区域性农田景观格局对麦蚜及其天敌种群的生态学效应

Ecological Effect of Regional Agricultural Landscape Pattern on Wheat Aphids and Their Natural Enemies

明确农田景观格局对害虫及其天敌种群的生态学效应,是开展区域性害虫生态调控的基础.以前的研究大多集中于小空间尺度下、单个景观因子对昆虫种群的作用,而从省级范围的大空间尺度、多个景观因子的分析很少.本文以山东省区域性小麦种植区为研究对象,基于遥感影像和土地覆盖分类数据以及田间调查的昆虫种群数据,分析了景观组成类型(component type)、构成比例(component proportions)和形状结构(shape structure)多因子对麦蚜及其天敌寄生蜂和瓢虫种群的综合作用.结果发现,农田景观组成类型中斑块类型(patch type)越多,越利于麦蚜和天敌瓢虫种群数量的增长;且斑块密度(patch density)越大,越利于麦蚜寄生蜂和天敌瓢虫数量的增加;景观形状结构中边界密度(edge density)越高,也越利于麦蚜寄生蜂和天敌瓢虫种群数量的增加.进一步定量评估了农田景观组成类型、构成比例和形状结构对麦蚜及其天敌种群影响的作用大小.结果表明,三类景观格局因子对麦蚜影响较小,权重为9.81%;而对麦蚜寄生蜂的影响权重为25.87%;对天敌瓢虫种群高达47.86%.本研究清楚地表明,通过优化农田景观中作物与非作物生境布局,可直接调节和增加天敌昆虫种类与数量,有效控制和减少小麦蚜虫的种群数量,从而提高区域性农田景观中天敌昆虫的生物控害服务功能.

Knowing the ecological effects of agricultural landscape pattern on population dynamics of insect pests and their natural enemies is fundamental for ecolgical regulation and management of insect pests.Previous research studied the ecological effect of simple landscape factor on insects on the micro scale; however,few of them focused on the ecological effect of multiple landscape factors on the macro scale.In this study,we took the planting region of wheat in Shandong province,China as a typical example,and analyzed the ecological effects of agricultural landscape patterns（component type,component proportions and shape structure）on population dynamics of an insect pest（wheat aphids）and their two natural enemy insects（parasitic wasp and predatory lady beetle）on the basis of the remote sensing data,land coverage type distribution and the survey data of insect population dynamics in fields.The results showed that the more patch types in agricultural landscape helped to increase the population numbers of wheat aphids and predatory lady beetle per unit area.The higher patch density and edge density enhanced the population numbers of the two natural enemy insects（parasitic wasp and predatory lady beetle）per unit area.The relative contributions of three landscape factors（component type,component proportions and shape structure）in explaining the variation of insect population numbers（wheat aphids,parasitic wasp and predatory lady beetle）were quantified.For the wheat aphids,the total variation explained by the above three landscape factors was only 9.81%.While three landscape factors accounted for 25.87% of the total variation for the parasitic wasp and 47.86% for the predatory lady beetle.The results suggested that the optimization of agricultural landscape such as crop patterns and non-crop habitats can help to directly regulate and increase the relative abundance and richness of natural enemy insects,and to indirectly suppress and reduce the population numbers of wheat aphids,enhancing regional biological control of natural enemy insects for pests on wheat.