| dc.description.abstract | Marine habitats have undergone dramatic changes, particularly over the last few decades. Human-related causes, such as habitat alteration, overexploitation, pollution, climate change and introduction of alien species have affected marine ecosystems worldwide, with severe impacts on many species, including several seabirds. Seabirds, and particularly (but not exclusively) those species that act as top-predators, are excellent monitors of the health of marine ecosystems. However, in order to make use of them as bioindicators, we have to understand how potential limiting factors influence their ecology. In turn, this information is also useful for the conservation of their populations.
In this thesis I study a diversity of limiting factors of potential importance for the breeding ecology of two threatened seabirds, the southern rockhopper penguin and the black-browed albatross, at a mixed seabird colony on the Falkland Islands. An analysis of nesting habitat quality (Chapter 2) indicated that this did not explain variation in rockhopper penguin breeding success, which was most likely influenced by predation. An analysis of spatial and temporal variability of nesting success of black-browed albatrosses has shown that disease (Chapter 3), possibly coupled with parasites (Chapter 4) was the main cause for chick mortality differences between areas and years, whilst the consequences of a diet (Chapter 5) with a strong fisheries-related component for breeding success and chick development are still to be determined conclusively.
This multi factor approach together with a relatively long-term set of data are important to produce more robust conclusions (with atypical years put into context), and to tentatively assign changes in breeding parameters to individual factors. My results help to provide a more complete insight of the potential factors threatening two species of conservation importance at this colony and in the context of the Falklands. | en_GB |
