祁连山祁连圆柏幼苗种群结构及空间分布格局

以祁连山中段不同海拔高度(2 600～3 400 m)祁连圆柏天然更新幼苗为研究对象，通过典型样地调查，采用点格局法分析其种群结构及空间分布格局。结果表明：1)祁连山祁连圆柏天然更新幼苗数量稀少且不能正常发育生长，在1 m²样方尺度上，幼苗密度最大为1.53±1.00株·m^-2,祁连圆柏幼苗高度主要集中Ⅰ、Ⅱ级(0.5～20 cm),高度大于50 cm的幼苗数量严重不足甚至缺失，种群结构不稳定，处于衰退状态。2)祁连圆柏幼苗数量随着海拔升高先增大后减少，在海拔3 100 m和3 200 m样地内幼苗生长状况较好，较低海拔和较高海拔幼苗生长状况较差。3)在0～10 m空间尺度下，祁连山祁连圆柏幼苗以聚集分布为主要特征，只是在个别尺度下呈随机分布，这是祁连山祁连圆柏种群长期适应自然环境的结果。因此，在祁连山浅山区退化林分生态修复中，植被配置格局应以集群配置为主。研究结果可为揭示祁连圆柏种群天然更新障碍机制及祁连山林区特别是阳坡的植被恢复提供理论参考。

Population Structure and Spatial Distribution Patterns of Sabina przewalskii Seedlings in the Qilian Mountains

The population structure and spatial distribution patterns of Sabina przewalskii seedlings at an altitude of 2 600 to 3 400 m in the middle of the Qilian Mountains were analyzed by used the typical plots investigation and point pattern method.The results showed that 1) the number of regenerated seedlings was rare and the seedlings could not grow normally.The maximum seedling density was 1.53±1.00 plants·m^-2,their heights were mainly concentrated in grade Ⅰ and Ⅱ(0.5-20 cm).Seedlings with the height over 50 cm were seriously insufficient and even missing,indicating the population structure were unstable and in a recession state.2) With the increase of altitude,the seedling density of S.przewalskii firstly increased and then decreased,the seedling growth was better at an altitude of 3 100 and 3 200 m,but showed poor growth status at the lower and higher altitude.3) Within the spatial scale of 0-10 m,S.przewalskii seedlings exhibited aggregation distribution,but presented random distribution at individual scale,which was the result of long-term adaptation of S.przewalskii.Therefore,for the ecological restoration of damaged forests in the shallow mountainous areas of the Qilian Mountains,the vegetation configuration pattern should be primarily based on the cluster configuration.The study provides theoretical references for demonstrating the natural regeneration barrier of S.przewalskii population and the vegetation rehabilitation in the Qilian Mountains,especially on the sunny slope.