Loss of species

Butterflies are coming under increasing pressure

Fewer and fewer butterflies are fluttering through Vorarlberg.

(Bild: krone.at / Leserreporterin Waltraud U.)

After four years of butterfly monitoring in Vorarlberg, experts are sounding the alarm: "We are also losing more common species," they warn. The animals are coming under increasing pressure. 

Researchers are dependent on help from the public to document the dwindling diversity of species, as the data situation is inadequate. One of these projects is the "Vorarlberg butterfly monitoring project", which has seen 11,000 butterfly individuals counted and identified since 2020 in a joint effort by laypeople and experts. One of the results from the four-year report presented on Friday: it has increasingly "fluttered out".

There are 160 butterfly species and around 2,360 moth species in Vorarlberg, many of which are under severe pressure. Landscape and climate-related changes are shifting distribution boundaries, while trade and tourism are bringing previously non-native species to new regions - with uncertain consequences. According to Johannes Rüdisser from the Institute of Ecology at the University of Innsbruck, who heads the butterfly monitoring program co-financed by "Blühendes Österreich", too little is actually known about the state of insect biodiversity in Austria. So far, species have been counted for red lists, for example. However, for their ecological performance, for example in pollination or as food for birds and small mammals, population trends are also important, especially for more common and widespread species.

Small fox most common
The butterfly monitoring program, which was extended to the whole of Austria in 2023 and has been running in Tyrol since 2018, aims to close this gap. The popular butterflies, which are relatively easy for the public to spot and identify, can be used as biological indicators to draw conclusions about the general ecological status. In Vorarlberg, experts counted 8,000 butterflies from 108 species at a hundred randomly selected meadow sites over the four years, with around 3,400 observations made by volunteers. 68 percent of the species occurring in Vorarlberg were documented. The most frequently counted species was the small fox, followed by the small cabbage white butterfly and the large ox-eye butterfly.

It became clear: "Even the cabbage white butterfly, known as a garden pest, no longer occurs in large numbers," says Rüdisser. In frequently mown and fertilized valley locations, an average of only seven butterflies were counted in the four annual samples, compared to 13 on slopes and 17 on alpine pastures. According to the experts, there were probably significantly more in the past, with 20 to 25 in valley locations. Long-term observation is therefore crucial, as this is the only way to identify trends.

According to Peter Huemer, Head of the Natural Science Collections of the Tyrolean State Museums and leading butterfly expert, emphasized: "We are also losing more common species." In addition to butterflies, there are thousands of little-known butterflies that fulfill important functions for the ecosystem. For populations of rare species, some of which are now only found in isolated locations, mowing too early, fertilization or more frequent extreme weather events due to climate change could spell the end. Climate change is still underestimated as a factor here, says Huemer. Nature conservation areas therefore have an even more important stepping stone function.

Ruth Swoboda pointed out that the observations of the population are enormously important.

(Bild: Mathis Fotografie)

On behalf of inatura, Director Ruth Swoboda emphasized that observation data from the public is becoming increasingly important for documenting the current state of nature. The Dornbirn museum therefore invited people to get to know butterflies and to help document them via the observation.org platform on "Es kreucht, fleucht, fliegt und sprießt Tagen" from April 26 to 28. inatura referred to the international biodiversity competition "City Nature Challenge 2024", in which 700 regions worldwide are taking part this year until April 28, twelve of which are in Austria.

Abandon blockade against EU renaturation law
Together, the experts urged the Austrian provinces to abandon their blockade of the EU renaturation law. Provincial Councillor Daniel Zadra (Greens) emphasized that Governor Markus Wallner (ÖVP) had unfortunately agreed with the position of the provinces and assured them that they would continue to try to persuade them to support the law. Projects such as butterfly monitoring provide important data as "alarm systems" as a basis for political decision-making and create education and awareness among the population. After all, it is "not just about a few beautiful butterflies", but also about the future of food production.