Along Vienna’s tracks, a biodiversity renaissance 

2 September 2021

Butterflies and bees will soon be flying along Vienna’s tram lines, offering a parallel sight to that of commuters on their way to work.

In an effort to increase biodiversity and give a much-needed boost to the insect population, Wiener Linien – the city’s public transport company – plans to facilitate the conditions and eventually further the number of pollinators and wild plants that live next door to Vienna’s tram and subway tracks.  

It’s here where cities display their harshest looks – among metal, cement and graffiti – that nature finds an opportunity to thrive, Austrian researchers say.

Much to their surprise, scientists at Vienna’s University of Natural Resources and Applied Life Sciences (BOKU) discovered that an abundance of insects and wild plants have made the city’s metro and tram lines their home.

An insect paradise

Zoologists were stunned to find 378 different plant and 220 insect species along Vienna’s public transport. Residents include Italian locusts that “seem to feel particularly at home along the tracks,” in the words of BOKU’s wild bee specialist and Project Leader Bärbel Pachinger.

The final inventory not only counts 25 grasshoppers, 40 butterfly and 155 wild bee species but seven endangered butterfly species and a rare coarse-dotted sweat bee of the Lasioglossum genus.

Colourful meadows spring next to Vienna’s transport lines ©Alexander Zalokar

“So far, only two sightings of this bee are known in Austria, the most recent of which was 48 years ago, so this is a bit of a sensational finding!,” Pachinger reveals.

Now Wiener Linien will strive to encourage the development of this 3.7-hectare natural haven that quietly lives across noisy public transport lines.

Fostering biodiversity will be key to the insects’ reproduction. Although the project is still in its early stage, the transport company and BOKU researchers have already devised new maintenance plans.

Each of the 25 areas in which insects and wild plants live, for example, will be mowed less frequently to allow nature to prosper. The creation of new flower meadows and treatment of unwanted plant species are also being considered.

Countering bees’ declining trend

“This cooperation project is very important for us,” says Wiener Linien Managing Director Günter Steinbauer.  “Insect diversity is in great distress due to a lack of green meadows in the city and climate change. Improved maintenance of Wiener Linien’s green spaces can make a significant contribution to helping our plants and animals in the city. The public transport network should become a network of biodiversity.”

Indeed, factors such as intensive agriculture, pesticides and pollution are causing a decline in the population of bees and other pollinators that play a vital role in the planet’s ecosystems. In recent years, Europe and the US have experienced a 30 per cent loss of hives while grassland butterflies in Europe have decreased by 39% since 1990. .

Nurturing biodiversity will not just offer Vienna’s commuters an enjoyable glimpse into nature but will also be in line with the Austrian capital’s environmentally friendly profile, according to Vienna’s City Councillor of Public Transport Peter Hanke.

Last year, Vienna was crowned the world’s greenest city by ‘Resonance Consultancy’, a branding and marketing firm specialised in tourism, real estate, and economic development. “Public transport makes a significant contribution to this. The green spaces next to the rails also provide a safe habitat for numerous animals and plants. The study shows how important this is for climate protection in our city,” says Hanke.



Daniela Berretta Eurocities Writer