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首页> 外文期刊>Marine ecology progress series >Long-term changes in the breeding seasonally of Peruvian seabirds and regime shifts in the Northern Humboldt Current System
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Long-term changes in the breeding seasonally of Peruvian seabirds and regime shifts in the Northern Humboldt Current System

机译：秘鲁海鸟繁殖季节的长期变化和北部洪堡洋流系统的政权转移

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摘要

In the highly productive Northern Humboldt Current System, 3 seabird species, the Guanay cormorant Phalacrocorax bougainvillii, the Peruvian booby Sula variegata and the Peruvian pelican Pelecanus thagus, commence breeding in austral spring, coinciding with the lowest availability of their prey, the Peruvian anchovy Engraulis ringens. This strategy ensures the matching of increased prey availability when young achieve independence in summer. This pattern was observed during the last decade when anchovy was abundant. However, over the last century, the abundance of anchovy has varied widely due to contrasting interdecadal regimes in oceanographic conditions and fishing activity. We hypothesized that these regime shifts affected the abundance and availability of prey and may have conditioned the breeding seasonality of seabirds. We examined the timing and magnitude of the onset of breeding using dynamic occupancy models and related these parameters to the seasonality of oceanographic conditions, abundance of anchovy and fishing pressure. During a regime of lower anchovy abundance (1977-1990), cormorants showed the highest flexibility, adjusting the timing of breeding from spring to winter and skipping reproduction in the worst conditions. Boobies showed the lowest flexibility, maintaining the same magnitude and timing of onset of breeding in spring. Pelicans showed intermediate flexibility, foregoing breeding during the worst conditions, but maintaining the onset of breeding in spring. The 3 species used sea surface temperature as a cue for the initiation of breeding. Furthermore, given their better diving abilities, cormorants could monitor prey availability changes associated with the reversion in the seasonality of the oxycline depth.
机译：在高产的北部洪堡洋流系统中，关押cor的，鸟，ay子uga，秘鲁鸟苏拉variegata和秘鲁鹈鹕Pelecanus thagus等3种海鸟开始在南方春季繁殖，这与其猎物的可利用性最低-秘鲁an鱼Engraulis有关铃声。这种策略可确保年轻人在夏天获得独立时增加猎物的利用率。在过去的十年中，当凤尾鱼丰富时观察到了这种模式。然而，在上个世纪，由于在海洋学条件和捕捞活动中年代际制度的对比，of鱼的丰度变化很大。我们假设这些制度的转变影响了猎物的数量和可用性，并可能调节了海鸟的繁殖季节。我们使用动态占用模型检查了繁殖开始的时间和幅度，并将这些参数与海洋条件的季节性、,鱼的丰度和捕鱼压力相关。在较低的cho鱼丰度时期（1977年至1990年），showed表现出最高的灵活性，调整了春季至冬季的繁殖时间，并在最恶劣的条件下跳过繁殖。鸟显示出最低的柔韧性，在春季繁殖时保持相同的数量和时间。鹈鹕表现出中等的柔韧性，可以在最恶劣的条件下繁殖，但在春季仍保持繁殖的开始。这3个物种利用海面温度作为开始繁殖的线索。此外，鉴于their潜水员具有更好的潜水能力，他们可以监测与土霉素深度季节性变化相关的猎物可利用性变化。

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