Benthic food distribution as a predictor of the spatial distribution for shorebirds in a wetland of central Chile

Coastal landscapes of central Chile are important places for species of resident and migratory shorebirds. Estuarine environments are critical habitats that provide resting places and food resources for large concentrations of shorebirds to replenish their energy during their migration. We hypothesized that shorebirds choose particular habitats based on food availability in a tidal wetland of Aconcagua River, central Chile. We evaluated composition and abundance of benthic ensemble in foraging areas, and its local spatial distributions in these foraging areas. The main prediction was that selected trophic items may reflect the main distribution of shorebirds. The total benthic invertebrates registered were 11,514 individuals, corresponding to 25 taxa, being crustaceans, polychaetes, oligochaetes, and insects the major taxonomic groups. The total and foraging shorebirds registered were 2,105 and 1,136 individuals, respectively; corresponding to 18 species belonged to 4 Families: Charadriidae, Haematopodidae, Recurvirostridae and Scolopacidae. Tidal flats around the study site exhibit non-random spatial distributions of feeding shorebirds, responding to food availability within the Aconcagua river wetland. Our integrated analysis showed significant differences between tidal flat areas based on abundance and composition of benthic trophic items (mediated by sediment characteristics), and some relationships between foraging shorebirds and trophic items in particular tidal flat areas. These results have implications for shorebird conservation and future wetland management, mainly in relation to environmental changes and other causes of habitat loss and destruction linked with worldwide decline in many shorebird populations.