Predation by great skuas at a large Shetland seabird colony
Predation by great skuas at a large Shetland seabird colony
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大贼鸥在大型设得兰群岛海鸟栖息地进行捕食
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
R. Furness
中科院分区：
文献类型：
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作者：
S. Votier;S. Bearhop;N. Ratcliffe;R. Phillips;R. Furness
摘要1.贼鸥是海洋生态系统中的顶级掠食者，可能对它们捕食的海鸟群落产生有害影响。然而，人们对捕食率知之甚少，也难以量化。使用生物能量学模型，我们估计海鸟捕食的大贼鸥，Stercorarius贼鸥，在英国的一个大殖民地（Hermaness，设得兰群岛）。我们调查的影响，饮食专业化和渔业管理的捕食和探索的专业鸟类捕食者的实验性删除的效果。2.赫马内斯大贼鸥在两个繁殖季节中，每个季节需要491·5 × 106 kJ和546·6 × 106 kJ的能量。繁殖贼鸥分为两组：一小部分（5%）的专业鸟类捕食者或绝大多数（95%）的机会性喂养鸟类或专门的渔业丢弃物。在1999年，贼鸥消耗了80 000公斤的鱼，2001年增加到90 000公斤以上。每年约有13000只海鸟被贼鸥吃掉，其中26 - 29%被专业鸟类捕食者吃掉。3.虽然很难评估，但大贼鸥似乎对海鸟种群产生了负面影响。改变模型的输入，以测试不同的情况下，渔业丢弃物的减少将导致增加海鸟捕食率。然而，在研究期间拟议的渔业管理改革并没有减少丢弃率，反而增加了。4.合成与应用。生物能量学模型的使用表明，大贼鸥捕食可能会对海鸟种群产生负面影响。渔业丢弃物的可获得性是影响海鸟捕食率的一个重要因素，但短期内可能难以预测渔业管理变化的影响。专业的鸟类捕食者消耗大量的海鸟猎物，但这在种群水平上不太重要。虽然实验性地去除专门的鸟类捕食者可能会以最小的损失减少贼鸥的捕食，但尚不清楚同种是否会取代它们并保持高捕食率。
Summary 1. Skuas are top predators in marine ecosystems and may have detrimental effects on seabird communities they prey upon. However, predation rates are poorly understood and poorly quantified. Using a bio-energetics model we estimate seabird predation by great skuas, Stercorarius skua , at a large UK colony (Hermaness, Shetland). We investigate the influence of dietary specialization and fishery management on predation and explore the effect of experimental removal of specialist bird predators. 2. Great skuas at Hermaness required 491·5 × 10 6 kJ and 546·6 × 10 6 kJ of energy in each of two breeding seasons. Breeding skuas fell into one of two groups: a small proportion (5%) of specialist bird predators or the vast majority (95%) that fed opportunistically on birds or specialized on fishery discards. During 1999, great skuas consumed ≈ 80 000 kg of fish, which increased to over 90 000 kg in 2001. About 13 000 seabirds were consumed by great skuas each year, with 26‐29% being consumed by specialist bird predators. 3. Although it is difficult to assess, great skuas appear to be having a negative impact on seabird populations. Altering model inputs to test differing scenarios revealed that reductions in fishery discards would result in increased seabird predation rates. However, proposed changes in fishery management over the period of the study did not reduce discarding rates, which instead increased. 4. Synthesis and applications . The use of a bioenergetics model reveals that great skua predation may negatively affect seabird populations. Availability of fishery discards is an important factor influencing seabird predation rates, but predicting the effect of changes in fishery management may be difficult in the short term. Specialist bird predators consume large quantities of seabird prey, but this is less significant at the population level. Although experimental removal of specialist bird predators may reduce predation at a minimal loss of skuas, it is unclear whether conspecifics may replace them and retain high rates of predation.