摘要
采用时空替代法,在长白山北坡分别选取了红松针阔叶混交林演替序列的5个不同阶段:草地、灌木林(幼龄林)地、白桦林地、阔叶杂木林地和红松阔叶林地,进行土壤CO_2排放通量昼间变化野外同步观测研究,旨在揭示温带森林不同演替阶段下的土壤呼吸CO_2排放过程的差异,探究其与温度、湿度、土壤理化性质等环境因子的关系。结果表明:(1)温带森林不同演替阶段下的土壤CO_2排放通量具有统一性,均为大气CO_2的源,这种统一性确保了小的时段(如昼间)观测能通过换算,实现CO_2排放量的估算。(2)CO_2排放通量的昼间排放都呈现出明显的单峰型,峰值在13:00—15:00左右,草地和灌木林地的峰值大概在13:00左右,明显提前于白桦林地、阔叶杂木林地和红松阔叶林地(14:00—15:00左右)。红松阔叶林地的土壤呼吸有明显的滞后性特征,峰值在15:00左右,比其他几个样地明显推迟。(3)土壤CO_2排放通量平均值由低到高排列依次为草地(2.760μmol m^(-2)s^(-1))、灌木林地(2.854μmol m^(-2)s^(-1))、白桦林地(3.048μmol m^(-2)s^(-1))、阔叶杂木林地(3.696μmol m^(-2)s^(-1))、红松阔叶林地(4.61μmol m^(-2)s^(-1))。随着温带森林演替的正向进行,土壤CO_2排放通量依次增大,次序为草地<灌木林地<白桦林地<阔叶杂木林地<红松阔叶林地。(4)环境因子中,0—5 cm土壤温度与土壤CO_2排放通量相关系数最高,土壤温度监测对土壤CO_2排放量的估算作用明显。
Climate warming is mainly caused by increasing atmospheric CO2 and CH4. Soil respiration plays an important role in the carbon balance of terrestrial ecosystems. Currently, the increase in atmospheric CO2 is due to human activities, natural distubances and processes. Soil respiration is one of the natural processes that release CO2 to atmoshphere from soil. Quantitative analysis of soil respiration is critial to assess forest ecosystem carbon budget under climate change scenairos. The temperate forest is one of the important components of terrestrial ecosystems. The forest in the Changbai Mountains is the typical temperate forest in China. Therefore, researching of soil respiration in the forests of Changbai Mountains is of great concern in estimating soil carbon budeget in China. In the growing season of 2013 （ August）, we emploed the temporal-spatial substitution method to determine sample plots on the north slope of the Changbai Mountains, which coverfive vegetation succession stages： grassland, shrub forest broad-leaved-mixed forest, and broad-leaved Korean pine reveal the similarities and differences in soil CO2 emission （ young forest） , secondary birch （ Betula platyphylla ） forest, （Pinus koraiensis ） forest. The objectives of this study were to processes at different succession stages of temperate forests, and to investigate the relationship between soil CO2 emission flux and soil temperature, moisture, physicochemical properties and other environmental factors. The field synchronous observations were conducted to determine the daily variation of soil COz emission flux based on the temporal-spatial substitution method. The results showed that： 1 ） Soil CO2 emission flux of the temperate forest was unity at all the five vegetation succession stages. The unity of CO2 emission flux ensured that we could observe brief periods （such as during daylight） to estimate the CO2 emissions; 2） The CO2 emission flux during daytime produced an obvious single-peak that appeared at approximate
出处
《生态学报》
CAS
CSCD
北大核心
2017年第8期2673-2683,共11页
Acta Ecologica Sinica
基金
国家自然基金资助项目(41571078
41171072)
长白山科学研究院开放基金课题(201501)
中国地震局资助项目(201208005)
关键词
土壤CO2排放通量
环境因子
温带森林
演替
长白山
soil COzemission flux
environmental factors
temperate forests
succession
Changbai Mountains
