Abstract

CORONATO, A et al. Geomorphological characteristics of mountain watershed rivers colonized by Castor canadensis in Tierra del Fuego, Argentina. Ecol. austral [online]. 2003, vol.13, n.1, pp.15-26. ISSN 1667-782X.

The geomorphology of a Fuegian Andes watershed colonized by the introduced species Castor canadensis has been analyzed. The main objective was to distinguish the physical conditions of the occupied streams. Geomorphological analysis and mapping techniques were applied; also, colonization monitoring surveys in the entire watershed was made through terrestrial and aerophotogrametrical methods. Were made aerial surveys during the autumn. Streams of first and second order and low gradient (0-6º) were those chosen by Castor canadensis for settlement. The higher-order streams were seasonally occupied, but restricted only to their secondary landforms. The northern part of the watershed is larger in size, drainage density and stream numbers; therefore, it offers more settlement possibilities. The rivers of the lateral hanging valleys were more densely occupied than those of the slope units. Several of the conditions of rivers for Castor canadensis settlement observed in Tierra del Fuego were similar to those observed in the Northern Hemisphere.

Keywords : Watershed; Geomorphology; Tierra del Fuego.

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