Warsaw rushes – an ambitious environmental project in the capital city

From 2020 to 2023, Warsaw implemented an environmental EU project called Protecting endangered species associated with aquatic habitats in Warsaw. The main objective of the activities, known under the working name Szuwar Warszawski, was to improve living conditions and protect endangered animal species and habitats associated with reservoirs and watercourses on the territory of Warsaw.

Warsaw rushes – project details

The uniqueness of the project lay in its location in an urban area and its very wide area of operation – 290 hectares. After implementation, it turned out that the impact was much larger, reaching almost 330 hectares.

The project was carried out under a contract for funding from the European Union’s aid fund in the amount of PLN 4.9 million, with a total value of PLN 8.5 million.

The activities carried out by the Warsaw Greenery Board covered several districts: Wilanów, Ursynów, Mokotów, Śródmieście, Żoliborz, Bielany, Wawer, Praga-Południe and Praga-Północ, including the Middle Vistula Valley Natura 2000 area (Special Bird Protection Area – Bird Directive). In this section, the Vistula River forms numerous islands, large sandbanks that are the habitat of many species of gulls, terns and plovers. The banks of the river, including the floodplain, are overgrown with thickets of wicker and meadows and pastures. About 50 species of wetland birds nest in the Middle Vistula Valley, including at least 23 species of European importance.

Covered for special protection in the project in question were: black tern(Chlidonias niger), little bittern(Ixobrychus minutus), kingfisher(Alcedo atthis), white-tailed eagle(Haliaeetus albicilla), middle-spotted woodpecker(Dendrocopos medius), partridge(Mergus merganser), river plover(Charadrius dubius) and least tern(Sterna albifrons). Also to be mentioned are the amphibians covered: the natterjack toad(Bombina bombina), great crested newt(Triturus cristatus), green toad(Bufotes viridis), grass frog(Rana temporaria) and water frog(Pelophylax esculentus).

Summary of initiatives undertaken: Kabacki Forest and Sobieski Canal

During the implementation of the project, a number of activities were carried out to actively protect and improve the habitat conditions of populations of rare and nationally protected animal species, including the improvement of water and wetland conditions and the conservation status of valuable plant communities. The project included various construction and habitat activities. Inventories, surveys, opinions, agreements and expert opinions, including nature and conservation surveys, and hydrological surveys were carried out. Necessary approvals and permits were obtained.

One of the goals of the project was to improve the retention characteristics of selected areas. To this end, levees were constructed on drainage ditches in the Kabaty Forest and levees on the Sobieski Canal were adapted.

Kabacki Forest is one of the most valuable plant communities and animal habitats in the Warsaw area and the largest nature reserve in the Mazowieckie Voivodeship. A significant threat to the area is its drainage, resulting from a dense network of drainage ditches. The 2016 Conservation Plan for the S. Starzynski Kabacki Forest Nature Reserve recommended the construction of wooden dams on drainage ditches. The dams, by damming up the water flowing through drainage ditches, stop the drainage of the area and the outflow of water from the reserve.

These small and technically uncomplicated structures help maintain adequate water levels in existing reservoirs. As a result, they support valuable plant communities: willow, poplar, alder and ash riparian forests, oxbow lakes and natural eutrophic water bodies with Nympheion, Potamion communities, riparian oak-ash forests, subcontinental oak-ash forest, subcontinental oak-ash forest, and animal populations, mainly amphibians, reptiles and birds.

The adaptation of the damming structure on the Sobieski Canal was aimed at maintaining proper water levels in the Morysin Nature Reserve and Wilanow Lake. The reserve’s protection plan includes regulating the damming, i.e. maintaining the ordinates of the damming level, which has the effect of ensuring a constant flow of water in the Sobieski Canal and stopping excessive outflow of water from the reserve, but also preventing long-term flooding of the area.

To this end, an adaptation of the existing levee on the Sobieski Canal, which was not fulfilling its function, was carried out – damaged elements were replaced and a new barrier with a gate was made, which prevents illegal use of the levee, footbridge and passage to the reserve outside the designated routes. Thus, the quality of the device’s service was improved and access to the structure by outsiders was made more difficult, while improving water relations and reducing anthropopressure.

Renaturalizations of coastal zones

A spectacular change for the residents, visible in the city’s landscape, was the renaturalization of the shore zones of Brustman’s Ponds, the Vlasnyskie Gliniky on Tolwińskiego Street and the historic Piaseczynski Canal on the Stanislawowska Axis (an 18th-century urban premise, today partially obliterated in the city space, but most legible thanks to the direction set by the canal). Here, interdisciplinary cooperation with conservation services was crucial.

As part of the work, artificial bank reinforcements made mainly of concrete and PVC were rebuilt. The artificial materials were replaced by natural reinforcements, i.e. stone erratics or vegetated mats, pallets and coconut pickets, among others. Where possible, the slope of the banks has been softened and shallow bottoms have been created at the edges of the reservoir, making it easier for animals – especially smaller ones – to access the water. The slopes and the immediate surroundings of the reservoirs were planted with native vegetation.

A platform in the form of a vegetated floating island has been installed on the Piaseczyn Canal. It is overgrown with native rush vegetation and anchored to the bottom of the canal with a weight. The platform was installed in 2020 and is constantly used by numerous animals. It serves as a refuge for local wildlife, mainly amphibians and birds, including the nurogos, which make the spring migration with their young through the Piaseczynski Canal, leading them from the nearby Royal Baths, through the Canal and Czerniakowski Port to the Vistula River.

In the Moczydło I and Moczydło II reservoirs in Ursynów and the reservoirs along the Siekierkowska Route, which are the drainage system for the expressway, the slopes of the bottom along the shoreline have been softened and some of the fortifications have been removed in favor of a natural zone of coastal vegetation. The plants will provide both shelter and a food base for animals.

In addition, a footbridge was created at Moczydle I, elevated on joists above ground level, so amphibians can pass under it without the risk of being trampled by walkers, which is part of preventing the effects of anthropopressure.

At the Moczydło II reservoir, a shallow in-ground depression was made, which periodically fills with water and provides a safe place with calm, shallow water, conducive to amphibian breeding. Habitat elements on the banks of the reservoirs along the Siekierkowska Route were made of stones and wood, while floating islands are planted with reed vegetation and provide a convenient habitat for birds and amphibians to rest and even nest.

Thanks to these measures, habitat conditions for wild animals have been improved, barriers at the water-land interface have been removed, access to water has been facilitated, and places have been prepared where they can find shelter and breed, which is especially important for protected species.

Active protection of local species

Activities aimed at the active protection of selected species consisted of securing existing and creating new nesting sites, such as platforms for the black tern and the white-tailed eagle, improving access to water for animals associated with aquatic environments, such as the renaturalization of the coastal zone and the purchase of land near the Moczydło II reservoir. In Ursynów, the buffer zone of the Las Kabacki nature reserve includes areas valuable for the reproduction of endangered animal species, especially amphibians.

To be able to effectively protect these habitats, it is advisable to unify land ownership. This allows for consistent conservation efforts and prevents the creation of infrastructure that could harm the animals, such as physical barriers in the form of fences. In order to carry out this task, a land appraisal was carried out with the help of an appraiser, after which discussions were held with the owners of the land parcels about buyouts.

Eventually, in 2022, it was possible to acquire an area located exactly between two parcels of land already owned by the City. This consolidated the ownership of the land next to the reservoir and continued the restoration work begun under the project, as well as the conservation measures for the aquatic habitat and the amphibians and other animals living in the area.

The clearing of grasslands and sandy banks to protect the river plover has been done by removing trees and their undergrowth once, with uprooting and removal of biomass. The river plover nests on the ground, in sandy and gravelly areas with little vegetation, most preferably on exposed parts of the river banks, or on sandy islands. There are fewer and fewer sites meeting these conditions in Warsaw.

In order to protect the nesting sites of the plovers, we carried out de-bushing of the area of the beach, sandy coastal casts in the Vistula River inter-coastal area in the Natura 2000 area in the Wilanów district. This activity supports the protection of existing sites convenient for nesting of the river plover by maintaining only low vegetation in their area, and responds to threats listed in the 2016 Natura 2000 protection plan for the Middle Vistula Valley.

The Vistula river’s interbank in Warsaw is a habitat and breeding ground for the white-tailed eagle. In order to protect the species of these birds, a nesting platform with a diameter of about 1 m was installed in 2020. It was made of wooden elements and branches and placed on a tall tree in a riparian forest in the Wawer district, at a height convenient for the white-tailed eagle of 12 meters. This increased the possibility of nesting birds in the area.

Action against invasive species

Another measure to protect selected species associated with aquatic habitats is the removal of non-native invasive species, both fauna and flora, fish trapping and the elimination of knotweed and ash-leaf maple.

In the Moczydło II water reservoir in Ursynów, fish trapping was carried out twice. Individuals caught by electrofishing were inventoried, measured and weighed. Representatives of native species were released into the water, while individuals of alien species were humanely killed and donated to the Warsaw Zoo for animal food. Alien species were also caught during the implementation of restoration work.

Invasive animal species compete with native ones in terms of resources such as food, living and reproductive space, and often decimate native fauna through predation. The harvesting of non-native fish species also supports amphibian conservation by reducing the number of predators, especially during the breeding season, when most amphibians are closely associated with aquatic environments.

In the part of the task dealing with alien invasive species of flora, mainly knotweed and ash-leaf maples were removed. The work covered the area between the Vistula embankments in the Praga-Północ, Praga-Południe and Mokotów districts, as well as a section of the Piaseczynski Canal embankment in Downtown. The knotweed was mowed and disposed of for two years, eight times a year.

On three occasions over a two-year period, ash-leaf maple undergrowth was selectively removed along with undergrowth of other non-native species present in the work area, such as acacia robinia and walnut, while native plant specimens were avoided and left behind. A girdling treatment, which is the removal of a ring of tissue from the trunk of ash-leaf maples in the Praga-North and Praga-South areas, was performed once. This procedure has the effect of weakening the trees and leading to their slow death and subsequent natural decay. The method is innovative on a national scale.

Alien flora species destroy valuable natural communities, taking up space while negatively altering animal habitats. Removing invasive flora species reclaims space for native species, such as willows and poplars, which form the basis of Warsaw’s riparian forests.

Warsaw initiative a good example

Implementation of the project contributed to the implementation of the provisions of the key document Strategy #Warsaw2030, setting the direction of the city’s development. One of the visions defining Warsaw is Friendly Place, according to which the capital is, among other things, a space that skillfully combines urban and natural environments. In addition, one of the strategy’s goals is Functional Space, according to which residents live in a clean natural environment.

Both of these issues are reflected in the project. Its implementation contributed to improving the condition of the natural state and improving the quality of Warsaw’s green areas, as well as increasing biodiversity, retention, detention and biologically active area, thus reducing the urban heat island effect. Thanks to the workshops conducted during the project and the films promoting it, residents’ knowledge of the natural heritage, including the Vistula Valley, was increased, while pro-environmental attitudes were popularized.

The project was implemented both in wilderness areas, such as nature preserves and the Vistula River’s intercoastal, and on ponds in small green areas between residential neighborhoods. The project reconciled the requirements of the natural environment with urban functioning, significantly affecting the landscape of the area.

The project implemented by the Warsaw Greenery Board is the winner in the green-blue infrastructure category of the Eco-city competition, organized by UNEP/GRID-Warsaw and the French Embassy in Poland. The consistent appreciation of the key role of natural ecosystems in building the blue-green infrastructure of cities and initiatives for their maintenance, improvement and restoration were noted.

The article was prepared by Olga Rosłoń-Skalińska, Deputy Director for Investment and Development at the Warsaw Greenery Board.