Aims Potaninia mongolica, as a remnant species of ancient monospecific genus distributed in the northwest desert area, belongs to the category of national secondary key protected plants in China.The present study aims to investigate the structure, intra-and interspecific relationships, as well as the adaptation strategies to the environment of different types of P. mongolica populations.In particular, the age structure, spatial distribution patterns, and spatial correlations between size classes of P. mongolica populations were analyzed.Methods Potaninia mongolica population concentrated in the gravel land (referred to as the Alxa population) and distributed in sandy soil in the eastern marginalia of distribution area (referred to as Erdos population) were selected.Through the size structure analysis method, P. mongolica individuals were categorized into three size classes, namely class I: d ≤ 10 cm; class II: 10 cm < d ≤ 30 cm; and class III: d > 30 cm, where d stands for the cubic root of the product of crown length, crown width and plant height.Moreover, the age structure, spatial distribution patterns, and spatial correlations between size classes of the selected P. mongolica populations were analyzed using the Ripley's K-function through spatial point pattern analysis.Important findings Results of the study include: 1) The Alxa population of P. mongolica was dominated by class II plants, accounting for 69%, whereas class I plants accounting for only 5% of the total population.However, the Alxa population was observed to be stable because of asexual reproduction.On the other hand, for the Erdos population, the proportion of class II and III plants were similar, and no class I plants were observed, which resulted in limited population renewal by seed propagation.2) The Alxa population was randomly ©植物生态学报 Chinese Journal of Plant Ecology 李晓田等: 东阿拉善珍稀濒危植物绵刺种群结构与点格局分析 507
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)