False heath fritillary (Melitaea diamina)
Photo © Jürg Schlegel, ZHAW Wädenswil
Sponsoring ZHAW: Supplementing of butterfly inventory of the canton of Zurich
During the cantonal butterfly inventory, some municipalities of the canton of Zurich were already investigated in 2010/2011 with regard to their butterfly fauna. Due to the restricted public-sector funds available, however, it has not been possible to investigate many municipalities up to now. Thanks to the sponsoring by Martec Handels AG, it was possible in 2018/2019 to incorporate the municipalities of Kilchberg, Rüschlikon and Thalwil that had not been mapped up to then.
This produced interesting results in 2018: Although Kilchberg and Rüschlikon do not have any conservation areas, there were nevertheless 19 or 20 different butterfly species there. In Thalwil, thanks to the existence of some flat moors there were even 39 species. The “Red List” species alcon blue (heavily endangered), false heath fritillary and lesser marbled fritillary (both potentially endangered) and the attractive species high brown fritillary and western marbled white are, for example, particularly worthy of mention. Like many other butterflies, these species prefer unfertilised, flower-rich grassland that is not mown too early.
The results from 2019 are also promising: a total of 33 butterfly species were found in Zollikon, 21 of which were registered for the first time for this municipality. Among them were also 4 rare species on the “Red List”. In Zumikon, the species diversity was more modest and amounted to a total of 20 butterfly species, but this is also due to the smaller area size.
The insights from the mapping offer an important basis for further ecological enhancements in favour of a diverse butterfly fauna on Lake Zurich.