Individual specialization in the foraging and feeding strategies of seabirds: a review
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Trophic relationships are a central theme in ecology and play a crucial role in the survival of organisms, because the availability of food resources varies over time and space. Until recently, most ecological studies treated conspecific individuals as ecologically equivalent, but intra-specific variation in individual foraging and feeding strategies can be large. Studies documenting the occurrence of individual specialization in seabirds (n = 94) increased substantially since the year 2000, and rapid and significant advances are being made since then. This review summarizes existing knowledge within this subject, examines the relative incidence of individual specialization and investigates the possible ecological implications of individual specialization in seabirds. Our results show that, to date, the incidence of individual specialization is documented in around 12 % of the total extant seabird species although some studies (n = 12) did not find evidences of individual specialization in the foraging and feeding strategies of some seabird populations. Most studies were conducted at higher latitudes, leading to a lack of knowledge on the incidence of this trait in tropical seabird populations. Results suggest that the incidence of individual specialization may be potentially widespread within seabirds, but may fluctuate spatio-temporally among/within species and populations due to the frequency of specialists, predictability of resources or environmental conditions. This study supports the hypothesis that individual specialization may have important ecological consequences at both individual and population levels, such as implications in breeding performance or in intra-specific competition and, consequently, a high impact on ecological processes and foraging dynamics. Further investigation is required to identify the mechanisms that generate individual specialization and its ecological implications at both population and individual levels.
KeywordsStable Isotope Analysis Individual Specialization Ecological Implication Isotopic Niche Seabird Species
This research was cosponsored by the Foundation for Science and Technology (Portugal) and the European Social Fund (POPH, EU) through a postdoc grant to Filipe R. Ceia (SFRH/BPD/95372/2013). We are grateful to Stefan Garthe, Vitor Paiva, João C. Marques and José Xavier for discussion and insight on early draft of this manuscript which greatly improved this review. Comments and suggestions by Kyle Elliott, Thomas Bodey and one anonymous reviewer improved the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Human rights and animal standards
This article does not contain any studies with human participants or animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.
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