White gulls dependent on ice are disappearing from the Arctic

 作者:詹军     |      日期:2019-03-05 03:14:05
Ole Jorgen Liodden/NaturePL AS ARCTIC sea ice dwindles, a gull that depends on it for finding food is disappearing from the ocean around Greenland. Ivory gulls range throughout the Arctic, living on or near pack ice in the far north. The Canadian population is known to be in steep decline: numbers in the early 2000s were about 80 per cent lower than in the 1980s. To find out whether the gulls living near the Greenland Sea are also declining, Claude Joiris of the Royal Belgian Institute of Natural Sciences in Brussels examined data he collected aboard an icebreaker travelling between Greenland and Svalbard between 1988 and 2014. Joiris found a sevenfold fall in the ivory gull number after 2007. But it’s not clear what caused that “drastic decrease” (Polar Biology, doi.org/bqfr). Of all the Arctic seabirds, ivory gulls are most closely associated with sea ice, says Nina Karnovsky at Pomona College in Claremont, California. That makes them particularly vulnerable to its loss. If ice doesn’t form near where they’re breeding, for example, they might not be able to feed their chicks. Tracking survival and migration patterns could help researchers figure out what’s going on before it’s too late, says Kyle Elliott at McGill University in Montreal,