doctoralThesis
Padrões de ocorrência e coexistência de mamíferos de médio e grande porte na Caatinga
Fecha
2020-04-28Registro en:
MARINHO, Paulo Henrique Dantas. Padrões de ocorrência e coexistência de mamíferos de médio e grande porte na Caatinga. 2020. 187f. Tese (Doutorado em Ecologia) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2020.
Autor
Marinho, Paulo Henrique Dantas
Resumen
Dry tropical forests are threatened and little-known ecosystems where the association between the semiarid climate and the generally high environmental degradation imposes challenges for the persistence of wild fauna. In this context, medium to large-sized mammals (MLSM) are especially affected by anthropogenic disturbances, among which, carnivores are intensely persecuted, impairing their role in structuring biological communities through predation and intraguild competition. In this thesis, we investigated the occurrence and coexistence patterns of MLSM in different landscapes of the Caatinga, the Brazilian dry tropical forest, using camera trapping data. Specifically, we 1) carried out the first systematic survey of MLSM in the Rio Grande do Norte state (RN), sampling 10 priority areas for conservation; 2) we described the daily and seasonal activity patterns and estimated the temporal overlap among mesocarnivores using circular statistics and non-parametric analyzes of activity overlap; 3) we investigated the patterns of spatial co-occurrence between a dominant mesopredator (Leopardus pardalis) and sympatric mesocarnivores, considering seasonality and using conditional co-occurrence models; and finally, 4) we tested the relative effects of environmental and anthropogenic predictors on MLSM’s occupancy in a landscape disturbed by high cattle density and during a period of extreme drought, using Bayesian occupancy models in a multi-species approach. As main results, we found 1) a wealth of 14 MLSM’s species in the Caatinga of RN, which represents 50% of the MLSM registered at the north of the São Francisco River, including threatened species as a top predator (Puma concolor). 2) Mesocarnivores were mainly nocturnal throughout the dry and rainy seasons, overlapping most of their daily activity, but segregating the peaks of greater activity, which may represent a coexistence mechanism. Meanwhile, Herpailurus yagouaroundi was diurnal, avoiding encounters with competitors and synchronizing its activity with potential prey. 3) Spatially, the other mesocarnivores used the habitat regardless L. pardalis’ presence, with the exception again of H. yagouaroundi, which seems to prefer the same locations as this dominant mesopredator, probably because they have better conditions and resources, while temporal segregation decreases the risk of aggressive encounters. 4) MLSM occurred mainly in patches of forest vegetation, which represent a key habitat for the persistence of this group in a degraded landscape under prolonged drought, and where many species showed an extremely low abundance. Therefore, these environments must be protected to guarantee MLSM’s persistence in Caatinga. Our results reinforce the relevance of priority areas and habitats for mammals’ conservation in the Brazilian dry tropical forest, in addition to elucidating the intraguild coexistence strategies that maintain the mesocarnivores diversity in this semiarid environment.