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Brasília

Description:  Brasília, Federal District, is Brazil's capital, located in the Brazilian Central Plateau, locally known as the Cerrado region. The city is expanding very rapidly over the 5,814 km2 of the Federal District. Brasília was planned in the 1950s to be in the center of the country, strategically located in order to promote Brazil's inland development. Many of the governmental and urban facilities were built in the early sixties.

The Cerrado is the second largest biome of Brazil, after the Amazon rain forest, representing 22 % of the country, or approximately 2 million km2. It is a tropical seasonal savanna, with a continuous layer of herbaceous species (mainly C4 grasses) at the peak of the vegetation growth, scattered with shrubs and trees that sometimes form a continuous canopy. It has a characteristic flora, which distinguishes it from other Brazilian biomes, such as the Amazonian and coastal rain forests or the Northeastern Caatinga. The Cerrado savanna is criss-crossed with corridors of mesophytic evergreen forest that occur along the rivers (gallery forest). Other types of vegetation occur infrequently such as hyperseasonal savannas (veredas), and dry savannas (campo rupestre). Four physiognomic types of savanna are commonly recognized in the Cerrado: campo limpo (grassland), campo sujo (shrub savanna), cerrado sensu strictu (savanna) and cerradão (woodland), which differ from each other by the relative abundance of woody and herbaceous (mainly grasses) species.

The annual average rainfall is around 1,500 mm. Approximately 86 % of the Cerrado receives between 1,000 and 2,000 mm of precipitation annually, putting the region into an intermediary climatic position between the rainy Amazonian and the arid Caatinga. About 90% of total precipitation falls between October and March, resulting in two distinct climatic seasons (wet and dry).

During the rainy season grasses are active and produce a large amount of green biomass that dries out during the dry season. The accumulation of dead material facilitates the occurrence of fire, especially at the end of the dry season. Cerrado has the richest flora among tropical savannas and is one of the world's environmental 'hot-spots'.
Over 10,400 species of vascular plants are found, fifty of which are endemic. Fauna diversity is very high also with 180 species of reptiles, 113 of amphibians, 837 of birds and 195 of mammals.

The Cerrado has a high diversity of soil types, geology, geomorphology, and climate. Most Cerrado soils are very deep and well drained, on gentle slopes (commonly less than 3 %), high in clay and iron oxides, and a mix of clay and secondary minerals. However, some soils are acidic; contain a low amount of organic matter; have a low concentration of calcium, magnesium, phosphorus and potassium; have a high concentration of iron and aluminum, and have a low cation exchange capacity. The high aluminum concentration in the soils is a matter of concern and argument. While high aluminum saturation in the cation exchange capacity of the soil can decrease crop productivity, some native trees are able to accumulate large amounts of aluminum in their leaves.

The Cerrado is mostly composed of five topsoils: Latisols, or oxisols (cover 46% of the Cerrado); Cambisols and Litholic Neosols (occupy 10% of the Cerrado); Quartzarenic Neosols and Argisols (cover 15% each). The remaining 14% of the Cerrado is covered with various other soil types. The Federal District is located in the Brazilian Central plateau on the South American tectonic plate. Rocks are mostly from the Pre-Cambrian period, covered with laterite from the Cenozoic period.


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