Ecologia de uma assembléia de serpentes no semiárido neotropical

Abstract

Herein we present a four chapter study on the ecology of a snake assemblage from the Brazilian semi-arid. The first chapter is the comparison of the efficiency of four traditional methods used to sample snakes: time-constrained search, occasional encounters by the staff, occasional encounters by thirds and pitfall traps with drift-fences. We conclude that the concomitant use of these methods is effective and complementary to determine the species richness of an area, but if the objectives are related to species abundance or assemblage structure the methods may be overlaid and the use of these methods together should be cautious. In the second chapter we present a summarized descriptive autoecology of the 22 species of snakes found in the study area. During this study most individuals were represented by Oxybelis aeneus and Philodryas nattereri. The third chapter deals with the effects of interspecific interactions on the structure of the assemblage. In this chapter we indicate, through a null model approach, the existence of dietary, spatial and temporal guilds. The dietary guild seems to be the most important niche dimension segregated by the snakes in the area. The fourth chapter is an investigation on how climate and prey availability affect the structure of the snake assemblage. We show that although there is no overall pattern of response, predictors related to temperature and prey availability are those that influence a greater number of species in the area.