基于CMIP6气候变化情景下南极小须鲸(Balaenoptera bonaerensis)在宇航员海栖息地变化分析

南极小须鲸(Balaenopterabonaerensis)作为顶级捕食者,在南大洋生态系统中起着重要调节作用。目前对南极小须鲸的研究大多集中在捕食和季节性迁移上,在栖息地分布以及气候变化对栖息地影响方面研究亟待补充。基于MaxEnt模型和CMIP6的数据,分析了当前情形以及不同排放情景下,到21世纪中期和21世纪末期宇航员海南极小须鲸栖息地的分布和变化。研究结果表明,南极小须鲸主要分布在宇航员海的东部,当前的高度适生区占整个区域的13.96%。深度、海冰密集度和混合层深度最小值是南极小须鲸分布的主要影响因子,三者的累积贡献为60.5%。气候变化情景下南极小须鲸栖息地呈现缩小的趋势。高排放情景下南极小须鲸的栖息地面积减小更快,从21世纪中期到末期这个时期南极小须鲸的栖息地面积减小速率比从当前到21世纪中期快。到本世纪中期,所有情景下的宇航员海东部仍存在南极小须鲸的栖息地;到本世纪末,中排放情景和高排放情景下的宇航员海已不适合南极小须鲸生存,海冰密集度的减小是造成这一现象的主要原因。

HABITAT CHANGES OF ANTARCTIC MINKE WHALE (BALAENOPTERA BONAERENSIS) IN THE COSMONAUT SEA UNDER CMIP6 CLIMATE CHANGE SCENARIOS

As an apex predator, the Antarctic minke whale (AMW) regulates the Southern Ocean ecology. The majority of present study focuses on AMW concentrates on feeding and seasonal migration, and good understanding on habitat distribution and the influence of climate change on habitat is strongly demanded. Based on the MaxEnt (maximum entropy) model and the CMIP6 (Coupled Model Intercomparison Project in the sixth phase) data for the near future and far future, suitable habitat of AMWs at present and in the future was evaluated. Results show that, the suitable habitat concentrated in the eastern Cosmonaut Sea, in which the highly suitable area accounts for 13.96% of the total area. The most important environmental variables affecting the distribution of AMWs are depth, ice concentration, and mixed layer minimum thickness, and their combined contribution reached 60.5%. Under the three climate change scenarios in CMIP6, the habitat of AMWs will decline. Under the higher emission scenario, the suitable area of AMWs would fall more quickly, and the suitable area of AMWs would drop at a higher pace between the mid 21st century and the last 21st century than between the present and the mid 21st century. In all the scenarios, AMW habitats would stay available in the eastern half of the Cosmonaut Sea in the mid 21st century; but in the last 21st century in the medium and high emission scenarios, the Cosmonaut Sea would be no longer appropriate for AMW survival. This phenomenon is mostly caused by the reduction in sea ice concentration.