Wetlands of the Fueguian steppe, the influence of domestic grazing

COLLANTES M; ESCARTÍN, C; BRAUN K; RAUBER, R.B

Ushuaia

Simposio; Jornadas científicas del IMCG Field Symposium; 2005

International Mire Conservation Group, Provincia de Tierra del Fuego, Consejo Federal de Inversiones

Northern Tierra del Fuego wetlands, named vegas or mallines, are lowlands having a clay soil layer that prevents water leaking and determining temporal or permanent flooding. Vegas have a variability given by soil, geology and vegetation. They are highly productive communities having grasses and hygrophytic vegetation. Extensive sheep cattle rearing has been the major human activity in the last 100 years in this region, and overgrazing has been related to soil trampling and erosion, weed invasion by Caltha sagittata (Ranunculaceae) and desertification in the area.In this study we describe the main types of vegas of the fuegian steppe in relation with the environmental variation and we analyze the effects of sheep grazing.The fuegian steppe. Northern Tierra del Fuego steppe covers about 15.000 km2 from the Strait of Magellan to approximately 54° S. Its weather is cold oceanic with mean temperatures of 10ºC in summer and 0ºC in winter. Mean anual rainfall is of 350 mm, evenly distributed throughout the year, though a high water deficit occurs in summer due to high potential evaporation rates caused by strong winds