As per the estimates, Opuntia cacti currently make up 23%-30% of the low vegetation cover in the Valais region.
Authorities said the cactus species belonging to the genus Opuntia, or prickly pears, are proliferating in parts of Valais, home to the pyramid-shaped Matterhorn mountains, encroaching on natural reserves and posing a biodiversity threat, The Guardian reported.
Opuntia species and similar cacti have also been identified in some of the hills around Sion, the capital of Valais. As per the estimates, Opuntia cacti currently make up 23 per cent-30 per cent of the low vegetation cover in the region, the report added.
Yann Triponez, a biologist working in the canton of Valais’ nature protection service, said, “In some parts of Valais, we estimate that the cacti can occupy one-third of the available surface.”
“A lover of dry and hot climates, this invasive and non-native plant is not welcome in the perimeter of prairies and dry pastures of national importance,” The Guardian report said citing the municipality of Fully in the Rhone valley.
The cacti species have reportedly been present in the Swiss canton at least since the late 18th century when it was imported from North America, the report added.
The cacti presence has also been reported in neighbouring Alpine regions, including Ticino and Grisons in Switzerland, and the Aosta valley and Valtellina in Italy. Environmentalists believe that a warmer climate in the Alps allows a longer vegetation period. With the rapid decrease in the snow cover, the invasive species might be getting the ideal conditions to spread.
In the Alps, snow is becoming rarer at lower altitudes. According to the MeteoSwiss report, the number of snow days under 800 metres of altitude in Switzerland has decreased by half since 1970. The Alps are now covered with snow for about a month which is less than the historical averages, the report added. The environmentalists called the situation “unprecedented in the last six centuries.”
Peter Oliver Baumgartner, a retired geology professor commissioned by the canton to study and write a report on the plants said, “These species bear -10C or -15C without any problem. But they want to be in a dry place and don’t like the snow cover.”
The average temperature in Switzerland is now 2.4-degree celsius warmer than averages between 1871 and 1900. Temperatures across the range have been rising twice as fast as the global average, the report added.
Source : The Hindustan Times