Resource partitioning within a tropical seabird community:: new information from stable isotopes
Resource partitioning within a tropical seabird community:: new information from stable isotopes
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DOI：
10.3354/meps07587
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发表时间：
2008-01-01
影响因子：
2.5
通讯作者：
Weimerskirch, H.
中科院分区：
文献类型：
--
作者：
Cherel, Y.;Le Corre, M.;Weimerskirch, H.
与温带和极地物种相比，热带海洋环境的特点（生产力低，季节性小）和热带海鸟觅食方式和猎物的多样性差表明，热带海鸟总体上包含一个狭窄的同位素生态位范围，物种之间有很大的重叠。为了验证这一假设，我们检测了莫桑比克海峡欧罗巴岛5种海鸟血液和羽毛的稳定碳（δ C-13）和氮（δ N-15）同位素组成。血δ C-13和δ N-15值在繁殖期间具有5个不同且不重叠的营养生态位，但差异不大。海鸟有两个不同的觅食区域（δ C-13），一个由黑燕鸥Sterna fuscata和白尾热带鸟Phaethon lepturus使用，另一个由红脚鲣鸟Sula Sula和大Fregata minor和较小的fariel frigatebird使用。海鸟种类总体上包含不到1个营养级（δ N-15），这与主要以飞鱼和鱿鱼为食的饮食一致。羽毛δ C-13和δ N-15值表明，在繁殖期和非繁殖期（换羽期），群落的营养结构不同，表明成鸟不再是中心觅食者时，摄食生态发生了变化。稳定同位素方法强调了性别相关（红足鲣鸟）和年龄相关（大军舰鸟的幼鸟和成年鸟）的喂养策略。该研究还表明，繁殖中的成年鸟可以用不同的猎物来喂养自己，而不是喂给雏鸟（黑燕鸥）。在热带远洋生态系统中，海鸟总体上与大型掠食性鱼类（长鳍金枪鱼、黄鳍金枪鱼和鲣鱼）具有相同的营养水平，但它们的δ N-15值低于深海大眼金枪鱼和旗鱼。我们的结论是，分析血液和羽毛中的稳定同位素值似乎是研究热带海鸟全年食物和摄食生态以及确定其觅食策略的性别和年龄相关差异的有前途的替代方法。该方法的一个局限性是缺乏海洋等温线的资料；未来旨在同位素特征化热带海洋环境的研究可以帮助将消费者签名与地理来源联系起来。
Characteristics of the tropical oceanic environment (low productivity, little seasonality) and poor diversity of tropical seabird foraging methods and prey relative to temperate and polar species suggest that tropical seabirds overall encompass a narrow range of isotopic niches, with large overlaps among species. To test this hypothesis, we examined the stable carbon (delta C-13) and nitrogen (delta N-15) isotopic composition of blood and feathers of 5 seabird species from Europa Island, Mozambique Channel. While differences were small, blood delta C-13 and delta N-15 values characterized 5 distinct and non-overlapping trophic niches during the breeding period. Seabirds used 2 distinct foraging areas (delta C-13), one used by sooty tern Sterna fuscata and white-tailed tropicbird Phaethon lepturus and one used by red-footed booby Sula sula and great Fregata minor and lesser F ariel frigatebirds. Seabird species overall encompassed less than 1 trophic level (delta N-15), which is in agreement with a diet mainly based on flying fish and squid. Feather delta C-13 and delta N-15 values showed that the trophic structure of the community was different during the breeding and non-breeding (moulting) periods, suggesting a shift in the feeding ecology when adult birds were no longer central-place foragers. The stable isotope method underlined sex-related (red-footed booby) and age-related (great frigatebird immatures and adults) feeding strategies. It also suggested that breeding adults could feed themselves on different prey than those given to their chicks (sooty tern). Within the tropical pelagic ecosystem, seabirds overall shared the same trophic level as large predatory fishes (albacore, yellowfin and skipjack tunas), but they had lower delta N-15 values than the deeper-dwelling bigeye tuna and swordfish. We conclude that analyzing stable isotope values in blood and feathers appears to be a promising alternative method for investigating food and feeding ecology of tropical seabirds year round, and for determining sex- and age-related differences in their foraging strategies. A limitation of the method is the lack of information on marine isoscapes; future studies aimed at isotopically characterizing the tropical marine environment could help to associate consumer signatures to geographic origins.