Data collection
To identify datasets suitable to address our research questions, we
performed a search in the ISI Web of Science and SCOPUS (using the
search string provided in Appendix S1; records published until
31.12.2017 were considered). To minimise potential publication bias
(i.e., the file drawer problem, Rosenthal 1979) and to maximise the
number of relevant datasets we also searched for unpublished data by
contacting potential data holders through researcher networks. Datasets
had to meet the following requirements to be included in the analysis:
(i) pollination and/or pest control services in crops were measured in
both crop fields adjacent to floral plantings and control fields without
planting; (ii) the replication at the field level was ≥ six fields per
study (three fields with plantings and three without; i.e.,
disqualifying small-scaled plot treatment comparisons within fields). We
contacted data holders fulfilling these requirements and requested
primary data on plant species richness of plantings, time since
establishment, landscape context and crop yield (see below) in addition
to measured pollination and pest control services. Overall, we analysed
data from 35 studies. We here define a study as a dataset collected by
the same group of researchers for a particular crop species and
ecosystem service (pest control or pollination) in a particular region
during one or several sampling years. We collected 18 pest control
service and 17 pollination service studies, representing a total of 868
service-site-year combinations across 529 sites (fields with or without
adjacent floral planting; see Supporting Table S1 for detailed
information about studies). In eight of these studies (122 sites) both
crop pollination and pest control services were measured (Table S1).