DINÁMICA DE LA VEGETACIÓN DE LOS HUMEDALES DEL PARQUE NACIONAL LAGUNA BLANCA (NEUQUÉN, ARGENTINA). PROPUESTA DE UN MODELO DE ESTADOS Y TRANSICIONES.

A states and transitions model is presented for the Laguna Blanca National Park wetlands. For the description of the states, vegetable community characteristics, such as dominating life form, coverage, and floristic diversity; soil characteristics, as texture, pH, and salinity; and geomorphologic characteristics were used. The combined action of variations in hydrologic regime and wetland management (continuous grazing) has promoted changes in the original vegetation, which allowed four states to be described-grouped in hydrophytes, mesophytes, halophytes, and xe­rophytes, and six transitions to be considered. From the tendencies observed, we can conclude that the states show different stability to continuous grazing. Prolonged drought and consequent system salinization affects the ecosystem forage diversity and productivity. It can be established that the system currently maintains itself due to lateral water recharge and local precipitation, which would imply that, if the perturbation continues, there will be a decrease of hydrophytes and mesophytes prairies, and an increase of halophytes and xerophytes [ABSTRACT FROM AUTHOR]