Análise da viabilidade populacional de bugios-ruivos Alouatta guariba clamitans (Cabrera, 1940), em uma paisagem fragmentada no sudeste do Brasil

Abstract

Analyses of population viability in areas under strong anthropic pressures are of great value to conservation, assisting in the management focused on factors that harm the populations. The aims of this study were: (1) obtain the extinction probability, in 100 years, for populations of brown howler monkeys (Alouatta guariba clamitans) inhabiting remnants of Atlantic Rainforest in Taubaté, Southeast Brazil, (2) identify the minimum viable population size (MVP), and (3) the minimum dynamic area (MDA). Between August 2014 and July 2015, from 8 h until 17 h, we carried out broad surveys in 21 forest fragments, totalizing 84 field days (672 hours) of sampling effort. The presence of brown howler monkeys was confirmed in 12 fragments. Using the software Vortex v.10.1, through 1,000 iterations, we then simulated scenarios considering the existence of migration between fragments distant up to 50 m from each other, and no migration above this distance. We considered different types and frequencies of catastrophes: fragmentation (1 to 3 % per year), electrocution (0 to 1 %), attacks by domestic dogs (0 to 1 %), running over (0 to 0.5 %), and hunting (0 to 1 %). We obtained a probability of extinction smallerthan10%for50%(n=6) of the forest remnants, configuring a metapopulation system. The results suggest that is essential ensuring connectivity and protection the fragments against catastrophes. If the rate of disorders, such as fragmentation, doesn’t increase, we can expect a relative stability of the brown howler monkeys metapopulation in the region. The exception is the local population inhabiting an isolated fragment of 37 ha, for which the extinction seems to be imminent (89 % of probability), unless some management measure (assuring population reinforcement) is taken.