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首页> 外文期刊>Marine biology >Pronounced long-term trends in year-round diet composition of the European shag Phalacrocorax aristotelis
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Pronounced long-term trends in year-round diet composition of the European shag Phalacrocorax aristotelis

机译：欧洲粗毛alaaristotelis全年饮食组成的明显长期趋势

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摘要

Populations of marine top predators are exhibiting pronounced demographic changes due to alterations in prey availability and quality. Changes in diet composition is a key potential mechanism whereby alterations in prey availability can affect predator demography. Studies of long-term trends in diet have focused on the breeding season. However, long-term changes in non-breeding season diet is an important knowledge gap, since this is generally the most critical period of the year for the demography of marine top predators. In this study, we analysed 495,239 otoliths from 5888 regurgitated pellets collected throughout the annual cycle over three decades (1985-2014) from European shags Phalacrocorax aristotelis on the Isle of May, Scotland (56 degrees 11'N, 02 degrees 33'W). We identified dramatic reductions in the frequency of lesser sandeel Ammodytes marinus occurrence over the study, which was more pronounced during the non-breeding period (96% in 1988 to 45% in 2014), than the breeding period (91-67%). The relative numerical abundance of sandeel per pellet also reduced markedly (100-13%of all otoliths), with similar trends apparent during breeding and non-breeding periods. In contrast, the frequencies of Gadidae, Cottidae, Pleuronectidae and Gobiidae all increased, resulting in a doubling in annual prey richness from 6 prey types per year in 1988 to 12 in 2014. Our study demonstrates that the declining importance of the previously most prominent prey and marked increase in diet diversity is apparent throughout the annual cycle, suggesting that substantial temporal changes in prey populations have occurred, which may have important implications for seabird population dynamics.
机译：由于猎物可用性和质量的变化，海洋顶级捕食者的种群显示出明显的人口变化。饮食组成的变化是关键的潜在机制，由此猎物可利用性的改变会影响捕食者的人口统计学。饮食长期趋势的研究集中在繁殖季节。但是，非繁殖季节饮食的长期变化是一个重要的知识鸿沟，因为这通常是一年中最重要的海洋捕食者人口统计的时期。在这项研究中，我们分析了在整个三十年（1985-2014年）的整个年度周期中，从五月岛（苏格兰）（56度11'N，02度33'W）的欧洲粗毛Ph（Phalacrocorax aristotelis）收集的5888份反潮颗粒中的495,239耳石。 。我们发现，在整个研究过程中，较少的沙门菌沙门菌发生频率显着降低，在非繁殖期（1988年为96％，2014年为45％）比繁殖期（91-67％）更为明显。每个颗粒中的沙e的相对数量丰度也显着降低（占所有耳石的100-13％），在育种和非育种期间也有相似的趋势。相比之下，C科，科达科，leu科和Go科的频率都增加了，导致年猎物丰富度从1988年的每年6种增加到2014年的12种。我们的研究表明，以前最著名的猎物的重要性下降了。整个年度周期中饮食多样性明显增加，这表明猎物种群发生了较大的时间变化，这可能对海鸟种群动态产生重要影响。

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