The Uruguayan savanna is a subtropical grassland and savanna ecoregion that extends from the extreme southern part of the Brazilian state of Rio Grande do Sul to include the entire country of Uruguay and a small section of Argentina along the Uruguay River.
The Uruguayan savanna, also known as the Brazilian-Uruguayan savanna, is a subtropical grassland and savanna ecoregion that extends from the extreme southern part of the Brazilian state of Rio Grande do Sul to include the entire country of Uruguay and a small section of Argentina along the Uruguay River.
Mainly consisting of medium-tall grasslands, these savannas encompass a mosaic of gallery forests, palm savannas, and outcroppings of submontane forests.
The gallery forests are found along the Uruguay, Negro, Yaguarí, Queguay, and Tacuarembo rivers in the easternmost part of the region. In contrast, submontane forests and palm savannas are scattered throughout the ecoregion.
The complex geology of the Uruguayan savanna region includes Precambrian, cretaceous, Jurassic rocks, and more recent sedimentary rocks. In addition, two-million-year-old metamorphic and magmatic rocks are predominant on the eastern side of the ecoregion.
In addition, a strip approximately 200 km (124 mi) wide from the coastal area to the northern part of the ecoregion contains six-million-year-old metamorphic rocks.
Annual precipitation ranges from approximately 1,000 mm (40 in) in the south to 1,300 mm (50 in) north. The average temperature ranges from 16 ºC (61 ºF) in the south to 19 ºC (66 ºF) in the north.
Flora and Fauna
The Uruguayan savanna hosts 72 species of mammals, including four marsupials, 17 bats, five placenta mammals, 17 carnivores, two even-toed hoofed mammals, and 20 rodents.
Some of the native mammals in the savannas are the pampas deer (Ozotoceros bezoarticus), Guazauvirá deer (Mazama gouazoubira), and capybara (Hydrochoerus hydrochaeris), the world's largest rodent.
Most of the mammals from this ecoregion are found in the gallery forests along the Uruguay River and the small ravines of the north.
The savannas are home to about 80 avifauna species. These include the greater rhea (Rhea americana), ochre-breasted pipit (Anthus nattereri), yellow cardinal (Gubernatrix cristata), saffron-cowled blackbird (Xanthopsar flavus), and pampas meadowlark (Sturnella militaris).
The Uruguayan savanna is critically endangered since few small isolated patches of intact habitat remain. Furthermore, the whole ecoregion has been severely altered by cattle ranching, one of the main pillars of the national economy in Uruguay.
The Uruguayan government, however, is acting to preserve what remains of the native flora in this ecoregion.
Map depicting the location of the Uruguayan savanna ecoregion in Uruguay, Brazil, and Argentina