Habitat preferences of lesser rheas in Argentine Patagonia.

BELLIS, L. M., M. B. MARTELLA J. L. NAVARRO AND P. E. VIGNOLO.

BIODIVERSITY AND CONSERVATION

Año: 2006 vol. 15 p. 3065 - 3075

0960-3115

This work reports the .rst results of a 3-year study (1998 – 2001) on habitat use and preferences by wild lesser rheas (Rhea pennata pennata) in the ecotone Monte–Patagonian steppe of Argentina. Ponds and four di.erent habitat alternatives for lesser rheas were determined using satellite images and di.erent structural vegetation characteristics: steppe, shrubland, shrub steppe, and mallines. Lesser rheas (adults, juveniles and chicks) used all habitats available to feed, although they showed preference for mallines, open areas that o.er good visibility and abundant food resource. Rheas used shrub steppe and steppe for nesting, but they did not show preference for either habitat type. Nest site had a higher percentage of vegetation cover than control sites. Lesser rheas apparently preferred concealed sites for nesting since they o.er protection from severe climate conditions and from predators. Our results suggest that habitat preference by lesser rheas counterbalances pro.tability of feeding to the corresponding cost of predation.This work reports the .rst results of a 3-year study (1998 – 2001) on habitat use and preferences by wild lesser rheas (Rhea pennata pennata) in the ecotone Monte–Patagonian steppe of Argentina. Ponds and four di.erent habitat alternatives for lesser rheas were determined using satellite images and di.erent structural vegetation characteristics: steppe, shrubland, shrub steppe, and mallines. Lesser rheas (adults, juveniles and chicks) used all habitats available to feed, although they showed preference for mallines, open areas that o.er good visibility and abundant food resource. Rheas used shrub steppe and steppe for nesting, but they did not show preference for either habitat type. Nest site had a higher percentage of vegetation cover than control sites. Lesser rheas apparently preferred concealed sites for nesting since they o.er protection from severe climate conditions and from predators. Our results suggest that habitat preference by lesser rheas counterbalances pro.tability of feeding to the corresponding cost of predation.Rhea pennata pennata) in the ecotone Monte–Patagonian steppe of Argentina. Ponds and four di.erent habitat alternatives for lesser rheas were determined using satellite images and di.erent structural vegetation characteristics: steppe, shrubland, shrub steppe, and mallines. Lesser rheas (adults, juveniles and chicks) used all habitats available to feed, although they showed preference for mallines, open areas that o.er good visibility and abundant food resource. Rheas used shrub steppe and steppe for nesting, but they did not show preference for either habitat type. Nest site had a higher percentage of vegetation cover than control sites. Lesser rheas apparently preferred concealed sites for nesting since they o.er protection from severe climate conditions and from predators. Our results suggest that habitat preference by lesser rheas counterbalances pro.tability of feeding to the corresponding cost of predation.