植物生态学报 ›› 2014, Vol. 38 ›› Issue (11): 1155-1165.DOI: 10.3724/SP.J.1258.2014.00111

• 研究论文 •    下一篇

中亚热带常绿阔叶林不同演替阶段土壤呼吸及其温度敏感性的变化

范跃新,杨玉盛,郭剑芬(),杨智杰,陈光水,谢锦升,钟小剑,徐玲琳   

  1. 福建师范大学地理科学学院, 湿润亚热带山地生态国家重点实验室培育基地, 福州 350007
  • 收稿日期:2014-06-09 接受日期:2014-08-29 出版日期:2014-06-09 发布日期:2014-11-17
  • 通讯作者: 郭剑芬
  • 基金资助:
    国家自然科学基金(41401346);国家自然科学基金(30800877);福建省科技厅公益类重点项目(K3-295);福建省教育厅B类项目(JB13028)

Changes in soil respiration and its temperature sensitivity at different successional stages of evergreen broadleaved forests in mid-subtropical China

FAN Yue-Xin,YANG Yu-Sheng,GUO Jian-Fen(),YANG Zhi-Jie,CHEN Guang-Shui,XIE Jin-Sheng,ZHONG Xiao-Jian,XU Ling-Lin   

  1. State Key Laboratory Breeding Base of Humid Subtropical Mountain Ecology, School of Geographic Sciences, Fujian Normal University, Fuzhou 350007, China
  • Received:2014-06-09 Accepted:2014-08-29 Online:2014-06-09 Published:2014-11-17
  • Contact: GUO Jian-Fen

摘要:

为探明中亚热带地区常绿阔叶林演替序列土壤呼吸(Rs)的变化趋势及其影响机制, 在福建省建瓯市万木林自然保护区选取演替时间分别为15年(演替初期)、47年(演替中期)和110年(演替后期)三个不同演替阶段, 进行了为期1年的野外原位观测。结果发现: 演替初期、中期和后期的Rs分别为2.38、3.32和3.91 µmol·m -2·s -1, 温度敏感性(Q10值)分别为2.64、1.97和1.79; 与演替初期相比, 演替后期的Rs显著增加64.29%, Q10值显著降低32.30%; 不同演替阶段Rs的季节变化模式相似, 温度和含水量可分别解释季节变化的69.5% (初期)、81.9% (中期)和61.3% (后期); 回归分析发现, Rs与凋落物年归还量、细根生物量和土壤全氮和土壤有机质碳含量显著正相关。表明本研究区内植被演替促进了土壤碳排放, 降低了土壤呼吸的温度敏感性; 土壤碳输入增加、养分含量的提高和细根生物量增大是中亚热带常绿阔叶林Rs随演替进程逐渐增大的主要原因。

关键词: 森林演替, 中亚热带, 土壤呼吸, 温度敏感性

Abstract: Aims Studies on the influences of forest succession on soil respiration (Rs) and its temperature sensitivity (Q10) are controversial, leading to uncertainties in the accuracy of global carbon budget. Our objectives were to determine: (1) changes of Rs and Q10 in a succession series of mid-subtropical forests, (2) seasonal variations of Rs and its relationships with temperature and water content, and (3) the underlying mechanism of changes in Rs with succession.Methods We selected stands of an evergreen broadleaved forest at the early successional stage (15 years), middle successional stage (47 years), and late successional stage (110 years) under similar site conditions in Jian’ou, Fujian. Monthly Rs was measured by using an infrared gas exchange system from September 2009 through August 2010. Soil temperature and moisture were measured concurrently. The relationships of Rs with annual litterfall, fine root biomass, contents of soil organic carbon (SOC) and total nitrogen (TN) in the 0-20 cm soil layer were tested by linear regression analysi. Important findings The average values of Rs were 2.38, 3.32 and 3.91 µmol·m -2·s -1, and the average values of Q10 were 2.64, 1.97 and 1.79, respectively, in the early, middle, and late successional stages. Compared to in the early successional stage, Rs was increased significantly by 64.29% while Q10 was decreased by 32.30% in the late successional stage. The seasonal patterns of Rs were similar among the three successional stages; soil temperature and water content explained 69.5%, 81.9% and 61.3% of the seasonal variations. According to regression analysis, soil respiration was positively correlated with annual litterfall, fine root biomass, and contents of SOC and TN in the 0-20 cm soil layer. Succession promoted carbon emission and reduced soil respiration sensitivity in our study, which might be related to the increases in fine root biomass, carbon input and soil nutrient with forest succession.

Key words: forest succession, mid-subtropics, soil respiration, temperature sensitivity (Q10)