estimation of carbon storage in alpine grassland biomass was often based on largescale spatial sampling,ignoring community composition and spatial difference of grasslands,which may affect the accuracy of results.The distribution pattern of above-and below-ground biomass and their contributions to total biomass carbon of 10 main vegetation types in the alpine grassland were analyzed.The results showed that:(1)Biomass carbon of the alpine grassland was 1.53 Pg(1 Pg=1015 g)within an area of 167.33×10^6 hm^2,with above-and below-ground biomass being 0.19 Pg and 1.34 Pg respectively.Stipa purpurea,Carex moorcroftii,and Stipa purpurea-Kobresia pygmaea communities contributed 69.3%to the total biomass of alpine grassland due to their large coverage and high biomass carbon density.(2)The average biomass car-bon density was 690.80 g C·m^-2 in alpine grassland.S.purpurea(196.14 g C·m^-2)and Rosa multiflora(177.93 g C·m^-2)had the highest aboveground biomass carbon density(AGC),while R.multiflora(1491.18 g C·m^-2)and S.purpurea-K.pygmaea(1306.51 g C·m^-2)had the highest belowground biomass carbon(BGC),which were significantly higher than other communities(P<0.05).(3)The vertical distribution of BGC could be divided into two types.Communities of Ceratoides latens,Kalidium foliatum,Potentilla fruticosa,S.purpurea,Carex moorcroftii,S.purpurea-K.pygmaea,R.multiflora,Orinus thoroldii and Sophora moorcroftiana were classified as the"exponential function type",with BGC of which being mainly distributed in the 0-10 cm soil depth.Blysmus sinocompressus community was classified as the"quadratic function type",with BGC of which being mainly distributed in the depth of 40-60 cm.Evaluation of above-and below-ground biomass carbon storage of different grassland communities is meaningful for improving the accuracy of biomass carbon estimation,providing data support for grassland management.