A estrutura de taxocenose de lagartos em uma região de Caatinga no Piauí, Nordeste Brasileiro. A influência de fatores históricos e ecológicos

Abstract

We assessed the roles of historical and recent factors on the structure of a Neotropical lizard community from Serra da Capivara, in the semiarid Caatinga of north-eastern Brazil. We found no correlation between microhabitat variables and species distribution patterns. Null model analyses indicated that mean trophic niche overlap was different than expected by chance, indicating a community structured along the trophic niche axis. We suggest that the lack of spatial niche segregation and species association may be related to current environmental conditions, such as habitat homogeneity and climatic variables. Morphological and dietary niches were influenced by historical factors, with phylogeny accounting for most of the variation in our data. Most of the variation is accounted for by the divergence of basal lineages (Gekkota/Scincomorpha/Iguania), but also conspicuous in specific families such as Gymnophthalmidae. These segregations influence behaviour and foraging modes of the given clades. Finally, these results are quite similar to those found for lizard communities in Seasonal Tropical Dry Forests (STDFs) and Cerrado savannahs, which can be a starting point to discuss about the relationship between these formations to Caatinga domain.