Abstract

TARIFA, Teresa et al. Vizcachas (Lagidium viscacia, Chinchillidae) in fragmented habitats in the city of La Paz and surrounding areas: Basis for its conservation. Ecología en Bolivia [online]. 2004, vol.39, n.1, pp.53-74. ISSN 1605-2528.

In 1999, in the city of La Paz and its surroundings, we investigated 13 sites (from 17 potential locations) where we found populations of viscachas (Lagidium viscacia) isolated on small fragments of remnant habitats each day more threatened by urban development of the city. At seven sites we found viscachas in cliffs or steep slopes with rocks; at the other six sites they were in cliffs or steep slopes formed by clay soil of glacial origin (löss). Some authors do not consider this appropriate habitat for viscachas. Through the use of nine indirect criteria of disturbance with four degrees of intensity, we determined the degree of deterioration for each one of the sites. In 1999, five sites had low, five sites had medium, and three sites had high levels of disturbance. In 2003, we re-visited eight sites, two of the sites were completely destroyed, two exhibited low disturbance, three medium, and one high. The comparison of the vegetation of one highly disturbed site with one with little disturbance showed significant differences, as much for the general area as for areas near viscacha burrows. Nevertheless, percentage of items in categories of plants was notably similar, and both areas had comparable diversity indices for the transects across the area as well as adjacent to the burrows. Finally, we identified seven threat factors that, in interdependence with the natural history of the viscacha, affect the conservation of this species in the city of La Paz and its surroundings. Among the most critical threats are habitat fragmentation, the quality and size of the habitat, and loss of the ecosystem itself.

Keywords : Lagidium viscacia; viscachas; Bolivia; fragmentation; conservation; local extinction; urban development.

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