Abstract: Ammopiptanthus mongolicus is one of the national secondary key protected plant species. The paper aims to reveal the spatial distribution patterns of A.mongolicus and their changes during development. In this study,A.mongolicus from the East Alashan Desert was selected as the research object. Utilizing size structure,the A. mongolicus individuals were divided into three classes on their size,and then,the population of A. mongolicus at three developmental stages were analyzed by using the paired correlation functions g(r). The results showed that the young growing,mature stable and declining populations were spatially staggered. In the growing and stable populations,the young (class I) individuals of A. mongolicus were aggregated at small scale and randomly distributed at medium and large scales,while the middle-aged (class II) individuals were uniform at small scale,increasingly aggregated at medium-scale and randomly distributed at large scale. From the stable to the declining populations,the uniform distribution of older individuals (class III) of A.mongolicus increased at a small scale,and the other scales were dominated by random distribution. There was a positive correlation between class I and class II plants at the medium and small scales,and had a significant negative correlations between class III plants on the other two classes at the small scale. The results could provide a theoretical basis for the conservation of A. mongolicus population.

Key words: Ammopiptanthus mongolicus, Developmental stages, Spatial distribution pattern, Spatial association

摘要： 为了揭示国家二级保护植物沙冬青（Ammopiptanthus mongolicus）种群在发展过程中的空间分布格局及变化规律，本研究选择东阿拉善荒漠的沙冬青作为研究对象，采用大小结构法将沙冬青植株分为3个等级，运用成对相关函数g（r）对3个发育阶段沙冬青种群进行分析。结果表明：年轻的增长型、成熟的稳定型和衰退的下降型种群在空间上交错分布。在增长型和稳定型种群中，沙冬青幼龄（Ⅰ级）个体呈现小尺度聚集，中、大尺度随机分布，中龄（Ⅱ级）个体呈现小尺度均匀分布，中尺度聚集性增加，大尺度随机分布。从稳定型到下降型种群，沙冬青老龄个体（Ⅲ级）在小尺度上均匀分布加大，其他尺度以随机分布为主。沙冬青在中、小尺度上Ⅰ级与Ⅱ级植株存在正关联，小尺度上Ⅲ级植株对另两个级的植株存在显著负关联。研究结果为该种的保育提供理论依据。

关键词: 沙冬青, 发育阶段, 空间分布格局, 空间关联性