Expected enhanced support of pollination

The Bosque Vertical do Centro Cultural de Belém (CCB) in Lisbon (Vertical Forest at CCB), designed by Francisco Caldeira Cabral, is an innovative vertical garden inaugurated in 2020. Spanning two 17-meter-high walls with 7,524 plant pots, it enhances urban biodiversity by attracting birds and insects (Ref 3). This project offers recreational and aesthetic benefits, making the entrance of the cultural centre into a green space (Ref 4).
The garden helps reduce air pollution by absorbing pollutants and producing oxygen. It uses a drop-by-drop irrigation system made from recycled PVC, ensuring efficient water usage and retention (Ref 1). Furthermore, the garden improves air quality, aims to mitigate urban heat island effects, and conserves water (Ref 2, Ref 5).

The NatureRx Rain Garden Pilot is a community-driven initiative aimed at addressing urban runoff and its associated challenges, implemented by Bí URBAN, a community hub and social enterprise in Dublin focused on urban regeneration. The pilot project developed in Stoneybatter, Dublin involves diverting rainwater from residential rooftops into specially designed rain gardens (1). The area is used as the first trial area by installing around 100 rain gardens (3, 11). Built to fit neatly into available spaces, these self-sustaining planters will filter rainwater through the garden, with overflow pipes in place to prevent flooding during heavy downpours (1).
It is expected that these gardens will transform sterile urban spaces into green areas, enhancing biodiversity, providing habitats for pollinators, and acting as carbon sinks (1,3).

The Sacred Heart Church, a historical landmark in Detroit's Eastern Market since 1875, faced persistent stormwater and surface flooding issues. The church's parking lot, once marked by cracked concrete and stagnant water, has been transformed through an innovative Green Stormwater Infrastructure (GSI) retrofit. GSI leverages natural processes to manage stormwater, using plants to absorb, retain, and slow runoff. This retrofit, a collaboration between The Nature Conservancy and the parish, stands as one of Detroit's largest GSI projects at a faith-based institution. By introducing bioretention gardens filled with native plants, the project manages runoff from 1.4 acres of impervious surfaces and diverts 1.5 million gallons of water annually from the sewer system. This green space not only mitigates flooding and reduces combined sewer overflows (CSOs) but also provides a cooling effect, enhances community recreation, and significantly cuts the parish's drainage charges by 49%.(Ref.1,2,3)

The Republic Services Garden is a one-acre garden created and located in Hance Park, a large urban park located in downtown Phoenix, Arizona. As part of the larger revitalization of the park, the garden was created to showcase native desert plants, recycled materials, and shaded seating, serving as a model for eco-friendly urban landscaping. Its key goals are to enhance the park's appeal, create a welcoming community space, and demonstrate the potential of sustainable design in cities. By blending nature with urban infrastructure, the garden helps mitigate the urban heat island effect, addresses water scarcity, and supports habitat restoration. The project is a collaboration between the City of Phoenix and the Phoenix Parks and Recreation Department, with financial backing from Republic Services, the second-largest waste disposal company in the U.S. (Refs. 1, 5, 7, 12, 15).

The Africatown Heritage House Bioswale is a gently sloping green space with multiple functions which include catchment of runoff water and filtration of pollution in the runoff water (Ref 2), erosion control (Ref 2), and creation of habitat for biodiversity (Ref 1). It also has an educational purpose for students and the local community (Ref 2) and contributes to overall beautification (Ref 5).
The Bioswale was built by Birmingham-Southern College’s Environmental Center (Ref 6) and developed through the collaboration between the Mobile County Commission, the Mobile Area Lodging Association, Mobile County Training School, Mobile County Training School Alumni Association, and the National Academies of Science (NAS) Gulf Research Program (Ref 2). The project aims to address heavy rainwater management (Ref 5) and drainage issues (Ref 3).

Detroit’s neighborhoods grapple with a dual challenge: neglect and flooding. When the city stopped maintaining alleys in the late 1980s, responsibility shifted to residents. However, with limited resources and a declining population, many of these alleys fell into disrepair, becoming symbols of urban decay. This neglect is further compounded by the increasing frequency and intensity of severe storms, which have exposed the city's vulnerabilities in stormwater management, leading to regular flooding.

To address these challenges, the "Alley Activation" project, launched in 2020 by a team of researchers at the UM-Dearborn in partnership with local residents and organizations, seeks to transform neglected alleys into vibrant greenways, rain gardens, and pollinator habitats. The project focuses on cleaning and greening alleys located in 2 neighborhoods namely Littlefield and McNichols. The activated alleys are bounded by Littlefield, Hartwell, McNichols and Outer Drive roads. These roads enclose an area of 141,436 square meters, located in the Bethune community and the Hubbell Puritan neighborhoods. Alley Activation involves clearing blocked alleyways and turning them into inviting, productive spaces that support sustainability goals. These revitalized alleys serve as a "green capillary system," contributing to the city's environmental, cultural, and social well-being. As these spaces are cleared, they offer a fresh opportunity to re-imagine their role and potential within the community. (1,2,3,4,5)

Mehr Bienen für Berln - Berlin blüht auf is a project that aims to provide an example of how public green spaces can be upgraded to be pollinator-friendly, thus creating urban habitats for wild bees and other insect species (Ref. 4). The project was implemented by the German Wildlife Foundation in cooperation with the Berlin Senate Department for Mobility, Transport, Climate Protection and Environment and other stakeholders, in all 12 Berlin districts, whereby the districts support the allocation of the exact location for the NBS (Ref. 3; Ref. 4). Measures for each location are compiled based on the specific surroundings, use and existing vegetation with a low mowing frequency in all areas (Ref. 2; Ref. 4). Most of the areas are road median strips, roundabouts, designated areas in parks or residual commercial areas (Ref. 4). After the first phase (2018-2022), the project has now entered its second phase (2023-2025) and was renamed to “Mehr Bienen in Berlin - Aus Grün wird Bunt” (engl.: More bees in Berlin - from green to colourful) (Ref. 3). The main goals are to reach a minimum of 100 flowering areas in 2025, to halt the sharp decline in bees and other insects, and to inspire citizens to protect wild bees (Ref. 1,2, 3). The project has so far limited acceptance among the population, as the areas are regarded as unkempt due to the low mowing frequency. Public relations work, like the installation of information signs next to the areas, is intended to increase understanding among the public (Ref. 4).