Combining Methods to Describe Important Marine Habitats for Top Predators: Application to Identify Biological Hotspots in Tropical Waters
Résumé
In tropical waters resources are usually scarce and patchy, and predatory species
generally show specific adaptations for foraging. Tropical seabirds often forage in
association with sub-surface predators that create feeding opportunities by bringing prey
close to the surface, and the birds often aggregate in large multispecific flocks. Here we
hypothesize that frigatebirds, a tropical seabird adapted to foraging with low energetic
costs, could be a good predictor of the distribution of their associated predatory species,
including other seabirds (e.g. boobies, terns) and subsurface predators (e.g., dolphins,
tunas). To test this hypothesis, we compared distribution patterns of marine predators in
the Mozambique Channel based on a long-term dataset of both vessel- and aerial
surveys, as well as tracking data of frigatebirds. By developing species distribution
models (SDMs), we identified key marine areas for tropical predators in relation to
contemporaneous oceanographic features to investigate multi-species spatial overlap
areas and identify predator hotspots in the Mozambique Channel. SDMs reasonably
matched observed patterns and both static (e.g. bathymetry) and dynamic (e.g.
Chlorophyll a concentration and sea surface temperature) factors were important
explaining predator distribution patterns. We found that the distribution of frigatebirds
included the distributions of the associated species. The central part of the channel
appeared to be the best habitat for the four groups of species considered in this study
(frigatebirds, brown terns, boobies and sub-surface predators).
Domaines
Sciences de l'environnementOrigine | Fichiers éditeurs autorisés sur une archive ouverte |
---|
Loading...