Data from: Retracing the response of Rangifer to postglacial climate change in Arctic islands

We compiled published datasets of mitochondrial DNA sequences which
informed Quaternary population history scenarios. These scenarios were
evaluated in a coalescent-based approximate Bayesian computation (ABC)
modelling framework (using DIYABC RF) to test hypotheses of
postglacial island (re)colonisation and to estimate timings of population
divergence and admixture. Population events were compared with modelled
paleo-sea ice cover and published ice sheet chronologies. Rangifer
tarandus L. play a key role in Arctic ecosystems as the most numerous and
widespread large herbivore. Sea ice is vital for maintaining genetic
connectivity in Arctic islands, yet the historical role of sea ice in
shaping R. tarandus biogeography is unknown. We studied the role of sea
ice changes and ice sheet retreat since the last glacial period in the
timing of island dispersal. We compiled published datasets of
mitochondrial control region sequences that informed population history
scenarios, which were evaluated in a coalescent-based approximate Bayesian
computation (ABC) modelling framework to test hypotheses of island
(re)colonisation and to estimate divergence and admixture. Population
events were compared with modelled and proxy-based paleo-sea ice cover and
published ice sheet chronologies. Our analysis supports Holocene dispersal
onto deglaciated Arctic islands, rather than High Arctic glacial refugia.
The degree of population admixture and the effect of sea ice was dependent
on regional geography and climate history. North American initial island
population divergence occurred as sea ice cover was declining. A lack of
strong genetic structure and the occurrence of late Holocene admixture
suggest that Canadian Arctic Archipelago populations were somewhat
connected by sea ice during the Holocene. The Svalbard, Franz Josef land,
and West Greenland colonisations arose through long-distance dispersal.
Here, divergence times occurred post-deglaciation but broadly align with
subfossil-based colonisation estimates, suggesting dispersal limitation
due to sea ice conditions, potentially requiring appropriate ocean
currents and sea ice drift directionality and speeds. Our study sheds
light on the Late Quaternary (~60 ka - present) history of Arctic island
Rangifer and suggests that ice sheet retreat, sea ice, and ocean currents
were important in shaping present-day genetic patterns. Regional
differences in postglacial dynamics suggest that dispersal during
contemporary climate change may vary regionally and depend upon
diminishing connectivity provided by sea ice.