Volume 174, 5 June 2016, Pages 71–81
Highlights
- •
- Yves Bay is an intertidal mudflat with an exceptional granulometric gradient.
- •
- Available benthos resource for Calidris alpina and Calidris canutus is assessed.
- •
- Densities of four dominant molluscs and one annelid species are mapped.
- •
- Prey distribution are predicted along ET and MSG gradients.
- •
- Potential trophic niches vary spatially between the shorebird species.
Abstract
The case study of Yves Bay (Pertuis Charentais, France) highlighted links between environmental gradients (i.e.
sediment characteristics and emersion time) and prey distribution and
availability for the two most numerous shorebird species overwintering
in Yves Bay: the red knot Calidris canutus and the dunlin Calidris alpina.
Two hundred and fifty-two stations were sampled on a predetermined
250 m regular grid covering the intertidal mudflats of this major
wintering site in France for east-Atlantic migratory shorebirds. The
distribution of principal benthic species abundance and biomass was
modelled along two environmental gradients: sediment structure
(particularly pronounced north–south sand-mud gradient) and emersion
time. The effect of emersion time combined with sedimentary structure
strongly explained abundances and biomasses of the main prey for C. canutus and C. alpina in the bay (Cerastoderma edule, Hydrobia ulvae, Macoma balthica, Scrobicularia plana, and Nephtys hombergii).
This study highlighted prey species-specific spatial
segregation/overlapping as well as spatial interferences in the trophic
niche of the two shorebirds.
Graphical abstract
Keywords
- Grain size;
- Tidal cycle;
- Trophic zonality;
- Marine molluscs;
- Marine annelids;
- Bay of Biscay;
- France;
- Pertuis Charentais;
- Yves Bay;
- 46°02′N–01°03′W
© 2016 Elsevier Ltd. All rights reserved.
