Seabird modulations of isotopic nitrogen on islands.

Autor: Stéphane Caut, Elena Angulo, Benoit Pisanu, Lise Ruffino, Lucie Faulquier, Olivier Lorvelec, Jean-Louis Chapuis, Michel Pascal, Eric Vidal, Franck Courchamp
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: PLoS ONE, Vol 7, Iss 6, p e39125 (2012)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0039125
Popis: The transport of nutrients by migratory animals across ecosystem boundaries can significantly enrich recipient food webs, thereby shaping the ecosystems' structure and function. To illustrate the potential role of islands in enabling the transfer of matter across ecosystem boundaries to be gauged, we investigated the influence of seabirds on nitrogen input on islands. Basing our study on four widely differing islands in terms of their biogeography and ecological characteristics, sampled at different spatial and temporal intervals, we analyzed the nitrogen isotopic values of the main terrestrial ecosystem compartments (vascular plants, arthropods, lizards and rodents) and their relationship to seabird values. For each island, the isotopic values of the ecosystem were driven by those of seabirds, which ultimately corresponded to changes in their marine prey. First, terrestrial compartments sampled within seabird colonies were the most enriched in δ(15)N compared with those collected at various distances outside colonies. Second, isotopic values of the whole terrestrial ecosystems changed over time, reflecting the values of seabirds and their prey, showing a fast turnover throughout the ecosystems. Our results demonstrate that seabird-derived nutrients not only spread across the terrestrial ecosystems and trophic webs, but also modulate their isotopic values locally and temporally on these islands. The wealth of experimental possibilities in insular ecosystems justifies greater use of these model systems to further our understanding of the modalities of trans-boundary nutrient transfers.
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