Abstract

Beaver (Castor canadensis) is an exotic species that was introduced to Tierra del Fuego in 1946. Beaver dams have altered riparian areas existing before their invasion. This study evaluates the impact of beavers on the N. pumilio riparian forest structure in sites with and without beavers in two locations on Tierra del Fuego Island. At both sites, density, diametric distribution and basal area for alive and dead trees were measured. Most trees damaged by beavers were saplings or corresponded to a lower diameter class (< 25 cm, DBH). It was possible to observe that sites with beavers located in both sectors had individuals with significant lower diameter (P < 0.01). Also, sites with beavers had an individual mean density (R