Abstract: The spatial distribution pattern and autocorrelation of plant populations reflect the configuration of their individuals in horizontal space and their interrelationship. This paper took Artemisia ordosica population on semi-fixed dunes in the Tengger Desert as the research object. The spatial distribution pattern and autocorrelation of the plant height and crown width of A.ordosica on four micro geomorphic types were analyzed by using g(r) function and global and local Moran's I index. The results showed that， the order of density of Artemisia ordosica population on different micro geomorphic types was:leeward slope>dune bottom>dune top>windward slope,and the orders of plant height and crown width were opposite to the order of population density. The populations of Artemisia ordosica on the sample plot and four different micro geomorphic types were clustered in the range of 0～14 m. The plant height and crown width of A. ordosica showed positive spatial autocorrelation on all distance scales,and the aggregation patterns were mainly high-high,low-high and low-low aggregations. The study revealed the spatial pattern and aggregation characteristics of A. ordosica on semi-fixed dunes in study area,which could have a positive guiding role in formulating corresponding measures for wind prevention and sand fixation and establishing a scientific and reasonable model for sand fixed vegetation in future.

Key words: Artemisia ordosica, Spatial pattern, Moran's I index, Semi-fixed dunes, The Tengger Desert

摘要： 植物种群的空间分布格局和自相关性反映了种群个体在空间上的配置状况和彼此间的相互联系。本文以腾格里沙漠半固定沙丘上的油蒿(Artemisia ordosica)种群为研究对象，利用g(r)函数和全局与局部Moran's I指数等方法在4种微地貌类型上对油蒿种群株高和冠幅的空间分布格局和自相关性进行分析。结果表明：油蒿种群在不同微地貌上的密度大小顺序为背风坡>丘底>丘顶>迎风坡，株高冠幅的大小顺序与种群密度大小的顺序呈相反的趋势；油蒿种群在0～14 m尺度范围内均为聚集分布；油蒿种群的株高和冠幅表现为正向空间自相关，主要表现为高高、低高和低低聚集的聚集模式。研究揭示了研究区半固定沙丘上油蒿种群的空间分布和聚集特征，对今后制定防风固沙措施以及建立科学合理的植物固沙模式具有积极的指导作用。

关键词: 油蒿, 空间格局, Moran's I指数, 半固定沙丘, 腾格里沙漠