Climate and Soil Conditions Across the South Brazilian Grasslands

The climate of the South Brazilian grassland region is influenced by wet tropical air masses from the Atlantic and the Amazon during spring and summer, and by wet Polar air masses from the south of the South American continent during fall and spring. Precipitation is well distributed throughout the year and the average temperature of the warmest month exceeds 22 °C across most of the South Brazilian grasslands. This characterizes a Cfa climate according to Köppen’s classification, except in the northeastern portion, where due to elevation the average temperatures in the warmest month are below 22 °C, corresponding to a Cfb climate. Episodically, the region suffers effects from the El Niño Southern Oscillation (ENSO). During the warm phase, the South Brazilian grasslands experience increased precipitation, while in years of ENSO’s cold phase, locally known as La Niña, the opposite occurs. Scenarios of climate change indicate a trend of increasing precipitation in the coming decades. The soils in the northern portion of the South Brazilian grasslands are mainly deep soils with low natural fertility, while in the south, where elevations are lower, soils of all functional classes occur: shallow, deep soils with high and low fertility, and hydromorphic soils. The soil characteristics are not an inhibiting factor for the occurrence of grassland vegetation, but they do influence their species composition. Both soil and climate have shaped land use history in the region, and climate change is expected to influence both natural and anthropogenic ecosystems and their dynamics.