Assessing five decades of garden bee studies

Urban Farm DB summary

A systematic review covering roughly five decades of bee research in urban and community gardens, analyzing 227 publications through early 2022. It clarifies the potential of gardens to support diverse bee communities, the role of citizen-tended green spaces in pollinator conservation, and existing research gaps, pointing toward future directions for urban pollinator conservation and participatory monitoring.

Only numbers and their conditions are stored, as structured data — never the source's own sentences. Metric and condition names stay in English, as coded.

• 28

  studies reviewed(urban garden bee study)

  Biodiversityn = 28

  setting

  urban-garden

  study design

  review

  span

  five-decades

  countries

  14

• 14

  countries covered(urban garden bee study)

  Biodiversityn = 28

  setting

  urban-garden

  study design

  review

• 674–830 species

  bee species documented(urban garden bee)

  Biodiversityn = 28

  setting

  urban-garden

  study design

  review

  note

  674 conservative count excluding morphospecies; 830 liberal count including morphospecies

• non eusocial ground nesting generalist native most common

  dominant functional traits(urban garden bee)

  Biodiversityn = 28

  setting

  urban-garden

  study design

  review

• comparable to global bee taxa→ No change

  parasitic and specialist proportion(urban garden bee)

  Biodiversityn = 28Control: proportions for global bee taxa

  setting

  urban-garden

  study design

  review

• biased toward northern hemisphere

  geographic bias(garden bee research)

  Biodiversityn = 28

  study design

  review

  span

  five-decades

Direction of conclusions

Each author conclusion is recorded only as a coded direction per topic. Read the original for the conclusion itself.

• BiodiversitySupportsWith caveats

Urban garden spaces are potentially important habitats for bee conservation. Gardens can host diverse flora, which provide floral resources across foraging seasons for bee species. Recent reviews have focused on the impacts of cityscapes on urban bee assemblages in different green spaces. Urban gardens are distinct from other urban green spaces, and bee communities in urban spaces have been an increasing topic of study over the past few decades. We reviewed 28 urban garden bee studies spanning five decades and 14 countries to compile an original metadataset of bee species' functional traits to understand the conservation value of gardens, identify gaps in bee sampling efforts, and summarize the calls to action included by their authors. Studies of urban garden bees have documented between 674 (conservative count, excluding morphospecies) and 830 (liberal count, including morphospecies) bee species. Urban garden bee communities were taxonomically and functionally diverse, although bee species that were non-eusocial, ground-nesting, generalist foragers, and native were most common in garden habitats. The proportion of parasitic bee species and specialist foragers found in urban gardens was comparable to proportions for global bee taxa. This suggests that gardens contain the hosts and forage needed to support bees with specialized life history requirements, and thus represent high quality habitat for a subset of bee communities. Garden bee research was strongly biased toward the northern hemisphere, which signifies a large gap in our understanding of garden bee communities in other regions. The variety of, and non-standard sampling methods in garden bee research makes it difficult to directly compare results between studies. In addition, both intentional low taxonomic resolution and a lack of collaboration with taxonomists constrains our understanding of bee diversity. Our analyses highlight both successes of past urban garden bee studies, and areas of opportunity for future research as we move into a sixth decade of garden bee research.