Butterflies inventory

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.

In 2020, another two Zurich municipalities were mapped that had not been systematically surveyed for almost 30 years. Specifically, these were the communities of Weiningen and Uitikon, west of the city of Zurich. In Weiningen, a total of 38 butterfly species were found, of which 22 could be reported for this municipality for the first time. Among them were also five rare species on the Red List. In Uitikon, the species diversity was also impressive and amounted to a total of 35 butterfly species, including four rare Red List species.

The year 2021 continued with the communities of Regensberg and Schöfflisdorf, also west of the city of Zurich. In Regensberg, a total of 31 butterfly species were found, nine of which were reported for the first time for this municipality. Among them were two rare species on the Red List. In Schöfflisdorf, the species diversity was also impressive and amounted to a total of 34 butterfly species, including two rare Red List species.

The insights from the mapping offer an important basis for further ecological enhancements in favour of a diverse butterfly fauna on Lake Zurich.