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Click here to go back Details of this species in Tierra del Fuego (Argentina) Status: Alien Invasiveness: Invasive Occurrence: Established and expanding Source: Anderson and Maley, 2004 Arrival Date: 1946 Introduction: Intentional, legally Species Notes for this Location: Castor canadensis (beavers) were introduced to Argentine Tierra del Fuego in November 1946, from Canada. 25 mating pairs were released into the Argentine side of Lake Fagnano by the Argentine Navy, around the Claro River. The beavers then spread into the several rivers draining from Fagnano Lake, and reached Yehuin Lake by the 1960s. By 1993, they were distributed from the Carmen Silva River in the north to the Beagle Channel shoreline in the south. They occupied 91% of all streams in the 53 watersheds within Argentine Tierra del Fuego (Lizarralde, 1993; in Jaksic et al., 2002). Today, there are approximately 25,000 beavers in Argentine Tierra del Fuego (Lizarralde, 1993; in Jaksic et al., 2002). They prefer streams of low gradient for settlement, although higher gradient streams are seasonally occupied (Coronato et al., 2003). Management Notes for this Location: The beaver is subject to a control programme by the Chilean government on Tierra del Fuego Island. The Argentinian government permits the hunting of beavers throughout the year. Tierra del Fuego currently has a provincial law which forbird the introduction of exotic species (Di Paola and Kravetz, 1999). Location Notes: Impacts: Economic/Livelihoods: Beavers impact on forestry activities as the beaver dams kill trees in adjacent areas. Ecosystem change: The beaver, in building its dams, destroys trees by ringing them and inundates Nothofagus forests (Jaksic et al., 2002). Herbivory: Beavers feed on leaves and bark. Interaction with other invasive species: Beavers impact on forestry business because the beaver dams kill trees in adjacent areas, allowing exotic plants to invade meadows. Modification of nutrient regime: The beaver alters the nutrient dynamics of Nothofagus forests in Tierra del Fuego (Jaksic et al., 2002). Last Modified: 13/04/2006 4:15:13 p.m.