Landscape habitat association of the most threatened neotropical grassland bird populations: advantages and pitfalls of current land use practices.

DI GIACOMO, ADRIÁN S.

Brasilia, Brasil

Congreso; XIX Annual Meeting of the Society for Conservation Biology; 2005

Society for Conservation Biology

The Aguapey River in the Campos grasslands of Argentina is the last refuge for a complete assemblage of rare and threatened birds. We evaluated the influence of landscape attributes on the occurrence and density of six globally threatened and endemic passerines. We used point counts to census birds, and quantified landscape attributes 200-m and 1000-m from the count centers. Strange-tailed Tyrants (Alectrurus risora) selected sites with a high proportion of tall-grass habitat in lowlands. Saffron-cowled Blackbirds (Xanthopsar flavus) and Black-and-white Monjitas (Heteroxolmis dominicana) preferred a mixed landscape with marshes associated with dry upland grasslands. Occurrence of endangered seedeaters (Sporophila palustris, S. cinnamomea and S. ruficolli) was not associated with any landscape attributes analyzed. Seedeaters are probably responding to local habitat features. The Campos grassland is used primarily for livestock grazing and afforestation; up to 50% of the remaining grassland habitat has been planted with exotic trees. If this trend continues, Saffroncowled blackbirds will become extinct in the Campos. GIS tools allow us to predict new populations of threatened birds, and to provide guidelines for establishing future reserves and wildlife management. Our study indicates that future reserves must contain a complete landscape gradient to preserve populations of all these endangered species.