Beta Diversity of Plant-Pollinator Interactions in Anthropogenic Landscapes

Data are of plant-pollinator interactions from twenty-one sites in the Dublin region of Ireland (Figure 1) sampled four times between 5 May and 20 August 2018 at monthly intervals. Plants and pollinators were sampled along a 2m x 1km transect within each 1.5km radius site, with sub-sections of the transect allocated proportionately to all land cover types comprising more than 1% of the selected site (e.g. pasture, arable, continuous urban fabric; see Figure S1 Legend). Transects in residential areas were positioned along the boundary between pavements and residential gardens, so that 1m of the transect width was located in gardens and the other 1m was located on pavements and road verges. Transect locations were chosen using a random number generator to select points, and transect sections were located as close as possible to those points. Where land cover types were particularly dominant within a site, a maximum transect section length of 250m was walked, with multiple transects of the same land cover walked across multiple locations. Flowers were sampled by noting every flowering species on the outward walk of the transect and then counting the floral units of each species on the return walk. A floral unit was defined as an individual flower or collection of flowers that an insect of 5 mm body length could walk between (see Baldock et al. 2015, Supplementary Material Table S4) and comprised a single capitulum for Asteraceae, a secondary umbel for Apiaceae and a single flower for most other taxa. Grasses, sedges and wind-pollinated forbs were not sampled. Flower-visitor interactions were quantified by walking along each transect and recording every insect on flowers up to 1m either side of the transect line to a height of 2m, where appropriate, e.g. along hedgerows. An attempt was made to net all bees and hoverflies (Syrphidae), which were frozen and later identified to species. All other flower visiting insects were recorded at the family level (Coleoptera, Diptera, Lepidoptera). Bees and hoverflies were identified using Falk (2015) and Stubbs & Falk (2002) respectively, with identifications checked by taxonomists (See Acknowledgements). Plants were identified using Rose & O’Reilly (2006) and the phone application Plantnet (available at: https://identify.plantnet-project.org/), 85% to species and the rest to genus or morpho species. Sampling for flower visitors and their interactions took place between 09:00 and 19:00 hours on dry, warm, non-windy days.

本数据集涵盖爱尔兰都柏林地区21个样地的植物-传粉者互作数据（图1），于2018年5月5日至8月20日期间按月度间隔开展4次采样。

每个半径1.5km的样地内，沿2m×1km的样带开展植物与传粉者采样，样带子区段按占所选样地面积1%以上的所有土地覆被类型的比例进行分配（例如牧场、耕地、连续城市建成区；详见图S1图例）。居民区的样带沿人行道与住宅花园的边界布设，样带宽度的1m位于花园内，剩余1m位于人行道及道路路缘。样带位置通过随机数生成器选取点位确定，样带区段尽可能贴近所选点位。若某土地覆被类型在样地中占比极高，则单一样带区段的最大步行长度为250m，同一土地覆被类型可在多个点位布设多条样带。

花卉采样通过在样带单程行走时记录所有开花物种，返程时统计各物种的花单位（floral unit）数量。花单位的定义为体长5mm的昆虫可在其间爬行的单朵花或花簇（详见Baldock等2015年补充材料表S4），具体分类如下：菊科（Asteraceae）为单个头状花序，伞形科（Apiaceae）为次级伞形花序，多数其他类群则为单朵花。本研究未对禾本科、莎草科及风媒传粉的草本植物进行采样。

花访客互作通过沿每条样带行走进行量化，记录样带两侧1m范围内、高度2m以下停留在花朵上的所有昆虫（适用于树篱等场景）。研究人员尝试采集所有蜜蜂和食蚜蝇（Syrphidae），将其冷冻后后续开展物种级鉴定。其余所有访花昆虫仅记录至科级水平，包括鞘翅目（Coleoptera）、双翅目（Diptera）与鳞翅目（Lepidoptera）。蜜蜂与食蚜蝇的鉴定分别参考Falk（2015）和Stubbs & Falk（2002）的文献，鉴定结果经分类学家复核（详见致谢部分）。

植物鉴定参考Rose & O’Reilly（2006）的专著及手机应用Plantnet（可从https://identify.plantnet-project.org/获取），其中85%的物种可鉴定至种级，其余鉴定至属级或形态种级。

花访客及其互作的采样均在干燥、温暖且无风的日子的09:00至19:00之间进行。