Variação no padrão de atividade de mamíferos em resposta à sazonalidade em um parque nacional da floresta tropical seca brasileira

Abstract

The Brazilian seasonally dry tropical forest (Caatinga) is a semi-arid environment marked by a long dry period and a short rainy period that results in a great fluctuation in the conditions and resources for fauna. Medium to large mammals are usually the group most threatened by human activities, and thus are considered indicators of biotic integrity of the environment. Thus, understanding their ecology is essential for the effectiveness of management and conservation strategies, especially within protected areas, which, despite being the main strategy used for the persistence of biodiversity, are still scarce in the Caatinga. The objective of this work was to investigate the ecology of the mammal assemblage in Furna Feia National Park, and how seasonality influences the ecology parameters of the assemblage and the species. More precisely, we characterized the richness, frequency of records, composition, simple occupancy and activity pattern of the species and their relationship with seasonality. We collected the data throughout the rainy and dry seasons of 2018, using camera traps at 44 and 40 sampling points, with an effort of 2267 and 1639 camera-days, respectively. Rarefaction curves, circular statistics, and occupancy models were some of the analyses used to characterize the assemblage and its seasonal patterns. We obtained 485 records of 11 species of mammals distributed in six orders and nine families, including two species threatened with extinction in Brazil and/or by the IUCN (Leopardus emiliae and Herpailurus yagouaroundi) and the first photographic record of free-living Dicotyles tajacu for Rio Grande do Norte. Species with the highest frequency of records include Subulo gouazoubira, Euphractus sexcinctus and Sapajus libidinosus. Meanwhile, Leopardus pardalis, H. yagouaroundi and D. tajacu were the least recorded. Regarding the activity pattern, S. gouazoubira changed from the rainy to the dry season, from diurnal to nocturnal. While the other species analyzed seem to distribute their activities to avoid the hottest times of the day, especially during the drought. The species richness did not change, but relative abundance was higher in the wet than in the dry season for most species, except for D. albiventris, which showed the opposite trend. Some species exhibited no variation in occupancy and detectability, while others such as S. gouazoubira were more detected and expanded their occupancy in the wet season. This work represents the first systematic survey with camera trap for an important UC in the Caatinga, and the results on seasonal and circadian activity rhythm will improve the understanding of animal ecology and the mechanism of permanence in seasonally dry environments.