基于地统计学的重庆市桉树云斑天牛幼虫空间分布特征研究

Geostatistical Analysis on the Spatial Dstribution Characteristics of Batocera lineolata Larvae in Eucalypti Plantations

利用重庆市18个区/县98个桉树林样点天牛的危害调查结果,应用地统计学方法进行云斑天牛的空间分布情况研究。结果表明:在局部视野下,3类不同受害程度桉树林云斑天牛种群数量及空间分布特征差异明显;轻度、中度和重度桉树林天牛幼虫种群空间分布最适拟合模型分别为高斯模型、球型模型和球型模型,3类受害林的天牛幼虫种群分布均属于聚集型;天牛幼虫数量在轻度、中度与重度受害林中的空间自相关性存在较大差异,但均具有明显的空间依赖性,空间依赖范围分别为3.18、6.40、31.75 m;空间分布图显示,天牛幼虫的种群空间分布特征为明显的聚集型。在大尺度视野下,这些区/县间的桉树云斑天牛幼虫种群数量差异显著;各调查区/县的天牛危害以中度和重度为主,且具有明显的天牛高风险危害和扩散中心特征。交通道路及林分中树木分布格局是影响丘陵山地桉树云斑天牛种群分布特征的关键因素。

The spatial distribution characteristics of Batocera lineolata larvae population in the representative locations of eucalypti plantations from a local perspective and 98 locations of eucalypti plantations in 18 counties of Chongqing in a large scale were studied using geostatistics methods.The results showed that the population density and the spatial distribution characteristics of the 3 eucalyptus plantations with different damage degrees were obvious differences.The semi-variogram analysis indicated that Gaussian models,spherical models and spherical models were suitable for simulation of spatial distribution of BL larvae in slightly,moderately and heavily infested forests,respectively.These models indicated the distribution of the larvae in the 3 infested forests belong to aggregation type.The spatial dependence existed in the three infested forests,and the dependence is more obvious in the heavily infested forests.The spatial distribution pattern generated by the Kriging interpolation showed that BL larvae had intensive spatial aggregation in the three infested forests.In the large-scale view,there were significant differences in the BL larval population among these eucalypti plantations of different counties.Meanwhile,the zoning map and spatial distribution map of BL hazard degree obtained by inverse-distance weighting showed that the BL larvae was mainly moderately and severely harmful in these eucalypti plantations of the surveyed counties,and had a significant aggregation distribution,which is related to the existence of some high risk area of BL larvae.Traffic roads and tree distribution pattern of eucalypti plantations could be the key factors affecting the extensively spread and the spatial distribution characteristics of BL.