Land use and Socio-economic change

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)

The model farm is a small-scale organic vegetable farm according to the principle of a "market garden", meaning little machine use is required [1]. More than 40 different vegetables were grown in an effective growing area of 720 m2, using principles of regenerative agriculture promoting soil health [Ref. 4, 6]. An important outcome is sustainably producing vegetables for schools and care homes in the municipality [Ref. 1-3]. The initial vision was to "showcase both the farming and business model behind a sustainable and successful small-scale farming enterprise" and drive the "integration of regenerative farming practices in the continuous evolution of urban and rural multifunctional landscapes" [Ref. 4, 6]. The model farm offers education and cooperates with a local college [Ref. 1, 6]. The model farm is part of the Climate-KIC SATURN project which aims to reconnect urban and rural areas and address the climate crisis through sustainable food production [Ref. 1, 5, 7].

The Grangegorman Community Garden is a collaborative project involving several stakeholders in restoring a neglected space within the TU Dublin campus and transforming it into a community garden. The project emerged from a partnership between academic and service departments of the university, a primary school, a land development agency, a multinational organization, and a property estate agent.
The project's ultimate goal is to establish a permanent community garden with strong investment, ensuring ongoing support for current users and welcoming a new, diverse group of participants. (1,6)
Launched at the start of 2024, the project focuses on rejuvenating the space, with restoration efforts continuing until December 2024. The garden features four allotment-style beds separated by gravel paths and is surrounded by 12 foliage beds (Ref 1). The initiative aims to provide educational opportunities centered on sustainability and horticulture, while also developing a sustainable, collaborative governance framework for the garden (Ref 6). It aligns with various national, local, and inter-organizational frameworks, strategies, and plans related to community engagement, biodiversity, and climate action (Ref 1).

Lomas are endemic seasonal ecosystems found in Peru and Chile. They provide a variety of benefits such as soil stabilisation, air purification, recreational spaces, water retention, and are habitats for endemic and threatened species (Ref 7). They are of great ecosystem value to the city of Lima, as green areas have been reduced in the urban area, occupying up to 24% of urban green ecosystems. These ecosystems are threatened by unplanned urban growth, traffic, pollution and lack of government regulation. Given this context, Eab Lomas is a project that focuses on the conservation, management and rehabilitation of the ecosystems found in the Lomas of Lima (Ref 1, 2, 3, 4, 5). It focused on 4 lines of action: conservation of Lomas' ecosystems; implementation of territorial planning; economic diversification focused on the conservation and recovery of vegetation through low-impact recreational activities; and management of water resources (Ref 1, 2, 3, 4).

Air pollution is one of the most pressing sustainability challenges in the UK, with particulate levels exceeding both WHO guidelines and EU safe limits in many cities (Ref 6). In 2014, Birmingham was identified by the WHO as one of nine UK cities breaching air pollution safety guidelines (Ref 2, 3).

In 2012, a soil-based green wall was installed at Birmingham New Street Train Station as part of a project aimed at improving air quality, as diesel train services contribute significantly to nitrogen oxide (NOx) pollution. However, most of the plants did not survive. In 2017, Network Rail commissioned a private company to reconstruct the wall using a hydroponic system (Ref 3). The new green wall was installed in 2018 and completed in May 2019 (Ref 1, 3).

This hydroponic green wall not only enhances the urban environment with calming green infrastructure, but also helps mitigate air pollution and promotes biodiversity with the addition of 16,600 plants (Ref 1, 2, 3).