| Summary: | Tese de Doutoramento em Ciência, Tecnologia e Gestão do Mar Global warming is forcing persistent and unprecedented changes in the marine environment, imposing a major challenge to scientists, policy makers and environmental managers in finding solutions for the oceans future sustainability. Marine top predators, such as seabirds, are largely regulated by food web dynamics, offering unique insights into marine ecosystem status and change. Therefore, predicting seabird responses to variations in resources availability and anticipating their ability to cope with future environmental conditions can provide relevant supporting information for the management and conservation of marine species and habitats. In this thesis, I used GPS tracking datasets of Cory’s and Cape Verde shearwaters (Calonectris borealis and Calonectris edwardsii, respectively) and mechanistic modelling approaches, such as system dynamics and individual-based models, to explore hypothesis related to the foraging ecology of shearwaters breeding in the North Atlantic Ocean (Berlengas, Azores, Madeira and Cape Verde archipelagos). In particular, I investigated individual-level mechanisms underlying shearwaters foraging behaviour during chick rearing, and evaluated behavioural strategies that enable individuals to maximize their fitness under contrasting foraging conditions. A special emphasis was given to processes related with their sensorial and cognitive capacities to locate prey at sea, and the need to balance the demands of self-feeding and chick provisioning within the constraints imposed by central place foraging. I also explored ecological imbalances triggered by human-induced environmental changes with consequences for the reproductive ecology of Cory’s shearwaters through predatory pressures at breeding sites. This study revealed: 1) a potential link between shearwaters foraging behaviour and the decision processes associated with timing of nest arrival; 2) a synergistic effect between olfactory foraging and local enhancement for the ...
|
|---|