Stable isotopes indicate sex-specific and long-term individual foraging specialisation in diving seabirds

被引:228
作者
Bearhop, Stuart
Phillips, Richard A.
McGill, Rona
Cherel, Yves
Dawson, Deborah A.
Croxall, John P.
机构
[1] Queens Univ Belfast, Sch Biol & Biochem, MBC, Belfast BT9 7BL, Antrim, North Ireland
[2] British Antarctic Survey, NERC, Cambridge CB3 0ET, England
[3] Scottish Univ Res & Reactor Ctr, E Kilbride G75 0QF, Lanark, Scotland
[4] CNRS, CEBC, F-79360 Villiers en Bois, France
[5] Univ Sheffield, Dept Anim & Plant Sci, Sheffield Mol Genet Facil, Sheffield S10 2TN, S Yorkshire, England
基金
英国自然环境研究理事会;
关键词
penguin; shag; trophic level; delta C-13; delta N-15;
D O I
10.3354/meps311157
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
An important aspect of foraging ecology is the extent to which different individuals or genders within a population exploit food resources in a different manner. For diving seabirds, much of this information relates either to short-term dietary data or indirect measures such as time budgets. Moreover, dietary specialisation can be difficult to detect due to biases associated with conventional sampling techniques. We used stable isotope ratios in blood and feathers to infer trophic and habitat specialisations among 4 diving seabird taxa - the gentoo penguin Pygoscelis papua, the macaroni penguin Eudyptes chrysolophus, the South Georgian shag Phalacrocorax (atriceps) georgianus and the Kerguelen shag P. (atriceps) verrucosus. This allowed us to investigate foraging specialisation and assess whether social dominance or differences in foraging preferences explained the observed patterns. In all taxa where sexes were known we found that males foraged at a higher trophic level (delta N-15 values) than females, although this was not significant in macaroni penguins. We believe that this is linked to a dual foraging strategy among female macaroni penguins. For South Georgian shags, we found that sex-related dietary differences persisted for long periods (inferred from stable isotope analyses of feathers and blood). We suggest that the trophic differences are driven by differences in physiological performance, with males tending to dive deeper than females because of their larger size, and hence able to access higher trophic level prey items. Moreover, male and female shags tend to forage at different times of day; therefore, social dominance by males is unlikely to be driving the observed differences. We also recorded highly significant relationships between stable isotope signatures in blood (representing the breeding season diet) and those in feathers (mostly representing the previous non-breeding season diet) in both the South Georgian and Kerguelen shags. This strongly suggests that these 2 taxa include individuals with distinct foraging specialisation (and most probably foraging locations) that are maintained over long periods.
引用
收藏
页码:157 / 164
页数:8
相关论文
共 65 条
[1]  
Agnew DJ, 1995, PENGUINS: ECOLOGY AND MANAGEMENT, P299
[2]   Seasonal and interannual variation in foraging range and habitat of macaroni penguins Eudyptes chrysolophus at South Georgia [J].
Barlow, KE ;
Croxall, JP .
MARINE ECOLOGY PROGRESS SERIES, 2002, 232 :291-304
[3]   Variability in mercury concentrations of great skuas Catharacta skua:: the influence of colony, diet and trophic status inferred from stable isotope signatures [J].
Bearhop, S ;
Phillips, RA ;
Thompson, DR ;
Waldron, S ;
Furness, RW .
MARINE ECOLOGY PROGRESS SERIES, 2000, 195 :261-268
[4]   Factors that influence assimilation rates and fractionation of nitrogen and carbon stable isotopes in avian blood and feathers [J].
Bearhop, S ;
Waldron, S ;
Votier, SC ;
Furness, RW .
PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY, 2002, 75 (05) :451-458
[5]   SEXUALLY DISTINCT DAILY ACTIVITY PATTERNS OF BLUE-EYED SHAGS IN ANTARCTICA [J].
BERNSTEIN, NP ;
MAXSON, SJ .
CONDOR, 1984, 86 (02) :151-156
[6]   The diet of the South Georgia shag Phalacrocorax georgianus at South Orkney Islands in five consecutive years [J].
Casaux, R ;
Ramón, A .
POLAR BIOLOGY, 2002, 25 (08) :557-561
[7]   Sex differences in diving depths and diet of Antarctic Shags at the South Shetland Islands [J].
Casaux, R ;
Favero, M ;
Silva, P ;
Baroni, A .
JOURNAL OF FIELD ORNITHOLOGY, 2001, 72 (01) :22-29
[8]  
CATRY P, IN PRESS SEXUAL SEGR, P351
[9]   Using stable-isotope analysis of feathers to distinguish moulting and breeding origins of seabirds [J].
Cherel, Y ;
Hobson, KA ;
Weimerskirch, H .
OECOLOGIA, 2000, 122 (02) :155-162
[10]   Isotopic discrimination between food and blood and feathers of captive penguins: Implications for dietary studies in the wild [J].
Cherel, Y ;
Hobson, KA ;
Hassani, S .
PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY, 2005, 78 (01) :106-115