Data for: Hedgerows have contrasting effects on pollinators and natural enemies and limited spillover effects on apple production

Agricultural intensification has resulted in a decline in insect biodiversity and threatens the provision of valuable ecosystem services. Agri-environment schemes (AESs) have been implemented in an effort to conserve biodiversity on farmland and increase agricultural sustainability, but their effectiveness can vary widely. To better determine which factors influence AES effectiveness, the relative roles of local habitat features, habitat quality, and landscape context need to be further explored. The aim of this study was to determine the most important factors influencing field margin AES effectiveness in commercial apple orchards, in terms of arthropod biodiversity conservation and ecosystem service provision. We surveyed wild bees and aphid natural enemies in field margins and apple trees in 20 orchards, ten bordered by hedgerow field margins (an AES) and ten with herbaceous field margins (no hedgerows present, not an AES). We considered field margin floral resources and the cover of semi-natural habitat in the surrounding landscape as indicators of local habitat quality and landscape context, respectively. We furthermore quantified pollination and pest control as measures of ecosystem service delivery and the relationship between arthropod communities and apple yield (initial and final fruit set) and quality. We found that hedgerow presence strongly predicted both pollinator and natural enemy communities and that these relationships were more pronounced than those with local habitat quality and landscape context. Hedgerows were negatively related to wild bee richness and abundance within the orchard, and positively related to natural enemy richness and abundance at the field margin but not within the orchard. We found no relationships between local and landscape factors and ecosystem service delivery, and no relationship between wild bee communities and apple yield, suggesting that apple is not pollen limited in our study system. There was, however, a negative relationship between natural enemy richness and initial fruit set. We conclude that annually cut hedgerows can benefit the conservation of natural enemies, but have limited arthropod-mediated private benefits for apple production, and likely need to be supplemented with additional local habitat resources for the conservation of wild bees. Our findings indicate that local habitat factors can strongly influence biodiversity regardless of landscape context, but that AESs likely need to be designed with separate biodiversity and ecosystem service targets, and specific taxonomic groups, in mind.

农业集约化已导致昆虫生物多样性下降，并威胁到珍贵生态系统服务的供给。农业环境计划（Agri-environment Schemes, AESs）已被推行，以期保护农田生物多样性并提升农业可持续性，但其实施效果差异显著。为明确哪些因素会影响农业环境计划的实施效果，需进一步探究本地生境特征、生境质量与景观背景的相对作用。本研究旨在聚焦节肢动物生物多样性保护与生态系统服务供给两大维度，明确商业苹果园中影响田埂类农业环境计划实施效果的核心因素。我们对20个商业苹果园的田埂与苹果树开展了野生蜂与蚜虫天敌调查，其中10个果园的田埂为树篱型（属于农业环境计划范畴），另外10个为草本型田埂（无树篱，不属于农业环境计划）。我们分别将田埂花卉资源与周边景观中半自然生境占比，作为本地生境质量与景观背景的表征指标。此外，我们以传粉服务与害虫防控服务作为生态系统服务供给的衡量指标，并分析了节肢动物群落与苹果产量（坐果初期与坐果末期）及果实品质之间的关联。研究发现，树篱的存在可显著预测传粉昆虫与天敌昆虫群落结构，且该关联相较于本地生境质量与景观背景的关联更为显著。树篱与果园内野生蜂的物种丰富度和个体数量呈负相关，而与田埂处天敌昆虫的物种丰富度和个体数量呈正相关，但在果园内部未发现此类关联。我们未发现本地与景观因子与生态系统服务供给之间存在关联，也未发现野生蜂群落与苹果产量之间存在关联，这表明在本研究体系中苹果未受花粉限制。但天敌昆虫的物种丰富度与坐果初期存在负相关关系。我们得出结论：每年修剪的树篱可助力天敌昆虫的保护，但通过节肢动物介导的苹果生产私人收益有限，且可能需要补充额外的本地生境资源以保护野生蜂。本研究结果表明，无论景观背景如何，本地生境因子均可显著影响生物多样性，但农业环境计划的设计或许需要分别考量生物多样性与生态系统服务目标，以及特定的分类类群。