干扰强度对亚热带米槠人促更新林土壤呼吸及其组分的影响

研究轻度干扰和重度干扰对亚热带米槠人促更新林土壤总呼吸、异养呼吸的影响.结果表明:与轻度干扰米槠林相比,重度干扰林的土壤呼吸及其各组分均下降,其中,自养呼吸(R_A,1.75 t C·hm^-2·a^-1)下降了40%.与轻度干扰林相比,重度干扰林土壤有机碳储量、细根生物量和凋落物量均显著降低.土壤温度可以分别解释轻度干扰林土壤呼吸(R_S)、异养呼吸(R_H)、自养呼吸(R_A)的84.7%、68.3%、5.1%,可以解释重度干扰林的84.4%、54.6%、21.7%.轻度干扰林和重度干扰林R_S、R_H、R_A的Q₁₀值分别为1.75、1.93、1.27和2.46、2.34、1.65.随着干扰强度的增加,森林生态系统碳储量降低,土壤呼吸下降,且土壤呼吸及其各组分对外界环境变化的响应更明显,生态系统表现出脆弱性,重度干扰下森林生态系统在短时间内难以恢复.

Effects of interference intensity on soil respiration and its components in Castanopsis carlesii forest with artificially assisted regeneration in subtropical China

The effects of interference intensity on soil respiration (R_S) and heterotrophic respiration (R_H) were studied in two Castanopsis carlesii forests with artificially assisted regeneration. The results showed that C. carlesii forest decreased the R_S and its components with the increasing interfe-rence intensity, particularly decreased its autotrophic respiration (R_A, 1.75 t C·hm^-2·a^-1) by 40% under high interference than under low interference. Compared with C. carlesii forest under low interference, soil organic carbon, fine root biomass, and annual litterfall biomass of C. carlesii forest were significantly reduced under high interference. Soil temperature could explain the seasonal variations of R_S, R_H, and R_A with 84.7%, 68.3% and 5.1% for the C. carlesii forest under low interference, and with 84.4%, 54.6% and 21.7% for the C. carlesii forest under high interference, respectively. The Q₁₀ values of R_S, R_H and R_A in the C. carlesii forest were 1.75, 1.93, 1.27 under low interference, and 2.46, 2.34, 1.65 under high interference, respectively. Carbon storage and soil respiration of forest ecosystem would decrease with the increasing interference intensity, the responses of soil respiration and its components to environmental change were obvious, and forest ecosystem showed vulnerability. It indicated the difficulty of restoring forest ecosystem with high interference during a short term.