Ecological restoration of ecosystems

Ngong is a town in southern Kenya, located near Nairobi in Kajiado County, on the slopes of the Ngong Hills. The municipality has experienced significant development and population growth due to improved infrastructure and social amenities. However, this expansion poses a threat to biodiversity, as increased demand for agricultural land, wood, and raw materials is depleting the area's forests and putting many species at risk of extinction. Overgrazing, illegal logging, invasive species, and climate change-induced extremes like droughts and floods have further exacerbated the situation.

In response, the Rufford Foundation proposed the Improving Ngong Hills Forest Conservation Efforts through Raising Local Community Awareness of Biodiversity Conservation project. The initiative seeks to restore the Ngong Hills forest ecosystem through community-driven conservation. A nursery for native species was established, and tree planting campaigns were conducted in collaboration with national and local governments, community-based organizations, indigenous groups, and schools. Additionally, awareness programs and capacity-building efforts were launched, engaging local schools in restoration activities and organizing workshops to train community members and officials. (Ref. 1, 2, 3, 4, 5)

The Rimac River Special Landscape Project, developed by the Municipal Programme for the Recovery of the Historic Centre of Lima (PROLIMA), is a municipal proposal that arose as a response to the significant degradation of the Rimac River as it passes through the historic centre of the Peruvian capital. The river has lost its character as a green corridor and potential public recreational space for citizens (1, 3). The main problems affecting the river are related to the erosion and risk of flooding of the river space, the ecological degradation of its channels and banks, the disconnection and low quality of adjacent public spaces and the urban fragmentation caused by car-oriented mobility (2). To recover its essence as an ecological green corridor, it was proposed to give back to the Historical Centre its riverside identity and to recover the water, environmental and scenic landscape. This project aims to restore the Rímac to its role as a geographical heritage and backbone of the city of Lima, creating a system of accessible and sustainable public spaces that will help to recover this water, urban and historical landscape, as well as providing a better quality of life for the residents and users of the Historical Centre (1).
The project consists of 4 stages of intervention: Puente del Ejército - Puente Santa Rosa / Puente Santa Rosa - Puente Balta / Puente Balta - Límite
of the CHL to the east (5). Among the interventions that make up the Special River Landscape Project are: the renaturation of the 4 km of the Rimac River as it passes through the city, the construction of 14 parks, 7 squares, 1 tree planting project, 24 street renovation projects, 7 bridges/pedestrian walkways, 10 building rehabilitations and 2 new public facilities (4). It is planned to start implementing the project by the end of 2024 (4).

To protect the Lomas de Primavera from urban pressure and other threats, the Lomas de Primavera Ecological Association has implemented strategies for its conservation. One of the strategies this organisation has promoted is reforestation activities. Working together with the Municipality of Lima and other interested actors, they have sought to expand Lima's green spaces, improve air quality, enhance flora, and promote tourism, among other benefits (1). Lima's Municipality has supported the project by donating 20,000 trees for reforestation and to prevent land encroachment (1), social organisations and environmental activists have joint efforts to plant more than 250 trees to support the conservation efforts (2, 7).
The Lomas de Primavera Ecological Association leads the project, organizing community management efforts to conserve the Lomas de Primavera sector. This association is based in the Agrupación Familiar Primavera Lomas de Carabayllo community (2). The association's conservation activities involve collaboration with various stakeholders at different levels. Locally, it works with community leaders and organizations. At the district level, it coordinates with the Carabayllo municipality and the NGO CIDAP to improve urban conditions. The metropolitan-level collaboration includes the Municipality of Lima and the ACR 'Sistema de Lomas de Lima' for ecosystem protection and valorization. Nationally, it partners with MINAM, SERNANP, MINAGRI, UNDP, UCV, and the Network of Peruvian Lomas to enhance ecosystem services, restore degraded areas, and conduct research on the Lomas (2).
The preservation and reforestation of these ecosystems is essential, as they have social, cultural and environmental value, including the following ecosystem services: provision of genetic resources, soil formation, pollination, aesthetic services, ecotourism, food, education, and archaeological and historical services (3)

Perch Creek is one of the many meanders that drain into Dog River (Ref 2), located just west of Mobile Bay (Ref 3). These areas include sensitive, tidally influenced marshes and flats where the brackish water of the Bay meets fresh waters (Ref 1). The Perch Creek Nature Trail & Preserve project aims to protect 96 acres on Perch Creek (Ref 3). It is part of efforts to revitalise Mobile’s coastal community and improve the water quality of the city's urban river (Ref 2), following the devastation of the BP oil disaster in 2010.
The project focuses on two main aspects: creating a low-impact recreational destination to spark economic redevelopment, and preserving Mobile’s coastal wetlands (Ref 1).
The conservation aspect involves wetland acquisition, marsh restoration, and invasive species management, improving water quality in both waterbodies (Ref 1). The area, rich in wildlife, requires habitat protection, including for migrating birds, foxes, alligators, manatees, and bald eagles (Ref 1). Brackish marshes on the property serve as nurseries for fish, while forested areas provide natural corridors for wildlife (Ref 3). The wetlands also play a role in flood control, acting as natural sponges to absorb rising tides and cleanse stormwater runoff before it reaches Mobile Bay (Ref 1). Additionally, they store stormwater, helping mitigate flooding as storms intensify (Ref 3).
The recreational aspect includes developing nature-based recreation, such as nature trails and kayak launches, as well as expanding public access to natural resources (Ref 3). In 2018, the Perch Creek section was added to the Alabama Coastal Birding Trail, with educational signage for kayakers (Ref 1).
This comprehensive project preserves vital habitats and flood-absorbing wetlands, while providing outdoor recreation opportunities and supporting the coastal community's recovery (Ref 2). It combines high-quality water resources, wildlife connectivity, scenic beauty, and outdoor recreation (Ref 3).

This initiative was launched by the local government of La Paz, focusing on afforestation of the Mallasa landfill, which was closed in 2004 (1-4 & 6-10). While some plantations were established in the area when the landfill was closed, the overall plan aimed to manage the waste until the site was sufficiently clean for new projects—a process expected to take at least a decade (6). By 2021, signs of biodiversity, including flora and fauna, had begun to return to the former landfill. In response, the municipality of La Paz implemented a project to plant 6,000 native tree species, along with other shrub species, to further enhance biodiversity regeneration and establish a second urban forest in the city (3 & 4 & 7 & 8).

The afforestation efforts took place between 2021 and 2022, coordinated through "forestry brigades" made up of diverse volunteer groups. These groups included members from public institutions, private company representatives, NGOs (both environmental and non-environmental), universities, religious organizations, and local citizen groups (8-10). A total of 12 hectares were reforested out of the 33-hectare area (1 & 7). Following this, the area was closed to the public and is expected to become a biodiversity sanctuary within ten years, with ongoing monitoring by the municipal environmental agency (7). Among the trees planted, some were chosen to attract birds with their fruit, others to support the pollination of hummingbirds and bees, while others were intended to enrich the soil with nutrients—all species being native to the region (3 & 7).

Additional goals of the initiative include raising awareness about climate change, fostering a sense of environmental stewardship through community engagement, and advancing the municipality's decarbonization plans (3 & 9). Some of the seedlings and saplings were purchased by the municipality at a cost of 6,160 euros, with private companies also contributing financial support to the initiative (1 & 7).

The Loma del Marión recovery project in Cartagena, Colombia, is a community-driven initiative supported by EPA Cartagena that focuses on restoring and conserving the remaining 1.2 hectares of tropical dry forest. Initially covering 33 hectares, the area has suffered degradation due to illegal encroachments, deforestation, and waste burning. The project has included planting over 3,000 plants and fostering community involvement in environmental conservation (ref 1). The main goals are to restore the ecosystem by reforesting native species, preventing landslide risks, and developing an ecopark that will serve as an educational and recreational space. Planned facilities include a library for learning about local flora and fauna, hiking trails, and a community garden to enhance local food security (ref 1,4). A notable educational initiative in the project is the formation of "Vigías del Ambiente" (Environmental Watchers), a group of 40 youths from the Red Nacional Jóvenes de Ambiente, supported by EPA Cartagena and CDKN. This initiative educates young people on climate change, conservation, and waste management through workshops and activities (ref 2, 3). In addition, the EPA is leading detailed studies of the tropical dry forest to identify and protect endemic species (ref 5). The project has resulted in significant environmental and social benefits, such as planting thousands of trees, boosting community engagement in conservation, and establishing youth groups dedicated to sustainable development and climate action (ref 3, 5).

The Green and Blue Axis (Eixo Verde e Azul, EVA) is an inter-municipal green corridor project connecting the municipalities of Sintra, Oeiras, and Amadora through a 15-kilometre green ecological axis along the Jamor River (Ref 2). It aims to renaturalize the river, improve water quality, and control flooding while promoting sustainable mobility through pedestrian and cycling routes (Ref 5). The project also enhances public access to green spaces and cultural heritage sites, such as the Queluz National Palace (Ref 6). EVA supports the Lisbon Metropolitan Area’s regional strategy for climate change adaptation, risk prevention, and low-carbon economy (Ref 4). Funded by the European Regional Development Fund and municipal budgets, the project has an overall investment of €11 million (Ref 1). EVA exemplifies inter-municipal cooperation, overcoming policy conflicts to achieve shared environmental, social, and economic goals, making it a model for integrated territorial development (Ref 4). The project’s long-term impact includes reduced carbon footprint and increased territorial cohesion.

In 2020, the Metropolitan City of Cagliari launched a project to enhance flood resilience and ecological integrity in the Mannu-Cixerri river system in southern Sardinia. The river traverses several communes within the metropolitan area, ultimately feeding into the Santa Gilla Lagoon, a vital wetland ecosystem west of the city.
The project, with a budget of €21 million, focuses on three key communes: Assemini, Decimomannu, and Uta. Rather than solely emphasizing structural flood defenses, the initiative integrates nature-based solutions (NbS) to mitigate flood risks while restoring riverine ecosystems. The Metropolitan City of Cagliari, in collaboration with the Sardinian Regional Public Works Department, is responsible for its implementation.
Key interventions include reinforcing and revegetating embankments, improving water flow along the Rio Mannu, and constructing new levee sections in a manner that enhances natural water retention. Additionally, the project involves upgrading bridges to facilitate better floodwater management. These measures align with the Sardinian Flood Risk Management Plan (PGRA) and aim to reduce flood hazards while promoting ecological benefits.
The project timeline began with a two-year preparation phase for the Preliminary Design Document, followed by a year-long tendering process for construction. These efforts represent a crucial step toward long-term flood resilience and environmental sustainability in the region. (Ref. 1, 2, 3)

The project to redevelop Archipelagos Square in Cagliari aims to transform this key urban space, which serves as a gateway between the city and its coastal areas, into a more functional and aesthetically pleasing environment. Currently, the area lacks cohesive design, leading to unregulated use and its transformation into an informal parking lot. The redevelopment will address these issues by enhancing the pedestrian experience and reducing vehicular traffic. Improvements in public comfort and safety will include better rainwater drainage, the removal of architectural barriers, and the creation of accessible pathways for all.
This project emphasizes environmental sustainability and the preservation of the local landscape. Key interventions include revitalizing green spaces, safeguarding native vegetation, and removing invasive species. Integrating walking and cycling paths will improve connectivity between the city, Marina Piccola, and Poetto beach, fostering outdoor recreational activities. A designated eco-system filter will recreate the natural dune environment, blending pedestrian areas with the surrounding landscape.
Funded by the Fondo Sviluppo e Coesione (FSC), the project has a total budget of 3 million euros, with construction lasting 10 months starting in October 2023. The redevelopment reflects the broader goals of Cagliari’s administration to promote sustainable urban mobility and improve the public realm, contributing to the city's vision of becoming a hub for nautical sports while enhancing the overall quality of life for residents and visitors (Refs. 1, 2, 3 & 4).

The Metropolitan Linear Park is a project initiated by the national government of Bolivia, funded by the Inter-American Development Bank (IDB) (1-8). The proposed park will be located along a disused railway corridor between the cities of La Paz and El Alto, spanning 18.2 km (8, p. 8). The project involves the construction of a linear park, divided into five sections, each with distinct objectives, uses, and designs (8, p. 9). This large-scale initiative aims to improve access to public spaces in La Paz and El Alto, enhance connectivity between the two cities, protect surrounding biodiversity and natural spaces, and strengthen resilience to and mitigate the effects of climate change (3 & 8, pp. 11-12).
To achieve these goals, the project design includes outdoor sports and recreational facilities, pedestrian and cycling circuits, as well as the restoration of parks, squares, and public spaces adjacent to the park corridor (8, p. 9). Some features include balcony corridors, flower and food-producing urban gardens, and viewpoints (5). The project also plans for the re-vegetation of the area with native species and aims to stop the environmental degradation of surrounding natural environments, such as the Pura Pura forest, which has been suffering from ongoing deforestation and waste dumping (8, p. 9). These efforts are expected to increase and support biodiversity in the area (7 & 8, p. 12).
Additionally, the project emphasizes social inclusion, with policies designed to incorporate women, indigenous populations, and persons with disabilities (8, pp. 7-8). The park is intended to raise awareness about climate change and biodiversity, ultimately improving the quality of life and health of nearby residents and the citizens of La Paz and El Alto (8, p. 13).