Resumen

GALLARDO, Giovana; NUNEZ, Angela  y  PACHECO, Luis F.. Line transects as an alternative to estímate vicuna (Vicugna vicugna) abundance: case study at the Sajama National Park, Bolivia. Ecología en Bolivia [online]. 2010, vol.45, n.1, pp.64-72. ISSN 1605-2528.

The method currently used to estimate vicuna (Vicugna vicugna) abundance in Bolivia and other countries is the total direct count in a given area (census). An alternative method to censuses was tested since it would be cheaper and provide comparable information in terms of precision and accuracy. Thus, we evaluated the line transect method which has been widely used to estimate wildlife density, particularly with species similar to vicuna in open habitats. Twenty transects were located in Sajama National Park and later walked (once each) immediately after the yearly census (2004), resulting in 96 observations of vicuna groups. A comparison of the abundance of vicunas (1,764 animals) derived from line transect counts with that obtained via a census over the same area (1,751 animals), suggested that the line transect method may be used as the preferred method because of its cost effectiveness in terms of vehicle and fuel use, though it required a slightly higher effort in terms of personnel measured as man-hours. The line transect method may also be more advantageous for estimates over large areas, given that the effort required tends to decrease with area surveyed (using correct sampling procedures) in contrast to censuses which require greater effort for larger areas surveyed.

Palabras clave : Census; Line transects; Monitoring; Sajama; Vicuna.

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