石羊河下游不同立地类型黑果枸杞种群分布格局

在样地调查的基础上,结合相邻格子取样方法,采用扩散系数(C)、丛生指标(I)、负二项参数(K)、聚块性系数(Ca)、平均拥挤指标(m*)、聚集度指标(G)、Moristia指数(Iδ)、Green指数(IG)等8个指标,对石羊河下游不同立地类型黑果枸杞种群分布格局、聚集强度进行了研究,结果表明:①沙地和盐碱地黑果枸杞个体数量较多,聚集程度相对较高,砾石和固定半固定沙地黑果枸杞的个体数量较少,聚集程度相对较低;②盐碱地和沙地黑果枸杞种群呈现聚集分布,固定半固定沙地和砾石样地相对于沙地和盐碱地的聚集程度有所减弱,有一定的随机趋势;③不同发育阶段的黑果枸杞种群格局类型总体呈现聚集分布的特点,随着龄级的增大,黑果枸杞种群分布格局表现出由聚集向均匀分布的变化趋势。

Distribution Patterns of Lycium ruthenicum Population in Different Site Types in Lower Reaches of the Shiyang River

Based on the methods of surveyed sample plots and adjacent lattice sampling,8 indexes were adopted as the diffusion coefficient (C),cluster index (I),negative binomial parameter (K),agglomeration coefficient (Ca),average crowding index (m*),aggregation index (G),Moristia index (Iδ) and Green index (IG). These indexes were used to study the distribution patterns and aggregation intensity of Lycium ruthenicum population in different site types in the lower reaches of the Shiyang River. The results showed that there were many L. ruthenicum individuals in the saline-alkaline land and sandy land,and the aggregation level was relatively high. However,the plants of L. ruthenicum in gravel land and fixed and semi-fixed sandy land were relatively less,and the aggregation level was relatively low. The L. ruthenicum population was distributed in an aggregation way in saline-alkaline land and sandy land,and the plants in the fixed and semi-fixed sandy land and gravel land were relatively less and their aggregation level was low;The L. ruthenicum population at different development stages was holistically distributed in an aggregation way,and with the increase of tree-age,the L. ruthenicum population changed from aggregation distribution to a uniform distribution.