El CHINCHILLÓN PATAGÓNICO

El chinchillón patagónico o pilquín es un roedor de tamaño mediano, de aproximadamente 2000-2500 g. de peso. Su aspecto es similar al de una chinchilla aunque de mayor tamaño. En los roquedales conforma colonias, constituidas por diferentes grupos familiares de dos a tres individuos, aprovechando las grietas de las rocas para establecer sus refugios. Este artículo relata aspectos de su ecología e implicancias para la conservación. Se estudian las generalidades del comportamiento, sus potenciales depredadores y se analizan los aspectos que pueden influir sobre sus poblaciones

Predator feeding ecology on Patagonian rocky outcrops: implications for colonies of mountain vizcacha (Lagidium viscacia)

ABSTRACT: On 10 rocky outcrops with mountain vizcacha colonies, diets and trophic relations of five predator species were analyzed to evaluate their impact in vizcacha populations. Diets included 17 prey items of which mammals represented 97% of biomass. Lagomorphs were the most important prey, followed by sigmodontines, tuco-tucos, and mountain vizcachas. The Barn Owl was a specialized predator, while the culpeo and lesser grison were generalized consumers. Predation of mountain vizcacha by Magellanic Horned Owls and culpeo foxes could increase vizcacha vulnerability because vizcacha populations are small and fragmented, and females produce only one offspring per year.Fil: Galende, Gladys I.. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Departamento de Zoología; ArgentinaFil: Raffaele, Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Effects of coypu (Myocastor coypus) abundances and diet selection on a wetland of the Patagonian steppe

We assessed diet selection, impact on vegetation, and explored habitat relationships with marsh birds of coypus(Myocastor coypus) in a steppe lagoon in Argentinean Patagonia. In two consecutive springs, abundance and spatial use of the coypus and nesting marsh birds were estimated by direct counts. The coypu was a selective consumer with seasonal variations in food items, and Myriophyllum sp. and Schoenoplectus californicus dominated its diet. Coypus and marsh birds showed a differential spatial use when rushes cover was high. However, when rushes cover decreased by coypu browsing, there was a similar use of space, and marsh birds were displaced to nest on the open water and other poorly protected areas of the rushes. Our results suggest that high abundances of coypu can have a detrimental effect on wetland ecosystems. Systematic monitoring and evaluation of their effects on wetlands in recently colonized areas is recommended.Fil: Galende, Gladys I.. Universidad Nacional del Comahue; ArgentinaFil: Troncoso, Adriana. Universidad Nacional del Comahue; ArgentinaFil: Lambertucci, Sergio Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentin

Diet selection of the southern vizcacha (Lagidium viscacia): A rock specialist in north western Patagonian steppe, Argentina

The southern vizcacha (Lagidium viscacia) is a rock specialist that inhabits small colonies in isolated rocky outcrops of northwestern Patagonia. This study analyzes its diet selection in relation to food availability, establishes the degree of dietary specialization, and discusses the potential competition with exotic herbivores. Diet composition and food availability were determined in summer and winter in eight rocky outcrops by microhistological analysis of fecal pellets, and food availability was estimated by the Braun Blanquet cover abundance scale. Vegetation cover differences were detected by using a random analysis of variance (ANOVA) factorial block design, and dietary preferences were determined by the confidence interval of Bonferroni. The southern vizcacha showed a specialized feeding behavior despite the consumption of a wide variety of items. Their diet was concentrated on a few types of food, mainly grasses, and the trophic niche was narrow and without seasonal variations. In winter, when food was scarce and of lower quality than summer, diet was dominated by Stipa speciosa, suggesting a selection according to the selective quality hypothesis. Our results (narrow trophic niche, restricted activity near rocky outcrops, and a diet with high proportions of low-quality grasses) showed that the vizcacha is an obligatory dietary specialist, and these characteristics made it highly vulnerable to changes in food availability. In this scenario, overgrazing caused by alien species with similar diets, as the European hare and livestock, could negatively affect their colonies.Fil: Galende, Gladys I.. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Departamento de Zoología; ArgentinaFil: Raffaele, Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentin