Transformaciones de un ecosistema palustre.: La gran ciénaga del Bermejo-Mendoza, siglos XVIII y XIX

The area that presently comprises part of the departments of Guaymallen, Lavalle and Maipu in the province f Mendoza was occupied until the beginning of the 20 th century by a large marshy and lacustrine system. This system has undergone variations in its extension and water volume along several centuries until its desiccation in the first quarter of the 20 th century. By the turn of the 18 th century and beginning of the 19 th the marsh started a disproportionate growth reaching enormous dimensions, thus provoking the loss of farming land and pasture fields. Our interest has been the study of the natural and anthropic causes that occasioned the transformation of this ecosystem. For this, we have resorted to historical documents, ancient maps, descriptions by voyageurs and scientists, complemented by field work in the relicts of the old marsh zone plus the analysis of aerial photographs and satellite images. The phenomenon can be attributed to the wrong watering management in the higher oasis zones, to the topographic characteristic of the terrain and the deficient drainage, jointly with geotectonic phenomena and a period of large snow precipitation in the cordillera that caused the ascent of the phreatic layers.