Effects of cattle grazing and burnings on the abundance, habitat selection, and nesting success of the Bay-capped Wren-Spinetail (Spartonoica maluroides) in coastal saltmarshes of the Pampas region

CARDONI, D. A.; ISACCH, J. P.; IRIBARNE, O. O.

THE CONDOR

COOPER ORNITHOLOGICAL SOC

Año: 2012 vol. 114 p. 803 - 811

0010-5422

The Bay-capped Wren-Spinetail (Furnariidae, Spartonoica maluroides) is the most specialized and threatened bird inhabiting Spartina saltmarshes in southeastern South America. These marshes are being modified at an increased rate, primarily by cattle grazing and burning, which make this furnarid highly vulnerable. To assess how land use affects Bay-capped Wren-Spinetail populations, we estimated their density under different intensities of burnings and cattle grazing, studied nesting habitat selection and nesting success, and conducted nest predation experiments to determine predation rates and predator type. We found similar population densities, nesting microhabitats, and nest predation rates in marshes with low grazing intensity and marshes with no grazing. In contrast, the species was absent from marshes with high intensity of grazing and burning. Nest height was the best predictor of daily survival rates. Nest predation experiments demonstrated that nest high influences predation intensity and predator type. Our results suggest that low grazing intensities are compatible with the presence and reproduction of the Bay-capped Wren-Spinetail. Thus, low-impact cattle raching is a viable alternative for the sustainable development of saltmarshes in southeastern South America.