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Master Thesis

Analyse multi-échelle de la réponse comportementale des oiseaux marins à la structuration spatiale de leur environnement pélagique

Abstract : In pelagic marine ecosystems, there is a strong hierarchical structure in all compartments of the ecosystem from the water body to predators. Seabirds small pelagic consumers are top predators and their behavior reflect to some extent the spatial structure of the underlying ecosystem and their prey. In this context, we study the geometry of foraging travels of seabirds (Peruvian booby and Guanay cormorants) and the size of physical structures in the ocean. A wavelet analysis is implemented in order to extract significant structures from seabirds tracks, nested or not, on a continuum of spatial scales. This method is efficient to extract areas restricted search (ARS) from the foraging tracks of the seabirds. It outmatches existing methods (i.e. FPT) because it permits to identify ARS of different scales and potentially nested. Moreover, it permits to characterize the ARS ('structure') and the patterns that compose it. The method used here allows to distinguish simple oscillations from real loops. The results of this work show that (1) considering ARS as indicators of foraging areas is not obvious and that (2) separate oscillation and loop is interesting because some differences exist between species (relative oscillations and loops proportions) and between years (inter-annual variability mostly in loop); (3) the study of size distributions of ARS without hypothesis requirement about a characteristic scale permits to study the relationships between seabirds behavior and physical processes and shows a good consistency between the sizes of ARS and the sizes of areas favorable for anchovy.
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Master Thesis
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https://dumas.ccsd.cnrs.fr/dumas-00881122
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Submitted on : Thursday, November 14, 2013 - 8:47:46 AM
Last modification on : Monday, July 6, 2020 - 3:38:21 PM
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Alexandre Mousseigne. Analyse multi-échelle de la réponse comportementale des oiseaux marins à la structuration spatiale de leur environnement pélagique. Sciences agricoles. 2013. ⟨dumas-00881122⟩

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