Habitat use and social structure of an isolated population of guanacos (Lama guanicoe) in the Monte Desert, Argentina

Abstract

We analyse patterns of habitat use and describe abundance and social structure of an isolated population of guanacos in the Lihue Calel National Park in central Argentina using data from foot surveys conducted during 1998, 1999 and 2000. Based on topography and vegetable structure characteristics we identified three types of habitats in the study area: hills, valleys and piedmonts, and lowlands. During surveys we recorded only three types of social groups in this population: solitary males, family groups and male groups. The guanacos used hills more often than expected, followed in preference by valley and piedmont. The guanacos avoided the lowlands where the vegetation is a dense cover of shrubs. This pattern of habitat selection, both a broad and fine scales, could be explained by habitat quality but also by a possible predator avoidance behaviour. The abundance of guanacos showed a positive trend during the study period with an increase of 21% after three years of study. However, the specificity of habitat requirements of guanacos and the fragility of this area under natural events such as wildfires could make guanacos to move other sub-optimal areas were they could become more vulnerable to predation and human persecution.