Getting your fingers dirty in the soil, watching the plants grow and spending a pleasant time with friends after work: urban gardens provide small oases in the midst of the hectic of city life. The city population is, however, growing and the pressure on these open spaces is increasing.
In the Project BetterGardens, WSL is studying private and allotment gardens in Swiss cities in cooperation with the Research Institute of Organic Agriculture FiBL. The aim is to find out which types of garden can best promote biodiversity in a city. What influences how city gardeners decide what to plant and how to tend their gardens? How does gardening affect the biodiversity and its impact on, for example, soil quality and insect pollination? How does gardening influence the wellbeing of the gardeners? Researchers are exploring these questions in four subprojects in Zurich, Bern and Lausanne.
The biologist, David Frey, surveyed the diversity of Zurich’s city gardens in his doctorate at WSL. He and his colleague Andrea Zanetta found 1070 different plant species in these gardens, but invasive neophytes were only sporadic. They identified as many as 1100 invertebrate species, 12 of which were recorded for the first time in Switzerland or on the Swiss Central Plateau. In the survey, “those gardens less focused on production” scored, as expected, better, i.e. gardens where species diversity is consciously promoted. “It is worth motivating gardeners to include different structures and plant species even in small areas as this promotes biodiversity,” says David.
Chris Young and Nicole Bauer from WSL are studying how the gardens affect the quality of life of those tending them. Their analyses show that gardens are important for cultivating social contacts and relaxing. Thus half of the respondents said that, after spending time in the garden, they felt much more relaxed than beforehand. Chris is also interested in who is using the allotments: “It used to be mainly working class people, often with migrant backgrounds. Today, it is increasingly people with degrees in higher education who want to have an allotment.”
Currently further analyses are being carried out in all the subprojects. The results should provide arguments for maintaining the green oases in cities. (Lisa Bose, Diagonal 2/17)