Increased knowledge of locals about local nature

This initiative is a community-based urban greening effort targeting environmental and social co-benefits in Cartagena’s El Pozón neighbourhood. It involved the planting of 491 fruit and timber trees along a 1,500-meter linear stretch, covering nearly two hectares in the Terraplén sector of the neighbourhood. Led by the "Establecimiento Público Ambiental" (EPA), it was developed in collaboration with various stakeholders, including the Gerencia de Espacio Público, Guardia Ambiental, SENA students, the Police, and community members (ref 1, 2). The project's primary goal was to enhance the environmental quality and aesthetics of the El Pozón neighbourhood by planting trees that provide ecological benefits, such as improving air quality, reducing temperatures, and enhancing biodiversity. Additionally, the initiative aimed to foster community engagement in environmental conservation, particularly in raising awareness about the importance of protecting and maintaining nature. The community is also expected to take on the responsibility of maintaining the planted trees, promoting a sense of ownership and sustainable stewardship (ref 1).

The Molentargius-Salt Works Regional Natural Park, spanning approximately 1,600 hectares, is located in South Sardinia between the towns of Cagliari and Quartu Sant'Elena, adjacent to the Poetto seafront. The park features diverse ecosystems, including wetlands and salt flats, and houses the Orto Botanico di Cagliari, which showcases native Mediterranean plants.
In 2016, a project was initiated by a group of stakeholders to preserve and enhance biodiversity within the park. The project's goals are to protect and promote the unique ecosystems, such as the fossil beach, and manage invasive species like the Louisiana crayfish. Through various activities—educational programs, public engagement, and conservation efforts—the initiative aims to raise awareness and deepen understanding of local biodiversity and its historical evolution.
A primary focus of the project is the conservation of the Orto Botanico area in Is Arenas, which contains a fossil beach that offers valuable geological insights into the region's past. Planned activities include cleaning and securing the area, creating educational pathways, and employing multimedia tools to engage visitors. The emphasis is on teaching the public, especially students, about biodiversity as a result of environmental adaptation through practical learning and cultural exchanges.
Another critical aspect of the project is the study and control of the invasive Louisiana crayfish, which threatens the park’s biodiversity by contributing to riverbank erosion and impacting native fauna. The project will incorporate scientific research on the crayfish and develop strategies to limit its spread, aiming to protect the park’s delicate ecosystems from further disruption by invasive species.
Lastly, the project emphasizes cultural exchange and social inclusion and fosters dialogue on the shared ecological challenges in Parco Molentargius. (Refs. 1, 2 & 5)

The Recovery of Green Area on Avenida del Lago is a group of activities aimed at restoring and preserving the ecological integrity of green space within an urban setting. This project involves multiple stakeholders, including the "Establecimiento Público Ambiental" (EPA) Cartagena, "Fundación Verde Que Te Quiero Verde", Asopopa, and local businesses such as Crepes and Wafles and Centro Comercial Caribe Plaza. The primary focus is environmental restoration, sustainable urban mobility, and public space recovery (ref 1). The project aims to rehabilitate the degraded green spaces along Lago Avenue by enhancing urban greenery, restoring mangrove ecosystems, and improving public access and mobility. It also focuses on reducing pollution, preventing informal waste disposal, and raising environmental awareness among local communities and businesses. These activities align with broader efforts to promote ecological sustainability and enhance urban resilience (ref 1, 3). Since 2020, activities have included the planting of trees, mangroves, and other native vegetation in the green spaces of the avenue. Regular clean-up campaigns have been organized to remove solid waste, and community education programs have been conducted to promote environmental stewardship (ref 2). Previously, Lago Avenue was an area plagued by pollution and homelessness, and with the project, the intention is to gradually transform the area into a wooded area or productive park (ref 2).

The Jardim do Caracol da Penha project transformed a vacant urban area into a community garden and recreational space in Lisbon. Initially planned as a parking lot, the project was reimagined by local residents, led by Rita Vieira Cruz, and submitted to the Participatory Budget in 2016, garnering over 9,000 votes (Ref 2). The one-hectare garden connects the Arroios and Penha de França parishes and features leisure areas, an amphitheatre, playgrounds, and a community garden (Ref 4). Its design was shaped by citizen input, emphasizing sustainability and accessibility, with plans to support activities such as outdoor cinema and community gatherings (Ref 2).

The City of Marseille is engaged in a city-wide project to develop community gardens across its territory. It supports project leaders by providing municipal land and offering a framework along with technical support (Ref 5). Currently, there are 80 community gardens, including 66 shared gardens and 14 family gardens, covering nearly 32 hectares in total (Ref 1).
Marseille aims to provide all residents with spaces for relaxation and socialization in every neighbourhood, particularly fostering shared gardening spaces in neglected land, forgotten squares, building bases, or areas awaiting development. (Ref 1). Community gardens contribute to the city's beautification and support biodiversity (Ref 1) and are founded on values of solidarity, conviviality, and fostering connections between generations and cultures (Ref 4). This initiative also addresses the issue of agricultural land disappearing due to urbanization, while Marseille's many abandoned wastelands offer genuine opportunities to rethink production models (Ref 3).
The city has created a Charter to be signed between the city and garden managers, which can include groups of residents or associations (Ref 2). The charter includes criteria such as citizen involvement, fostering social connections, promoting biodiversity, restoring soils’ health, planting local species, and eco-responsible gardening practices (Ref 2). In return, the city supports the development of these gardens, providing land and offering technical and methodological assistance, including soil analysis and advice on environmentally friendly gardening practices (Ref 2). Additionally, community gardens can serve an economic purpose by creating jobs and enabling the production of healthy and flavorful fruits and vegetables at a lower cost (Ref 2).

Phoenix is America’s fifth largest and hottest city, a sprawling urban heat island which has expanded without adequate consideration to climate and environmental factors like water scarcity and extreme heat (1). ​Multiple heat records were broken in 2023 including 133 days over 100F (37.7C), and 55 days topping 110F (43C) (1). Only around 9% of Phoenix is protected by tree canopies, yet this citywide figure masks vast inequities between wealthy, majority-white neighborhoods (1). As a response, the City of Phoenix has adopted an equity-driven heat mitigation plan to create a shadier, more livable environment amid rising temperatures and hundreds of heat-related deaths (1). Part of this plan created the Community Canopy Grant program, which offers public schools, churches and homes in qualifying census tracts – low-income neighborhoods with little shade funds for tree planting projects (1). One neighborhood, Grant Park is one of the city’s oldest neighborhoods – and one of the most neglected (1). It is a red lined neighborhood with higher pollution levels, less vegetation, more noise pollution and higher temperatures (1). To change the inequity and create enough shade to provide residents and passersby reprieve from the heat, the city planted around 40 trees in the Grant Park neighborhood within household yards (1-2). Residents can choose from a list of 19 native and desert-adapted trees including the Texas olive, Chinese red pistache and Chilean mesquites (1). The trees, which are a couple of years old and pretty heavy, are planted by contracted arborists (1). Following the planting process, each household was provided with a tree kit – a hose, irrigation timer and instrument to measure the soil pH and moisture, as well as written care instructions (1). This is the fourth tree planting effort by this city and the hope with this initiative is that it lasts (1).

Two stages of a project called "Flowering roadsides" have been created along a bike road stretch measuring 6,5 km between the areas of Gunnilse and Bergum in the eastern part of the City of Gothenburg. The projects came to be through citizens' initiatives and are carried out in cooperation between the City of Gothenburg and two local NGOs: The Bergum-Gunnilse Development Association and the Gothenburg branch of the Swedish Society for Nature Conservation (Gunnilse-Bergum utveckling & Göteborgs naturskyddsförening). The first stage of the project was carried out in 2021 and focused on taking inventory of species and ecosystems along the stretch and suggesting management options to promote biodiversity. The second stage is carried out from 2022 to 2024 and focuses on implementing and evaluating alternative management options to today's conventional management. Mowing and scraping are carried out to disturb weeds and benefit meadow flowers. Sand has been placed to create a habitat for wild bees. Signs were put up along the stretch to inform the public of the initiative, and benches will be renovated to create opportunities for recreation. The project receives funding from the Swedish Environmental Protection Agency through their local nature conservation investment, LONA. The project falls under the umbrella project of "the world's longest meadow", organised nationally by the Swedish Society for Nature Conservation [Ref. 1, 3, 4]. The goal of that project is to transform 1000 km of Swedish roadsides into flowering meadows with high biodiversity richness [Ref. 2].

The Olaya Herrera neighbourhood in Cartagena has been the focus of a series of projects that involve ecological restoration, environmental education, and community resilience building. These initiatives have centred around the restoration of the Ciénaga de la Virgen, an ecologically significant but heavily degraded coastal wetland bordering the neighbourhood. The primary goals of the projects in Olaya Herrera include the restoration of degraded mangrove ecosystems, mitigation of flooding and water pollution, strengthening community participation in environmental management, and promoting sustainable urban environments (ref 1, 2). The project is led by the EPA Cartagena, which coordinates actions such as collecting solid waste, planting timber trees and ornamental plants, and restoring green spaces that had become informal dumping grounds (ref 1). It also includes a community-led initiative called Los Guardabosques de Olaya that focuses on reforestation and environmental stewardship, it involves children, youth, and local mothers in reforesting mangrove areas around the Ciénaga de la Virgen. The community has established a mangrove nursery and employs innovative waste management practices, such as installing traps in canals to prevent solid waste from entering the Ciénaga (ref 2). The project also involves the private sector in 2022, the EPA led a campaign with local companies like Konfirma, Acuacar, and Pacaribe that focused on improving environmental health through the removal of 10 cubic meters of waste, promoting healthy living environments and fostering community participation in environmental monitoring and waste management practices​ (ref 4). Also, in collaboration with community leaders and local companies, the ANDI-TRASO Alliance supports large-scale reforestation and restoration activities in the southern parts of the Ciénaga de la Virgen adjacent to Olaya Herrera. The alliance plans to plant 40,000 mangrove seedlings (ref 6).

The ReDuna project, initiated in 2014, focuses on restoring the sand dune ecosystem in Costa da Caparica (Almada) in response to severe coastal erosion exacerbated by sea-level rise and winter storms. It aims to strengthen the resilience of dunes to environmental pressures while restoring ecological balance. Actions include sand nourishment, the installation of willow sand fences, and the planting of 100,000 native species. Community engagement was a key factor, involving local residents, NGOs, and schools in maintenance and replanting efforts. The project has been successful, with significant biodiversity recovery, establishing deep-rooted vegetation, and stabilising the dunes. Ongoing monitoring and adaptive management are central to its strategy, ensuring long-term sustainability. The ReDuna project serves as a replicable model for similar coastal protection initiatives globally (Ref 1).

Eliseo Collazos is located in the coastal desert ecosystem of the Lomas or ‘fog oasis’, an area that receives less than 10 mm of rainfall per year. Vegetation cover is of particular importance in the hills surrounding Lima, as it provides critical solutions to erosion, landslides and soil degradation in the ecologically degraded ecosystem of the Lomas. However, this ecosystem is facing risks from urbanisation, illegal mining and agricultural practices, resulting in the lack of the delicate mist-fed greenery for which the Lomas are known (2). This has led to increased particulate matter in the air due to exposure to sand and wind, aggravating respiratory diseases such as tuberculosis, which is prevalent in Lima's informal communities (2).
Low-income communities have inhabited this area, forced to migrate from the rainforest, highlands and city to the desert slums (4), who have only been able to settle in these landscapes with little access to resources, prone to disaster risk, little public investment in infrastructure and little access to green spaces (2). As a result, these communities live in poor conditions (1). For this reason, in 2013, the University of Washington, under its Urban Informal Communities Initiative programme (1), initiated a participatory project that sought to address the challenges faced by the inhabitants of this area (1, 2). In a series of participatory workshops, residents identified greenspace and food security as top priorities in their community; the Gardens, Greenspace and Health project responds to these priorities as an initial step towards the expansion of greenspace, agriculture and ecological restoration in and around the Eliseo Collazos community (2, 4).
Although individual families constructed them, the front yard gardens contribute to a shared public realm and community greening (4). The general project also involved the installation of fog catchers and the creation of common recreational spaces (4).