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The definition of limits of any geographic unit, based in the physiography of the landscape, is useful at the moment of developing environmental management politics and guidelines. Several authors have divided the Argentine Republic into regions according to the characteristics of native vegetation. The resulting units are known as phytogeographic provinces. The Monte Phytogeography Province is one of the largest ecoregions of the country and is defined as a unit where the environmental aspects are complex and difficult to categorize. In the present paper, a review of the limits of this phytogeographic province is made, according to bibliographic records of different authors. Survey trips were made and the collected data was georeferenced. A geographic information system was created with geodata and through records analysis, field work and adopting several criteria for its evaluation; the adjusted limits for the ecoregion were adjusted. A new map of the Monte Phytogeography Province is proposed for its use as input in the application of politics in the territory. [ABSTRACT FROM AUTHOR]

In low lands of endorreic basins, the water table is responsible for moving salts along the solum according to soil granulometry. The development of halophyte plants in saline zones would promote the deposit of fine sand, forming lithological discontinuities. An analysis in the water table fluctuations is proposed through edaphic variables, and its influence over different plant communities. Edaphic variables were analyzed in different zones of Salinas Grandes (Catamarca), such as bulk density, sand percentage and carbonates, related to electrical conductivity, pH and the depth of the discontinuities. These variables were correlated with plant cover, biodiversity and minimum rangeland requirement. Sand content, characteristic of these lithological discontinuities, is important in the processes of capillary breakdown over the phreatic ascent with high content of soluble salts. The kind of deposited materials in the surface influences directly over the bulk density. The discontinuity enables root growth due to a lesser influence of the phreatic and lesser concentration of soluble salts. This phenomenon promotes a higher solubilization of alkaline earth carbonates. [ABSTRACT FROM AUTHOR]