PLANT AND ARTHROPOD COMMUNITIES OF ALPINE ICE-RELATED LANDFORMS: ECOLOGICAL AND BIOGEOGRAPHIC IMPORTANCE

This PhD thesis is mainly organised as collection of research papers published, submitted, and in preparation. Chapter 1 outlines the state of the art, the main aims of the PhD project and the approaches used for reaching these objectives on peculiar study areas Chapter 2, “Vanishing habitats”, presents, as a first result, a scientific call for studying and monitoring glacial and periglacial habitats – refugia for a cold-adapted and threatened biodiversity - because of the lack of knowledge that still affects these habitats (Gobbi et al. 2021). The study points out the urgency in planning this research due to the risk of total disappearance of these habitats in the current scenario of global warming. Chapter 3, “Glacial and periglacial biodiversity”, is focused in analysing with multiple approaches the glacial and periglacial biodiversity. Studies 3.1-3.2 (Valle et al. 2022a-b) describe plants and arthropod communities of threatened glacial sites (Peirabroc, Clapier and Calderone glaciers) in peripheral mountain chains (Maritime Alps and Apennines, Italy, respectively). In these studies also important environmental parameters (e.g. debris thickness, soil temperatures and chemical parameters) have been correlated with biological communities. Study 3.3 focuses on glacial springtails and regards the description of a new species of ice-dwelling springtail from Calderone glacier (3.3, Valle et al. 2021). Studies 3.4-3.5 (Valle et al. 2020, Ornaghi et al. submitted) analyse the efficacy of cryophilic ground beetles (Carabidae: Nebrini) as ecological indicators of sub-superficial ice presence, through community, demographic (3.5) and morphometric (3.6) approaches. The paragraph 3.6 focuses on the biodiversity hosted by two of the few Dolomitic debris-covered glaciers, Sorapiss glaciers (Bernasconi et al. 2019). The last study (3.7, Fugazza et al. in submission) is a glaciological analysis that lays the foundations for studying in detail how the thickness of the stony debris accumulating on the glaciers influences the distribution of the biological community on debris-covered glacier. In chapter 4, “Toward a synthesis of glacial ecology”, we move from the detail spatial scale (i.e. the glacier) of the previous chapter to a regional scale (e.g. Alpine), that could be useful for global considerations. The first study (4.1, Valle et al. in preparation) gives a complete overview on taxonomy, ecology and biogeography of ice-dwelling cryphilic springtails from European Alps. The second study (4.2, in preparation) aims to answer the question “what is the fate of cold-adapted species during global warming and glacier retreat?”; in order to do this, a comprehensive database with abundance data of 513 species of plants, ground beetles and spiders sampled in 463 glacial and periglacial plots has been analysed. The second paper (4.3, Hågvar et al. 2020) is a review of ecological studies performed in Europe (Svalbard, Scandinavia and European Alps) and points out the ecological features of young environments close to retreating glaciers: these “virgin” soils are colonised by a pioneer peculiar biological community in which springtails results a key taxon of the early trophic chain and consequently the early successional stages. In chapter 5 are presented conclusions and perspectives of the research. Chapter 6 reports the comprehensive Curriculum Vitae of my PhD, including all papers published, in submission and in preparation, congresses, teaching activity, grants, awards, dissemination, education activities and other projects which I joined.