西鄂尔多斯荒漠灌丛生态系统碳密度

为了估算西鄂尔多斯天然荒漠灌丛生态系统碳密度并揭示碳储量在不同层片（灌丛植株、草本层、枯落物层及土壤层）、器官间的分配规律，以该区5种优势荒漠灌丛（沙冬青Ammopiptanthus mogolicus、霸王Zygophyllum xanthoxylum、四合木Tetraena mongolica、半日花Helianthemum songaricum和红砂Reaumuria songarica）群落为对象，测定了5种灌丛生态系统碳密度。结果表明：西鄂尔多斯5种荒漠灌丛生态系统碳密度40.28~55.51 t·hm^-2，其中土壤层碳密度占绝对优势（97.15%~98.51%），为39.40~54.48 t·hm^-2，且在0~50 cm随着土层深度的增加而增加；植被层生物量密度垂直分布格局表现为灌丛层 > 草本层 > 枯落物层，灌丛层碳密度空间上表现为距离黄河越近碳密度越大（沙冬青和半日花灌丛生物量碳分别占各自植被层生物量密度的92.16%和62.42%），而草本层碳密度表现出与之相反的规律；草本层根系生物量碳也是灌丛生态系统碳重要组成部分，碳密度8.41~38.29 g·m^-2，占植被层碳密度的5.36%~45.18%；除红砂灌丛外，灌丛草本层地下部分碳密度显著高于地上部分（P<0.05）；灌丛个体碳储量分布表现为枝条 > 根系 > 叶片，粗枝和粗根是单株灌丛碳储量的主要贡献者，且在灌丛种间差异显著（P<0.05），根系生物量碳占植被层碳储量的20.00%~33.53%，叶片生物量碳占总植被层碳储量的2.02%~24.54%。

Carbon Density in Dominant Desert Shrub Species Ecosystem in West Ordos Region

To estimate carbon storage of natural desert shrub ecosystem in west Ordos plateau and reveal the distribution rules in different layers (shrub, herb, litter and soil) and organs of each shrub species, we set 3-5 sample plots respectively according to typical sampling method in five dominant desert shrub species(Ammopiptanthus mogolicus, Zygophyllum xanthoxylum, Tetraena mongolica, Helianthemum songaricum and Reaumuria songarica) in Yikebulage steppe desert experimental area and measured the carbon storage of desert shrub ecosystem using biomass harvest method. The results showed that the carbon storage differences among five desert shrub ecosystems and its carbon storage was in the range of 40.28-55.51 t hm^-2, in which the carbon storage of soil layer was the most(97.15%-98.51%) and the carbon storage was in the range of 40.28-55.51 t·hm^-2. The soil carbon storage was increasing with the soil depth. The biomass carbon density in plant layer was shrub layer > herb layer > litter layer. The biomass carbon density of shrub layer was more with the distance increasing to Yellow River and the biomass carbon density of the nearest site of A. mogolicus and the farthest site of H.songaricum was respectively 92.16% and 62.42% of the plant layer. However, the herb layer showed the opposite rule as the shrub layer. The root biomass carbon was the main part of shrub ecosystem and its biomass carbon density was in the range of 8.41-38.29 g·m^-2, which was 5.36%-45.18% of plant layer carbon density. Except P. songarica shrub ecosystem, the carbon storage of belowground part in other four desert shrubs was more than aboveground part (P<0.05). The carbon storage of single shrub showed that branches>roots>leaves. The thick root sand branches were the main contributors to carbon storage of single shrub and showed obvious differences among shrub species (P<0.05). The roots and leaves carbon storage was 20.00%-33.53% and 2.02%-24.54% of the total plant layer.