Glacial biodiversity of the southernmost glaciers of the European Alps (Clapier and Peirabroc, Italy)

We applied a multi-taxa approach integrating the co-occurrence of plants, ground beetles, spiders and springtails with soil parameters (temperatures and chemical characteristics) in order to describe the primary succession along two glacier forelands in the Maritime Alps (Italy), a hotspot of Mediterranean biodiversity. We compared these successions to those from Central Alps: Maritime glacier forelands markedly differ for their higher values of species richness and species turnover. Contrary to our expectation, Maritime glacier forelands follow a 'replacement change model', like continental succession of Inner Alps and differently from other peripheral successions. We propose that the temperatures along these Mediterranean glacier forelands are warmer than those along other Alpine glacier forelands, which promote the faster species turnover. Furthermore, we found that early and mid successional stages of the investigated glaciers are richer in cold-adapted and endemic species than the later ones: we confirmed that the 'replacement change' model disadvantages pioneer, cold-adapted species. Given the overall correspondence among cold-adapted and endemic species, the most threatened in this climate phase, our results raise new concerns about the extinction risk of these species. We also describe supraglacial habitat of Maritime glaciers demonstrating that supraglacial debris represents an environment decoupled from the regional climate and may have an important role as refugium for coldadapted and hygrophilous plant and animal species, whose survival can be threatened by climate change and by a rapid ecological succession in the adjacent forelands.

Automated summary

We investigated the primary succession along glacier forelands in the Maritime Alps and compared them to those from the Central Alps. The Maritime glacier forelands showed higher values of species richness and turnover, contrary to our expectation. We propose that this is due to warmer temperatures along the Mediterranean glacier forelands, which promote faster species turnover. Furthermore, early and mid successional stages of the investigated glaciers are richer in cold-adapted and endemic species, highlighting the extinction risk faced by these species in the current climate phase. We also found that supraglacial debris on Maritime glaciers serves as a refugium for cold-adapted and hygrophilous plant and animal species, which are threatened by climate change and ecological succession in the adjacent forelands.