Effects of the shorebirds predation on the estuarine macrofauna of the patos lagoon , south Brazil

Abstract

A field experiment was performed between February and May 2002 to evaluate the predation effects of migratory shorebirds on the macrofauna structure at an intertidal mudflat of the estuarine region of the Patos Lagoon. Predators were excluded by use of the metallic cages (20 x 20 x 30 cm). The macrofauna densities in shorebird exclusion treatments were always lower or equal to controls, indicating a no significant predation effect. The lower macrofauna densities in shorebird exclusion cages were probably associated to crab intrusion, which had been benefited by protection of this treatment. The low shorebird predation effects observed in this study can be related to biological characteristics of these predators associated to the local environmental conditions during the realization of these experiments.