Literature search and inclusion criteria
We conducted a literature search in the
ISI
Web
of Science and Scopus databases (until 28 December 2021), using a
combination of different keywords depending on our research questions.
To find publications investigating the effects of urbanisation on
pollinator diversity, we used the keywords
[urban*
OR city OR cities OR town] AND
[pollinat*]
AND
[“species
richness” OR “species diversity”
OR
abundance
OR density OR
Assemblage].
We replaced the last combination with [trait OR phenology OR “body
size” OR nest* OR sociality OR
diet]
to find publications on the effects of urbanisation on pollinator
functional traits. To search for studies that investigate the effects of
urbanisation on pollination, we changed the last combination to
[”pollinat*
service” OR
”plant
reproduc*” OR
seed
OR fruit]. This search yielded 719, 708 and 504 publications in Web of
Science, and 454, 366 and 348 in Scopus, respectively. In addition, we
also surveyed recent reviews (e.g., Fenoglio et al. 2020; Wenzelet al. 2020) for relevant publications.
After removing duplicates, non-English papers and review papers, our
survey resulted in a total of 1 205 publications. The publications were
filtered by reading the title, abstract and full text according to the
following two
criteria:
(1) studies that reported pollinator abundance and/or richness,
phenology, nesting behavior, diet specialization, body size, sociality,
fruit set, seed set and visitation rates along urbanisation gradients,
or comparisons of urbanisation intensity within urban, urban-rural or
urban-natural land use categories; and (2) provided numerical data and
reported means, measures of
variance
and sample sizes for different categories of comparison, or regression
or correlation coefficients for urbanisation gradient studies. A total
of 133 publications met our criteria (Appendix S2).