The diversity of food plants for insects in the canton of Zurich has dramatically decreased over the past 100 years or so. This means that bees, flies and butterflies are increasingly deprived of their food base, a team of researchers from the Universities of Bonn and Zurich (Reto Nyffler, Michael Kessler) and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL has demonstrated. The results are transferable to the whole of Central Europe, with minor regional restrictions.
Stefan Abrahamczyk, Thomas Wohlgemuth, Michael Nobis, Reto Nyffeler, Michael Kessler: Shifts in food plant abundance for flower-visiting insects between 1900 and 2017 in the canton of Zurich, Switzerland, Ecological Applications, 23 April 2020. DOI: 10.1002/eap.2138