Landscape diversity enhances biological control of an introduced crop pest in the north-central USA
Landscape diversity enhances biological control of an introduced crop pest in the north-central USA
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DOI：
10.1890/07-1265.1
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发表时间：
2009-01-01
影响因子：
5
通讯作者：
Heimpel, G. E.
中科院分区：
文献类型：
--
作者：
Gardiner, M. M.;Landis, D. A.;Heimpel, G. E.
节肢动物捕食者和寄生蜂通过抑制食草性昆虫的数量在农作物中提供有价值的生态系统服务。许多天敌受到农田周围非作物生境的影响，了解土地利用模式是否以及在多大规模上影响天敌，对于预测景观如何改变生物防治服务至关重要。在这里，我们将重点介绍大豆蚜虫的生物防治，这是一种最近引入美国中北部的专门作物害虫。我们在密歇根州、威斯康星州、爱荷华州和明尼苏达州的26个重复田中测量了两年(2005-2006)向大豆提供的生物防治服务量。我们通过实验排除或允许进入受大豆蚜虫侵染的植物，并比较了14天内蚜虫种群的增长情况，来衡量天敌的影响。我们还监测了每一块田里的蚜虫和天敌的总体数量。捕食者，主要是瓢虫，在两年中都统治着大豆的天敌群落。在没有捕食者的情况下，大豆小蜂的数量显著增加，14天后，隔离网箱中的麦长管蚜数量是露地的5.3倍。我们计算了基于对蚜虫种群相对抑制度的生物防治服务指数(BSI)，并将其与每个地点周围多个空间尺度上的景观多样性和组成相关联。我们发现，BSI值随着景观多样性的增加而增加，因为与作物和非作物生境丰富的景观相比，以玉米和大豆田为主的Simpson D.景观对大豆的生物防治服务较少。瓢虫科的丰度与景观组成有关，与以农作物为主的景观相比，森林和草地丰富的景观中甲虫更为丰富。震源场周围1.5公里范围内的景观多样性和组成解释了BSI和瓢虫科丰度变化的最大比例。这项研究表明，天敌通过抑制一种关键的大豆害虫，减少杀虫剂的使用，提供了一种区域重要的生态系统服务。此外，它还表明，维持或加强景观多样性的管理具有稳定或增加生物防治服务的潜力。
Arthropod predators and parasitoids provide valuable ecosystem services in agricultural crops by suppressing populations of insect herbivores. Many natural enemies are influenced by non-crop habitat surrounding agricultural fields, and understanding if, and at what scales, land use patterns influence natural enemies is essential to predicting how landscape alters biological control services. Here we focus on biological control of soybean aphid, Aphis glycines Matumura, a specialist crop pest recently introduced to the north-central United States. We measured the amount of biological control service supplied to soybean in 26 replicate fields across Michigan, Wisconsin, Iowa, and Minnesota across two years (2005 2006). We measured the impact of natural enemies by experimentally excluding or allowing access to soybean aphid infested plants and comparing aphid population growth over 14 days. We also monitored aphid and natural enemy populations at large in each field. Predators, principally coccinellid beetles, dominated the natural enemy community of soybean in both years. In the absence of aphid predators, A. glycines increased significantly, with 5.3-fold higher aphid populations on plants in exclusion cages vs. the open field after 14 days. We calculated a biological control services index (BSI) based on relative suppression of aphid populations and related it to landscape diversity and composition at multiple spatial scales surrounding each site. We found that BSI values increased with landscape diversity, measured as Simpson's D. Landscapes dominated by corn and soybean fields provided less biocontrol service to soybean compared with landscapes with an abundance of crop and non-crop habitats. The abundance of Coccinellidae was related to landscape composition, with beetles being more abundant in landscapes with an abundance of forest and grassland compared with landscapes dominated by agricultural crops. Landscape diversity and composition at a scale of 1.5 km surrounding the focal field explained the greatest proportion of the variation in BSI and Coccinellidae abundance. This study indicates that natural enemies provide a regionally important ecosystem service by suppressing a key soybean pest, reducing the need for insecticide applications. Furthermore, it suggests that management to maintain or enhance landscape diversity has the potential to stabilize or increase biocontrol services.