Refuges of Antarctic diversity

Multiple colonization and dispersal events hide the early origin and induce a lack of genetic structure of the moss Bryum argenteum in Antarctica

“…The complex history of Antarctic colonization here recorded in B. argenteum and its persistence through glacial periods within the continent complements recent observations in multiple groups of terrestrial biota (Biersma et al., 2017; Convey et al., 2008, 2018, 2020; McGaughran, Tearuds, Convey, & Fraser, 2019), including many invertebrate groups, lichens, and other mosses that currently occur in habitats and areas that are also commonly characterized by B. argenteum . These important components of the Antarctic biota must therefore have had environmentally suitable refugia available to them (Convey et al., 2018, 2020). However, the precise locations of such refugia remain unknown (Pugh & Convey, 2008), as does the degree of connectivity or isolation between individual locations.…”

“…This supports a hypothesis of colonization from the AP or CA, and is consistent with evidence from Sanionia uncinata (Hedenäs, 2012) and the bipolar moss species Polytrichum juniperinum (Biersma et al., 2017). We recognize it is possible that some Antarctic biota could have survived on the sub‐Antarctic islands (particularly South Georgia) or volcanic South Sandwich Islands during glacial periods, from where they may have then recolonized continental Antarctica during warmer interglacials (Rogers, 2007); however, there is very little evidence available supporting this for terrestrial biota, other than for the South Sandwich Islands (Convey, Biersma, Casanova‐Katny, & Maturana, 2020; Convey & Smith, 2006).…”

“…A similar inference was made by La Farge, Williams, and England (2013) in the Canadian High Arctic, as well as by Roads, Longton, and Convey (2014) at Signy Island (South Orkney Islands) within bank‐forming mosses over a period of up to two millennia preserved in permafrost. In Victoria Land, cold‐based glaciers were widespread between c. 5–7 Ma and 2.5 Ma (Di Nicola et al., 2012; Smellie et al., 2014), providing the possibility of survival during glaciations through cryptobiosis, although it has to be accepted that the duration of glacial periods (tens to hundreds of thousands of years) is considerably longer than any currently available demonstration of cryptobiotic survival other than in microorganisms (Convey et al., 2020).…”

Evidence for strong environmental control on bacterial microbiomes of Antarctic springtails

“…These regions experience very different environmental conditions that strongly impact on the composition and functioning of their terrestrial ecosystems. Moreover, their microbiota and invertebrate fauna have long evolutionary histories in isolation 20 , 34 , 35 . The reduced diversity and richness of Antarctic springtail microbiomes, as well as the limited similarities observed between the four microbiomes analysed here, could be the result of strong environmental control, as well as of millions of years of evolutionary separation.…”

Evidence for Cryptic Diversity in the “Pan-Antarctic” Springtail Friesea antarctica and the Description of Two New Species

“…The dispersal abilities of species [6,7] The most diverse continental Antarctic invertebrates are springtails and mites, many of which are locally endemic. These groups have a long evolutionary history on the continent and must have survived multiple glacial cycles in refugia [15,[17][18][19][20][21]. Consistent with the scale of isolation of Antarctic terrestrial habitats and the limited active dispersal capabilities of their invertebrate biota, most population genetic studies so far performed on Antarctic springtail species have shown moderate levels of intraspecific genetic divergence.…”