Population viability analysis of howler monkeys (Alouatta palliata mexlcana) in a highly fragmented landscape in Los Tuxtlas, Mexico

We performed a population viability analysis (PVA) using a stochastic population model employing RAMAS/Metapop software: 1) to evaluate the contribution of demographic parameters to population growth, and 2) to simulate group trend and local extinction probability of the Mexican mantled howler monkeys Alouatta palliata mexicana in Los Tuxtlas, Mexico, under two landscape scenarios: isolated populations (IPS) and patchy population or metapopulation (MPS). We found that as the number of adult females per fragment increased, the rate of fecundity and relative reproductive success increased. As a consequence, the finite growth rate depended mainly on the survival of adult females. In both IPS and MPS the simulations suggested that the probability of extinction was exponentially dependent on fragment size. An estimation of 60% of extinction was predicted when fragment size is lower than 15 ha. Simulations suggest that in MPS the expected population change could be lower than in IPS. The value of these analyses for conservation of the primate populations studied is discussed.