Abstract

GOMEZ-POSADA, Carolina; ALVAREZ, Zulima  and  GIRALDO-CHAVARRIAGA, Paola. Density and population status of red howler monkeys in an isolated bamboo forest fragment in La Tebaida, Quindío, Colombia. Univ. Sci. [online]. 2009, vol.14, n.1, pp.8-15. ISSN 0122-7483.

The majority of forest remnants in the coffee growing region in Colombia are guaduales, forests with a predominance of thorny bamboos (Guadua spp.). These remnants support the last remaining populations of red howler monkeys found between 800 and 1,300 m of altitude in the Central Cordillera of Colombia. Objective: To assess the population status of howler monkeys in a 51.4 ha-bamboo forest fragment at 1,100 m of altitude. Methods and results: The estimated howler population density in the fragment, based on direct counts, was of 163.4 individuals and 16.9 groups per km², which is higher than that commonly reported for this species in continuous forests, although similar to the estimated density in isolated fragments of mountain forests. In spite of the high density, the group size and composition are similar to those usually reported for this species, with more immature individuals than female adults (1.13:1). This finding suggests that the population is under a stable condition. We estimated an abundance of just 84 howlers in the fragment. The guadual, narrow and elongated, is isolated by surrounding productive systems and has a low plant diversity. Nevertheless, guadua plants provide a suitable structure for the displacement and shelter of howlers. Conclusion: Our results demonstrate the tolerance of this species to the fragmentation and its plasticity in persisting in altered environments. However, the high density of individuals, low plant diversity, forest isolation, edge effect, and close contact with anthropic productive systems, are all possible threats to the persistence of this population.

Keywords : Alouatta seniculus; group size and density; Guadua spp; Maravélez valley; pre-montane forest.

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