Effect of Changes in Throughfall on Soil Respiration in Global Forest Ecosystems: A Meta-Analysis
Effect of Changes in Throughfall on Soil Respiration in Global Forest Ecosystems: A Meta-Analysis
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DOI：
10.3390/f14051037
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发表时间：
2023-05
期刊：
影响因子：
2.9
通讯作者：
Xingkai Xu
中科院分区：
文献类型：
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作者：
Xingkai Xu
迄今为止，人们对全球范围内森林生态系统的土壤二氧化碳（CO2）排放如何对降水量的变化作出反应以及所涉及的关键影响机制的认识有限。本次荟萃分析选择了37项在穿透雨操作条件下在地球仪森林生态系统中进行的研究，共有103个配对观测结果。实验类别，如气候类型，森林类型，土壤质地，和穿透雨操纵的变化面积的大小，包括资格的年度土壤CO2排放量的变化穿透雨的响应。温带森林土壤CO2年排放量对穿透雨变化的响应比热带和亚热带森林更敏感，这可能是由于温带森林土壤碳（C）的滞留时间相对较长、季节性冻融事件以及温带陆生植物地下部分非结构性碳水化合物的浓度相对较高所致。一个相对较大的积极响应的土壤CO2排放量增加的穿透水，观察到在地中海森林，由于在生长季节降水量小，大多是粗糙质地的土壤。除气候类型外，穿透雨改变对土壤CO2排放（lnRCO2）的影响大小因森林类型和土壤质地类别而异。通过对穿透雨变化与lnRCO2值的回归分析，得出在年降水量变化增加10%的条件下，全球尺度森林生态系统土壤CO2年排放量将增加6.9%。结构方程模型分析结果表明，细根生物量和土壤微生物生物量沿着年降水量的变化，将显著影响穿透雨引起的全球森林生态系统土壤CO2年排放量的变化。该元分析的结果强调，土壤呼吸组分的测量，土壤有机C分解的启动效应，以及不同树种的地上和地下部分之间的C分配在降水条件改变的情况下，值得更多的关注在未来。
To date, there has been limited knowledge about how soil carbon dioxide (CO2) emissions from forest ecosystems at a global scale respond to the altered precipitation, and the key influencing mechanisms involved. Thirty-seven studies conducted under throughfall manipulation conditions in forest ecosystems around the globe were selected in this meta-analysis, with a total of 103 paired observations. Experimental categories such as climate types, forest types, soil texture, and the area size of changes in throughfall manipulation were included to qualify the responses of annual soil CO2 emissions to the altered throughfall. The responses of the annual soil CO2 emissions to the altered throughfall would be more sensitive in temperate forests than those in tropical and subtropical forests, probably due to the relatively long residence time of soil carbon (C) and the seasonal freeze–thaw events in temperate forests, as well as the relatively high concentration of non-structural carbohydrates in the belowground part of temperate terrestrial plants. A relatively large positive response of the soil CO2 emissions to the increased throughfall was observed in Mediterranean forests due to small precipitation during the growing season and mostly coarse-textured soils. Besides climate types, the sizes of the effect of the altered throughfall on the soil CO2 emissions (lnRCO2) varied with forest types and soil texture categories. Based on the regression analysis of the lnRCO2 values against the changes in throughfall, the annual soil CO2 emissions in forest ecosystems at a global scale would be increased by 6.9%, provided that the change in annual precipitation was increased by 10%. The results of structural equation modeling analysis indicate that fine root biomass and soil microbial biomass, along with the changes in annual precipitation, would substantially affect the altered throughfall-induced annual soil CO2 emissions in global forest ecosystems. The findings of this meta-analysis highlight that the measurement of soil respiration components, the priming effects of soil organic C decomposition, and C allocation between the aboveground and belowground parts of different tree species under the altered precipitation conditions, deserve more attention in the future.