Rising demand for food production poses a major threat to biodiversity by placing competing pressures on land. Diversified farming systems are one widely promoted nature-based solution to this challenge, which aim to integrate biodiversity-based ecosystem services into agricultural production. The underlying theory behind this approach is that diverse communities enhance ecosystem service provision, although the evidence to support this theory is often inconsistent for reasons that are not always clear. Here we investigate the contribution of pollinators to ecosystem function in a model example of a diversified farming system, silvoarable agroforestry comprising apple trees intercropped within arable fields. We assess pollinator species richness, species diversity, and functional trait diversity, between agroforestry fields and paired monoculture arable controls, and within agroforestry fields at set distances from tree rows, to quantify their potential contributions to pollination service. Species richness and diversity, and functional richness and dispersion, of wild bees were found to be significantly higher in agroforestry systems, despite weak effects on mean trait values. No significant effects were found for hoverflies. Supplemental bee species found in agroforestry systems were shown to increase functional diversity primarily by enhancing niche complementarity, effectively filling in gaps in niche space for traits, which could be partly attributed to a higher abundance and diversity of floral resources in the associated understorey. Nationally rarer bee species also contributed substantially to functional richness but not consistently to functional dispersion, suggesting that while they provide a unique functional role, their contributions to ecosystem services remain limited by low local abundances. These mechanistic insights reveal how the relationship between biodiversity and ecosystem functioning can be influenced by farm management practices through their effect on the spatial and temporal availability of habitat resources.

对粮食生产的不断增长的需求给土地带来了竞争压力，从而对生物多样性构成了重大威胁。多样化的耕作系统是针对这一挑战的一种广泛推广的基于自然的解决方案，旨在将基于生物多样性的生态系统服务整合到农业生产中。这种方法背后的基本理论是多样化的社区增强了生态系统服务的提供，尽管支持这一理论的证据往往不一致，原因并不总是很清楚。在这里，我们研究了传粉媒介对生态系统功能的贡献，这是一个多样化农业系统的模型示例，包括在可耕地间种植的苹果树的可造林农林业。我们评估传粉媒介物种丰富度、物种多样性和功能性状多样性，在农林业领域和成对的单一栽培耕地控制之间，以及在距树行一定距离的农林业领域内，量化它们对授粉服务的潜在贡献。尽管对平均性状值的影响较弱，但在农林业系统中发现野生蜜蜂的物种丰富度和多样性以及功能丰富度和分散度明显更高。对食蚜蝇没有发现显着影响。在农林业系统中发现的补充蜜蜂物种被证明主要通过增强生态位互补性来增加功能多样性，有效填补性状生态位空间的空白，这可能部分归因于相关林下植物资源的丰度和多样性。全国稀有的蜜蜂物种也对功能丰富性做出了重大贡献，但对功能分散的贡献却不一致，这表明虽然它们提供了独特的功能作用，但它们对生态系统服务的贡献仍然受到当地丰度低的限制。这些机制见解揭示了生物多样性和生态系统功能之间的关系如何通过农场管理实践对栖息地资源的空间和时间可用性的影响而受到影响。