Green space and habitat

The himmelbeet is an intercultural, inclusive community garden in Berlin that has been inviting people to garden and harvest their own produce since 2013. The garden offers around 200 raised beds that are communal and can be rented by neighbors, individuals and institutions (Ref. 1; Ref. 3). The project aims to familiarize children and adults with ecology, sustainability and healthy eating and to offer space for social exchange and education, while being inclusive to people with different (dis)abilities and backgrounds (Ref. 2; Ref. 6). The design and implementation of environmental education workshops are a vital part of the work. (Ref. 1; Ref. 6) With its own café and vegetable production, himmelbeet is strongly oriented towards the principles of the economy for the common good. The garden team also looks after other gardens in the city - on behalf of educational institutions, social institutions, housing associations and neighborhoods. (Ref. 1; Ref. 6)
Originally located in Ruheplatzstrasse, the garden moved in 2021 to Gartenstrasse, because of land disputes with the providing land owners and the demand of the space for other social projects. (Ref. 8; Ref. 11)

Iasi has limited access to green-blue open spaces and fails to meet national and European standards for per capita green space and proximity to larger green areas. Additionally, the city experiences significant fragmentation in its green spaces. To address these issues, the municipality of Iasi launched a project in 2020 to restore a vacant and degraded area, transforming it into a park. Funded by European resources, the project aims to rehabilitate the neglected land by constructing a green park and introducing local vegetation. The primary goal is to provide a leisure and relaxation space for local citizens and visitors while improving the quality of the surrounding air by converting much of the terrain into green space. The vacant land is situated in the historic Ticau neighborhood, which has been affected by municipal neglect, characterized by poor infrastructure and limited connectivity to the city's main areas. Furthermore, the project aims to reduce the heat island effect by creating green oases in a city marked by many “hard surfaces,” such as paved areas, which contribute to this phenomenon expected to intensify in the coming years. Originally scheduled for completion by the end of 2022, the project has been delayed due to a lack of funds and is now expected to be finished by the end of 2024 (Refs 1, 2, 3, 4, 6, 7, 11).

Lima Verde is one of the pillars of the metropolitan mayor's government plan and is supported by SERPAR. It aims to reforest hillsides, hills, and central berms of metropolitan and local roads, as well as public recreational spaces, to create urban lungs that generate oxygen and scenic beauty for the benefit of the health of all residents (Ref 1, 3). Its goal is to plant one million trees in four years (2022 - 2026) in different parts of North, East and South Lima (Ref 3, 5, 6). This project is being carried out to respond to the increasing problem of urban heat islands that are being generated, especially in the most vulnerable districts where there is no shade due to a shortage of trees (Ref 1, 4). It is therefore focused on areas where the environmental quality is low, where the pollution is high and where there is more danger of higher temperatures (Ref 1, 7).
This programme aims to include youth volunteers, district municipalities, educational institutions, grassroots social organisations, neighbourhood leaders, residents and other entities that favour environmental conservation (Ref 1, 2, 3, 5).

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).

Trénelle-Citron, located north of downtown Fort-de-France and separated by the city bypass, La Rocade, was originally established in the 1940s by Black Martinicans migrating from rural areas. Today, the neighborhood faces significant economic and social challenges. In 2016, young residents from the neighborhood alongside a local NGO launched a grassroots initiative to improve their community. They transformed a former municipal quarry, which had deteriorated into an informal dump, into a thriving shared urban garden, benefiting the local population. This project, based on traditional ecological gardening techniques and the cultivation of native crops, aimed to revitalize Trénelle-Citron—a densely populated area grappling with social exclusion, a shortage of green spaces, and limited economic opportunities for its youth (Ref 2).

The garden, developed on municipal land with guidance from the Ypiranga Martinique NGO, support from the local school, and collaboration from various stakeholders, now plays a vital role in the area. It raises awareness about agroecology, offers socioeconomic opportunities, promotes healthier lifestyles, and fosters social connections among residents. Spanning approximately 1,000 m², the site includes an office, a covered area, tool storage containers, market garden plots, a composting area, and a chicken coop managed by a local resident (Ref 7). In Martinique, such shared urban gardens are increasingly seen as important tools for sustainable development (Ref 5).

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).

Reforestation project for the "Cerro de la Popa", which is Cartagena's highest point and one of the main tourist attractions because of the view and its colonial convent (Ref 6). The hill currently faces illegal occupation and environmental deterioration caused by deforestation, poor solid waste management, burning, logging, and the loss of vegetation cover (Ref 4, 5). The intervention in La Popa consists of reforestation activities, environmental education activities with children, and awareness-raising activities with adults about caring for fauna, flora, and water bodies (ref 2, 3). SSince 2020, the Establecimiento Público Ambiental (EPA Cartagena) has led the recovery initiative, prompted by the urgent need to counter the increasing encroachment by migrants and vulnerable populations (Ref 4). The project comprises reforestation efforts, environmental education sessions with children, and community outreach to raise awareness among adults regarding the protection of local fauna, flora, and water bodies (Refs 2, 3). As part of a broader municipal agenda, the initiative remains active, with the most recent intervention conducted on July 11, 2024 (Ref 2).

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).

The Tbilisi Urban Forest is an ecological restoration project of 5,5 ha spanning two pilot areas initiated in 2020. Located on Mtatsminda ridge around Tbilisi, it is part of a larger reforestation effort within the 700-ha forest territory (Ref. 1,2). The project is funded by the Cartu Foundation and led by the Development and Environment Foundation along with Tbilisi City Hall. Restoration is undertaken to addresses significant challenges such as forest dieback caused by pest infestations, climate change adaptation as well as the creation of recreational infrastructure (Ref. 3,5). Through collaboration among interdisciplinary scientists and urban planners, a novel reforestation strategy has been developed that integrates patches of locally sourced plant communities tailored to diverse soil and slope conditions. This approach incorporates existing trees with new saplings, carefully grafted into existing soil pockets, and focuses on a biodiverse palette of endemic and climate-adapted species (Ref. 1,5). While the project implementation could not be carried out as planned, lacking public participartory due to Covid 19, still 100 jobs were created locally (Ref. 2). Ultimately, the Urban Forest project will enhance ecological connectivity, biodiversity and tourism and also serve the public as an improtant recreational site (Ref. 1,2).