Alpine blooming of “snow fleas”: the importance of snow for Alpine springtails (Hexapoda: Collembola) ecology and biodiversity

Springtails can occur in large populations on the snow surface. This peculiar habitat hosts specialized winter-active springtails living in colonies and using this seasonal habitat for feeding, effective dispersal and migration. Snow-active species have never been studied in Southern European Alps: the aim of this work is to study snow-active springtails of Adamello-Brenta Nature Park ("PNAB"; Italy), a peripheral mountain range of relevant biogeographic interest using integrative taxonomy. Springtail "bloomings" were sampled for 17 months by an environmental assistant of the park. Nine assemblages of springtails were found when temperatures were higher than 0 degrees C; eight were monospecific, with a total of five species found. The snow-active springtail fauna found includes both common Central-Northern European nival species like Desoria hiemalis (first record for Italy, although genetically differentiated from Northern Alps populations), Ceratophysella sigillata (known in Italy mainly from caves) and three species likely new to science (Hypogastrura cf. kelmendica sp1, Hypogastrura cf. kelmendica sp2, H. cf. peloponnesica, all belonging to the Hypogastrura socialisgroup). Snow is an important ephemeral habitat for springtails, for the biodiversity hosted and for its importance as an ecological corridor. We could hypothesize that snow, especially in peripheral mountain chains, acts as a fragmentary ephemeral habitat for those cold-adapted springtails. This could constitute a relevant aspect to take into consideration for conservation biology, especially in the context of the ongoing climate change. On the other hand, the Alpine chain probably acts as an ecological barrier for nival species, since isolated species and populations were found in PNAB.