张掖市龙首山红砂种群结构和分布格局研究

Population Structure and Distribution Pattern of Reaumuria Soongoricain Longshou Mountain of Zhangye City

对张掖市龙首山天然红砂分布区的红砂种群结构和空间分布格局进行了研究。根据年龄大小结构图和存活曲线以及静态生命表分析了红砂种群动态,用扩散系数C,负二项分布中的K值,平均拥挤度m*,丛生指数I,Cassie指标CA和聚块性指标(m*/m)6个分布指数对格局类型进行了判断,并根据双向轨迹方差法分析了种群格局规模。结果表明,红砂种群的自然更新状况良好,各龄级苗木均有分布。种群的年龄结构接近于增长型,表现为中龄级(10cm<d≤30cm)丰富;种群存活曲线趋向于DeeveyⅠ型,种群目前处于较为稳定的状态;种群的聚集强度为0.831 8,分布格局类型为聚集分布;种群有两种空间格局规模,分别为4m×4m和8m×8m。

This paper studied on the population structure and spatial pattern of Reaumuria soongorica in Longshou Mountain of Zhangye City by analyzing the population changes with age structure, survival curve and static life table of Reaumuria soongorica, assessed the spatial pattern by diffusion coefficiency C, K value of negative bidirectional function, mean congestion degree m＊ , clumping index I, Cassie index CA, con- glomeration index m＊/m, and analyzed the population pattern scale using two-way track variance method. The results indicated that the Reaumuria soongorica population was in a natural succession with all-age plant evenly distributed. The age structure was close to that of growing phase with the crown diameter of middleage plant at 10 cm〈d≤30 cm and survival curve tended to be Deevey Ⅰ , of which the population was in a stable stage. The spatial pattern was of aggregation with the index at 0. 8313 and there were two patterns of scale as 4 m×4 m and 8 m×8 m respectively.