Research & reports

Misha Leong, Claire Kremen, George Roderick · PLoS ONE · United States (California)

This study investigated pollinator-plant interactions in a periurban landscape on the outskirts of the San Francisco Bay Area, California, where urban, agricultural, and natural land uses interface. Using standardized observations of floral visitation and measurement of seed set in yellow starthistle (Centaurea solstitialis), a common grassland invasive, it tested the hypothesis that increasing urbanization would decrease bee visitation rates, viable seed set, and pollination efficiency (the relationship between bee visitation and seed set). Contrary to expectation, bee visitation was found to be highest in urban and agricultural land use contexts. However, seed set rates in these human-altered landscapes were lower than in natural sites. The study attributes this mismatch between visitation and seed set to higher plant diversity in urban and agricultural areas — driven by more introduced species — which reduces pollinator efficiency. If consistent across other plant species, the novel plant communities and generalist bee species favored by human-altered landscapes would reduce pollination services.

Mary M. Gardiner, Caitlin E. Burkman, Scott P. Prajzner · Environmental Entomology · United States

This article discusses the ecological value of urban vacant land in the United States, particularly its role in supporting arthropod biodiversity and ecosystem services. It notes that vacant lands can offer opportunities to preserve declining species and restore ecosystem functions. The article emphasizes the need for quantifying the current ecological value of vacant land and assessing how changes in its ecosystem management affect biodiversity and ecosystem processes, with a specific focus on arthropods.

Klaire Elise Freeman · OhioLink ETD Center (Ohio Library and Information Network) · United States (Cleveland)

A study in Cleveland, Ohio, examined the role of wasps in urban gardens and vacant lots, collecting 13,339 arthropods, including 5,165 wasps across 24 families and 369 morphospecies. The findings showed higher wasp abundance, species richness, and number of families in vacant lots compared to urban gardens. Specifically, vacant lots had 2,703 individuals and 288 morphospecies, while gardens had 2,462 individuals and 231 morphospecies.

Kevin C. Matteson, Gail Langellotto · Cities and the Environment · United States (New York City)

This study used mark-recapture and translocation experiments to assess the residency and movement of the urban butterfly, Pieris rapae, within and among community gardens in New York City. While most marked butterflies used gardens transiently, recruitment and residence time were higher in larger gardens and those with more flowers. The study demonstrated the butterfly's ability to move through developed landscapes and locate floral resources.

Kevin F. Welzel · Berkeley Scientific Journal · United States (California)

This study examined native bee pollination at two urban agricultural sites in Berkeley, California: the Oxford Tract and Berkeley Youth Alternative garden. It observed squash, tomato, strawberry, and sunflower plants, collecting data on distance from natural habitat, native bee pollinator diversity, and visitation rates. The study found mixed results for genus richness and evenness, and a t-test indicated no significant difference in visitation rates for each plant type between the two sites.

Sarah Mead-Willis · The Deakin Review of Children s Literature · United States (Brooklyn)

"The Honeybee Man" by L. Nargi is a 2011 picture book about Fred, a Brooklyn resident who keeps three honeybee colonies on his townhouse roof. The book illustrates Fred's urban beekeeping, showing how his bees collect nectar across the borough and how he harvests and distributes honey to neighbors. It aims to educate young families about local ecology and human community, explaining bee behavior and the processes of beekeeping and honeymaking.

Kevin C. Matteson, Gail Langellotto · Urban Ecosystems · United States (New York City)

A study in community gardens in densely populated Bronx and East Harlem, New York City, evaluated local and landscape factors influencing bee and butterfly richness. Contrary to predictions, models showed that within-garden variables like floral area and sunlight availability were the most influential factors for both bee and butterfly richness. Marginal support was found for models of bee richness including the number of surrounding building units, which showed a negative association.

Kevin C. Matteson, Gail Langellotto · Insect Conservation and Diversity · United States (New York City)

The ability of adding 70 plants of seven native wildflower species over two years to augment beneficial insect richness, including bees, butterflies, and predatory wasps, was assessed in New York City community gardens. Bayesian analyses failed to find a strong influence of the native plant additions on beneficial insect richness, even after correcting for prior floral abundance. Butterflies and megachilid bees were found to heavily utilize introduced ornamental and crop flowers in these gardens, even when native flowers were present.

Colla S.R., Willis E., Packer L. · Cities and the Environment (CATE), 2(1):4 · Canada (Toronto area)

A foundational study comparing bee diversity and abundance on green roofs and ground-level sites near Toronto. With suitable plants and management, green roofs can host bee communities comparable to ground habitats, discussing implications for urban pollinator conservation and rooftop agriculture.

Kevin C. Matteson, Gail Langellotto · Cities and the Environment · United States (New York City)

In 2005, a study compiled a list of crop plants in 19 New York City community gardens, classifying them by bee pollination dependence. Using mark-recapture methods, the abundance of the common eastern bumble bee (Bombus impatiens) was estimated. Wild populations of B. impatiens were found to be abundant in New York City community gardens, where it is the most prevalent native bee species and visits various crop flowers.

J. C. Pawelek, Gordon W. Frankie, Robbin W. Thorp, Maggie Przybylski · Cities and the Environment · United States (California)

A community garden in San Luis Obispo, California, was modified by planting bee-attractive plants to attract native bee pollinators. Garden modification and monitoring of native bees occurred from 2007 through the 2009 growing season. The diversity of collected and observed native bees increased each year, with 40 species in 17 genera recorded to date.

Peter A. Werrell, Gail Langellotto, Shannon U. Morath, Kevin C. Matteson · Cities and the Environment · United States (New York City)

A study in New York City community gardens examined how the spatial area dedicated to cucumbers (Cucumis sativus), relative to other flowering plants, influenced the deposition of conspecific and heterospecific pollen on cucumber plants, and also examined the effect of overall garden size on that pollen deposition. Female flowers were collected from potted cucumber plants placed experimentally in the gardens for the study, as well as from cucumbers established in raised beds by community garden members; pollen grains were isolated in the laboratory by acetolysis and the numbers of heterospecific and conspecific pollen grains were quantified. The abstract does not report quantitative results or conclusions.

Kevin C. Matteson, John S. Ascher, Gail Langellotto · Annals of the Entomological Society of America · United States (New York City)

Bees were surveyed over 4 years in community gardens in heavily developed neighborhoods of the Bronx and East Harlem, New York City, yielding 1,145 individuals from 54 species (13% of recorded New York State bee fauna). Soil-nesting individuals were relatively rare (25%), possibly due to a lack of suitable nesting soils, and parasitic species were scarce (5.6% of species, 2.6% of individuals); exotic species were common, comprising 27% of individuals and 19% of species collected. Compared with other bee faunal surveys in New York and New Jersey, including Central Park and Prospect Park, bee richness in these urban gardens was reduced and the species composition was biased toward exotic and cavity-nesting bees, though the gardens still supported a diverse bee assemblage despite their small size and location within highly urbanized areas.