According to a USGS study, many polar bears have moved northward since their area does not contain any sea ice. Global warming is pushing the bears northward. Scientists discovered that the 19 recognized subpopulations of polar bears are divided into four genetically similar clusters. These correspond to environmental and oceanographic factors. The four groups are: the Canadian Archipelago (Canadian), Southern Canada, Eastern Polar Basin and Western Polar Basin. They have observed directional gene flows towards Canada over the past 1-3 generations. The lead author of the study, Dr. Elizabeth Peacock (USGS researcher), said that “The recent directional gene movement northward by the polar bear is something unique.” Our analyses of more historical gene flow did not reveal any movement. The predominant gene flow came from the Eastern Polar Basin, South Canada, and the Canadian Archipelago. This is where sea ice melts less frequently due to cooler north latitudes and circulation patterns. Recent directional gene flow. This movement has been observed in the region with greater sea ice all year. The researchers tracked the polar bear genes and found they were moving towards North. Based on climate change, researchers discovered that the Arctic Archipelago has more sea ice than other areas. Peacock stated: “By studying the genetic makeup of Polar Bears, we are able to estimate the levels and directions gene flow which represent the past stories of mating, movement and expansion of the population, as well as the future story of migration and contraction.” Dr. Peacock believes that the polar bear’s recent move northward is an entirely new phenomenon. Polar Bear Specialist Group Image. The researchers found that the females of polar bears are more tightly bound to their birth regions than the males. It is difficult to track male polar bears because of their longer necks than their heads. This makes it more difficult for them to be collared. The study confirmed that today’s polar bears are the result of one or more hybridizations with brown bears. In the most recent study, there was no evidence that polar bears are currently hybridizing with brown bears. Scientists believe the hybrid bears observed in Canada’s Northern Beaufort Sea are the result of an unusual and localized event. The availability of sea ice year round is decreasing due to global warming. Image: USGS Alaska Science Center. The research also showed that polar bear population growth was greater in areas with less ice than it was for brown bears. It was reversed for periods of less ice. This study was conducted by the USGS, the Government of Nunavut, which is the largest and most northern territory of Canada, and scientists from institutions that represent all five countries where polar bears are found (Russia, Norway Greenland Canada, the USA, and Canada). Citation: “Implications from the Circumpolar Gene Structure of Polar Bears For Their Conservation in A Rapidly Warming Arctic,” Peacock E. Sonsthagen SA. Obbard ME. Boltunov A. Regehr EV. et al. PLoS One: e 112021. doi: 10.1371/journal.pone. 0112021.
