The butterflies of Central Europe did not die evenly, but were decimated in two clearly distinguishable phases. This is the result of a working group led by Jan Christian Habel from the University of Salzburg based on records of the museum »Haus der Natur« in Salzburg. As the team in "Science of the Total Environment" reports, the first wave began at the end of the 19th century and mainly affected butterflies in sensitive ecosystems such as bogs. The second wave started around the mid -1960s and continues to this day. Since the mid -1990s, some endangered species have stabilized thanks to the nature conservation measures, the team reports.
A total of around 60,000 observations of 168 daily and ram species flowed into the investigation. The data comes from a region with an extension of around 7000 square kilometers in north Austria and range from 1920 to 2019. At the beginning of the examination, the stocks of numerous species declined, especially those in wetlands and other habitats previously not used. Their decline can be explained by direct habitat destruction when many bogs were drained at the turn of the century and converted into arable land. Many of the affected species are only available in moors in higher locations that have not been destroyed.
The second wave of extinction began after the Second World War and affected many species that had previously coped well in cultural landscapes used by humans. "The industrialization of agriculture with intensive use of plant protection products and artificial fertilizers, which was beginning at this time, seems to be responsible here," says Thomas Schmitt from the Senckenberg German Entomological Institute in Müncheberg, one of the co-authors of the study. As a result, many natural landscape elements such as flowery, meager valley meadows have disappeared.
The examination refers to the butterflies of northern Austria, but in the opinion of the working group, the results of the study can also draw conclusions for other regions of Europe. The trends in land use were similar to the continent, and the area of study was so diverse that the results were transferable to other regions. The findings of the working group confirm the trend to less diversity, which is also known from other insect groups. The data also shows the success of nature conservation, but above all that the second wave of the butterfly loss continues. "This trend is still negative," says Schmitt.
