Effects of an alien invertebrate species and wave action on prey selection by African black oystercatchers (Haematopus moquini)

摘要: Shorebirds foraging in the intertidal have been shown to exert a significant effect on assemblage level processes; this is particularly true of oystercatcher–limpet–algae system. The African black oystercatcher (Haematopus moquini) endemic southern coastline, where it plays role ecosystem processes as rocky-shore predator, especially mussels and limpets. This understanding was based studies rocky shore environment that has since considerably modified following invasion an alien mussel (Mytilus galloprovincialis). not only changed relative proportions different food types shore, but also greatly increased overall biomass. We tested previous model selection by oystercatchers reflected prey abundance intake male female differed owing bill morphology. predicted difference would persist despite nature base. wave action modify result both its influence behaviour impact searching handling times birds. Overall, sexes consumed more limpets than expected encounter rate alone, contrary prediction, taken post did differ between sexes. Dietary convergence interpreted biomass which densities invasion. Also prediction there no evidence waves acted indirect modifiers interaction their prey. results study indicate models trophic cascades will need be altered event change level, then effects behavioural changes key predator.