Researchers/university

Lima is the capital of the region with the lowest coverage of green spaces. According to the World Health Organisation (WHO), a city should have at least 9m2 of green space per inhabitant. Lima is just over 3m2 square metres, which means a deficit of almost 60 million square metres. In this context, actions from the public and private sectors are essential to add this type of space to the city. In response to this need, Grupo Centenario carried out a green project on one of its plots of land in San Isidro, where real estate projects will be developed (1, 2, 3, 4).
A square was built with a green area with wild and low-consumption species, knocking down the walls that surrounded the land for years, turning it into a place for everyone to see and use (1, 2, 3, 4). The Choquehuanca Square was built to contribute to the community and make it a better place to live. It is located on a plot of land that was previously enclosed by walls, converting it into an area of 3,945 m2 with a green space that occupies 70% of the square (1, 2, 3). This is a temporary project, as the green space was opened while projects are being developed on this land (1, 2, 3).

Biotope City Wienerberg is located in the southern part of Vienna on a 5.4-hectare site that once housed a Coca-Cola factory. It lies at the edge of the Wienerberg recreational area, surrounded by business parks and tower blocks to the west and predominantly detached houses to the east (Ref. 1).
The project embodies the concept of an "urban biotope" (Ref. 2), grounded in the principle that nature's mechanisms of self-regeneration are essential for mitigating the challenges of urban living and climate change. By integrating urban and natural spaces, Biotope City fosters both human-nature connections and social interactions through activities like community gardening. The project’s centerpiece is its extensive green infrastructure, including trees and green roofs, which serve to cool the microclimate, purify the air, enhance water retention, and create carbon sinks while providing habitats for local wildlife. These green spaces aim to improve physical health through cooling effects on hot days and support mental well-being with their calming influence (Ref. 1; Ref. 2).
Biotope City encompasses:
Around 980 flats, including 400 subsidized flats and 200 SMART flats
A school, a kindergarten, and 2,000 square meters of children's and youth playgrounds
600 square meters of community gardens and 3,850 square meters of ground-floor gardens
250 trees, 8,900 square meters of meadows, and 13,600 square meters of green roofs
2,200 square meters of façade greening
The inner courtyards and roof areas are designed for gardening, while façades are greened, and balconies are equipped with integrated plant troughs. Even the spaces between buildings are climate-effective, featuring unsealed catchment and seepage areas to manage water sustainably (Ref. 1).
The project’s implementation took 18 years and involved collaboration among various stakeholders. The concept was initiated by the Biotope City Foundation and funded by eight different investors (Ref. 2).

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 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).

In Phoenix, many residents live in dead zones with little or no access to fresh food. These zones are called 'food deserts,' which represent a low-income area with low access to a grocery store (3). Out of the 43 food deserts identified by the city, 18 are fully or partly in south Phoenix (2-3). In 2017, Two researchers from Arizona State University’s School of Sustainability and Leuphana University Lüneburg in Germany began exploring the idea of creating a sustainable food forest cooperative in Phoenix to provide fresh, healthy food, supporting local entrepreneurs, and promote environmental sustainability (1). The project's development team spent months immersing themselves in the world of food forests, by exploring different types of community gardens, discussing preferred characteristics, anticipating local challenges, and identifying potential collaborators (1). As a result, The Food Forest Cooperative was established and planted roots in a 0.5 acre (0.20 ha) plot within the Spaces of Opportunity Community Garden in 2022 (1). This food forest engages the local community by offering educational opportunities around the value of culturally relevant, whole fruits and vegetables, medicine making, and learning about the many uses of edible/medicinal plants (4). The Food Forest Cooperative as a multi-generational project that members preserve for their children, and their children’s children (2). The intention behind the project is to address food insecurity in south Phoenix and empowering the community to take ownership of it and reconnect with their ancestors through the land and food (2). Through the Cooperative, members can contribute different skills, from administrative work to manual labor to community education and traditional medicine (2). It was created to empower community members and challenge the patterns of our food system through the blending of environmental, social and economic goals (4).

D-Town Farm, located within Detroit’s River Rouge Park, is a landmark urban agriculture initiative led by the Detroit Black Community Food Security Network (DBCFSN). Since its establishment in 2008, this seven-acre farm—the largest in Detroit—has embodied the organization’s commitment to food sovereignty, justice, and security for the city’s African American community. Each year, the farm cultivates over 30 varieties of fruits, vegetables, and herbs using sustainable and regenerative practices. Key operations include large-scale composting, rainwater retention, solar energy generation, and beekeeping, all of which support its ecological and educational missions.
Beyond production, D-Town Farm serves as a community hub. From May through September, it hosts public events that offer educational and recreational opportunities for children and families. The farm also provides hands-on training for aspiring growers through internships and volunteer programs, fostering community engagement and agricultural skill development. Volunteers play a crucial role in daily operations, with ongoing opportunities available throughout the growing season.
D-Town Farm’s mission extends beyond agriculture, serving as a platform for broader advocacy. By challenging barriers to food access, it addresses food deserts with a focus on empowerment and education. The farm supports the local economy by supplying fresh produce to restaurants, farmers markets, and residents, while its health-focused initiatives, such as the youth-centered Food Warriors Development Program, aim to reduce health disparities within the community.
The DBCFSN’s work at D-Town Farm exemplifies a model of community cooperation and self-determination, promoting equity and justice in the food system. By engaging with both local and broader urban communities, D-Town Farm not only strengthens Detroit’s leadership in urban agriculture but also contributes to food justice movements nationwide.
(Ref.1,2,3,4)

Situated in the southern suburbs of Kunming City, Dianchi is one of the largest freshwater lakes in Yunnan and the sixth largest in China (Refs 1, 2). However, due to rapid industrial development, agricultural activities around the lake, land reclamation, and population growth, Dianchi Lake became severely polluted, ranking among the most contaminated lakes in China. This pollution threatened biodiversity and degraded natural habitats (Refs 1, 2, 3). The introduction of exotic species further disrupted the lake’s ecological balance (Ref 1).
In response, the Kunming Institute of Zoology (KIZ), with funding from the Chinese Government, World Bank and the Global Environment Facility (GEF) launched the Lake Dianchi Freshwater Biodiversity Restoration Project. This initiative aimed to restore natural habitats, improve water quality through biological means, and foster community engagement and institutional capacity, creating a sustainable framework for the long-term conservation of Dianchi's unique freshwater biodiversity (Refs 1, 4).
The project was implemented across four key components: Wetland Management and Restoration, Surveys and Monitoring of Species Conservation, Capacity Building and Training, and Public Awareness (ibid.). The project was rated 'Satisfactory' in terms of outcomes, sustainability, and execution under a comprehensive evaluation framework that employed multiple indicators (Refs 4, 5).

Since the 1980s, the Graefekiez neighborhood in Berlin's Friedrichshain-Kreuzberg district has been a traffic-calmed area where all road users are treated equally, driving is limited to walking speed, and cars are permitted to stop anywhere. However, this once-progressive concept no longer functions effectively due to the significant increase in cars and delivery vehicles over the years. The streets no longer resemble a traffic-calmed zone, with traditional layouts featuring roadways, sidewalks, and parking spaces. As a result, many users fail to recognize the traffic-calmed nature of the area, leading to safety issues: vehicles drive too fast, delivery traffic causes conflicts, and streets are difficult to navigate safely.
Berlin’s transport sector faces the challenge of meeting legally mandated CO₂ reduction targets. Achieving these goals requires bold measures, including limiting private motorized transport (MIV), especially in densely populated areas where residents and visitors have access to alternative modes of transportation.
The "Graefekiez" project addresses these challenges through urban redevelopment aimed at improving livability and promoting sustainable urban mobility. Car parking has been banned from the streets, freeing up space for communal use such as lounge areas. As part of the "Graefekiez" project, the district office is converting parking spaces into green spaces and expanding tree disks to adapt to the climate and promote a sponge city.
The project was developed collaboratively with residents and NGOs through a participatory process led by the Friedrichshain-Kreuzberg district office, in partnership with the Berlin Social Science Center and Paper Planes e.V. Implementation began in 2023 on Graefestraße and Bockhstraße.After a six-month trial period, the district office decided in 2024 to make the measures permanent.
This initiative advances a safer, greener, inclusive urban environment while meeting climate and community goals. (Ref. 1, 2, 3)

In the 1980s, rapid industrialization, urban population growth, and increased water usage led to severe pollution in Dianchi Lake, exceeding its environmental capacity and significantly degrading its water quality (Ref 1). This deterioration had serious effects on nearby ecosystems, including Cuihu Lake (Ref 2). Cuihu Lake (翠湖), also known as Green Lake Park, is a well-known park and body of water in the center of Kunming, Yunnan Province, China. In Cuihu lake the decline in water quality caused a sharp reduction in native species like the golden line barb, which depend on the local ecosystem for survival, pushing them to near extinction and destabilizing the entire ecosystem (ibid.).
To address this, several effective initiatives have been launched to restore Cuihu Lake’s ecosystem in recent years (Ref 2, 3). One of them was started in 2020 when a restoration project was initiated by the site's administration in collaboration with Dr. Li Weiwei’s team from the Kunming Institute of Zoology, Chinese Academy of Sciences. The project focused on creating micro-habitats and restoring the aquatic ecosystem (ibid.). Ecosystem and biodiversity restoration efforts were conducted across a 5,000 m² area on the east side of Green Lake Park, covering approximately 1/27th of the lake (ibid.).
As a result, more than 20 aquatic animal species are now thriving and contributing to water purification, while three submerged plant species cover over 50% of the project area (Ref 2, 3, 4). Bird diversity and numbers are also increasing, with species like white-breasted kingfishers, green-winged teals, and crested guinea-fowls returning to the area (ibid.). Additionally, there has been a significant improvement in water quality (ibid.).