Abstract: In order to explore the spatial variation of C and N density in Artemisia sacrorum communities and to identify the driving factors,this experiment measured the vegetation C and N density of the Artemisia sacrorum communities in semi-arid region of northern Shanxi and semi-humid area of southern Shanxi,and analyzed their correlations with the ecological factors such as average annual temperature,average annual precipitation,soil physical and chemical properties and above-ground and underground biomass. The results indicated that,the spatial distribution of C and N density in Artemisia sacrorum communities was different between northern Shanxi and southern Shanxi. The C and N density of Artemisia sacrorum community were 651.83 C·m^-2 and 20.63 g N·m^-2 respectively in Southern Shanxi,and were 418.89 g C·m^-2 and 13.90 g N·m^-2 respectively in Northern Shanxi. The C density and N density of each component of the community was used as representative sampling points for RDA sequencing. The results showed that the main ecological factors that caused the C and N density differences of the communities in the two regions were aboveground biomass,underground biomass,annual average temperature,annual precipitation,soil organic carbon content and soil gravel ratio. In conclusion,there are differences in the spatial distribution of carbon and nitrogen density between southern Shanxi and northern Shanxi. The spatial differences of carbon and nitrogen density are closely related to the accumulation of biomass in different climatic areas. The environmental factors driving the differentiation of carbon and nitrogen density of Artemisia artemisia communities in southern and northern Shanxi are annual average temperature,annual precipitation,soil organic carbon content and soil gravel ratio.

Key words: Artemisia sacrorum community, C and N density, Spatial variation, Ecological factors

摘要： 为明确山西铁杆蒿（Artemisia sacrorum）群落碳、氮密度的区域差异，以及导致这种空间变化的驱动因素，本试验以山西省铁杆蒿草地群落为研究对象，通过测定晋北半干旱地区和晋南半湿润地区铁杆蒿群落的碳（C）、氮（N）密度，分析了其与年均气温、年降水量、土壤理化性质和地上、地下生物量等生态因子的相关性。结果表明：山西南北铁杆蒿群落碳、氮密度空间分布存在差异，晋南地区铁杆蒿群落的群落碳、氮密度分别为651.83 g C·m^-2和20.63 g N·m^-2，晋北地区铁杆蒿群落的群落碳、氮密度分别为418.89 g C·m^-2和13.90 g N·m^-2。以群落各组分碳、氮密度代表样点进行RDA（Redundancy analysis）冗余分析排序得出造成两地区群落碳、氮密度分异的主要生态因子均为地上生物量、地下生物量、年均气温、年降水量、土壤有机碳含量以及土壤砾石比。可见，山西晋南和晋北地区铁杆蒿群落碳、氮密度空间分布存在差异，不同气候区铁杆蒿群落碳、氮密度空间差异与生物量的积累密切相关，驱动晋南和晋北地区铁杆蒿群落碳氮密度分异的环境因素为年均气温、年降水量、土壤有机碳含量以及土壤砾石比。

关键词: 铁杆蒿群落, 碳、氮密度, 区域差异, 生态因子