LAUSR

ABSTRACT Introduction: The Alps are one of the richest biodiversity ‘hot spots’ in Europe, but also one of the most threatened in the context of climate change. Here, we report the results of a long-term survey of the bryophyte flora of Queyras, a high-altitude limestone area, which can serve as baseline data to document and monitor the flora of this poorly-known area. Methods: Bryophyte distribution data were collected in the course of six field trips between 1981 and 2017. The dataset includes 6890 observations in 154 1 km2 MGRS gridsquares. Key results: The bryophyte flora of Queyras includes 500 species, of which 34% are newly reported here and 8% were previously reported but not seen in the course of the present survey. For each species, distribution maps at the level of 1 km2 MGRS gridsquares, frequency, and elevation range are reported. Queyras includes ten species of high conservation relevance in Europe, namely the liverworts Mannia fragrans and Riccia breidleri and the mosses Didymodon glaucus, Grimmia mollis, Hygrohypnum styriacum, Molendoa hornschuchiana, Orthotrichum crenulatum, Platyhypnum molle, Schistidium grande and Tayloria acuminata. Conclusions: Our study illustrates the extent to which the bryophyte flora of even such noteworthy botanical places as Queyras is extremely rich and holds a substantial proportion of species of high conservation relevance at the European level, but is poorly documented, calling for a substantial effort aiming at inventorying, mapping and protecting the unique bryophyte flora of the Alps.