Resource landscapes explain contrasting patterns of aggregation and site fidelity by red knots at two wintering sites

Table 1 Diet proportion, availability and spatial autocorrelation of molluscs in the Wadden Sea and at Banc d’Arguin

Species^a	Proportion in diet^b	Numerical density (1/m²)	AFDM_flesh (mg/m²)	Autocor. intercept	Autocor. range^c (m)
Wadden Sea
Cerastoderma edule	0.99	762	760	0.51	900
Limecola balthica	< 0.01	31	268	0.04	0
Peringia ulvae	< 0.01	427	134	0.52	1600
Ensis directus	< 0.01	35	70	0.26	600
Mya arenaria	< 0.01	40	38	0.44	1100
Abra tenuis	< 0.01	36	34	0.52	700
AFDM_flesh intake rate (mg/s)^d				0.97	1700
Banc d’Arguin
Loripes lucinalis	0.49	251	1337	0.63	400
Diplodonta circularis	0.19	8	101	0.03	0
Dosinia isocardia	0.13	25	77	0	0
Abra tenuis	0.14	32	31	0.65	0
Senilia senilia	0.06	6	29	0.15	200
AFDM_flesh intake rate (mg/s)^d				0.18	50

^aOnly mollusc species with more than 10 mg AFDM_flesh per m² that are in the upper 4 cm of the sediment and ingestible by red knots
^bAFDM_flesh proportion of all listed mollusc prey in the diet, based on dropping data (hinge measurements)
^cRange is defined as the distance at which the spatial autocorrelation drops below 0.1. The autocorrelation function is estimated by exponential regression of the Moran’s I index at discrete distances. Species specific autocorrelation functions are based on the summed AFDM_flesh density at each location
^dAutocorrelation function of the predicted intake rate (see Fig. 5), taking in account only those prey species that had an estimated average proportion of more than 0.01 in the diet

ISSN: 2051-3933