Accustomed to seeing snow on their mountains in winter, and edelweiss in summer, and how global warming intensifies, residents Swiss The canton of Valais is facing an unexpected sight on its slopes: cacti!

According to local authorities, an invasive cactus species belonging to the genus Opuntia, commonly known as prickly pear, has invaded Valais areas, threatening biodiversity.

“A lover of dry and hot climates, the invasive alien plant is not welcome in the areas of meadows and pastures of national importance,” reads a press release from the municipality of Fili in the Rhone Valley, announcing an eradication campaign at the end of 2022.

Species of Opuntia and related cacti grow in some of the hills around the Valais capital, where prickly pear is currently estimated to make up 23-30% of the low vegetation cover. Their presence has also been recorded in the adjacent Alpine regions, including Ticino and Graubünden in Switzerland and the Aosta and Valtellina valleys in Italy.

“According to our estimates, in some areas of the Valais, cacti occupy a third of the available surface,” explains Jan Trypone, a biologist at the regional nature conservation service. According to him, prickly pear has been present in Valais since at least the late 18th century, when it was introduced from North America.

However, authorities fear that the warmer climate in the Alps is creating fertile soil for an extended growing season, at the same time, the limited snow cover leaves room for them to spread.

“These products can withstand up to -10, 15 degrees Celsius without problems. However, they need dry soil, not snow cover,” said Peter Oliver Baumgartner, a retired professor of geology who was commissioned by the cantonal authorities to study the plants and present his findings in a report.

According to Triponet, Valais is one of Switzerland’s biodiversity hotspots. “We have about 3,000 species of flora in Switzerland, of which 2,200 grow in the Valais,” he says, expressing concern that the spread of cacti in nature reserves and protected areas will cause ecological chaos. “When there are these cacti, nothing else grows. Each unit covers the ground and prevents the growth of other plants,” he warns.

Snow is less common at low altitudes, even in the Alps.

Snow became less frequent at lower altitudes, even in the Alps. The number of snow days below 800 meters in Switzerland has halved since 1970, according to the Swiss Meteorological Service.

In fact, a recent study published in the scientific journal Nature Climate Change shows that snow cover in the Alps lasts about a month less than the historical average, describing the situation as “unprecedented in at least six centuries.”

Average temperatures in Switzerland have risen by 2.4 degrees Celsius compared to the corresponding years 1871-1900.

Source: Guardian