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西南高山地区生态系统类型丰富、地形复杂,是响应全球气候变化的重点区域,对全球气候变化具有重要的指示作用。研究应用生态系统模型CEVSA(Carbon Exchange between Vegetation,Soil,and the Atmosphere)估算了1954—2010年西南高山地区土壤有机碳(Soil Organic Carbon,SOC)的时空变化,分析了其对气候变化的响应。结果表明:1西南高山地区1954—2010年平均土壤有机碳密度为14.16 kg C·m-2,在空间分布上,SOC密度自东南向西北递增,与温度显著负相关(r=-0.447,P<0.01),而与降水量相关性不显著;2西南高山地区1954—2010年SOC总量变动范围为6.95~7.64 Pg C,增加趋势显著(P<0.05),平均每年增加0.013 Pg C,土壤有机碳密度平均增加26.94 g C·m-2;3常绿针叶林、常绿阔叶林和草地SOC密度增加趋势均显著,除常绿阔叶林SOC密度与温度相关性不显著外,其他两种植被类型SOC都与年平均温度显著正相关(草地:r=0.527,P<0.01;常绿针叶林:r=0.501,P<0.01),且3种植被类型SOC与年降水量均相关性不显著;4由于作为土壤有机碳输入的凋落物产生量对温度不如异养呼吸敏感,所以未来升温条件下,土壤有机碳储量的增速减缓或者呈下降趋势。
The southwest alpine region is rich in ecosystem types and complex topography. It is a key area responding to global climate change and plays an important role in guiding global climate change. The temporal and spatial variations of soil organic carbon (SOC) from 1954 to 2010 in the Southwest Alpine Region were estimated using the model of the carbon exchange between Vegetation, Soil and the Atmosphere (CEVSA). The response to climate change was analyzed. The results showed that: (1) The average SOC soil organic carbon density in 1954-2010 was 14.16 kg C · m-2 in the southwest of China. In the spatial distribution, SOC density increased from southeast to northwest and had a significant negative correlation with temperature (r = -0.447, P <0.01), while the correlation with precipitation was insignificant. (2) The total amount of SOC in 1954-2010 ranged from 6.95 to 7.64 Pg C in the southwest alpine region, with a significant increase (P <0.05), with an average increase of 0.013 Pg C per year Organic carbon density increased by an average of 26.94 g C · m-2. The trend of increasing SOC density of evergreen coniferous forest, evergreen broad-leaved forest and grassland was significant except that the correlation between SOC density and temperature was not significant, The SOC of the other two vegetation types was positively correlated with annual mean temperature (grassland: r = 0.527, P <0.01; evergreen coniferous forest: r = 0.501, P <0.01) But the correlation was not significant. 4 As the amount of litter produced as input of soil organic carbon was less sensitive to heterotrophic respiration than that of heterotrophic respiration, the growth of soil organic carbon storage slowed down or declined in the future.