“…The strongest negative trends in Arctic sea ice have been observed around Svalbard and the northern Barents Sea (Comiso et al, ; Onarheim et al, ; Stroeve et al, ). Therefore, our study provides an early warning that continued sea ice decline linked to global warming will lead to increased genetic isolation and population differentiation through genetic drift, not only in Svalbard reindeer but also other Arctic wildlife, such as Peary caribou (Jenkins et al, , ; Mallory & Boyce, ), Arctic fox (Geffen et al, ; Norén et al, ), polar bear (Laidre et al, ), and muskox (Hansen et al, ). Indeed, the populations of Svalbard reindeer that were reintroduced into West Spitsbergen are already facing increased demographic isolation due to sea ice loss (Nilsen et al, ; Pedersen et al, ), which increases their vulnerability to current climate change and the increased frequency of extreme winter weather events (Hansen, Aanes, Herfindal, Kohler, & Sæther, ; Peeters et al, ).…”