Biodiversity (conservation and/or restoration)

The "Ruas Verdes+" (green streets) project, implemented in the parishes of Areeiro and Arroios in Lisbon, is part of a broader European initiative, Conexus, aimed at promoting green solutions in highly urbanized areas (Ref 3). The project primarily focuses on creating a tree-lined pedestrian corridor along Carlos Mardel and Francisco Sanches streets, establishing a continuous axis between the Casal Vistoso Urban Park and the Caracol da Penha Garden (Ref 1). This corridor is designed to mitigate urban heat island effects, enhance ecological connectivity, and improve residents' quality of life (Ref 5). The pilot phase includes planting 20 trees on Rua Carlos Mardel and removing a minimal number of parking spaces to balance urban greening with local needs (Ref 1). Additionally, planters are being introduced in the Bairro dos Actores area to test the community’s response to greening initiatives (Ref 1). The project also involves public participation through gardening workshops, encouraging residents to contribute to the greening effort by adding plants to their balconies (Ref 4). This initiative aims not only to enhance the urban environment but also to foster social inclusion and community engagement while addressing the challenges of climate change in Lisbon's densely populated areas (Ref 5).

Thessaloniki has a dense urban structure with limited open and green spaces. As a coastal city severely impacted by climate change, it faces multiple interconnected challenges, including extreme weather events, flooding, and peri-urban forest fires. These issues are further compounded by the city's aging infrastructure and deteriorating buildings, increasing its vulnerability (Ref 1).
Kipos 3, a community garden, is part of the "Green Neighborhoods" project proposed in the Thessaloniki 2030 municipal resilience strategy (ibid.). Established in 2015 on a 600-square-meter plot donated by the municipality, the garden is now managed by 30 local families under the continued stewardship of the Municipality (Ref 2, 3). The garden's creation was supported by a team of architects, landscape architects, and agriculturists, and features a variety of herbs and edible plants grown using permaculture methods (Ref 3).
The garden hosts a greenhouse along a range of environmental, recreational, and educational activities, providing an opportunity to foster a more cohesive, inclusive, and resilient community. It also serves as a space for synergies and discussions about the future of the city (Ref 3, 4). Recognized as a good practice, the intervention has been showcased in national, European, and international networks (Ref 2, 4).

Fjärdingsparken is a city park that has been constructed in two phases, the second finishing in 2023 [Ref. 1]. The initial phase of the plan focuses on building a new kindergarten, and it includes developing the park surrounding the kindergarten to increase locals' access to green space and recreation. The first phase also involved building a football field at the park's edge [Ref. 1, 4, 5]. The second phase continued the park's development focusing on rain water management and biodiversity. The park was constructed so that up to 900 m3 of rainwater can be managed in the park during a 100-year rain, protecting the surrounding area from flooding. This is part of a flooding strategy for the city. The park includes a meadow, aiming to provide habitat for flowers and plants supporting pollinators and butterflies. It also contains amenities such as an outdoor gym, a dog park, and a "play forest" designed for children. The climate impact of constructing the park was evaluated in an attempt to reduce GHG emissions [Ref. 1-3].

The Floating University was initiated in 2018 at the rainwater retention basin of the former Tempelhof airport in Berlin. Though not an official university, it serves as a space for transdisciplinary, communal learning, transforming an abandoned urban site into a vibrant community resource. The project reclaims the basin, hosting workshops and events that range from ecological lectures to cultural and art programs, fostering collaboration between diverse disciplines and communities.
The architecture collective raumlaborberlin originally envisioned the project as a six-month initiative. Artists, universities, and seminar groups contributed to designing the space and organizing workshops. However, due to its success, an NGO, Floating e.V., was established to sustain the project. Today, the NGO manages the site and continues its mission of engaging communities with urban and ecological themes.
After Tempelhof airport closed in 2008, the basin was infrequently cleaned, leading to contamination and sediment accumulation. Over time, a wetland ecosystem emerged, attracting plants, insects, birds, mammals, and amphibians. This natural development complements the Floating University’s infrastructure, which consists of open timber structures like a kitchen, art installations, communal spaces, vertical gardens, gardening beds, and an auditorium. These structures integrate seamlessly with the basin’s existing technical framework and wetland environment.
Floating e.V. aims to make the basin accessible to Berlin’s urban population while sparking discussions about urban climate, resource management, and water cycles through diverse and artistic programs. Smaller initiatives focus on specific ecological themes, such as plant diversity and soil health, through projects like a seed archive and soil lab.
The Floating University exemplifies how abandoned urban spaces can be revitalized into hubs for learning, creativity, and ecological awareness. (1-3, 8, 9)

The "Parque Espíritu del Manglar" in Cartagena is a multi-zone public space designed to promote recreation, environmental awareness, and cultural identity. The park, which has undergone a significant reconstruction, offers a wide array of recreational equipment and spaces for contemplation in a natural setting. It is divided into six thematic zones: Entrance Zone; Sports Area, Open-Air Theatre, the Tertulia Island, offering scenic views, public restrooms, and statues such as the iconic "Macondo" tree, a tribute donated by Gabriel García Márquez’s family; Children’s Central Zone, featuring a pirate-themed mangrove ship and an Environmental Observation Deck. (ref 1).
With the reopening of the park, EPA Cartagena introduced an ecological trail on Tertulia Island, where a mangrove restoration process has been carried out, focusing on plant health and climate resilience. This area also hosts wildlife such as macaws, sloths, turtles, raccoons, and green herons—species that cannot be reintroduced into their natural habitats. (ref 2)
The park now serves as an active site for environmental education, particularly for children, with programs addressing solid waste separation, climate change, and the protection of natural resources. Its reopening has also been recognized as a key step in strengthening family-oriented tourism and promoting sustainable urban development in Cartagena. (ref 2)

The city-wide project Urban Trees for Berlin was launched in 2012 with an ambitious goal: to plant 10,000 roadside trees within five years. This campaign, a key part of the Berlin Senate's Urban Green Space Strategy, is a collaboration between the Senate Department responsible for the environment and Berlin’s district authorities. Initially set to end in 2017, the campaign was extended through 2026.
The project was created to address the loss of numerous roadside trees that were removed due to age, pests, climate stress, and other factors. Limited funds had been available to replace these trees, resulting in negative impacts on Berlin's urban climate, including higher temperatures and worsened air quality, which affect both residents and visitors. The campaign aims to reverse these impacts by securing funding for new trees, restoring greenery to the city streets, and promoting a lasting positive image of Berlin’s urban trees.
The campaign operates on a co-funding model, where individuals, organizations, and companies donate €500 per tree (individually or collectively), with the Senate covering the remaining costs from the state budget (approximately €2,000 per tree). The planting schedule and locations are organized twice annually, with information shared online to keep the public informed.
In 2022, a new assessment of the project’s progress was conducted, commissioned by the Senate to the Arbo-tec office. Around 1,000 of the 3,500 trees planted as part of the campaign by autumn 2022 were evaluated. The selected locations included plantings from all previous construction phases, spanning 12 Berlin districts, with each district having 80 trees assessed from various phases and construction lots. This comprehensive evaluation is intended to ensure the long-term success and sustainability of the Urban Trees for Berlin initiative. (3, 4)

The project aims to modernize Ciurchi Park, also known as "Tătărași Park," due to the degraded state of its current infrastructure (1 - 8). Initiated by the Municipality of Iași, the initiative seeks furthermore to increase the amount of green space per inhabitant in the city and reduce overcrowding in other parks, thereby diversifying options for citizens (1 - 9). Planning for the project began in 2022, and the bidding process for its execution was released in April 2024, which is still awaiting a decision (1, 2. 7).
The implementation is expected to involve interventions in existing green spaces, including the planting of 120 trees, 1,000 bushes, and approximately 2,000 species of flowers and ornamental plants. The project will also feature a monitoring program for tree species, management of existing vegetation to protect healthy trees, and removal of invasive or degraded plants (1, 2, 4, 8). Additionally, it will include benches, facilities for physical exercise, an underground waste collector, and a rainwater drainage system, among other infrastructure improvements (1 to 8).
The project is expected to be financed by the local budget and EU funds, with a total estimated cost exceeding 5,000,000 euros, including taxes (2, 4). It is included in the Integrated Urban Development Strategy 2015-2030 for the city (8, p. 12).
The goals of the project are to modernize the park, improve accessibility for citizens in the surrounding area, minimize management costs for the municipality, ensure a sustainable habitat for flora and fauna with minimal invasive interventions, and harmonize architectural proposals with the landscape (6, 8, p. 32). Other objectives include protecting biodiversity, enhancing the park’s aesthetics and the overall city environment, and reducing CO2 emissions, which will ultimately improve the quality of life for surrounding residents (8, p. 141).

Bound by miles of steel, concrete, or brick walls, Berlin’s rivers and artificial canals often look alike. Plastic bottles, along with ducks, swans, and perhaps the occasional coot seeking scraps from humans, are some of the few visible signs of life. Underwater, the scene is similarly sparse and monotonous, with only a handful of resilient species able to endure the harsh conditions.
In response to this lack of biodiversity, researchers from the Leibniz Institute for Freshwater Ecology and Inland Fisheries in Berlin collaborated with the engineering firm Wite to create the Vertical Wetland project. This initiative introduced plant boxes that attach to sheet piling along canal walls, extending into the water to form miniature habitats. These boxes serve as refuges for insects, birds, fish, and other small animals, offering hiding spots and sheltered spaces for egg-laying among the roots and boxes protruding into the water. Known as "ecological stepping stones," vertical wetlands enable animals to rest and safely traverse urban waterways, fostering biodiversity along urban riverbanks.
Vertical wetlands present a quick and cost-effective way to ecologically upgrade sections of urban waterways. Although they can’t fully replace natural riverside habitats, these mini-habitats offer substantial ecological benefits. Native river floodplain plants, including willows, reeds, rushes, and shallow-water species like irises and marsh marigolds, provide the foundation of these structures. All materials used are environmentally friendly and biodegradable.
By covering the grey, industrial surfaces of riversides, the vegetation cools the local environment, both on land and in the water, and helps improve water quality. Plant shading cools water, reducing eutrophication risks and creating a healthier habitat for aquatic life.
The Vertical Wetland project’s pilot installation was successfully implemented and tested in 2023 in the Berlin-Spandau Ship Canal. (1, 3, 6)

The Detroit RiverWalk is an urban development project along the Detroit River, designed to reconnect residents with their waterfront and revitalize a historically industrial area. Once characterized by abandoned buildings and industrial debris, the riverfront between the MacArthur and Ambassador Bridges had long been inaccessible to the public. To address this, the Detroit Riverfront Conservancy was established in 2003 to lead the redevelopment of this space.
The RiverWalk currently stretches along a 3.5-mile section, with plans to expand to 5.5 miles, integrating ecological restoration, public access, and recreational opportunities. The esplanade features native landscaping, artistic elements, and amenities, including four pavilions, a custom carousel, and areas for fishing, walking, biking, and inline skating.
Environmental remediation has been a crucial part of the project. In collaboration with the U.S. Environmental Protection Agency’s Great Lakes National Program Office, the Detroit Riverfront Conservancy successfully cleaned up 13,000 cubic yards of contaminated sediment, significantly reducing pollution and contributing to the removal of the Detroit River from the list of the most polluted sites in the Great Lakes. Furthermore, the project also includes greenways, park creation and revitalization.
The RiverWalk is not just a public space; it symbolizes Detroit’s transformation from a Rust Belt city to a sustainable urban environment. It exemplifies the power of public-private partnerships in revitalizing urban areas. The RiverWalk continues to expand, with plans to connect various parks and extend to the Ambassador Bridge, further enhancing the city’s waterfront. Its success was recognized in 2021 when it was named the Best Riverwalk in America by USA Today, cementing its status as a model for urban renewal and community engagement. (Ref. 1, 2, 3, 4)

Salines Beach, a popular destination for over a million visitors annually (Ref 9), is facing severe erosion due to rising sea levels and poor coastal management. Since 1995, the beach has lost more than 20 meters in width. This loss has been worsened by vehicle traffic and the introduction of coconut trees in the 1950s, which reduced the native root systems that once helped to stabilize the coast (Ref 5). Now, the encroaching sea threatens to swallow the road that runs along the beach.
In response, the Salines Conservation Committee—comprised of concerned community members and environmental groups—has been advocating for urgent action to halt the erosion. They have called for a renaturalization of the area through the replanting of endemic species and restrictions on car traffic, both aimed at restoring the beach’s natural resilience.
When part of the road collapsed in July 2022, the committee took immediate action, organizing community-based interventions. These efforts included blocking traffic, raising public awareness, and planting over 60 endemic plants in the damaged area. The aim was to reestablish a root network capable of anchoring the coastline and capturing shifting sands (Ref 1; 2). The intervention was described as "a response to the urgent need to rebuild the root network, an ecological engineering solution recognized as the most effective method for retaining beach sand and slowing coastal erosion" (Ref 2; 1). The intervention on this section of the coast was first completed, then discarded by the municipality of Sainte-Anne (Ref 2). Regional and National agencies are currently undertaking the restoration works but it is unclear the stage of completion (See Ref 3).