尺度与方向依赖的二化螟种群空间格局及其模拟抽样研究

Population Spatial Distribution Pattern of Chilo supressalis and Its Simulated Sampling in Different Scales and Directions

为探明昆虫空间分布中可能存在的分形特征 ,在昆虫分布型经典分析方法的基础上引入尺度和方向变量 ,研究了越冬代二化螟幼虫种群空间格局及其模拟抽样精度随尺度和方向变化而变化的规律 .结果表明 ,以单株为单位 ,二化螟种群属聚集分布中的广义负二项分布 ,其分布具空间异质性 ,在同一尺度下 ,样方间变异系数和聚集程度按行、块、列依次递减 ;在相同尺度和抽样分数下 ,越冬代二化螟种群田间取样以列抽样估计精度最优 ,行抽样最差 ,块抽样居中 ,列抽样时 2× 1～ 6× 1尺度估计精度多优于 1×

To study fractal character which might exist in the distribution of insect, two new variables, scale and direction,were introduced to characterize spatial distribution pattern of the over wintering larvae of Chilo supressalis and its simulated sampling. The results indicate that: 1) The population is up to generalized negative binomial distribution in 1×1 scale; 2) Its distribution shows spatial heterogeneity. Coefficient of variation and aggregation degree reduce in the order of line grille, block grille and row grille in the same scale; 3) The sampling estimated precision also decreases in the order of line sampling, block sampling and row sampling in the same scale and sampling fraction; 4) As for row sampling, the scales from 2×1 to 6×1 are more precise than that from 1×1 scale in the most situations.