Thermokarst depressions are widespread phenomena due to permafrost degradation in the Arctic, whereas only few are known from mountain permafrost of the mid-latitudes. In the Italian Central Alps, close to the Stelvio Pass (2,763 m above sea level), a ski run was built in 1987. Since 1981, statistically significant air warming has been recorded, especially during summer (+0.65°C per decade). Permafrost temperature recorded at the nearby Share Stelvio Borehole between 1990 and 2011 exhibited a rapid increase (> 0.8°C per decade) and an active-layer thickening (7 cm/year). Between the years 1999 and 2003, some thermokarst depressions started to develop, initially in the lower part of the ski run and then extending to higher elevations. The depressions increased in number, size, and depth with time. Since ski-run construction, the area remained free of vegetation until early 2000, when vegetation colonization started, showing a coupling with the onset of thermokarst development and summer warming. Vegetation changes accelerated with the ingress of pioneer and early-successional as well as of late-successional species. Moreover, the ingress of shrub species (Salix spp.) typical of lower elevation belts (subalpine and even montane) was dated to 2004. All the observed features show a rapid and coupled response of the abiotic and biotic components of this ecosystem to climate warming. Our data also confirm the similarity of the observed responses and dynamics of the alpine tundra with the Arctic tundra with regard to both permafrost and vegetation.

中文翻译：

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意大利中阿尔卑斯山脉的近期热岩溶演化

由于北极永久冻土退化，热岩溶洼地是普遍现象，而中纬度山区永久冻土的已知现象很少。在靠近斯泰尔维奥山口（海拔 2,763 m）的意大利中部阿尔卑斯山，1987 年建造了一条滑雪道。自 1981 年以来，记录到了具有统计意义的空气变暖，尤其是在夏季（每十年 +0.65°C）。1990 年至 2011 年期间在附近 Share Stelvio Borehole 记录的永久冻土温度显示出快速增加（> 0.8°C 每十年）和活动层增厚（7 厘米/年）。从 1999 年到 2003 年，一些热岩溶洼地开始发育，最初在滑雪道的下部，然后扩展到更高的海拔。凹陷的数量、大小和深度随着时间的推移而增加。自滑雪道建设以来，该地区一直没有植被，直到 2000 年初植被开始定植，这表明与热岩溶发展和夏季变暖有关。植被变化随着先驱和早期继承物种以及晚期继承物种的进入而加速。此外，灌木物种的进入（Salix spp.) 典型的低海拔带（亚高山甚至山地）的历史可追溯至 2004 年。所有观察到的特征都显示该生态系统的非生物和生物成分对气候变暖的快速耦合反应。我们的数据还证实了观察到的高山苔原与北极苔原在永久冻土和植被方面的响应和动态的相似性。