Why Afro-Siberian Red Knots Calidris canutus canutus have stopped staging in the western Dutch Wadden Sea during southward migration
| Autor: | Bernard Spaans, Theunis Piersma, Casper Kraan, Anne Dekinga, Jan A. van Gils |
|---|---|
| Přispěvatelé: | Piersma group |
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
SHOREBIRD
habitat suitability molluscivore shorebirds Intake rate Foraging Population Intertidal zone PATCH-CHOICE macrozoobenthos Biology migration INTERTIDAL FLATS West africa foraging Calidris canutus canutus AFFECTS FORAGING DECISIONS FOOD WADERS LENGTH education Ecology Evolution Behavior and Systematics Overwintering East-Atlantic Flyway education.field_of_study Ecology ORGAN SIZE Fishery COST-BENEFIT-ANALYSIS Benthic zone connectivity Animal Science and Zoology predicted intake rate BEHAVIOR |
| Zdroj: | Ardea, 98(2), 155-160. Nederlandse Ornithologische Unie |
| ISSN: | 2213-1175 0373-2266 |
| DOI: | 10.5253/078.098.0204 |
| Popis: | Afro-Siberian Red Knots Calidris canutus canutus use the western Dutch Wadden Sea as a refuelling area during southward migration from Taimyr to West Africa. Here we document the decline of their food stocks in this area, based on a yearly large-scale benthic mapping effort, from 1996 to 2005. For each benthic sampling position, intake rate (mg/s, ash-free dry mass) was predicted by an optimal diet model based on digestive rate maximization. Over the ten years, when accounting for a threshold value to meet energetic fuelling demands, subspecies canutus lost 86% of its suitable foraging area. Over this period, the proportion of probable canutus in mist-net catches in July-August declined relative to overwintering islandica Knots. This suggests that canutus dropped even more in numbers than islandica, for which we showed earlier a food-explained decline in numbers. We discuss the possible causality between a decline in the quality of intertidal mudflats in the Dutch Wadden Sea and population declines of Knots in the West-African wintering quarters. |
| Databáze: | OpenAIRE |
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