CONICET | Buscador de Institutos y Recursos Humanos

Space use in deserts has usually been considered only along the horizontal dimension; however, vertical structure could be an important variable for habitat segregation among small mammal species. Our study assessed the use of vertical space by small mammals of the Monte Desert by live-trapping animals at different heights. We recorded 1,336 captures of 4 rodent and 1 marsupial species in 27,600 trap-nights. All 5 species were captured on the ground and in tree layers, but only the gray leaf-eared mouse (Graomys griseoflavus) and the desert mouse opossum (Thylamys pallidior) significantly used the vertical space. G. griseoflavus used the arboreal space independently of habitat, plant species or branch diameter, whereas T. pallidior showed a more selective behavior, being present at higher heights and on large-diameter branches of Prosopis trees than others. All rodent species used lower more than higher heights of arboreal strata. They used heights more or only during the dry season when resource availability is low. Our study suggests that vertical structure offers greater opportunities to acquire resources when these are scarce and plays a role in the coexistence of small desert mammals.