American mink (Mustela vison) in Tierra del Fuego: Ecology of an introduced predator

The American mink (Mustela vison Schreber) was released on to Tierra del Fuego Island in the 1940’s, subsequently spreading to adjacent islands in the fuegian archipelago. The main effects of its introduction in other parts of the world include the reduction, and even local extirpation, of prey populations and the displacement of native mustelids. Knowledge of the ecology of this introduced predator is essential for planning control and eradication strategies. We, therefore, evaluated abundance, distribution, habitat characteristics and diet of mink along the Argentine coast of the Beagle Channel. We then constructed a habitat suitability model based on den positions and vegetation cover in GIS. We estimated density of dens on different habitat type (forest, shrubland, peat, grassland and muddy beach) and human presence along 600 m transects set every 5 km. Scats was also collected for diet analysis. We found mink dens only in forest and shrubland habitats. Distribution was heterogeneous and unrelated to human presence. Most minks dens were established within 5-11 m from the coastline and in slopes between 5º-30º. Diet differed between winter and summer, with mammals being the most consumed item in both seasons, while in summer the consumption of fish, birds and crustaceans increased. These results allow us to propose that conservation strategies should be based on the establishment of high priority areas and corridors, focusing captures along coastal forests.