Interactions between shorebirds and benthic invertebrates at Culbin Sands lagoon, NE Scotland: effects of avian predation on their prey community density and structure

Mendonca, Vanda Mariyam; Raffaelli, David George; Boyle, Peter R.

http://hdl.handle.net/10400.1/11923

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Authors

Mendonca, Vanda Mariyam

Raffaelli, David George

Boyle, Peter R.

Abstract(s)

In the North Sea, during autumn-winter, intertidal flats often receive a massive influx of migratory shorebirds (wildfowl, waders and seabirds), which utilise the high prey densities that are available. The present study was conducted at Culbin Sands lagoon, NE Scotland, in 1994-1996, to investigate benthic invertebrate standing stock, and the energy flow from benthic invertebrates to shorebirds. Benthic invertebrate standing stock was estimated to be 500 kJ m(-2) yr(-1), and shorebird consumption efficiency to be 18% of the available standing stock. A series of manipulative field experiments were then conducted to test the effects of shorebirds on benthic invertebrate densities and community structure. Birds were excluded from caged areas (exclosures), and benthic invertebrate densities (total and by class size) in caged and uncaged areas were compared for each season separately. During autumn-winter, especially the gastropod Hydrobia ulvae and larger-sized (> 15 mm) clams Macoma balthica were observed to be the roost impacted species, being significantly more abundant in bird-exclosures than in bird-accessed areas.

Keywords

Knots Calidris-Canutus Cost-benefit-analysis Body-mass regulation Moray firth Scrobicularia-Plana Wintering dunlin Macoma-Balthica Delaware Bay Energy Food