Effects of variability in prey abundance on reproduction and foraging in chinstrap penguins (Pygoscelis antarctica)
Effects of variability in prey abundance on reproduction and foraging in chinstrap penguins (Pygoscelis antarctica)
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DOI：
10.1111/j.1469-7998.2006.00090.x
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发表时间：
2006-08-01
影响因子：
2
通讯作者：
Tershy, B. R.
中科院分区：
文献类型：
--
作者：
Croll, D. A.;Demer, D. A.;Tershy, B. R.
生活史理论预测，海鸟等长寿物种的成年动物应该最佳平衡对当前和未来后代的投资。然而，当试图优化对后代供应的投资时，海鸟亲代照顾中最耗费精力的部分，成年海鸟需要应对猎物可用性的巨大年际波动，从而应对雏鸟供应的成本。面临这种不确定性的成年人可以通过在多年来保持对觅食努力的持续投资和让雏鸡供给波动或保持雏鸡供给恒定和不同的觅食努力投资之间的连续体中的某个策略来机械地平衡父母的照顾。利用船载猎物水声评估、企鹅身上附有的时间深度记录仪以及繁殖群的陆基观测，我们研究了 1990-1992 年南设得兰群岛海豹岛附近南极磷虾南极磷虾丰度的年际变化如何影响南极帽带企鹅繁殖过程中的觅食和繁殖努力。磷虾密度的区域测量值相差 2.5 倍（1990 年、1991 年和 1992 年分别为 47.0、23.8 和 61.2 g·m(-2)），并且与繁殖成体体重和繁殖性能（繁殖群体规模、雏鸡饲养持续时间、雏鸡生长、繁殖成功率和雏鸟体重）的年度测量值相关。相比之下，企鹅觅食努力的测量（潜水深度、潜水持续时间、每天的旅行次数（-1）、旅行持续时间、潜水旅行次数（-1）和潜水率）在年份之间没有差异。我们得出的结论是，帽带企鹅会减少繁殖成功率，而不是增加觅食努力以应对猎物丰度的减少，其方式与长寿海鸟生活史策略的预测一致。
Life-history theory predicts that adults of long-lived species such as seabirds should optimally balance investment in current and future offspring. However, when trying to optimize investment in offspring provisioning, the most energetically costly component of seabird parental care, adults need to contend with large interannual fluctuations in prey availability and hence the cost of chick provisioning. Adults faced with this uncertainty can mechanistically balance parental care by adopting a strategy somewhere along the continuum between maintaining constant investment in foraging effort between years and letting chick provisioning fluctuate or holding chick provisioning constant and varying investment in foraging effort. Using ship-based hydroacoustic assessment of prey, time-depth recorders attached to penguins and land-based observations at the breeding colony, we examined how foraging and reproductive effort in breeding chinstrap penguins Pygoscelis antarctica responded to interannual variation in the abundance of Antarctic krill Euphausia superba in the vicinity of Seal Island, South Shetland Islands, 1990-1992. Regional measures of krill density varied by a factor of 2.5 (47.0, 23.8 and 61.2 g m(-2) in 1990, 1991 and 1992, respectively) and was correlated with annual measures of breeding adult body weight and reproductive performance (breeding population size, duration of chick rearing, chick growth, breeding success and fledgling weight). In contrast, measures of penguin foraging effort (dive depth, dive duration, number of trips day(-1), trip duration, number of dives trip(-1) and dive rate) did not differ between years. We conclude that chinstrap penguins reduce reproductive success rather than increase foraging effort in response to decreases in prey abundance in a manner consistent with predictions of life-history strategies for long-lived seabirds.