三峡水库消落带湿地碳储量及空间格局特征

Spatial Pattern of Carbon Area of the Three Storage in the Drawdown Gorges Reservoir

以GIS为支撑,以三峡水库消落带的空间关系、高程变化和坡度分布为基础,分析了三峡水库消落带碳储量的空间格局。结果表明,三峡水库消落带碳储量(单位:tC)约为514 862.3 tC;不同高程带碳储量变化由高到低依次为高程带160～170 m、150～160 m、170～175 m、145～150 m,其中高程带160～170 m的碳储量最高为229 367.46 tC;不同坡度带碳储量变化由高到低依次为坡度带5°～15°、0°～5°、15°～25°,其中坡度大于25°的区域,由于水流冲刷和基岩出露,植被生长稀少,因此不考虑其地上部分和地下部分碳储量,估算该区域碳储量为0,这也是不同高程带和不同坡度带计算出来的碳储量相差较大的原因。研究认为三峡水库独特的调节方式和消落带植被夏季生长茂盛可吸收并积累大量碳,具有较大的碳汇潜力;同时在迭加土壤、气候、人为干扰等多种因素后,碳储量表现出了明显的沿高程梯度和坡度梯度变化的趋势。

The spatial patterns of carbon storage were analyzed based on GIS and the natural environments in the drawdown area of the Three Gorges Reserxoir （TGR）. The results showed tbal carbon storage in the drawdown area was 514 862.3 tC and the area is gradually playing a role as a regional carbon sink. Carbon storage changes along the elevation grade, with 160 - 170 m above ,ueau sea level having the largest carbon storage at 229 367.46 tC and other elevations following in the order： 160 170 m〉150 - 160 m〉170 - 175 m 〉145 - 150 m. Carbon storage was zero in areas with greater land slopes （ 〉25°） due to water erosion and exposed bedrock leading to sparse growth of vegetation. In different slope zones, carbon storage was in the sequence： 5 °- 15°〉0°- 5°〉 15° -25°. On the whole, due to the regulation and operation modes of TGR the drawdown zone had luxuriant vegetatinn in stummer, which had uptake and accumulation of large carbon and had big carbon sequestration potential. Under these couditiuus, the distribution of carbon storage along the elevation grade and the slope grade in drawdown area of TGR are deeply affected by the soil, climate, human impacts and others.