Comparison of assemblages and some life-history traits of seabirds in the Humboldt and Benguela systems
Comparison of assemblages and some life-history traits of seabirds in the Humboldt and Benguela systems
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DOI：
10.2989/18142320609504205
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发表时间：
2006-11-01
影响因子：
1.2
通讯作者：
Zavalaga, C. B.
中科院分区：
文献类型：
--
作者：
Crawford, R. J. M.;Goya, E.;Zavalaga, C. B.
分别有 21 种和 15 种海鸟在洪堡和本格拉上升流系统中繁殖。这两个系统中只有两种海鸥是常见的，其中一种是本格拉系统的特有亚种。十一个物种和两个亚种是洪堡系统特有的（或接近特有的）；本格拉系统有七个物种和一个亚种。每个系统都有特有的企鹅、苏利德企鹅、鸬鹚和燕鸥，主要以鳀鱼 Engraulis spp.、沙丁鱼 Sardinops sagax 或这两种鱼为食。秘鲁鹈鹕 Pelecanus thagus 也主要以这些猎物为食。充足的食物供应导致许多海鸟的数量达到了很高的水平。对于以凤尾鱼和沙丁鱼为食的四对物种来说，洪堡系统中的物种都具有使它们比本格拉物种增长得更快的生物学特性。这反映了洪堡系统中抑制海鸟种群的环境扰动频率较高。此外，这两个系统都有一种在海岸附近进食的小型特有鸬鹚和一种在邻近大陆沙漠繁殖并在海面进食的小型特有燕鸥。一个系统特有的几种海鸟在另一个系统中没有明显的生态等同物：洪堡系统中的鹈鹕、潜水海燕、四只风暴海燕和一只海鸥；本格拉系统中的一只鸬鹚和一只海鸥。一些具有热带或亚南极亲缘关系的物种在系统的边界繁殖。其他的也在淡水系统中繁殖。在洪堡系统中捕食的灰鸥 Larusmodeus 在山地沙漠中繁殖。
There are 21 and 15 species of seabirds that breed in the Humboldt and Benguela upwelling systems respectively. Only two species of gull are common to both systems, one as an endemic subspecies to the Benguela system. Eleven species and two subspecies are endemic (or nearly so) to the Humboldt system; seven species and one subspecies to the Benguela system. Each system has an endemic penguin, sulid, cormorant and tern that feed mainly on anchovy Engraulis spp., sardine Sardinops sagax or both these fish. The Peruvian pelican Pelecanus thagus also feeds primarily on these prey items. A plentiful availability of food has resulted in many of these seabirds attaining high levels of abundance. For the four pairs of species that feed on anchovy and sardine, those in the Humboldt system all have a biology that enables them to increase more rapidly than their Benguela counterparts. This reflects the higher frequency of environmental perturbations that depress seabird populations in the Humboldt system. In addition, both systems have a small endemic cormorant that feeds near the coast and a small endemic tern that breeds in the adjacent mainland desert and feeds at the sea surface. Several seabirds endemic to a system have no obvious ecological equivalent in the other system: the pelican, a diving petrel, four storm-petrels and a gull in the Humboldt system; a cormorant and a gull in the Benguela system. Some species with tropical or subantarctic affinities breed at the boundaries of the systems. Others breed also in freshwater systems. The grey gull Larus modestus, which feeds in the Humboldt system, breeds in montane deserts.