摘要
北极熊是北极最重要的哺乳动物之一,近年来数量却在减少。海冰作为北极熊狩猎、活动和繁殖的平台,是其栖息地的重要组成部分。因此其种群栖息地变化主要依赖于海冰变化。本文基于美国雪冰中心的海冰密集度和NOAA提供的ETOPO1基岩数据,分析了北极海冰密集度、开阔水域面积、海冰消退时间、海冰出现时间、开阔水域季节长度的年际变化,进而评价北极熊栖息地的稳定性。结果表明,海冰密集度呈现降低的趋势,开阔水域面积增大,多年冰数量减少,大多变为一年冰。海冰消退时间提前,海冰出现时间延后,开阔水域季节长度大幅增加,与1992年相比增加了72 d。19个栖息地中,巴伦支海是开阔水域面积和季节长度变化贡献最大的海域,增加速度分别为9.71×103km2/a和71.69 d/10a。以开阔水域季节长度变化率为依据,将北极熊栖息地划分为稳定、次稳定和不稳定3个等级。总共有3个稳定栖息地,包括分布在相对其他栖息地而言纬度较低的楚科奇海、西哈得孙湾和南哈得孙湾。13个次稳定栖息地,包括拉普捷夫海、喀拉海、东格陵兰、巴芬湾、戴维斯海峡、福克斯湾、布西亚湾、麦克林托克海峡、梅尔维尔子爵海峡、挪威湾、北波弗特、南波弗特和兰开斯特海峡。3个不稳定栖息地,均位于70°N以北,包括北极盆地、巴伦支海和凯恩盆地。稳定区主要位于低纬度,不稳定区全部位于高纬度。该分级结果表明高纬度地区虽然海冰覆盖多,但是年际变化十分显著,不稳定的3个区域内北极熊对海冰变化适应时间更少,年际迁移变化大,对北极熊的生存发展更为不利。
Polar bear is one of the most important mammals in the Arctic, but its number decreased in recent years. Polar bears are sensitive to changes of the sea ice distribution and depend on sea ice as a platform for hunting, moving and reproducing. In other words, sea ice is an important part of polar bear habitat. Climate is the main factor of sea ice changes. Therefore, it is very important to understand the current situation of polar bears as well as the effect of climate on the Arctic ecosystem. Although many researchers have devoted to find polar bears habitat using aerial survey in recent years, their methods require considerable human involvement and cannot be used to detect all habitats rapidly and effectively. Thus, it is necessary to find a method to quickly assess the polar bear habitat changes. Based on the sea ice concentration products from the United States National Snow and Ice Data Center （NSIDC） and the ETOPO1 bedrock product provided by the NOAA, the inter-annual variability of sea ice concentration, open water area, sea ice retreat, sea ice advance and the length of the open water season in the Arctic were analyzed. Then, the polar bear habitat stability were analized. The results indicate that from 1989 to 2016 the sea ice concentration has decreased, open water area increased and multiyear ice decreased. Most of the multiyear ice has converted to one-year ice. The sea ice appeared later and retreated earlier, so the length of the open water season increased significantly, an increase of 72 days compared to 1992. Barents Sea is the region with the most significant changes in open water area and the length of open water season among 19 habitats, with increasing rates of 9.71×103 km2/a and 71.69 days/decade, respectively. Based on the change rates of the length of the open water season, we divide the polar bears habitats into three levels of conditions： stable, sub-stable and instable. The three stable habitats, including the Chukchi sea, Western Hudson Bay and Southern Hudson Bay are located
作者
李海丽
柯长青
LI Haili;KE Changqing(School of Geographic and Oceanographic Sciences,Nanjing University,Nanjing 210023 China)
出处
《地球信息科学学报》
CSCD
北大核心
2018年第9期1327-1337,共11页
Journal of Geo-information Science
基金
国家重点研发计划项目(2018YFC1407203)~~
