Protection of natural ecosystems

The Filter Ecosystem project, completed in 2007, aims to improve water quality and enhance the ecological health of the Molentargius wetland area in Sardinia, Italy, also known as the Molentargius Saline Regional Nature Park. This diverse territory includes freshwater basins such as Bellarosa Minore and Perdalonga, saline water basins like Bellarosa Maggiore and Stagno di Quartu, and the predominantly dry area known as Is Arenas.
The Molentargius ecosystem is a crucial European site for various aquatic birds and features diverse flora, including endemic species and endangered plants on the "Red List." It is one of the few globally recognized wetlands of international importance for aquatic birds located entirely within a large urban center, protected as a biotope by the RAMSAR Convention in Sardinia's major urban area. Since the 1980s, it has suffered environmental degradation due to inadequate infrastructure for wastewater management and human pressures.
Implemented by the city of Cagliari, the project employs a phytoremediation technique to supply water to the ponds. This involved constructing a phytoremediation system between the Bellarosa Maggiore and Bellarosa Minore ponds, functioning as a surface flow filter ecosystem resembling a marsh or wetland.
The system enhances natural self-purification processes, promoting prolonged contact between water, organic matter, and plants. This setup creates microhabitats that support microbial flora crucial for purification. The project's primary goal is to treat wastewater from the Is Arenas treatment plant, ensuring that the treated water meets optimal conditions for sustaining the wetlands' biodiversity. Additionally, the project will expand reed bed areas, vital habitats for avian species, and is designed to purify up to 300 liters of water per second to meet the area's needs (Refs. 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.).

The Çukurova University Botanical Garden was initiated in 1972 by the Department for Landscape Architecture to protect and conserve the rich native and non-native biodiversity of the region for future generations (Ref. 5,9). Its establishment responds to the lack of Botanical Gardens in Türkiye despite the country's great diversity. The Garden also wants to offer protection for increasingly threatened species in the face of rapid and uncontrolled urbanization (Ref. 5,9). Being located close to two Deltas and an important agricultural region, the collection also aims to include a great number of wetland and agricultural species, drawing public attention to the importance of these ecosystems (Ref. 6). As such, the University invites every school in Adana to visit and participate in its ongoing educational activities and primary school children are offered hands-on gardening programmes (Ref. 1,2). Furthermore, visitors can immerse themselves and learn about various vegetation zones, including endemic maquis, where stairs, walking paths and information boards have been installed (Ref. 4). The University maintains research activities in the Botanical Garden and in on site laboratories, which regularly host interns (Ref. 4). To ensure the stready supply of plant material for landscaping and education, nurseries have been set up and in 2020 a 250 m² medicinal and aromatic plant greenhouse was added where students of the Faculty of Agriculture are trained and endemic species grown (Ref. 9,10).

Coastal erosion is a well-known consequence of climate change, driven by rising sea levels, extreme storms, and powerful coastal surges. Dollymount Strand, a popular spot for bathing and water sports in Dublin, is particularly vulnerable. Located on North Bull Island and managed by Dublin City Council, the area is part of several protected zones, including a Special Area of Amenity, a Special Area of Conservation, a Special Protection Area, a Ramsar Wetland, a Natura 2000 site, and the UNESCO Dublin Bay Biosphere. To help mitigate this issue, Dublin City Council has implemented a solution that works with, rather than against, natural processes.
During late summer and autumn—particularly following high tides, warm weather, and storms—a type of seaweed called Ectocarpus siliculosis naturally accumulates along Dublin Bay’s beaches. Instead of removing it, the council allows the seaweed to remain, recognizing its essential role in maintaining the beach’s rich biodiversity. Ectocarpus contributes to the health of the coastal ecosystem, supporting marine life and enhancing the natural resilience of Dublin Bay. (1.2)

This project, implemented in several schools across Fort-de-France in 2018, focuses on creating arboretums in schools to educate children about Martinique's native natural heritage and raise awareness of biodiversity loss. An arboretum is a curated collection of trees selected for scientific, conservation or public enjoyment.
The initiative, led by the Martinican National Botanical Conservation, is supported technically by the municipal landscaping department and administratively by the city of Fort-de-France and the Martinican School Rectorate. It includes three main activities: a seminar on Martinique's rich yet fragile botanical heritage, an excursion into a forest, and a tree planting event at schools featuring native or endangered plant species. The program has reached at least six schools in and around Fort-de-France.
(Ref. 1,2,5)

The intervention of the Ecological Park of La Molina is an urban-landscape design project developed between the San Martín de Porres University, through the IVUC, the Institute of Housing, Urban Planning and Construction, and the Municipality of La Molina (7). This is the first ecological park in the city of Lima, located in a characteristic ecosystem such as Las Lomas, between 600-1000 m.a.s.l. (1). It is a natural area that is part of the hill system of Villa María del Triunfo, located in the Subtropical Coastal Desert ecoregion, and is part of the Regional Conservation Area ‘Sistema de Lomas de Lima’ (7). The City Council decided to open this space in 2022 to the public, as a 200-hectare area, designed to bring people closer to nature, through outdoor activities and environmental education about its fauna, flora and microclimates (1). Thus, citizens can enjoy a recreational area with multi-purpose spaces and sports circuits; a cultural area where workshops and an open-air amphitheatre are held; an ecological interpretation area with exhibition galleries and an interpretative route; and an administrative and control area (1). The park also envisages reforestation efforts in areas that are currently arid and infertile to convert them into green areas for the enjoyment of citizens (1). In 2023, conservation efforts were reinforced for an additional 50 hectares, due to the danger posed by encroachment and land trafficking (4).

The municipality of Ciudad Juarez, in collaboration with UN-Habitat, has drafted a redevelopment strategy for an area known as "Paso de Oñate." This intervention falls within the broader framework of "Vision Ciudad Juarez 2040." The plan involves constructing a forested green belt along the southern edge of the Rio Grande (/Bravo) in the northwest part of Juarez, bordering the USA.
Currently in the planning stage, the project aims to restore the ecological function of various degraded areas along the Rio Grande, transforming them into a continuous, green, walkable, and recreational space. The strategy includes allowing vegetation to recover, introducing native plant species, and increasing tree cover to rehabilitate unmaintained parks, derelict areas, and degraded riverbanks. These areas will be equipped with new features and integrated with existing parks, schools, and playgrounds. The envisioned green corridor will enhance walking conditions, improve the perception of safety, offer recreational opportunities for all age groups, and deliver valuable ecosystem services such as temperature regulation, improved air quality, and water retention.
In addition to its ecological goals, the project has a historical and geographical dimension. It aims to incorporate cultural heritage elements, such as the monument of the New Citizen, Paso de Oñate, Turtles Park, and the beginning of the Acequia Madre. It will also connect with other green space initiatives, including the Mega Park "El Chamizal" and the "Corredor Cultural," which runs through the city center.
This intervention is being prioritized due to the area's ongoing social and ecological decline. Paso de Oñate is a critical border crossing point, which negatively affects mobility and air quality. The area also suffers from a high concentration of vacant housing, which contributes to the residents' perception of insecurity. (Ref. 1, 2, 3, 4)

Berlin has faced severe water shortages in recent years, with ponds, small lakes, and pools suffering significantly. Many have dried out or disappeared, causing habitats for countless animals and plants to vanish. Urbanization exacerbates the issue, as more areas become sealed, preventing rainwater from replenishing soil and water bodies. Recognizing the urgency, Berlin introduced the Eco-Account, a strategic reserve of areas and initiatives to mitigate the effects of urban development on nature and landscapes. Central to this is the Blue Pearls for Berlin program, focusing on revitalizing small water bodies to restore biodiversity and ecological balance.
The project identified approximately 30 ponds, pools, lakes, and ditches from over 100 candidates to be transformed into "blue pearls." These revitalized areas will support local ecosystems and improve Berlin’s water cycle. The Berlin Rainwater Agency, alongside departments responsible for nature, climate protection, and water management, is spearheading the initiative in collaboration with the Berlin Nature Conservation Foundation.
Two pilot sites—the Schleipfuhl/Feldweiher water complex in Marzahn-Hellersdorf and the Lankegrabenteich in Steglitz-Zehlendorf—were prioritized for restoration in 2024. These efforts include improving water quality and creating diverse habitats for wildlife. Enhancing small water bodies not only provides a refuge for animals and plants but also contributes to climate adaptation. Restored ponds and lakes can cool surrounding areas and improve the urban microclimate by utilizing locally accumulated rainwater. Blue Pearls for Berlin, approved by the Senate in 2022, aligns with the city’s Eco-Account framework, ensuring that these restored blue spaces offset ecological damage caused by infrastructure and urban projects. The initiative offers Berliners new ways to experience nature, fostering a balance between development and environmental preservation. (Ref. 1, 2, 4, 6, 7)

The D'Olive Creek Restoration project is designed to address the significant environmental challenges facing the D’Olive Creek Watershed and its tributaries (Tiawasee and Joe’s Branch), primarily caused by increased urbanization. Over the last several decades, the area has experienced severe erosion, sedimentation, and habitat degradation due to stormwater runoff from new residential and commercial developments. This runoff has led to stream channel instability, loss of wetlands, and impaired water quality in both D'Olive Creek and Mobile Bay, threatening aquatic and wildlife habitats (Ref 2).
The project involves restoring degraded streams and implementing management measures to reduce the downstream impacts within the watershed. Key activities include stormwater retrofits, stream restorations, and continuous monitoring. These efforts aim to stabilize stream segments and significantly reduce sediment loading into the northeast quadrant of Mobile Bay. This is crucial for improving water quality and clarity, which is necessary for re-establishing submerged aquatic vegetation (SAV) beds that serve as critical nursery areas for shellfish and finfish (Ref 1). By using natural materials like rock and living plants, the project also seeks to create a sustainable and ecologically balanced watershed system (Ref 3).
The anticipated outcomes include enhanced water quality in D'Olive Creek and Mobile Bay, reduced erosion and sedimentation, and the restoration of vital habitats, which will contribute to the region's overall ecological health (Ref 1, 3). This restoration project is part of a broader strategy outlined in the 2002 Comprehensive Conservation Management Plan for the Mobile Bay Estuary (Ref 1).

Tempelhofer Feld stands as an innovative green solution in the heart of Berlin, addressing several issues of environmental justice, biodiversity, and urban resilience. Within the S-Bahn ring, only one in 20 residents lives in areas well-served by green spaces, and districts like Neukölln, Kreuzberg, and Tempelhof would face even greater scarcity without this vast expanse. Many residents in these neighborhoods lack access to private green spaces such as gardens or balconies. Without nearby parks, people are compelled to travel to other districts, exacerbating the congestion of green spaces and increasing local traffic.
Since its opening in 2010, Tempelhofer Feld has provided Berlin with over 300 hectares of open, green, leisure, and recreational space, making it one of the largest urban open spaces globally. Once the site of bustling air traffic, it is now a sanctuary for activities such as skating, strolling, gardening, picnicking, birdwatching, kiteboarding, and more. These wide-ranging uses showcase its transformation into an accessible, multifunctional green space that serves as a social equalizer, particularly for disadvantaged neighborhoods, a significance amplified during the Covid-19 pandemic.
The field is not just a recreational haven but also a vital ecological refuge. With over two-thirds of its area designated as green space, it hosts diverse ecosystems, including extensive natural meadows, lawns, and protected habitats for birds and other species. Certain areas are closed to the public to preserve these sensitive environments, emphasizing the balance between human activity and ecological conservation. Since 2019, animal landscape keepers, including around 100 resident sheep, have contributed to sustainable land management practices, promoting biodiversity and ecological health (Ref. 2).
Managed collaboratively by political, administrative, and societal actors, the site exemplifies integrated citizen participation in urban planning. (Ref. 3)