Ecological restoration of ecosystems

“An integrated solution for groundwater, rainwater, waste water, streams and ponds creates attractive housing in a new suburb (NyE), with room for exciting architecture. The water cycle plays a key role in urban development in Denmark, and water is one of the ever-present elements in our lives. Århus needs to prevent flooding caused by climate change, avoid polluting our groundwater, and improve the environment in streams and ponds to allow the use of water to create recreational value for the residents. This way, Århus can build a balanced aquatic environment, which will ultimately create a better city.” (Ref. 1)

The establishment of the first stage consisting of 650 homes, day care center and grocery store was initiated in the autumn of 2016 after more than 10 years of planning, and in the summer of 2018, the first residents moved into Nye. More homes are on the way. (Ref 14). In its current form of just over 150 ha, it has a capacity of approx. 15,000-20,000 inhabitants or approx. 10,000 homes at full expansion (Ref 15)

The botanical garden of Athens was reconstructed in 2004 to protect and maintain the biodiversity of the area. Covering a land of 1,860 sq.m., this Botanical Garden hosts over 2,500 different kinds of plants from all over the world and a rich variety of flora. All the plants and trees are protected in the park. The community also sends seeds all over the country to spread and maintain biodiversity throughout the region and hold agroecological events to increase the concern and educate the locals (Ref 1,3). The park also has a lake and a library inside it. (Ref 2)

The revitalisation of the park Gaštanica Koliba in Bratislava Nove Mesto is intended to stop the degradation of its ecosystem, preserving existing vegetation while improving the local climate and efficient use of rainwater. Over 100 trees were treated, including some of the local population of chestnut trees. A local seepage pit was installed to retain water both to the benefit of the local vegetation as well as to prevent erosion and landslides. The park has also been fitted with recreational facilities and is now illuminated to improve its accessibility for the local population. (7, 8, 9)

The 18 km long Rheindorfer stream flowing into the Rhine has faced increased urbanization, industrial activity and surface sealing over the last decades of the 20th century. As a result, numerous interventions were made to its original structure, such as the creation of a concrete bed for the stream and the straightening of the stream course. Meanwhile, an increasing amount of pressure was put on its water carrying capacity. In order to improve the flood retention capacity of the stream, the renaturalization project of the stream was executed in some parts of the water body. The project aims were 1) to restore the natural course of the stream and the state of the riverbeds, thus enhancing the stream's capacity to buffer floods, 2) restore the natural biodiversity of the floodplain and 3) to create a recreational area for locals (1,2).

The BiodiverCity-project aimed to develop products, services and processes which support and enhance the city’s biodiversity and thus contribute to a vision of a green, attractive and healthy city (ref. 1). The project had been divided in three steps, step 1 involving preliminary studies and step 2 was practical work for two years. During step 2 different cases were identified to test new ways to e.g. increase the city's biodiversity. Step 3 included spreading to other sectors through seminars, education and exhibition activities. It also included the commercialization of green solutions (ref. 2).

The Rákos-patak Green Corridor is a large-scale development project aimed at revitalizing the environment of the Rákos Stream on a 23 kilometre long path from it's areas in the outskirts of Budapest to the city center. The most important element of the development project is the planned bicycle lane, which would connect the already existing bicycle lanes along the stream into a full 23 kilometre one. In some areas of the planned corridor, other developments will happen with the goal of preserving and restoring habitats which originally existed in the area before it was first regulated. Near the outer areas of the stream, afforestation will also take place. (Reference 9) The area of the stream is currently underdeveloped. According to the plans, the new green corridor could help decrease urban stress.

The Green and Blue Network in France is a national policy which "aims to restore ecological continuity in order to promote the migration of species and the resilience of ecosystems to face habitat threats and climate change. It also aims to strengthen the place of nature in the city and public awareness." In Montpellier, implementation of "this project has improved knowledge of the city's natural heritage and enhanced ecological continuity, as well as protecting, and sustainably managing high-potential sites and integrating the social dimension, raising public awareness, the observation of nature"(Ref. 2).

The River Alt Restoration Project at Stonebridge started in 2013 with an initial goal to remove culverts in order to create re-naturalised watercourses and maintain watercourses easier. It also involved the removal of rubbish and other obstructions to reduce the risk of flooding in the wider catchment (Reference 2). The project then evolved with a bigger goal to divert River Alt into a new 900-meter long linear park named Alt Meadows. Relevant engineering works were employed in the area. In addition, accessible paths and meadow, wetland and woodland habitats were created. The park was also linked into surrounding areas (like housing, shops, schools, etc.). The project benefits include the expected increase in wildlife biodiversity and improved water quality and flood protection (Reference 1, 3).
The project was led The Cass Foundation, in partnership with the Community Forest Trust, with funding from DEFRA’s Catchment Restoration Fund (via Environmental Agency) and Liverpool City Council. The Foundation remains responsible for maintaining Alt Meadows on behalf of the city council (Reference 3).

The action proposed by the Municipal Technical Service of Parks and Gardens at the Department of the Environment, aims at the regeneration of the forest with the repopulation of pines of different ages, to imitate a mountain in a natural state with the plantation of the Cartagena Cypress and Tetraclinex articulata, which has a good adaptation to the environment. Several plots (Plots 3, 5, 6, 8 and 12 of the project) have been repopulated with shrubs and trees such as cypress, esparto, rosemary, tomillos, lentiscos, tetraclinex and palmito, in the solana area, deciduous and riparian species, and to other silvicultural treatments, which increases the variety of existing vegetation. (Ref. 1) In addition, the project contemplates the construction of two viewpoints (Ref 1, 3). A new irrigation system is put in place for the re-use of water for sustainable use and water savings. (Ref. 7)

Recognizing that wilderness areas in cities are getting scarcer and neglected, the Biological Station Bonn Rhein-Erft conducted a city-wide project, in cooperation with the municipality of Bonn, funded by the Regional Rhineland Association, whose goal was to assess, map, evaluate and redevelop wilderness patches in Bonn. These contain roadside meadows, flower strips, hedges and small green patches growing on concrete walls or fences and pavement cracks. 10 of these "Wild corners" were designated as micro-wilderness areas, information signs were installed and an informative city walk conceptualized (1,4,10).