秦王川盐沼湿地角果碱蓬种群聚集分布格局与特征

植物种群的多尺度集聚与聚块特征变化是植物对环境协同适应的结果。运用成对相关函数与零模型方法,依据微地形的土壤盐分分布规律设置4个样地,在2 m×2 m的样方内设置400个小格子记录植物株数并取土样,分析了兰州秦王川盐沼湿地土壤盐分梯度下角果碱蓬种群(Suaeda corniculata)种群空间格局的集聚分布内在特征。结果表明:角果碱蓬种群集聚分布范围内呈现2个关键尺度的集聚现象,小尺寸聚块的集聚或叠加形成复合大尺度聚集,整体表现为嵌套双聚块分布;随着土壤盐分递减,种群集群分布中大聚块尺寸趋于增大,小聚块尺寸差异不明显;大尺寸聚块的数量明显减少,小聚块数量随种群植株数量变化,整个梯度呈现降低趋势;小聚块中植株个体平均数逐渐减少,复合大聚块中包含小尺度聚块平均数量呈降低趋势。内陆盐沼湿地土壤环境异质性背景下角果碱蓬种群集群分布中聚块特征的梯度变化,是植株个体形态与构成的调整适应,种群正负向生态关系、庇护与自疏效应梯度转换的结果。

Aggregated spatial patterns and characteristics of Suaeda corniculata in Qin wangchuan salt marsh

Multiple clustering of plant populations and variation in cluster characteristics is the result of collaborative adaptation by plants to the environment. According to the distribution of soil salinity in micro-topography, the experimental set up was four 2 m×2 m sample plots. Each sample was divided into 400 cells, the number of plants was recorded, and soil samples were collected. Using the null model, the data were analyzed for aggregated spatial patterns and characteristics of the Suaeda corniculata population in the Qin wangchuan salt marsh in Lanzhou city. The results showed that:Suaeda corniculata populations showed a complex spatial pattern with two critical scales of clustering, small-scale clustering was assembled into composite large-scale clustering through superposition and aggregation, and populations showed the nested double-cluster process at all scales. As the soil salinity decreased, the size of large-scale clusters tended to increase and the size of small-scale clusters did not show obvious differences. The number of large-scale clusters decreased significantly, and the number of small-scale clusters tended to increase with the increase in size of the plant population in the whole study area. The average number of plants in one small-scale cluster gradually reduced, and the average number of small clusters in one large cluster showed a decreasing trend, which were related to gradually reduce of the soil salinity. Under the background of soil environmental heterogeneity in the inland saltmarsh wetland, the gradient of variation in clustering characteristics was the adjustment of plant individual form and composition. It was also the result of gradient transformation of the population ecology relationship, protection, and self-thinning effects.