Data from: Monitoring insect pollinators and flower visitation: the effectiveness and feasibility of different survey methods

1. The status of pollinating insects is of international concern, but knowledge of the magnitude and extent of declines is limited by a lack of systematic monitoring. Standardised protocols are urgently needed, alongside a better understanding of how different methods and recorders (data collectors) influence estimates of pollinator abundance and diversity. 2. We compared two common methods for sampling wild pollinating insects (solitary bees, bumblebees and hoverflies), pan traps and transects, in surveys of 1km countryside squares (agricultural and semi-natural habitats) and flowering crop fields across Great Britain, including the influence of local floral resources (nectar sugar availability or crop flower density) on the insects sampled. Further, we compared the performance of recorders with differing expertise (non-specialist research staff, taxonomic experts and non-expert volunteers) in applying methods. 3. Pan traps and transects produced compositionally distinct samples of pollinator communities. In the wider countryside, pan traps sampled more species of solitary bee and hoverfly. In flowering crops, transects recorded greater numbers of individual bumblebees, but fewer species. 4. Across all taxonomic groups and countryside and crop samples, transects generally had lower rates of species accumulation per individual collected than pan traps. This demonstrates that differences between methods in estimating richness are not due to sampling effort alone. However, recorders possessing greater taxonomic expertise can produce species accumulation data from transects that is almost commensurate with pan trapping. 5. The abundance and species richness of pollinators (except solitary bees) on transects in the wider countryside was positively related to the availability of estimated nectar sugar. In crops, pollinator abundance responses to flower densities were idiosyncratic according to crop type, but overall the response was positive and negative for transects and pan traps, respectively. 6. Given these taxonomic and context-specific differences in method performance, we assess their suitability for monitoring pollinating insect communities and pollination services. We discuss the relevance of these findings within the context of achieving standardised, large-scale monitoring of pollinating insects.1. 传粉昆虫的生存状况已引发国际社会的广泛关注，但由于缺乏系统性监测，学界对其种群衰退的规模与范围仍知之甚少。当前亟需标准化的监测方案，同时也需更深入理解不同采样方法与记录者（数据收集者）如何影响传粉者丰度与多样性的评估结果。 2. 本研究在英国全境的1平方千米乡村样方（涵盖农田与半自然生境）及开花作物田中，对比了两种常用于野生传粉昆虫——独居蜂（solitary bees）、熊蜂（bumblebees）与食蚜蝇（hoverflies）——采样的方法：诱捕盘（pan traps）与样带法（transects），同时考察了本地植物资源（花蜜糖可获得量或作物花朵密度）对采样所得昆虫的影响。此外，本研究还对比了不同专业水平的记录者（非专业研究人员、分类学专家与非专业志愿者）应用这两种方法时的表现差异。 3. 诱捕盘与样带法所采集的传粉昆虫群落组成存在显著差异。在更广阔的乡村生境中，诱捕盘采集到的独居蜂与食蚜蝇物种数更多；而在开花作物田中，样带法记录到的熊蜂个体数量更多，但物种丰富度（species richness）更低。 4. 在所有类群、乡村生境与作物田的采样样本中，样带法每采集到单个个体所对应的物种累积（species accumulation）速率普遍低于诱捕盘。这表明两种方法在物种丰富度评估上的差异并非仅由采样投入导致。不过，具备较高分类学专业知识的记录者，通过样带法所得到的物种累积数据几乎可与诱捕盘法相媲美。 5. 在乡村生境的样带采样中，除独居蜂外的传粉昆虫丰度与物种丰富度，均与预估的花蜜糖可获得量呈正相关关系。在作物田中，传粉者丰度对花朵密度的响应因作物类型而异，但整体而言，样带法的响应为正，而诱捕盘法的响应为负。 6. 鉴于传粉昆虫采样方法在类群与情境上的表现差异，本研究评估了二者在传粉昆虫群落与传粉服务（pollination services）监测中的适用性，并就如何实现标准化的大规模传粉昆虫监测，探讨了本研究结果的现实意义。