Efeito do uso e cobertura da terra e atributos da paisagem sobre a distribuição, ocorrência e densidade do guigó-da-Caatinga (Callicebus barbarabrownae, Hershkovitz 1990)

Abstract

Habitat loss and fragmentation, exacerbated by the expansion of human activities, are currently the greatest threats to biodiversity. Forest-dependent species such as neotropical primates are among the most vulnerable to these changes. The blond titi monkey (Callicebus barbarabrownae) is a medium-sized primate endemic to the Caatinga and currently classified as Critically Endangered. As C. barbarabrownae is a forestdependent frugivorous primate, it is strongly threatened by habitat loss. This master thesis is divided into two chapters. In the first chapter, we investigated the spatial patterns and temporal changes in land use and land cover (LULC) classes in the geographic range of C. barbarabrownae and in landscapes with records (presence and absence) of this species. Callicebus barbarabrownae occurrence data were obtained from literature searches. The LULC data, used in both chapters, belong to Collection 7 of MapBiomas. Our results highlight that more than half of C. barbarabrownae's distribution area is currently covered by Farming and Non-Vegetated Areas, with Pasture as the predominant class. In landscapes where the species occurs, Savanna Formation, Pasture, Mosaic of Uses, and Forest Formation were the predominant classes. Pasture has a higher coverage proportion in landscapes of occurrence than in landscapes of absence and is the LULC class with the highest rate of increase over the years. The second chapter investigated the effect of landscape attributes on the density of C. barbarabrownae groups. Density data were collected in the field, from five expeditions carried out in different regions of the species' geographic range in the states of Bahia and Sergipe. We found group densities higher than those previously reported for the species. The models that best explained the variation in C. barbarabrownae group density included forest cover, chronic anthropogenic disturbance index (CDI), and clumpiness index as predictor variables in 300 ha landscapes. Group density is negatively related to forest cover, while CDI and clumpiness negatively affect the group density, although not significantly. Our results suggest that extensive livestock farming is currently the greatest threat to C. barbarabrownae, a species that is occurring in contexts of limited habitat availability. At the same time, group density is higher in landscapes with lower forest cover and remnants of more dispersed habitats, suggesting that groups are confined to the limited available habitat. This scenario raises concerns about the long-term viability of populations of this species, whose apparent persistence in such landscapes may be due to an extinction debt. Restoration efforts, especially in the northeastern and central regions of C. barbarabrownae's geographical range, and the establishment of Protected Areas, can serve as crucial allies in the preservation of this species.