Research & reports

Bruno Martins Dala Paula, Luana do Carmo Araujo de Oliveira, Emmanuel Duarte Almada, Filipe Freitas Chaves, Maura Neves Coutinho · Expressa Extensão · Brazil (Belo Horizonte)

This essay reflects on the relationship between urban agriculture practices and life care, based on a university extension project mobilized between resident groups of the Aglomerado da Serra communities in Belo Horizonte, Brazil, and members of Grupo Aroeira, over six years (2008-2013). The project was structured through main activities including surveying urban agriculture initiatives in the community, holding a cycle of 'Cultivating Health' meetings, forming a Medicinal Plants Group, creating a literacy class, and organizing open-air markets with urban agrobiodiversity products. This project aimed to cultivate and promote the care for the lives of the residents, valuing their popular knowledge, while bringing these experiences into the university through the practice of 'reverse extension'.

Kaitlin Hathaway · Digital Showcase Research, Scholarship, & Creative Works (University of Lynchburg) · United States (Lynchburg)

The Lynchburg College Community Garden at Beaver Point, United States, was established in 2016 by students and faculty to teach sustainable agriculture and enrich soil. In spring and summer 2017, projects included donating produce, promoting pollinators, raising chickens, and composting. The abstract also describes a designed rainwater collection and irrigation system.

Ebrahiem Babiker, Stephen Stringer, Hamidou F. Sakhanokho, John J. Adamczyk, Arlen D. Draper · HortScience · United States

'Muffin Man' is described as a new public-domain, edible ornamental cultivar of rabbiteye blueberry (Vaccinium virgatum), a species commercially important in the southeastern United States for its tolerance of common biotic and abiotic stresses, developed amid growing interest in edible landscaping as an alternative to conventional ornamental landscapes. The abstract text is truncated and provides no further cultivar details.

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.

Horta das Corujas · Horta das Corujas (blog oficial) · Brazil

The official blog of Horta das Corujas, a volunteer-run community garden on Praça das Corujas in the Vila Beatriz neighborhood of São Paulo. Opened on September 29, 2012, the roughly 800 m² garden practices agroecological vegetable and herb cultivation, restores a local spring, keeps bees, and hosts school environmental-education visits. It operates without formal permits, run by volunteers, with about 10-15 people regularly active.

Tammy E. Parece, James B. Campbell · Urban Agriculture & Regional Food Systems · United States

This study used the Normalized Difference Vegetation Index (NDVI) from U.S. Landsat 5, 7, and 8 satellites to assess the environmental impact of urban community gardens across three eastern U.S. cities—Roanoke, VA; Pittsburgh, PA; and Buffalo, NY—over the 2007–2015 growing seasons. It reports that establishing community gardens altered seasonal NDVI trajectories, sometimes declining initially but then increasing over time, revealing the vigorous vegetative character of urban agriculture.

Monika Egerer, Courtney Arel, Michelle D. Otoshi, Robyn D. Quistberg, Peter Bichier, Stacy M. Philpott · Journal of Urban Ecology · United States (California)

This three-year study in 19 urban community gardens on the California central coast examined how urban landscape intensification and diversity influence the abundance and richness of five arthropod groups (ants, bees, ladybeetles, parasitoids, spiders) across six spatial scales (200 m to 5 km). All arthropod groups were influenced by landscape factors, but this influence varied with spatial scale and local habitat features, likely due to arthropod community interactions and life history strategies.

Jennifer Wilhelm · University of New Hampshire Scholars Repository (University of New Hampshire at Manchester) · United States (New Hampshire)

This dissertation addresses agricultural extensification from several angles. Chapter 1's literature review showed an increase in research on urban and peri-urban agriculture (UPA) and ecosystem services, but highlighted a need for quantifying ecosystem services and functions to clarify ecological tradeoffs. Subsequent chapters focused on a mixed-methods study in New Hampshire, surveying approximately 600 residents (494 general population, 103 food system stakeholders) on their perception of forestland conversion to agriculture.

Monika Egerer, Alessandro Ossola, Brenda B. Lin · BioScience · United States (California central coast)

This study conceptualizes community garden soils within the novel ecosystem framework, arguing that gardeners cultivate novel agroecosystems from their garden beds' soil. On the California central coast, community garden soils may not be influenced by land-use legacies associated with geographic location. Instead, intensive soil reworking by gardeners can wash out legacy signals and decadal chronological trends, leading to soil homogenization that reduces biophysical ties to the underlying earth.

Edward Lagucki, Justin Burdine, Kevin E. McCluney · PeerJ · United States (Toledo, Ohio)

This study investigated associations between urbanization and flying arthropod communities in 30 gardens and parks in Toledo, Ohio, during July and August 2016, collecting 2,369 individuals across nine orders using elevated pan traps. Flying arthropod community composition was associated with percent impervious surface and canopy cover. Overall abundance was negatively associated with impervious surface and positively with distance to city center, with specific taxa showing similar responses, indicating urbanization reduces taxa important for urban agriculture.

Sable Liggera · Smith ScholarWorks (Smith College) · United States (Springfield, MA)

A project was conducted to compare methods for controlling and eradicating Japanese knotweed on the plot of Gardening the Community, an urban gardening organization in Springfield, MA. This study discussed the methodology, effectiveness, and ecological impact of two options: repetitive mowing and the use of the herbicide glyphosate. Glyphosate stem injection was determined to be the most efficient method, reducing knotweed volume by 95-100% after one year, but was rejected due to the organization's no-herbicide policy. The final recommendation was repetitive cutting, which showed a stable decrease in knotweed stem height if more than four cuts were applied in one growing season.

Étienne Normandin, Nicolas J. Vereecken, Christopher M. Buddle, Valérie Fournier · PeerJ · Canada

This study collected 32,237 wild bee specimens (200 species, 6 families) from 46 sites in Montreal and Quebec City in 2012 and 2013, across cemeteries, community gardens, and urban parks. It demonstrated that cities are home to diverse communities of wild bees, which in turn affect bee community structure and dynamics. Community gardens specifically harbored high levels of functional trait diversity, suggesting a substantial contribution to urban pollination services.

Sam Smiley · Catalyst Feminism Theory Technoscience · United States (Provincetown, MA)

This arts-based action research, conducted by media artist and researcher sam smiley, explored the process of building a sculpture from Japanese Knotweed, an "invasive species," in the B-Street community garden in Provincetown, MA, USA. A series of community interventions with gardeners, naturalists, and sculptors were organized during the May 2016 Appearances Environmental Arts Festival. This article debriefs the journey of the Knotweed Sculpture from the community garden to its ultimate destruction in a bonfire on National Seashore.

Monika Egerer, Stacy M. Philpott, Heidi Liere, Shalene Jha, Peter Bichier, Brenda B. Lin · International Journal of Biodiversity Science Ecosystems Services & Management · United States (California)

This study examined 25 urban community gardens in California to investigate relationships between soil properties and neighborhood socio-demographics, focusing on (1) how groundcover management affects soil properties, and (2) how socio-demographics, particularly social advantage, affect groundcover management and soil properties. Mulch groundcover was found to improve soil fertility and water holding capacity in gardens, and socio-demographic factors appeared to affect residents' access to mulch: neighborhoods with higher mobility (e.g., greater vehicle availability) but poorer public/environmental health indicators (e.g., poorer health care access) had higher soil organic matter, nutrient content, and water holding capacity. However, indicators of high-functioning soils were also found in the absence of mulch, suggesting that other factors such as social networks and organizational support may also be important for ecosystem services in urban agricultural systems.

Gerardo R. Camilo, Paige A. Muñiz, Michael Arduser, Edward M. Spevak · Journal of the Kansas Entomological Society · United States

A three-year survey (2013-2016 growing seasons) in St. Louis, Missouri, USA, sampled bees by aerial netting across vacant lots, city parks, community gardens and urban farms, collecting over 7,700 specimens, supplemented with BioBlitz data, personal collections, museum-collection records and the literature. The survey identified 198 bee species from five families in the city, of which only nine were non-native, and found St. Louis hosts nearly 45% of Missouri's bee diversity, a proportion the study describes as likely making it one of the most species-rich cities relative to its state's total bee fauna in the country.

Benjamin Iuliano, Alexandra Markiewicz, Paul Glaum · Michigan Journal of Sustainability · United States

A paper examining how community gardens have spread amid a decade of increased urban agriculture in American cities, and what effects this has on local ecosystems, with the title indicating a focus on potential effects on native pollinators. It states that socio-economic demographics may influence patterns of garden placement and quality, producing changes in biotic communities that urban ecologists are only beginning to understand. The available abstract breaks off while introducing a researcher hypothesis about increased floral resources, without stating further specific results.

Cat Buxton · · United States

This is an announcement for a free workshop on garden insects, held Thursday, June 22, 2017, from 6:30 to 7:30 p.m. at the Community Garden at Ratcliffe Park in White River Junction, Vermont. The workshop was led by a garden consultant and sponsored by the Upper Valley Food Co-op.

Stacy M. Philpott, Peter Bichier · Ecological Applications · United States (California)

The influence of local, garden-scale factors (herbaceous and arboreal vegetation abundance and diversity, ground cover) and landscape-scale factors (landscape diversity and surrounding land use) on predation services was examined in 19 urban gardens on the California central coast. Sentinel pests — moth eggs and larvae and pea aphids — were placed on greenhouse-raised plants in open plots versus bagged, predator-exclosure plots. Predation rates were high, with 40% to 90% of prey items removed in open treatments. Predation services varied with local and landscape factors, but significant predictors differed by prey species: predation of eggs and aphids increased with vegetation complexity in gardens, while larval predation declined with vegetation complexity. Smaller gardens experienced higher predation, likely due to greater predator abundance, and several ground cover features influenced predation services. In contrast to patterns in rural agricultural landscapes, aphid predation declined as landscape diversity increased.

Naim Edwards · Urban Agriculture & Regional Food Systems · United States (Ann Arbor)

This study investigated ant (Formicidae) species diversity in relation to garden attributes at three gardening sites in Ann Arbor, Michigan, along with predation experiments testing biocontrol of Cabbage Looper moths and Squash Bugs. It sampled 19 ant species from 12 genera, finding that soil texture, intense tilling and distance from less-disturbed areas significantly reduced species richness, with less-tilled plots averaging nearly double the species of tractor-tilled plots. Ants consumed Cabbage Looper eggs and larvae, and the authors conclude that reducing disturbance in and around gardens can promote ant biodiversity and beneficial pest predation.

Robyn D. Quistberg, Peter Bichier, Stacy M. Philpott · Environmental Entomology · United States (California)

This study investigated bee abundance and species richness in 19 urban community gardens on the California central coast using aerial nets and pan traps. Researchers found 55 bee species and identified that local factors, such as garden size, floral abundance, mulch cover, bare ground, and grass, were generally more important correlates than landscape factors. Medium bees were less abundant in areas with more medium-intensity developed land within 2 km.

William Kort · UWM Digital Commons (University of Wisconsin–Milwaukee) · United States

This study developed a framework for life cycle environmental assessment of urban organic waste utilization in urban agriculture, specifically fruit and vegetable production. Results suggest that a full "urban nutrient cycle" offers significant environmental benefits, including meeting up to 70% of vegetable and 17% of fruit consumption needs in Northern and Eastern U.S. cities, with potential water savings of 10-17% of annual domestic use. Optimizing resource recovery through source separation leads to 1-2% lower wastewater generation and up to 44% greater phosphorus recovery, while overall energy and emissions benefits are 1-2% of a city's annual totals.

Cat Buxton · · United States

This record describes a community event titled "Garden Insects 101: Attracting Beneficials & Deterring Pests" held on July 19, 2016, from 6 PM to 7 PM at the WRJ Community Garden at Ratcliffe Park in the United States. The event featured Cat Buxton discussing beneficial insects and pests.

Andrea Burr · Consilience · United States (St. Louis, Missouri)

This interdisciplinary pilot study in St. Louis, Missouri, USA (2013-2015) investigated relationships between pollinator health and urban land-uses. Wild bees were sampled weekly at urban farms, community gardens, and prairie pockets, and ethnographic interviews were conducted with 30 decision-makers in summer 2015. Informants described bees' role in crop yield and reported planting to attract pollinators, suggesting the city is viable for pollinator habitat.

David M. Lowenstein, Maryam Gharehaghaji, David H. Wise · Environmental Entomology · United States

A study at 28 urban food-production sites in the Midwestern United States measured the removal of sentinel eggs and larvae of the cabbage looper (Trichoplusia ni) by predators over a 3-day period. Predators removed 50% of eggs and 25% of larvae, with mortality rates not predicted by landscape factors and similar across residential gardens, community gardens, and farms. Laboratory assays confirmed that lady beetles, spiders, and pirate bugs consumed eggs and larvae at high rates.

Tammy E. Parece, Elena Serrano, James B. Campbell · The Professional Geographer · United States (Roanoke)

A socioeconomic evaluation in Roanoke, Virginia, analyzed ten variables, including food options, across census block groups to identify neighborhoods that would benefit from urban agriculture. The study found that one block group qualified in all ten variables, and two-thirds showed need in at least half, with most of these areas located in the city's middle. This analysis produced a hierarchy of locations based on socioeconomic need for new urban agriculture sites.