The site includes a large mountainous area in the Central Apennines, almost in the centre of the Italian peninsula and about 70 km west of Rome. It represents an “orographic island” in the Central Mediterranean basin, along the Apennines mountain range. Since 1993, the vegetation has been surveyed at six permanent high elevation plots (Mount Sevice research station, Mount Velino, 2125-2225 m a.s.l.) and (since 2005) at an additional 55 plots along two elevation transects (SW slope of Mount Velino and Mount Morrone), including primary and secondary grasslands, beech forests and alpine tundra. Since 2014, micro-climate data (GLORIA method) have been continuously recorded at the high elevation plots. Vegetation is surveyed yearly in the 6 high elevation plots (each 100 m2 in size) grouped in two cluster-plots (each of 3 plots). Structure and composition changes are studied in two ecologically opposite primary plant communities, both above the timberline: snow-bed grassland and alpine tundra, both characterized by extreme below zero temperatures all year round and frozen soil for 8 months per year, but with very different snow cover duration. Based on the first 30 years of observation, a clear trend toward a decrease of snow dependant species and a parallel increase in drought- and stress-tolerant species has been recognized, linked to a general process of climate change, more accelerated in Southern Europe.