Resource segregation in two herbivorous species of mountain lizards from Argentina

Lizard assemblages may experience resource partitioning in the spatial, trophic or temporal dimensions of their niche. Niche segregation does not always imply competition, and the role of interspecific competition is better understood when the response of species to the presence or absence of other species is evaluated. The aim of this study is to determine daily activity patterns and food consumption in two phylogenetically related species (Phymaturus roigorum and P payuniae). These saxicolous and herbivorous species live in sympatry in the volcanic region of Payunia, in central-west Argentina. One of these species can also be found in allopatry, allowing comparative studies on their lifestyle. We evaluated the temporal daily patterns of both species and their diet overlap. Although competition is not evident between the species studied here, it is shown that selectivity towards different plant species and the time schedule of foraging are the primary mechanisms that promote the coexistence of these lizards. Daily basking activity, however, was similar in both species.