Research & reports

Martin Šlachta, Tomáš Erban, Alena Votavová, Daniela Tomešová, Marta Václavíková, Taťána Halešová, Elena Shcherbachenko, Tomáš Bešta, Magda Edwards‐Jonášová, Renata Včeláková, Vladana Procházková, Pavel Cudlín · Journal of Apicultural Research · Europe

This study investigated pesticide contamination using larval food provisions (a mix of pollen and nectar) of mason bees (Osmia spp.) nesting in artificial shelters at twelve allotment garden sites in Prague and Brno, with seven commercial croplands (fruit orchards, oilseed rape fields) selected for comparison. In total, 79 samples of larval provisions were analyzed using a validated UPLC-MS/MS method covering 262 pesticides and related metabolites. Fifty-six pesticide residues were detected in the allotments and 74 in cropland sites, with 50 compounds common to both; fewer residues were found in allotments (mean 14.3±0.9) than in croplands (21.5±1.1; df=17.4, t=-2.9), though some residues exceeded 10 ppb. The highest levels were observed for the fungicide pyrimethanil (mean 1,989 ppb, maximum 3,983 ppb) and, among insecticides, thiacloprid (mean 136 ppb, maximum 170 ppb). The results supported the view of a lower risk of pesticide exposure in urban allotment gardens than in croplands, though given limited knowledge of sublethal effects of pesticides, and especially pesticide mixtures, on solitary bee development, the study recommends regulation or control of pesticide use in allotment gardens.

Elsa Blareau, Pauline Sy, Karim Daoud, Fabrice Réquier · Insects · France

A study near Paris, France, evaluated the effects of insect-mediated pollination service and potential pollination deficit on fruit set, seed set, and fruit quality (size, weight, malformation) in strawberries (Fragaria × ananassa) growing in an urban area, using flower-visitor observations and pollination experiments. Flower-visitor observations found that the pollinator community consisted solely of unmanaged (wild) pollinators, despite beehives being present in the surrounding landscape. Pollination experiments showed that wild-insect pollination improved fruit size as a qualitative measure of production but did not improve fruit set, and no evidence of pollination deficit was found in this urban environment.

Julia M. Schmack, Monika Egerer · Urban Ecosystems · Germany

A study in 30 urban community gardens in Berlin and Munich, Germany, observed 20 focal plant species and 13 common bee and non-bee flower visitor groups, examining how landscape urbanization and the availability of floral and nesting resources within gardens affected the complexity (nestedness, linkage density, connectance) of pollinator interaction networks. Dominant flower visitors changed over the growing season, with non-bee visitors such as ants and flies dominant early in the season and bees becoming important later. Nestedness of the flower visitor network increased with floral richness within gardens, while floral abundance, the impervious surface surrounding gardens, garden size, and nesting resource availability did not strongly influence the networks. The findings indicate that high floral richness in community gardens can ensure the complexity and stability of flower visitor networks, that non-bee visitors play an important role especially in the shoulder seasons, and that urban gardeners play a key role in mediating flower visitor interactions through their gardening practices.

Tainan Messina, Rui Figueira, José M.L. Santos · Ecosystem Services · Europe

A study in intensive farming systems of Central Portugal developed a methodology integrating species, trait and crop data, pest predation indicators and local farmers' expertise to estimate pest consumption by birds. Using point count data and each species' energy requirements and life-cycle characteristics, it estimated birds' daily invertebrate consumption and examined the relationship between birds and service provision along a tree gradient. Relating habitat requirements to pest control services via species guilds, the study found higher predation in annual crops close to trees or woody vegetation than in crop-only plots. After analyzing the methodology's main challenges and strengths, the study concludes that farmers' participation improved the accuracy and results of the analysis and that the methodology's holistic character can guide stakeholders and policymaking more effectively.

Lawrence D. Harder, Ronald M. Miksha · Oecologia · Germany (Munich)

A re-analysis of the observations behind Renner et al. (2021), which had concluded that an increase in managed honey bee hives between 2019 and 2020 intensified competition with non-Apis bees in the Munich Botanic Garden, Germany. The comment shows that the change in hive numbers did not statistically alter honey bee visitation to 29 plant species either within or between years, so the shift in the proportion of non-Apis bees among visitors is better explained as a response to reduced overall floral resource availability in 2020. The claim that urban beekeeping suppresses native pollinators is therefore supported by some observational studies and contested by re-analyses that find the statistical basis insufficient.

Jorge Godoy Román · Materia Arquitectura · Germany (Berlin)

This interview with Erika Mayr, an entomologist, horticulturist, ecologist, beekeeper, gardener, writer, and caretaker, explores her over 25-year dedication to understanding the importance of bees for other species. It highlights her personal relationship with bees, particularly in Berlin's urban environment, which involved various urban spaces and communities. Now based in Rome, Mayr shares her experiences and current projects in the city.

Demet Ülkü Gülpınar Sekban, Duygu Akyol · Journal of Urban Planning and Development · Turkey (Trabzon)

This study examined the contribution of residential gardens to ecosystem services in Trabzon City, Turkey. It was determined that both spatial needs and ecosystem benefits can be met with the same Green Infrastructure (GI) elements, and landscape value is supported by GI elements such as edible gardens, pollinator gardens, rain gardens, biological ponds, and green roofs. GI elements combining vegetation and water landscape elements have a higher potential for ecosystem services. The study concluded that green areas of residential gardens should be planned and designed through a holistic GI-oriented approach based on the total building parcel.

Monika Egerer · Renewable Agriculture and Food Systems · Germany

Researchers documented Lasioglossum limbellum, a bee species not previously recorded in the Berlin, Germany region, in a community garden built on concrete slabs and planted with annual and perennial vegetation. The species nests in cavities in soft rock cliffs, a habitat that does not functionally exist in urban areas, making its presence in the garden notable; the report presents the discovery as a basis for further research on wild-bee diversity and distribution changes in urban areas.

Renner S., Graf M., Hentschel Z., Krause H., Fleischmann A. · Oecologia · Germany (Munich)

Observed flower visitation on 29 plant species in a large Munich urban garden, finding that higher honeybee densities correlated with a significant shift from wild-bee to honeybee visits.

Ulrike Sturm, Tanja M. Straka, Alexandra Moormann, Monika Egerer · Insects · Germany (Berlin)

This study surveyed 111 community gardeners in Berlin and Munich, Germany, to understand the socio-psychological factors predicting pro-pollinator behavior. Using generalized linear models, the analysis revealed that gardeners who were fascinated by pollinators, held positive attitudes, and felt joy about seeing them reported intentions to protect or support pollinators. This suggests that fascination and joy can be harnessed for pollinator research and conservation efforts.

Theodorou P., Radzevičiūtė R., Lentendu G., Kahnt B., Husemann M., Bleidorn C., Settele J., Schweiger O., Grosse I., Wubet T., Murray T.E., Paxton R.J. · Nature Communications, 11:576 · Germany

A replicated experiment contrasting Central European cities with neighbouring rural sites, finding cities have lower overall insect richness (e.g. flies, butterflies) but higher bee species richness, flower-visitation rates and pollination than the countryside. It shows urban floral resources support bees while cautioning that not all insects benefit, informing the design of pollinator conservation in urban green spaces and gardens.

Elizabeth Nicholls, Adrian Ely, Linda Birkin, Parthiba Basu, Dave Goulson · Sustainability Science · United Kingdom (Brighton and Hove)

A review and case study in Brighton and Hove, UK, examined the contribution of small-scale urban and peri-urban agriculture to sustainable food production. Findings showed these small, labor-intensive systems with high crop diversity can be highly productive, offering environmental and social advantages over industrial agriculture through minimal synthetic inputs and local consumption. However, significant knowledge gaps persist regarding productivity, economic impacts, pesticide use, and biodiversity implications.

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.

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.

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.

Fortel L., Henry M., Guilbaud L., Mouret H., Vaissiere B. E. · Journal of Insect Conservation · Lyon, France

Surveys use of human-made nesting structures (trap nests / bee hotels) by cavity-nesting wild bees in an urban setting, examining how artificial nesting aids may supplement scarce urban nesting resources.

Petites ruches · · France (Auxerre)

The shared garden of the Maison de Quartier des Piedalloues in Auxerre, France, features lawns intentionally left high to attract butterflies such as the 'demi-deuil', which pollinate knautia flowers. Residents have also participated in creating palisades or 'branch walls' using split acacia stakes within the garden.

Lucy Bastin · · United Kingdom

Against a backdrop where about 90% of UK residents already live in towns or cities, and roughly 60% of the world's population is projected to live in urban areas by 2030, this essay argues that public land such as parks and allotments can easily be lost without a vocal set of "owners" to speak for it. It notes that most of the UK's "natural" areas have historically been created, managed, or modified by humans, and that overlooked brownfield sites can serve as valuable refuges for insect and plant species that can no longer persist in a countryside dominated by industrialized agriculture.