武夷山不同海拔土壤呼吸对变暖和变冷的响应

由于人类活动,我国亚热带地区正面临剧烈的气候变化,这可能对土壤呼吸有潜在影响.本研究选择武夷山国家公园内针叶林(1442 m)和常绿阔叶林(645 m)为对象,通过土柱置换试验模拟变暖(针叶林置换到常绿阔叶林)和变冷(常绿阔叶林置换到针叶林),探讨模拟变暖和变冷对土壤碳过程的影响,测定两个海拔样地的原位和置换处理的微气...

Responses of soil respiration to warming and cooling at different elevations of Wuyi Mountain

Subtropical areas are subjected to rapid climatic change owing to anthropogenic activities,which could potentially affect soil respiration.In this study,a coniferous forest(CF)at 1442 m and an evergreen broad-leaved forest(EBF)at 645 m were selected as research objects in the Wuyishan National Park,Fujian Province,China.The effects of simulated warming(soil monoliths transferred from CF to EBF)and cooling(soil monoliths transferred from EBF to CF)on soil carbon processes were explored using a reciprocal soil monoliths translocation experiment.The microclimate,soil respiration,soil organic carbon,soil total nitrogen and soil labile organic carbon were measured for in situ and transferred treatments at both elevations.The results showed that soils experienced warming had higher temperature and lower moisture.In contrast,soils experienced cooling had lower temperature and higher moisture.Simulated warming substantially increased soil respiration by 99.6%and significantly decreased temperature sensitivity(Q₁₀) compared with the CF incubated in situ.Simulated cooling substantially reduced soil respiration by 43.3%and increased Q₁₀ compared with the EBF incubated in situ.Soil temperature was the factor driving changes in soil respiration,whereas soil moisture had no relationship with soil respiration(P>0.05).At the end of the experiment,soil organic carbon contents of the EBF and CF were increased by 12%and 10%,respectively,which might be related to the decomposition of dead roots and leaf litter.The soil organic carbon content decreased slightly under both the warming and cooling treatments,which could be explained by the differences in intensity of soil respiration.At the end of the experiment,warming reduced soil microbial biomass carbon,but increased dissolved organic carbon.In contrast,cooling increased soil microbial biomass carbon and decreased dissolved organic carbon,indicating that soil labile organic C may not respond equally to warming and cooling.Therefore,the responses of soil respiration to warming and cooling should be considered for the construction of climate change response models when both warming and cooling are involved in the climate change.