Moss flora of two Alpine glacial and periglacial sites on crystalline and carbonatic bedrock

Mosses are important pioneer organisms in cold and wet habitats, such as glacial and periglacial habitats of the European Alps. These habitats include glaciers and rock glaciers, respectively, and are of increasing interest for being directly threatened by climate change and for hosting a specialized and often rare and endemic biodiversity (EU Habitats Directive, habitat code 8340, Natura 2000 network). However, the moss flora of rock glaciers was never studied, and, in general, few studies were performed specifically on mosses of ice-related landforms in the European Alps. The aim of this work is to give a first comparative checklist from two Alpine sites, the rock glacier of Lazaunkar (Bolzano, Italy) and the debris-cover glacier and rock glacier of Cima Uomo (Trento, Italy), with different bedrock compositions. Threatened species (according to the International Union for Conservation of Nature red lists) and extremely specialized high-elevation species were found in both sites, but mostly on crystalline bedrock in Lazaunkar. This biodiversity is the most threatened by climate change. These findings highlight how these habitats still need to be studied and monitored in the future.