Diversidad vegetal en siete unidades demostrativas del Chaco semiárido argentino

The Great American Chaco, a vast region having an apparent ecological unit, is immersed in a severe degradation process of its natural resources and biodiversity that includes and land use change, deforestation and desertification. It is the objective of this paper to estimate diversity indexes and analyze the ecological situation of seven demonstration units operated under PIARFON, Semiarid Chaco, Argentina Project. It is a continuation of the project PICTO Biodiversity in natural environments of the Argentinian Chaco. A research was done in the following locations: Quebracho Park, Santos Lugares, Buen Lugar, Maravilla, Ahi Veremos in the Alberdi Department; Tala Atun and Quimilioj in Garza, all in the Province of Santiago del Estero and Miramar-Bermejito, General Guemes Department in the Province of Chaco. The closure zone with plots devoted to the study of woody vegetation was established in a selected 5-hectare forest area. Diversity study was performed on 4m x 25m lots included among those of the Forest Inventory (1.000 m2). Species, number of individuals, and stratum they belong to were determined on each plot. In addition a species list was generated including the values of relative abundance,