Genetic roadmap of the Arctic: plant dispersal highways, traffic barriers and capitals of diversity

Abstract

SummaryWe provide the first comparative multispecies analysis of spatial genetic structure and diversity in the circumpolar Arctic using a common strategy for sampling and genetic analyses. We aimed to identify and explain potential general patterns of genetic discontinuity/connectivity and diversity, and to compare our findings with previously published hypotheses.We collected and analyzed 7707 samples of 17 widespread arctic-alpine plant species for amplified fragment length polymorphisms (AFLPs). Genetic structure, diversity and distinctiveness were analyzed for each species, and extrapolated to cover the geographic range of each species. The resulting maps were overlaid to produce metamaps.The Arctic and Atlantic Oceans, the Greenlandic ice cap, the Urals, and lowland areas between southern mountain ranges and the Arctic were the strongest barriers against gene flow. Diversity was highest in Beringia and gradually decreased into formerly glaciated areas. The highest degrees of distinctiveness were observed in Siberia.We conclude that large-scale general patterns exist in the Arctic, shaped by the Pleistocene glaciations combined with long-standing physical barriers against gene flow. Beringia served as both refugium and source for interglacial (re)colonization, whereas areas further west in Siberia served as refugia, but less as sources for (re)colonization.

Diversification of the cold-adapted butterfly genus Oeneis related to Holarctic biogeography and climatic niche shifts

“…Occurrences of all Arctic Oeneis species (Region C, Table S1) within Beringia support a primary refugial importance of this area for species survival (Yannic et al, 2014). Beringia was ice-free during the whole Pleistocene and served as refugium for mammals (Hope et al, 2013), plants (Eidesen et al, 2013) and other insects (Elias et al, 2000). Beringia could also represent another speciation centre for Oeneis butterflies, analogically to small mammals, which diversified in Beringia during glacial cycles by gradual adaptation (Hope et al, 2013).…”

“…Beringia could also represent another speciation centre for Oeneis butterflies, analogically to small mammals, which diversified in Beringia during glacial cycles by gradual adaptation (Hope et al, 2013). Further, we do not exclude the importance of smaller refugia outside of Beringia such as Siberia (Hope et al, 2010;Eidesen et al, 2013) for survival of some species/populations during the Pleistocene. More detailed studies, including population structure (cf.…”

“…Cold periods interconnected biota across the Holarctic by promoting lowland dispersal events (Schmitt and Haubrich, 2008;Todisco et al, 2012) and movements of Arctic assemblages to southern latitudes (Päckert et al, 2012;Eidesen et al, 2013) followed by in-situ speciation (Vila et al, 2011). This connectivity was probably associated to species' ecological q This paper was edited by the Associate Editor Francesco Frati.…”

“…along rivers) around the glaciated high mountain systems (Schmitt et al, 2006). The interactions of ecological preferences and geographical speciation processes in montane and Arctic regions are relatively well studied (Todisco et al, 2012;Eidesen et al, 2013;Yannic et al, 2014), but mainly using plants and birds as models (e.g. Drovetski, 2003;Kadereit and Baldwin, 2012;Fjeldsa, 2013).…”

Is the sword moss (Bryoxiphium) a preglacial Tertiary relict?

“…In fact, Alaskan specimens are embedded within an Asian clade and thus unrelated to the American clade. The closer relationships of Beringian populations or species to those of East Asia rather than to North American ones is recurrent in other mosses Kyrkjeeide, 2015) and vascular plants (e.g., Carlsen et al, 2010), wherein this pattern has been interpreted in terms of migrations across the Beringian land bridge (Eidesen et al, 2013). Kyrkjeeide (2015) further proposed that Asian populations moving eastwards through Beringia would fail to connect the remaining areas of North America due to the main direction of the Pacific storms from Asia northwards to Alaska, avoiding the coast of the Pacific Northwest (Mendelsohn et al, 2012).…”