长江安庆段河流湿地生态系统呼吸及其影响因子

研究湿地生态系统呼吸(Reco)对评价湿地生态系统碳汇功能具有重要的意义.采用涡度相关法对位于长江中游河流湿地的杨树人工林生态系统进行了长期的定位观测,根据2005-07-23～2007-12-15的数据对Reco进行估算,并分析Reco对主要环境因子的响应特征.结果表明:(1)Reco具有明显的季节变化,每年的最大值出现在8月份,最小值出现在1月份,Reco受空气温度、土壤温度和土壤含水量共同影响,总体上看空气温度是驱动Reco的主要因子;(2)在几种模拟生态系统呼吸的模型中,Van't Hoff方程、Arrhenius方程、Lloyd-Talor方程在统计意义上具有同等的能力,由空气温度和土壤含水量共同驱动的连乘模型对Reco的拟合效果最好;(3)使用连乘模型估算的2006年生态系统呼吸总量为1074.7 gC·m-2·a-1,2007年为1127.0 gC·m-2·a-1,与亚热带和温带的森林站点的测定值相接近.

Ecosystem respiration and its controlling factors in the riparian wetland of Yangtze River

Research of ecosystem respiration (Reco) in wetland ecosystem is critical for estimating wetland ecosystem carbon balance. Continuous eddy covariance measurements were made in a poplar plantation located in the riparian wetland of middle reaches of Yangtze River. Reco was estimated and analyzed for its regulatory factors based on data from 2005-07-23 through 2007-12-15. We found that: (1) Reco had an obvious seasonal fluctuation with peak Reco in August and minimum in January. The seasonal change was affected by canopy air temperature, soil temperature, and soil water content, with canopy air temperature as the most important factor; (2) exponential equations (e.g., Van′t Hoff, Arrhenius and Lyold-Talor) were effective in modeling Reco with canopy air temperature and soil water content; (3) Reco in 2006 and 2007 were 1074.7 and 1127.0 gC m-2 a-1, respectively, based on the multiplicative model. These estimates were closed to forest sites in subtropical and temperate zones.