Data for: Direct and indirect effects of management and landscape on biological pest control and crop pest infestation in apple orchards

Biological pest control, relying on naturally occurring predator-prey dynamics, is considered a key element to achieve more sustainable farming systems. However, the combined effects of local management and landscape factors on communities of natural enemies as well as the cascading effects on pest infestations are rarely addressed, especially in perennial crops. Here, we used Piecewise Structural Equation Modelling (PSEM) to test direct and indirect effects of landscape composition, landscape configuration and local management practices on natural enemy communities, the pest control services they provide and ultimately on pest infestation and pest-related yield damage in apple crops. To this end, we surveyed 12 organic and 12 Integrated Pest Management (IPM) orchards during three consecutive years, and we also established a semi-natural benchmark to quantify the extent to which predator communities in the orchards were degraded. Natural enemies had a different community composition and were more abundant in organic orchards compared to IPM orchards. This had a small and positive effect on sentinel egg predation rates in organic orchards, but overall had very little impact on actual apple pest infestation. On the contrary, apple pest infestation levels were directly and positively affected by organic management practices and by increasing semi-natural habitat cover and landscape edge density. Compared to a semi-natural benchmark, both agricultural management systems showed degraded predator communities, which translated into an impaired delivery of biological control services. Synthesis and applications. Our results indicate that organic management and habitat conservation can enhance natural enemies and stimulate pest control, but also show that these factors can enhance pest infestations and can even lead to an overall increase in pest-related crop damage. Our study thus highlights the complex interplay of ecosystem services and disservices provided by biodiversity, which should be taken into account when advising farmers, policy makers and land managers on effective and sustainable strategies to control pest species and safeguard crop production.依托自然捕食者-猎物动态的害虫生物防治（Biological Pest Control），被视为构建更可持续农业系统的核心要素之一。然而，当地管理措施与景观因子对天敌群落的联合效应，及其对害虫侵染的级联效应却极少得到研究，在多年生作物系统中尤为如此。本研究采用分段结构方程模型（Piecewise Structural Equation Modelling, PSEM），检验景观组成、景观配置与当地管理措施对天敌群落、天敌所提供的害虫防治服务，以及最终对苹果园害虫侵染与害虫相关产量损失的直接与间接效应。为此，我们连续三年调查了12个有机果园与12个害虫综合治理（Integrated Pest Management, IPM）果园，并设立半自然基准样地以量化果园内捕食者群落的退化程度。研究发现，有机果园的天敌群落组成与IPM果园存在显著差异，且天敌丰度更高；这一差异对有机果园的哨兵卵捕食率产生了微弱的正向影响，但对实际的苹果害虫侵染水平几乎无显著作用。与之相反，苹果害虫侵染水平直接且正向地受到有机管理措施、半自然生境覆盖度提升以及景观边缘密度增加的影响。相较于半自然基准样地，两种农业管理系统下的捕食者群落均出现退化，进而导致害虫生物防治服务的供给能力受损。综合与应用：本研究结果表明，有机管理与生境保护能够提升天敌丰度并强化害虫防治功能，但同时也发现，这些措施可能加剧害虫侵染，甚至最终导致害虫相关的作物产量损失整体上升。本研究由此凸显了生物多样性所提供的生态系统服务与生态系统反服务之间的复杂相互作用，在为农户、政策制定者与土地管理者提供害虫防治与作物生产保障的有效可持续策略时，应将这一相互作用纳入考量。