Census of the Blond Titi Monkey Callicebus barbarabrownae (Pitheciidae) in the Semi-Deciduous Atlantic Forest of Chapada Diamantina, Brazil

Abstract In Brazil, the destruction of the Atlantic forest and the Caatinga dry forest continues to the present, having a profound effect on the non-human primates. Here we present data on abundance of the critically endangered Callicebus barbarabrownae (Pitheciidae), the only primate endemic to the Caatinga, and evaluate if human presence impacts their distribution. We conducted over 152 km of line transect surveys, mostly in semi-deciduous forest near the Chapada Diamantina National Park, NE Brazil. The blond titi monkey occurred at an extremely low abundance, even when considering calls their abundance was lower than that reported for closely related species in different Atlantic forest areas surveyed previously. Although hunting pressure is high in the area, the reasons for their lower abundance are yet unclear. The presence of taller and relatively undisturbed forest seemed key factors for the presence of the species even in areas with heavy human presence. We speculate that they could prefer wetter ...