华北平原地区景观格局对麦田害螨种群数量的影响

农业生产的集约化经营导致农田景观格局日趋单一,而农田景观格局的变化势必对害虫种群产生深刻的影响,阐明景观因子对害虫种群的作用是通过生境管理进行害虫控制的基础。以华北平原地区的山东省为研究区域,24个县级单元为样点,通过对卫星遥感影像和土地覆盖分类数据的分析,获取了样点单元的景观格局指数,同时定点调查了样点单元的麦田害螨种群数量。利用相关性分析明确了影响麦田中两种害螨—麦岩螨(Petrobia latens(Müller))和麦圆叶爪螨(Penthaleus major(Duges))种群发生的主要景观因子。研究结果表明景观因子对麦田中两种害螨种群均有显著影响,而两种害螨对景观因子的响应并不一致。麦岩螨的发生量与森林的最大斑块面积指数和平均斑块面积均呈显著正相关,而与森林类的形状和水体的景观形状指数均存在显著负相关;麦圆叶爪螨的发生量同水体的总面积、斑块面积比例、最大斑块面积指数以及县域范围的平均斑块面积均呈显著负相关,而与水体类的形状呈显著正相关。因此在麦田害螨发生较重的地区,在区域性景观规划时,可以通过优化农田周围的森林和水体管理,不利于其种群发生,从而达到对麦田害螨种群生态调控的目的。

Impacts of landscape patterns on populations of the wheat mites, Petrobia latens (Müller) and Penthaleus major (Duges), in the North China Plain

The simplification of agricultural landscape associated with agricultural intensification may have significant effects on economically important insect pests. It is essential to clarify the landscape factors that significantly impact the populations of these pests, which forms the basis of pest control through habitat management. In the current study, 24 counties of Shandong province were selected as sampling units. The landscape indices of each county were calculated from the distribution of land coverage types, which were obtained by analyzing data from remote satellite sensing. Populations of white mites were also surveyed in each county during 2008-2010. The relationships between the average annual abundance of wheat mites (Penthaleus major Duges and Petrobia latens Müller) and landscape indices were examined by correlation analysis. The results showed that landscape indices had significant effects on the populations of wheat mites, and the responses of P.major and P.latens to the landscape indices were species-specific. The P.latens population was positively correlated to the LPI (Largest Patch Index) and MPA (Mean Patch Area) in the forest class, and was negatively correlated to the shape in the forest class and to the LSI (Landscape Shape Index) in the water class. The P.major population was negatively correlated with CA (Total Class Area), PLAND (Percentage of Landscape), and LPI of the water class and with the MPA of county. However, the edge effects of the water class had positive effects on the populations of P.major. Therefore, in region with higher population of wheat mites, the water and forest class close to the farmland should be optimized to control the wheat mite populations through ecological regulation and management.