Land cover composition data
The availability of crop pollinators strongly depends on landscape quality (Kennedy et al. 2013; Dainese et al. 2019). We therefore calculated the proportion of forest and (semi-)natural habitats combined in a 1km radius buffer zone for each sampling site. For the UK, data were extracted from the Land Cover Map for 2015 (LCM2015; 25m resolution raster) (CEH Data Licence Agreement – 1338). For the Netherlands, we merged data from the BRP shapefiles 2015 and 2016 (https://www.pdok.nl/introductie/-/article/basisregistratie-gewaspercelen-brp-) and the BBG (Bestand Bodemgebruik ) shapefile 2015 (https://www.pdok.nl/introductie/-/article/cbs-bestand-bodemgebruik) obtained from the RVO (https://english.rvo.nl) and Statistics Netherlands (CBS, https://www.cbs.nl/en-gb) respectively for an optimal coverage (especially for not improved grasslands). These habitats included the proportion of forest areas and natural areas (including natural grasslands), but excluded agricultural improved grasslands and pastures due to their generally intensive management strategy and low habitat quality for pollinators (Ekroos et al. 2020).