Anuran responses to spatial patterns of agricultural landscapes in Argentina

Context: Amphibians are declining worldwide and land use change to agriculture is recognized as a leading cause. Argentina is undergoing an agriculturalization process with rapid changes in landscape structure. Objectives: We evaluated anuran response to landscape composition and configuration in two landscapes of east-central Argentina with different degrees of agriculturalization. We identified sensitive species and evaluated landscape influence on communities and individual species at two spatial scales. Methods: We compared anuran richness, frequency of occurrence, and activity between landscapes using call surveys data from 120 sampling points from 2007 to 2009. We evaluated anuran responses to landscape structure variables estimated within 250 and 500-m radius buffers using canonical correspondence analysis and multimodel inference from a set of candidate models. Results: Anuran richness was lower in the landscape with greater level of agriculturalization with reduced amount of forest cover and stream length. This pattern was driven by the lower occurrence and calling activity of seven out of the sixteen recorded species. Four species responded positively to the amount of forest cover and stream habitat. Three species responded positively to forest cohesion and negatively to rural housing. Two responded negatively to crop area and diversity of cover classes. Conclusions: Anurans within agricultural landscapes of east-central Argentina are responding to landscape structure. Responses varied depending on species and study scale. Life-history traits contribute to responses differences. Our study offers a better understanding of landscape effects on anurans and can be used for land management in other areas experiencing a similar agriculturalization process.Facultad de Ciencias ExactasCentro de Investigaciones del Medioambient

Multiple factors associated with nest-site selection in a wetland-specialist, the Wren-like Rushbird (Phleocryptes melanops)

Diverse factors may limit nest-site selection; however, nest predation has long been considered a main factor driving nest-site selection in birds. Marsh-nesting birds face a particularly important trade-off between habitat features that impede their vision of the approach of potential predators and nest concealment from predators. Here, we analyse how different ecological variables influence nest-site selection in the habitat-specialist Wren-like Rushbird (Phleocryptes melanops) breeding in three different wetlands of the Pampas region of Argentina over 3 years. Rushbirds selected nest sites with higher heights and denser vegetation, compared to random sites. Nest height was positively associated with vegetation height and lower visibility from the point of view of aerial predators, and the nest entrance was oriented towards the region with greatest visibility of the nest from the point of view of Rushbirds. Rushbirds seem to flexibly adjust their nest location in response to high predation risk, building their nests under structures built by other birds when breeding colonies of herons and gulls (potential nest predators) are present. Initial nest-site selection is performed by males, which then attempt to attract females to a rudimentary nest. Females sometimes reject such sites and the male then selects a new nesting location. Our study highlights the potential for flexible sex differences in nest-site selection.Fil: Chiaradia, Nicolas Mariano. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Isacch, Juan Pablo. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Pretelli, Matías Guillermo. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cardoni, Daniel Augusto. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Conservation status of the buff-breasted sandpiper: historic and contemporary distribution and abundance in South America

Volume: 114Start Page: 44End Page: 7