INVESTIGADORES
IRIBARNE Oscar Osvaldo
artículos
Título:
Environmental heterogeneity, spatial segregation of prey, and the utilization of southwest Atlantic mudflats by migratory shorebirds
Autor/es:
RIBEIRO, P.; O. IRIBARNE; D. NAVARRO; L. JÁUREGUI
Revista:
IBIS
Editorial:
BOU Publications
Referencias:
Lugar: Oxford; Año: 2004 vol. 146 p. 672 - 682
ISSN:
0019-1019
Resumen:
We studied the relationships between the habitat use of migratory shorebirds and the spatial
distributions of the Southwestern Atlantic Fiddler Crab
Uca uruguayensis
, polychaetes, sediment
characteristics and tidal levels in the Río de La Plata estuary, Argentina, where
U. uruguayensis
is one of the most important intertidal species. Crabs have a well-defined
patchy distribution that is segregated spatially from that of polychaetes. Crab density on the
surface varied across the tidal cycle, reaching maximum values during low tide. Polychaete
density decreased with depth but showed no change through the tidal cycle; however, given
that sediment penetrability did change during the same period, their availability to probing
shorebirds is expected to change. Habitat use by shorebirds followed the spatial distribution
of prey; shorebirds that foraged on polychaetes (White-rumped Sandpiper
Calidris fuscicollis
,
Two-banded Plover
Charadrius falklandicus
and Hudsonian Godwit
Limosa haemastica
)
focused their attention on the areas with the highest densities of polychaetes, whereas
species that preyed mostly on crabs (Ruddy Turnstone
Arenaria interpres
, Whimbrel
Numenius
phaeopus
and Grey Plover
Pluvialis squatarola
) predominantly used areas with crabs. This
segregation occurred particularly during low tide, a period in which polychaetes became
fully available. Results show that the spatial and temporal heterogeneity of mudflats
in relation to the types and availability of prey has a strong effect on shorebird habitat
use.