Browsing by guanaco (Lama guanicoe) on Nothofagus pumilio forest gaps in Tierra del Fuego, Chile

The presence of guanaco (Lama guanicoe, Muller 1776, Camelidae) in forests of Nothofagus pumilio (Poepp. et Endl.) Krasser. (lenga) in Tierra del Fuego has been associated with browsing damage in the regeneration of these forests, but little quantitative data are available. In developing and implementing forest management plans for N. pumilio forests, the effects of guanaco browsing are a major source of variation in attaining regeneration and growth goals, however, guanaco is not generally accounted for in management planning in the region. In this study we examined the browsing damage levels of guanaco and introduced livestock on N. pumilio regeneration occurring in canopy gaps of forests in Tierra del Fuego, Chile (54°12′S, 68°45′W). Relationships were established between browsing levels and gap characteristics like gap size, gap age and abundance of regeneration. Results indicated that 88.7% of regeneration growing in gaps experienced some degree of damage by browsing, and that the degree of damage was higher in smaller gaps, which might depend on the size of guanaco herds. We also found that the degree of damage was positively related with the abundance of guanacos. However, no relationship was found between gap size and abundance of guanacos.