油松毛虫幼虫和蛹在油松各轮枝层分布的空间格局及其变化规律研究

将油松植株看作是处于不同空间层次的亚生境单元——“轮枝层”构成的一个多层次立体结构,以Taylor幂法则模型及笔者重新解释的Taylor幂法则,作为描述种群空间格局的基本模型和准则。采用模糊聚类分析,灰色聚类分析,趋势面分析等方法,研究油松毛虫在各轮枝层分布的空间格局及其在各层间的变化规律;并测定了种群个体在油松植株内层间垂直分布的种群聚集度。结果表明:(1)种群在各轮枝层分布格局的种群聚集度,均为逆密度制约型,并给出了种群聚集临界密度m_0的值,因而可以对各轮枝层的空间格局连续统作出定量描述;(2)各轮枝层的种群聚集度在各层间的变化是非线性的;可以按聚集特征参数划分一定类别;(3)种群个体在植株内垂直分布的种群聚集度也是逆密度制约型。

STUDIES ON THE POPULATION SPATIAL PATTERNS OF DENDROLIMUS TABULAEFORMIS (TSAI ET LIU) LARVAE AND PUPAE ON EVERY STRATUM OF VERTICILLATE-BRANCHES(SVB)OF PINE AND THE LAW OF SPATIAL PATTERN VARYING AMONG STRATA (SVBs)

In most of the reported studies on spatial pattern of insect populations,the natural habitat unit (NHU) of population individuals is essentially assumed as point,i.e., the number of individuals within a NHU as basic unit for surveying,assessing and interpreting spatial pattern, But in fact the NHU of insect population is generally a multidimensional structure rather than point. Therefore the much spatial information may be lost owing to this inappropriate assumption. In this paper, pine tree,the NHU of Dendrolimus tabulaeformis,is considered as one-dimensional axis composed of strata of verticillate-branches(SVBs) rather than points. Based on the above idea,spatial patterns of Dendrollmus tabulaeformis larvae and pupae on every SVB were assessed and interpreted with Taylor's power law model and the author's reinterpreted Taylor's power law,and the law of spatial patterns varying among strata was analysed with Fuzzy Clustering Analysis (FCA),Grey Clustering Analysis (GCA) and Trend Curved Surface Analysis (TCSA)methods. Also within-pine-tree vertical distribution aggregation of population was discussed. It coneiudes that: (1)according to the author's reinterpreted Taylor's power law, the spatial pattern of larvae and pupae on every SVB follows inverse densitydependent aggregation,and the critical density m of the population aggregation was calculated, so the spatial pattern continuum on every SVB can be deseribed quantitatively; (2)the resuits of FCA,GCA,and TCSA show that the alw of spatial pattern aggregation varying among Strata is non-liner and oscillatory,and the Strata can be clustered into several types according to the characteristics of the population aggregation; (3)within-pine-tree vertical distribution also follows inverse density-dependent aggregation.