Abstract

GOMEZ-POSADA, Carolina; RONCANCIO-D, Néstor; HINCAPIE-V, Paola  and  BETANCOURT-L, Andrés. DENSITY AND GROUP COMPOSITION IN THRE POPULATIONS OF RED HOWLER MONKEY (ALOUATTA SENICULUS) IN VALLE AND CAUCA, COLOMBIA. Bol. Cient. Mus. Hist. Nat. Univ. Caldas [online]. 2010, vol.14, n.1, pp.79-91. ISSN 0123-3068.

In the Valle del Cauca and Cauca departments in Colombia, three populations of red howler monkey were studied: two bamboo fragments (Nana Luisa Farm with 9.7 hectares, and the Montegrande municipal rural settlement with 60.3 hectares) and one area of continuous forests with forestry plantations and secondary forests (Cuenca del Nima). In 2004, population densities and group composition were evaluated using direct counts; additionally, information of the vegetation structure was collected. In the Nana Luisa Farm, a singlegroup of five individuals (51.5 indv/ km²) was found. The structure and composition of the group, the total isolation and small size of the forest, indicates a decreasing population. This population is considered in danger. In the Montegrande municipal rural settlement had a population of 154 individuals and a high density of howlers (254.9 indv/km²). In this fragment, some groups tended to be numerous, probably due to the impossibility of dispersion of the young individuals (effect of the isolation). The plant diversity of this forest and the number of trees for howlers was low, suggesting a limited offer of resources. This population is considered vulnerable. The continuous forest presented a density of 22.6 individuals/km², this value and the composition of the howler groups are similar to those usually reported for the species (in spite of the small sample size). This population is considered "healthy".

Keywords : Alouatta seniculus; population density; group composition; forestry plantations; bamboo forest fragment; mountain forest.

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