Factors shaping a lizard community structure in a semiarid region of north-eastern Brazil

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 phylogenetic structure in community composition. Spatial niche overlap was high for most species pairwise comparisons. Null model analyses indicated that mean spatial and trophic niche overlaps did not differ, while mean morphological niche overlap was significantly lower than expected by chance, indicating a community structured along the morphological niche axis but not along the trophic nor spatial niche axes. 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). These segregations influence behaviour and foraging modes of the given clades. Finally, these results are quite like those found for lizard communities in Seasonal Tropical Dry Forests (STDFs) and Cerrado savannahs, which can be a starting point to discuss the relationship between these formations to Caatinga domain.