Competition for feeding in waders: a case study in an estuary of south temperate Europe (Mondego, Portugal).
Data
2005
Autores
Cabral, João Alexandre
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Resumo
The loss of feeding areas may pose a threat to many wintering waders because increased competition arising
from reduced foraging space may force birds either to emigrate or to die. This has been demonstrated to
occur in northwest European estuaries, but virtually no studies have been performed in the estuaries of
southern Europe, where the loss of supratidal habitats (salines and saltmarshes), rather than intertidal
habitats, are currently the main threat to waders’ habitats. If these habitats are lost, waders may be forced
to move to the intertidal mudflats, perhaps increasing competition between individuals and ultimately
leading to starvation or emigration. We tested this hypothesis in the Mondego estuary, a small estuary on
Portugal’s west coast, which is presently under heavy human pressure. We used indirect methods to test for
the occurrence of both components of intra-specific competition: interference and prey depletion. We found
no evidence that either interference or depletion competition was occurring at present, either on the
mudflats or in the salines. Overall, the results suggest that the intertidal mudflats may still be able to
accommodate birds displaced from the destroyed supratidal salines, but modelling is required to predict the
effect that the combined loss of feeding area and foraging time that this would entail would have on their
fitness, and thus numbers.
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Palavras-chave
Competition , Feeding , Waders , Habitat loss , Portuguese estuary
Citação
Múrias T. et al., 2005