Using stable isotopes of nitrogen and carbon to study seabird ecology: applications in the Mediterranean seabird community

The application of the stable isotope technique to ecological studies is becoming increasingly widespread. In the case of seabirds. stable isotopes of nitrogen and carbon have been mainly used as dietary tracers. This approach relies on the fact that foodweb isotopic signatures are reflected in the tissues of the consumer. In addition to the study of trophic ecology. stable isotopes have been used to track the movement of seabirds across isotopic gradients, as individuals moving between isotopically distinct foodwebs can carry with them information on the location of previous feeding areas. Studies applying the stable isotope methodology to the study of seabird ecology show a clear evolution from broad and descriptive approaches to detailed and individual-based analyses. The purpose of this article is to show the different fields of application of stable isotopes to the study of the seabird ecology. Finally, we illustrate the utility of this technique by considering the particularities of the Mediterranean seabird community, suggesting different ecological questions and conservation problems that could be addressed by using the stable isotope approach in this community.