Agriculture intensification poses serious threats to natural enemy biodiversity and associated ecological services. The conservation or reestablishment of semi-natural habitats is used to counteract negative effects of agriculture intensification on natural enemies. Understanding specific functions of different habitats for natural enemies from a landscape perspective is an important step needed for the development of sustainable agriculture. Here, focusing on parasitoids of wheat aphids, we examined effects of the proportion and connectivity of two main semi-natural habitats (woodlands and fallows) present in landscapes, measured within circular buffer radii of 0.5, 1.0, 1.5, and 2.0 km around sampling sites, on parasitoid (mummy) density, biodiversity (Shannon diversity) and associated services (parasitism rate) in 35 wheat fields. We also compared local vegetation communities of these two semi-natural habitats to test whether plant characteristics can shed light on the potential mechanisms driving parasitoids responses to different landscape habitats. We found that the parasitoid diversity was much higher in landscapes dominated by woodlands, while fallows in the landscape promoted parasitoid density and parasitism. Woodlands connectivity at larger scales (such as 1.5 or 2.0 km) displayed positive effects on parasitoid activities, fallows connectivity at the smaller scale (0.5 km) had a positive effect on the hyperparasitism rate. In terms of vegetation characteristics, fallows provided more flowering plants and floral resources, while woodlands suffered less disturbance across years. Local vegetation composition of the semi-natural habitats indeed help explain their different effects on parasitoids at larger landscape scales. We suggested that future research should investigate the role of different types of semi-natural habitats. Conservation management should combine different habitats, such as perennial and annual habitats, to promote the functional complementarity for beneficial organisms. Based on results from local vegetation survey, we also suggested native flowering plants such as Capsella bursa-pastoris L., Lagopsis supina Steph., and Calystegia hederacea Wall. in fallows could be used as functional plants to conserve wheat aphid parasitoids.

农业集约化对天敌生物多样性和相关生态服务构成严重威胁。半自然栖息地的保护或重建用于抵消农业集约化对天敌的负面影响。从景观角度了解天敌不同栖息地的具体功能是发展可持续农业的重要一步。在这里，我们专注于小麦蚜虫的寄生蜂，检查了景观中存在的两个主要半自然栖息地（林地和休耕地）的比例和连通性的影响，在采样周围 0.5、1.0、1.5 和 2.0 公里的圆形缓冲半径内测量地点，在 35 个麦田中的寄生蜂（木乃伊）密度、生物多样性（香农多样性）和相关服务（寄生率）。我们还比较了这两个半自然栖息地的当地植被群落，以测试植物特征是否可以揭示驱使寄生蜂响应不同景观栖息地的潜在机制。我们发现，在以林地为主的景观中，寄生生物的多样性要高得多，而景观中的休耕促进了寄生生物的密度和寄生。较大尺度（如 1.5 或 2.0 km）的林地连通性对寄生蜂活动有积极影响，较小尺度（0.5 km）的休耕连通性对超寄生率有积极影响。在植被特征方面，休耕提供了更多的开花植物和花卉资源，而林地多年来受到的干扰较少。半自然栖息地的当地植被组成确实有助于解释它们在更大的景观尺度上对寄生蜂的不同影响。我们建议未来的研究应该调查不同类型的半自然栖息地的作用。保护管理应结合不同的生境，如多年生和一年生生境，以促进有益生物的功能互补。根据当地植被调查的结果，我们还推荐了本地开花植物，如Capsella bursa-pastoris L.、Lagopsis supina Steph. 和Calystegia hederacea Wall。休耕可用作保护小麦蚜虫寄生蜂的功能性植物。