Abstract

ELJALL, Ana; DIEGUEZ, Hernán; MENVIELLE, M. Fernanda  and  HODARA, Karina. Distribution and spatial patterns of the impacts of an exotic and invasive ecosystem engineer: Castor canadensis in Tierra del Fuego, Argentina. Ecol. austral [online]. 2019, vol.29, n.1, pp.63-71. ISSN 1667-782X.

The American beaver (Castor canadensis) is an ecosystem engineer introduced in 1946 in Tierra del Fuego, in the southernmost end of South America. Currently, beavers inhabit the different environments of the Fuegian archipelago, where they generate significant changes in the structure and functioning of ecosystems, mainly through the flooding of riparian areas by means of dam construction. The aim of this work was to describe, for the first time through an exhaustive survey, the spatial patterns of the distribution and density of beaver dams in the Argentinian portion of the Isla Grande de Tierra del Fuego. With this purpose, a geographic database was created, registering dams by means of visual interpretation of freely accessible satellite images with high spatial resolution. A total of 70682 dams were identified whose cumulative length exceeds 2300 km and flooded an area of at least 87 km². The highest dam density was observed in the cordilleran region, reaching maximum values of up to 123 dams/km² in the SE of Fagnano lake. In the southern portion of the island, 84% of the territory is less than 1 km away from its nearest beaver dam. The information generated in this work is free to use for research purposes. It can be used to test hypotheses about the biophysical and human controls of the invasion, the identification of priority areas for research and the development of management strategies, as well as for the monitoring of the invasion in space and time, the early detection of new invaded areas and the training of automatic methods for the detection of areas impacted by the beaver.

Keywords : Biological invasion; Exotic mammals; Patagonia; GIS; Google Earth.

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