Seabird assemblages observed during the BROKE-West survey of the Antarctic coastline (30-80 E), January-March 2006

Seabird surveys in January - March 2006 of a poorly known area of the Southern Ocean adjacent to the East Antarctic coast identified six seabird communities, several of which were comparable to seabird communities identified both in adjacent sectors of the Antarctic, and elsewhere in the Southern Ocean. These results support previous proposals that the Southern Ocean seabird community is characterised by an ice-associated assemblage and an open-water assemblage, with the species composition of the assemblages reflecting local (Antarctic-resident) breeding species, and the migratory routes and feeding areas of distant-breeding taxa, respectively. Physical environmental covariates such as sea-ice cover, distance to continental shelf and time of year influenced the distribution and abundance of seabirds observed, but the roles of these factors in the observed spatial and temporal patterns in seabird assemblages was confounded by the duration of the survey. Occurrence of a number of seabird taxa exhibited significant correlations with krill densities at one or two spatial scales, but only three taxa (Arctic tern, snow petrel and dark shearwaters, i.e. sooty and short-tailed shearwaters) showed significant correlations at a range of spatial scales. Dark shearwater abundances showed correlations with krill densities across the range of spatial scales examined.

This work was conducted on the BROKE-West voyage of the Aurora Australis.

2006年1月至3月，针对东南极海岸附近鲜为人知的南大洋海域开展的海鸟调查，共识别出6个海鸟群落，其中多个群落与南极相邻海域及南大洋其他区域已发现的海鸟群落具有可比性。本研究结果佐证了此前的学术观点：南大洋海鸟群落以海冰关联集合群与开阔水域集合群为典型特征，两类群的物种组成分别反映了本地（南极定居型）繁殖物种，以及远距离繁殖类群的迁徙路径与觅食区域。海冰覆盖度、距大陆架距离以及调查时段等物理环境协变量，会对观测到的海鸟分布与种群丰度产生影响，但受本次调查持续时长的限制，上述因素在海鸟集合群观测到的时空分布格局中所发挥的具体作用难以明确厘清。多个海鸟类群的出现频次在1至2个空间尺度上与磷虾密度呈现显著相关性，但仅有3个类群（北极燕鸥（Arctic tern）、雪鹱（snow petrel）以及深色鹱类，即乌鹱（sooty shearwater）与短尾鹱（short-tailed shearwater））在多个空间尺度上均表现出显著相关性。其中，深色鹱的种群丰度在本次检测的全部空间尺度范围内均与磷虾密度呈显著相关。本研究依托“极光号（Aurora Australis）”科考船的BROKE-West航次开展完成。