Research & reports

Paul Sherfey · Budkavlen · Global

This study explores human-animal relationships, particularly with insects, in collective gardens through observation and digital research. It demonstrates that in collective gardens, cultivating community is as important as cultivating organic produce, and this community includes not only humans but also animal species like insects. The article analyzes why gardeners show interest in building hotels and cafes, sowing meadows, and arranging festivals for insects, especially bees, and contrasts discourses about bees with the lack of similar discourse about wasps, considering how different cultural heritages affect the value placed on species.

Katherine C. R. Baldock · Current Opinion in Insect Science · Global

Urban expansion is a major threat to biodiversity, yet some pollinator groups, particularly bees, can thrive in urban areas. Recent studies indicate that local floral resources and the amount of impervious cover influence pollinator abundance, richness, and community composition. Urban intensification, chemicals, climate change, and increased honey bee colony densities all negatively affect urban pollinators.

Louis Amprako, Kathrin Stenchly, Martin Wiehle, George Nyarko, Andreas Buerkert · Insects · Ghana

In 36 fields around Tamale in Ghana's Northern Region, researchers used 72-hour pitfall and pan trap sampling to examine how different irrigation water sources shaped arthropod communities in urban and peri-urban agricultural systems. Among 14,226 specimens spanning 13 orders, 103 families, 264 genera, and 329 taxa, analyzed with non-metric multidimensional scaling and redundancy analysis, arthropods grouped by irrigation source, with dipterans -- notably the disease-vector eye gnat Hippelates pusio -- dominant under wastewater irrigation, three alien ant species indicating community shifts from invasive species, and seven ant species forming mutualistic relationships with aphids flagging a future risk of aphid pest outbreaks.

Kristen R. Birdshire, Adrian L. Carper, Christy E. Briles · Urban Ecosystems · United States

A study examined bee community responses along a high-plains semi-arid urban-rural gradient in Denver, Colorado, United States, using percent impervious surface across 12 sites to define urbanization extent and combining field assessment with geospatial analysis of local and landscape characteristics; wild bees were collected and analyzed against urbanization using linear modeling. Bee abundance and diversity decreased with increasing urbanization, indicating a negative impact of urban areas on bee communities. All bee guilds responded positively to local floral richness and negatively to landscape-level urbanization, suggesting a shared response pattern across bee types.

Bennett A.B., Lovell S. · PLoS ONE, 14(2):e0212034 · United States (Chicago)

A study of 19 urban agricultural sites in Chicago examining how surrounding land cover (landscape scale) and on-site design (local scale) shape bees and pollination services. Bee responses varied by body size and nesting habit: increasing impervious cover lowered bee richness and reduced pollination services, while more local floral area boosted small soil-nesting bees. It recommends minimizing impervious cover at large scales and adding floral resources locally so urban agriculture can conserve pollinators in the surrounding ecosystem.

Baldock K.C.R., Goddard M.A., Hicks D.M., Kunin W.E., Mitschunas N., Morse H., Osgathorpe L.M., Potts S.G., Robertson K.M., Scott A.V., Staniczenko P.P.A., Stone G.N., Vaughan I.P., Memmott J. · Nature Ecology & Evolution, 3(3):363-373 · United Kingdom

A large, well-replicated study of floral resources and pollinators across 360 sites in four British cities, comparing pollinator abundance among urban land uses. It shows that residential gardens, allotments and community gardens are urban pollinator hotspots, demonstrating that citizen-tended plots are central to urban biodiversity conservation, and models the benefit of interventions such as adding flowerbeds.

Ropars L., Dajoz I., Fontaine C., Muratet A., Geslin B. · PLOS ONE · Paris, France

In Paris, wild pollinator visitation rates were negatively correlated with honey bee colony densities, suggesting high-density urban beekeeping may compete with wild pollinators for floral resources.

Stacy M. Philpott, Simone Santos de Albuquerque, Peter Bichier, Hamutahl Cohen, Monika Egerer, Claire Kirk, Kipling Will · Insects · United States (California)

This study examined local and landscape factors influencing ground beetle (Carabidae) activity, species richness, and traits in 19 community gardens in coastal California. Gardens with higher crop richness and agricultural surroundings showed greater carabid activity density, but species and functional group richness did not respond to these factors. Gardens with more leaf litter had lower carabid activity but tended to have larger carabids, indicating both local and landscape factors influence carabid communities.

Gordon W. Frankie, Ingrid Feng, Robbin W. Thorp, Jaime C. Pawelek, Marissa H. Chase, Christopher C. Jadallah, Mark Rizzardi · Journal of Pollination Ecology · United States (California)

An extensive survey of bee-flower collection records from 10 California cities between 2005 and 2011 examined diverse bee species visiting native and non-native ornamental plants. A total of 7,659 bees were examined, identifying 229 bee species visiting both native and non-native plant types. Native bee species were common on both plant types, but substantially more non-native bee species visited non-native plants compared to native plants.

Kathleen L. Prudic, J. Keaton Wilson, Michelle C. Toshack, Katharine L. Gerst, Alyssa Rosemartin, Theresa M. Crimmins, Jeffrey C. Oliver · Insects · Global

This study introduced web-based citizen science programs to assist urban growers in managing insect biodiversity on city farms, a complex task given the estimated 30% of the global urban population engaged in food production. The programs aim to connect growers with relevant data and experts for informed insect management decisions. It suggests that combining citizen science volunteers with urban farmers can clarify ecosystem services, reduce insecticide use, and promote non-chemical alternatives.

Uvianeth Castañeda Maldonado · · Colombia (Bogotá)

The recognition and characterization of arvense flora (weeds) found in urban gardens assisted by the Bogotá Botanical Garden in Bogotá, Colombia, were conducted. A catalog of arvense recognition for the Capital District was developed, representing 36 species of weeds belonging to 15 families of the Magnoliopsida class. This catalog includes photographic records, field observations, and information on pollinator presence, serving as an important consultation tool for the district's flora.

Rachel E. Mallinger, Anne Yasalonis, Gary W. Knox, Wayne Hobbs · EDIS · United States (Florida)

This 7-page fact sheet aims to conserve approximately 315 species of native wild bees in Florida. Published by the UF/IFAS Entomology and Nematology Department, it shows how gardeners and land managers can aid bee conservation efforts by planting flowers in home or community gardens.

Kimberly M. Ballare, John L. Neff, Rebecca Ruppel, Shalene Jha · Ecological Applications · United States

This study assessed bee community composition at 20 grassland and 20 agriculture sites across two US metroplexes over three time periods, identifying 172 species from nearly 13,000 specimens. It found that regional land use differentially impacted bee abundance and diversity depending on local habitat management. Local bare ground and floral richness were significantly related to multiple metrics of bee diversity.

Monika Egerer, Jacob M. Cecala, Hamutahl Cohen · Sustainability · United States (California)

This study compared the effects of local and landscape features on wild bee species abundance and richness in 19 gardens and 11 nurseries in California, USA. Local features such as floral richness and ground cover, and landscape features like impervious land cover, were assessed. In gardens, floral richness, local habitat size, and urban land cover impacted wild bee species richness, while in nurseries, floral richness and the proportion of native plant species impacted wild bee abundance and richness.

M. Tsuruta, Kyo Itoyama · Japanese Journal of Applied Entomology and Zoology · Japan (Kawasaki City)

This study investigated the seasonal occurrences and species composition of Orius spp. in an okra field in Kawasaki City, Japan. Orius spp. were found on okra plants from early-summer to early-autumn, with peak occurrences advancing with earlier flowering times. The initial occurrence was not associated with the seasonal prevalence of thrips on okra plants, suggesting that the main factors influencing Orius spp. occurrence are prey-independent.

Sarah Taylor Lovell · · Global

This data describes the landscape attributes of nineteen sites as supplemental information for an article by Bennett, A.B., and Lovell, S.T., accepted for publication in PLOS ONE, which discusses how landscape and local site variables differentially influence pollinators and pollination services in urban agricultural sites.

Sarah Lovell · · United States

This record is a dataset description accompanying a PLOS ONE manuscript by Bennett and Lovell (2019) on landscape and local site variables and pollinators in urban agricultural sites; the data consist of the percentage of each bee pollinator group recorded in bee bowls and through direct observation.

Sofia Biffi, Cleandho Marcos de Souza, L. G. Firbank · Agriculture Ecosystems & Environment · United Kingdom

Seventeen urban food production sites of varying sizes in and around Leeds, UK, selected from an open-source database, were surveyed using pitfall traps to assess the abundance and diversity of epigeal invertebrates (beetles, springtails, and spiders) in relation to soil characteristics (organic carbon, moisture content, pH) and site area; soil productivity was assessed by growing radish (Raphanus sativus) under uniform conditions. The study found no correlation between epigeal invertebrate abundance or diversity and either site area or soil characteristics. The authors state this indicates there is, as yet, no evidence that urban food production sites are too small to draw on ecosystem services delivered by epigeal invertebrates.

Heidi Liere, Monika Egerer, Stacy M. Philpott · Journal of Urban Ecology · United States (California)

Ladybird beetles (Coleoptera: Coccinellidae) were collected from 19 community gardens across three counties of the California Central Coast during June to September of 2014 and 2015. Of the 19 species collected, only three were non-native to California (three specimens could not be identified to species). Similarity in species composition between gardens was not related to geographic distance, indicating no dispersal limitation among these mobile beetles. Instead, three landscape-level and seven garden-scale variables correlated with changes in community composition, and garden management practices such as ground cover altered the taxonomic and functional makeup of the ladybird beetle community.

Kratschmer S., Kriechbaum M., Pachinger B. · Urban Ecosystems, 21:429–446 · Austria (Vienna)

Monthly surveys on nine Vienna green roofs in 2014 recorded 992 wild bees of 90 species. Forage availability and fine substrates strongly boosted diversity and abundance; ground-nesting social bees and Sedum bloom-period foraging shaped a distinct rooftop bee community.

Gail Ann Langellotto, Andony Melathopoulos, Isabella Messer, Aaron Anderson, Nathan McClintock, Lucas Costner · Sustainability · United States (Portland, Oregon)

This study sampled bees from gardens in the Portland, Oregon metropolitan area and estimated typical foraging distances to assess whether urban gardens might supply pollination services to surrounding agricultural land. It estimates that when pollination-dependent crops are nearby, 30–50% of the garden bee community could potentially provide pollination services to adjacent crops, suggesting urban gardens could provision neighboring farms or serve as a refuge for pollinators.

Trevor A Lambkin · Metamorphosis Australia magazine of the Butterfly & Other Invertebrates Club · Australia

This article discusses native bees, noting their weak jaws result in a tickle-like bite and that indigenous peoples globally have extracted their honey for various uses. Research into native bees for crop pollination began in 1984, leading to the development of hive propagation techniques by 1987. The keeping of native bees, particularly the subtropical Carbonaria species, has since gained popularity among various groups including schools and community gardens.

Cindy Melissa Torres Peña · Dialnet (Universidad de la Rioja) · Spain

"SOS Polinizadores" is an educational project aimed at fostering knowledge and study of pollinating insects in ecosystems among students, teachers, and the broader educational community, including their impact on our lives and current threats. It also seeks to raise awareness about environmental problems and the sustainability of nearby ecosystems like parks, gardens, and urban and peri-urban vegetable gardens. The project was carried out in eight educational centers in Madrid in Spring 2017, with a guide provided for future implementation in other centers.

Brenda B. Lin, Monika Egerer, Alessandro Ossola · Frontiers in Built Environment · Global

This review examines how urban gardens might counter the ratcheting-down of everyday nature experience caused by urban green-space loss, by fostering biophilia. It outlines three pathways: exposure to diverse plants, animals and soils; understanding of natural processes tied to food production such as climate, pest control and pollination; and provision of a safe space for physical interaction with nature, and presents examples of urban gardens to illustrate biophilic design.

Chatura Vaidya, Kaleigh Fisher, John Vandermeer · Sustainability · United States

A study placed experimental bumblebee nests at 10 sites (nine of them community gardens) across an urbanization gradient (0-99% urbanization) in the United States to assess the effects of urbanization on colony development and reproductive success. Reproductive success and colony size were positively correlated with the nests' cumulative weight gain (p < 0.05), but the degree of urbanization had no significant effect on population growth rate or forager activity (p > 0.05). Growth rate was strongly negatively affected by the abundance of wax moth larvae (p < 0.05) and positively correlated with parasite diversity (p < 0.05) and the number of foragers entering the nest (p < 0.01). The study concludes that both bottom-up and top-down effects are equally important for pollinator population dynamics.