地表水分与放牧对巴音布鲁克天鹅湖高寒湿地有机碳密度的影响

Influence of Hydrological Gradient and Grazing Intensity on the Ecosystem Organic Carbon Density of Bayanbulak Swan Lake Alpine Cold Wetlands in Xinjiang,China

通过野外调查采样结合室内分析的方法,研究了新疆巴音布鲁克天鹅湖高寒湿地自然不同水分梯度与人为不同放牧强度影响下高寒湿地有机碳密度的变化特征。结果表明,在0~100cm土层内,无论是自然还是人为干扰条件下,湿地土壤有机碳密度均随着土层深度逐渐减小。同时,土壤有机碳密度均集中在0~20cm,其中,土层0~5cm土壤碳密度均为最高。在自然水分梯度下,地表常年积水区、地表季节性湿润区、地表常年干燥区土层0~5cm土壤有机碳密度分别为2.91,2.54,1.71kg/m2,其对应3个区域的生物量碳密度也有明显的差异（P〈0.05）。人为不同放牧干扰下,轻度放牧、中度放牧、重度放牧研究区域0~5cm土壤有机碳密度分别为3.08,2.26,0.24kg/m2。随放牧强度增加,植被生物量急剧减少,生物量碳密度也随之减少,特别是重度放牧区,与中度放牧区相比,生物量碳密度下降幅度显著（P〈0.05）。人类活动导致湿地植被退化是土壤碳储量减少的主要原因。

In order to study the impacts of natural hydrological gradient and grazing intensity on ecosystem organic carbon density（EOCD）of Bayanbulak Swan Lake wetland in Xinjiang,China,plant and soil samples were collected from sites with different hydrological gradients and grazing intensities.The results showed that soil organic carbon density（SOCD）decreased with the increasing depth in the entire 0-100 cm soil layer,with SOCD concentrated between 0-20 cm and the highest between the 0-5cm soil layer.Hydrological gradient significantly influenced EOCD.SOCD（soil 0-5cm）in the perennial water area,the seasonal humid area,and the soil layer of perennial dry area were 2.91kg/m2,2.54kg/m2 and 1.71kg/m2,respectively.There were significant differences in the plant biomass carbon density（POCD）in the 3corresponding areas（P 〈0.05）.Grazing intensity significantly influenced EOCD.SOCD（soil 0-5cm）in the lightly,moderately and heavily grazing intensity areas were 3.08kg/m2,2.26kg/m2 and 0.24kg/m2,respectively.Plant biomass and POCD decreased with the increasing grazing intensities,with BOCD in heavily grazing site significantly lower than that in lightly and moderately grazing sites（P 〈0.05）.Human activities might be the leading cause that led to the vegetation degradation,thus decreasing the carbon storage in the soil.