The study area

The approximate extent of this extensive ecoregion is 500,000 km2, including the provinces of Buenos Aires (except its southern extremity), northeastern La Pampa, southeastern Córdoba, southern Santa Fe, and Entre Ríos. Some studies also consider the grasslands in the provinces of San Luis and La Pampa to be part of this ecoregion. The climate in this area ranges from temperate-humid to subhumid, with precipitation varying from 600 to 1,000 mm and average annual temperatures between 15 and 18 °C.

The plain is characterized by a gentle relief only interrupted in the south by the mountain ranges of the Tandil and Ventania Systems, with heights of 500 and 1,000 meters above sea level, respectively. This region, classified as one of the most fertile in the world, is and has been since the late 19th century, the center of significant economic investments in the country, leading to significant transformations of its original landscape. Initially covered by a temperate grassland dominated by the flechillar community (grasslands with species of Stipa and Piptochaetium), today the predominant plant species in natural grasslands include Festuca ventanicola, Senecio leucopeplus, Sorghastrum pellitum, Paspalum quadrifarium and Cortaderia selloana . The region is primarily dedicated to the cultivation of cereals and oilseeds, as well as cattle farming. In recent decades, as a result of the modernization of agricultural technologies, the cultivated area has increased significantly (only corn, soybeans, and sunflower cover 30% of the region), and fields remain under crops for much of the year (second crops). Although sheep farming experienced a boom from the late 19th century until 1940, its significant decline began in the 1970s, and currently, most fields only maintain sheep for consumption purposes.