Apartment gardens offer untapped potential for biodiversity

Gardens around apartment buildings could do much more to support biodiversity if they were managed differently, studies have found. SRF reports on residents in Küsnacht who have transformed their shared garden into a habitat for wildlife.

The project began with an idea from tenants Annekäthi Frei and Peter Schiffhauer and is supported by all the building’s tenants. The municipality contributed to the costs, with the property owner covering the rest. Tenants also put in their own work, source materials and learn about wildlife-friendly gardening.

A heap of branches, soil and other garden waste provides shelter where hedgehogs, snakes and lizards can spend the winter. Other features include stone piles, a sandy patch where lizards can lay eggs, a tree stump, wildflower strips, shrubs and a small pond. The pond must be refilled twice a week to prevent it becoming a breeding ground for tiger mosquitoes.

Frei and Schiffhauer have seen a lizard in the garden but are unsure whether it is a common wall lizard or a female sand lizard, which they hope to find because it is rarer.

Daniel Baur, a professor of landscape architecture and urban design at Bern University of Applied Sciences, says the biodiversity potential of grounds around apartment buildings is much greater than previously assumed. Because these green spaces are connected, they could support biodiversity if maintained differently, he said.

Baur said a change in management could also reduce costs. A calculation made with real estate companies found savings of about 4.3 million, partly because less mowing would be needed.

Some neighbours initially found the garden’s natural compost heap unattractive. Frei said it can take time to understand that the heap has ecological value, while the cherry laurel beside it is an invasive species whose sale is now banned in Switzerland.