The Ministry of Spatial Planning in Switzerland informs NextCity that the biodiversity in cities with sufficient green spaces is higher than in agricultural landscape. A study of Bern University shows that the negative influence of urbanization upon biodiversity is less negative than that of intensive agriculture. Biologists Tabea Turrini and Eve Knop from the Institute of Ecology and Evolution published data of six Swiss cities in the journal “Global Change Biology” compared with their surrounding landscapes being intensively used by agriculture. The research also includes suggestions to promote biodiversity in cities. As a measure for biodiversity the researchers used tree-dwelling beetles, bugs, cicadas and spiders collected with a giant vacuum cleaner from birch trees.
They also divided the findings in “green” and “gray” cities: Trees within a radius of 500 meters next to other green elements reported in all groups of animals a significantly higher number of species than trees in “gray” areas. It is most notably that trees around major parks were not included, but only those scattered in the city proving the importance of small green elements such as small gardens and even single trees. In “green” cities an average of 39 species of the four studied groups of animals were found whereas in the “gray” cities, there were only 29 – the same lower number as in the intensively used agricultural land surrounding the cities. See also the related article in the NZZ.