Spontaneous vegetation in the city – urban nature at a traffic island at Molkenmarkt
In the centre of Berlin, there are only rarely areas where urban nature can develop spontaneously. Occasionally, however, such areas can be discovered during major urban redevelopment projects or in the vicinity of long-standing construction sites, as the example of a small traffic island at Molkenmarkt shows.
Urban redevelopment Molkenmarkt
In the historical centre, just behind the Berlin City Hall, streets and squares are currently being relocated. The historical city layout is to be made visible again here within the framework of an urban redevelopment and redensification. Before construction work begins, the areas are currently being examined for archaeological finds. The current and future course of the streets can be seen on the site of the Stadtwerkstatt which controls the public participation procedure.
Archaeological excavations at Molkenmarkt . Photo: C. Hajer.
Green traffic island
To the southwest there is a small triangular-shaped traffic island. It is about 30m long and has about 15m at its widest point. It will disappear to a large extent within the framework of future planning.
The map shows the situation three years ago. Shortly after, the trees were felled and the area cleared
The map shows the traffic island without vegetation
The ground of the site consists mainly of sand mixed with debris. Parts of the area are covered with pavement slabs. There are also piles of chaffed material from the felled trees. Apart from the root growth of previously existing trees, the traffic island was thus largely free of vegetation until 3 years ago. Since then, seeds of various species have been brought into the area by wind, animals, passers-by, passing cars or trucks and have been able to develop freely.
What has developed on site and what does it look like today?
Which plant species and how many can settle by urban nature in a short time and how has the vegetation developed?
View from the sidewalk in northeast direction with townhall (Photo: C. Hajer)
View southwest of the Nikolai quarter; various long grasses and larkspur (Photo: C. Hajer)
Mapping took about 6 hours, distributed over two afternoons on 21 and 23 June.
For the less known species I used the apps of “Flora incognita”, created by Max Planck Institute for Biogeochemistry Jena and “Naturblick” from the Berlin Museum of Natural History. Some plants could not be identified beyond doubt and could keep their secret. The current state includes the classic flowering first settlers, which form soil and herb layers, as well as first perennials and young trees as pioneer shrubs.
Plant identification with “nature view” – app from the Museum of Natural History (Photo: C. Hajer)
A total of 96 different plants were identified. For Berlin, the total species list of the State Commissioner for Nature Conservation in Berlin contains 1527 established plant species, 304 of which are neophytes, i.e. plants that only came to Europe after 1500. If one follows the data of the Naturrschutzbund NABU Berlin, there are 2,200 ferns and flowering plants. The high number of 96 species on the small area was surprising and not to be suspected at first sight. The current state of the vegetation includes the classic flowering pioneers such as various types of clover, evening primrose, viper’s head or compass lettuce, which form the soil and herbaceous layer there, as well as the first perennials and pioneer trees such as the sessile cherry, the tree of heaven and the bridle tree.
Detail from the list of detected plants (Photo: C. Hajer)
If the plants were allowed to grow there undisturbed for 30 years, the result would be a small urban grove. On a larger scale, this can be seen in the nature park Südgelände or in the wooded areas around the park at Gleisdreieck. Formerly used as marshalling yards, these areas were free of vegetation and could develop for decades without human intervention during the Wall era.
Occasional mowing could preserve some of the flowering plants on the traffic island. At the same time this would bring benefits for urban wildlife like insects and birds.
Flowering plants in the area (Photo C. Hajer)
High species diversity and resilience
In comparison with areas, planted with horticultural plants or meadows and woodlands designed in a near-natural way, however, such spontaneously grown vegetation areas show a higher biodiversity. This also applies in comparison with areas in Brandenburg. Moreover, there’s a better resistance of these plant communities to environmental influences. This also applies to climate impacts such as storms, flooding, drought, but also pest infestation.
Addendum
In October 2021, the area is finally cleared. Archaeologists are now also digging here for the origins of Berlin.
The a new documentary film “Natura Urbana“ by Mathew Gandy and Sandra Jasper, University of Cambridge, deals in detail with the historical development of Berlin’s wastelands as urban nature since World War II.