Urban fallow lands as a habitat

by Katharina Kiekbusch, Museum für Naturkunde Berlin

Fallow land is a habitat for wild bees

Wild bees find nectar and pollen there during the whole summer, as well as good nesting opportunities due to the diversity that exists there. A typical example of a wild bee that is present in fallow areas is the shaggy bee. It specializes in ruderal sites (fallows) and prefers sandy soils for nesting. It collects pollen only from composite plants, for example, small bitterweed. The Canadian goldenrod also belongs to the composite plants and is widespread on fallow land. It is native to North America, but has since become established here as well. What special about fallow land is that often immigrant plants, which in our country are only found in cities, grow there.

Small Shaggy-Bee © James K. Lindsey; Canadian goldenrod © Joanna Boisse

Fallow land promotes plant and pollinator diversity

Another typical plant that characterizes the landscape of a fallow is the blue viper's bugloss. It is pollinated by bees, hoverflies and butterflies. It is especially popular by butterflies; more than 40 species of butterflies have been located. Among them are the swallowtail and the painted lady. In addition to being a source of nectar, the blue viper's bugloss also serves as food for the caterpillars of the painted lady.

Blue viper's bugloss © Donald Hobern

Insect diversity promotes bird diversity

Due to the many insects, there is also plenty of food for birds. The red-backed shrike, for example, is such. He builds his nests in high thorny bushes, on whose thorns he impales his prey (insects and small vertebrates). Structure-rich hedgerow landscapes provide the habitat he needs.

Neuntöter © Kaeptn Chemnitz

Open spaces must be protected from sealing

However, with the increasing population density of people, the demand for housing is growing. Therefore, every space is used to cope with this problem. Open spaces make way for new buildings, soils are sealed - what happens to nature in the process? Suddenly, the habitat of many animals and plants is endangered and they are being restricted more and more. Urban fallow lands offer potential opportunities for more housing. Unlike parks, they are "wild" and disturbing in the eyes of some people, although they are just as important as habitats for many animals and for the climate as other, planned green spaces. They do just as much to contribute to the containment of climate change and improve the urban climate as deliberately burst green spaces. The more of it that is concreted over, the more animals will vanish and particularly endangered species will slide higher and higher on the list of endangered animals. The paradox is that some animal species " refuge " from the countryside to the city, because here they find a larger food supply that is no longer available in the countryside due to a wide variety of aspects. If they also lose their bases here, populations decline and again we humans are to blame. Therefore, it is important to pay more attention to urban fallow lands and to protect this special habitat, which has developed quietly and secretly, often outside our awareness.

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DOI: https://doi.org/10.7479/ws8v-z270/13