Change in Abundance of Pacific Brant Wintering in Alaska: Evidence of a Climate Warming Effect?
Change in Abundance of Pacific Brant Wintering in Alaska: Evidence of a Climate Warming Effect?
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阿拉斯加越冬的太平洋布兰特丰度变化：气候变暖效应的证据？
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Hines
中科院分区：
文献类型：
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作者：
D. Ward;C. P. Dau;T. Tibbitts;J. S. Sedinger;B. A. Anderson;J. Hines
在过去 42 年里，太平洋迁徙布兰特 (Brantabernicla nigricans) 的冬季分布已从低温带地区向北转移到亚北极地区。我们评估了阿拉斯加冬季布兰特的丰度和分布，以评估气候变暖是否可能导致最北部越冬种群的积极趋势。 1963 年至 2004 年间，阿拉斯加半岛末端冬季平均地表气温上升了约 1°C，导致冰冻天数减少了 23%，冰盖阻止鸟类获取食物资源的天数减少了 34%。越冬种群的趋势随着太平洋年代际振荡的状态而波动，在正（暖）阶段增加，在负（冷）阶段减少，这种相关性为阿拉斯加越冬鲽鱼种群的增长与气候变暖有关的假设提供了支持。越冬种群的规模与11月份强西北风的天数呈负相关，这表明入冬前是否出现有利于迁徙的顺风是白兰特从阿拉斯加迁徙还是在阿拉斯加过冬的关键因素。阿拉斯加半岛冬季的布兰特分布变化很大，并受到冰盖的影响，特别是在使用频繁的伊泽贝克泻湖。对先前标记的布兰特的观察表明，阿拉斯加的越冬种群主要由来自北极繁殖地的鸟类组成，这些鸟类似乎正在生长。随着气候变暖导致高纬度地区气温上升和冰盖减少，阿拉斯加冬季的布兰特数量可能会增加。
Winter distribution of Pacific Flyway brant ( Branta bernicla nigricans ) has shifted northward from low-temperate areas to sub-Arctic areas over the last 42 years. We assessed the winter abundance and distribution of brant in Alaska to evaluate whether climate warming may be contributing to positive trends in the most northern of the wintering populations. Mean surface air temperatures during winter at the end of the Alaska Peninsula increased about 1°C between 1963 and 2004, resulting in a 23% reduction in freezing degree days and a 34% decline in the number of days when ice cover prevents birds from accessing food resources. Trends in the wintering population fluctuated with states of the Pacific Decadal Oscillation, increasing during positive (warm) phases and decreasing during negative (cold) phases, and this correlation provides support for the hypothesis that growth in the wintering population of brant in Alaska is linked to climate warming. The size of the wintering population was negatively correlated with the number of days of strong northwesterly winds in November, which suggests that the occurrence of tailwinds favorable for migration before the onset of winter was a key factor in whether brant migrated from Alaska or remained there during winter. Winter distribution of brant on the Alaska Peninsula was highly variable and influenced by ice cover, particularly at the heavily used Izembek Lagoon. Observations of previously marked brant indicated that the Alaska wintering population was composed primarily of birds originating from Arctic breeding colonies that appear to be growing. Numbers of brant in Alaska during winter will likely increase as temperatures rise and ice cover decreases at high latitudes in response to climate warming.