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Bioclimatic classification of Brazil
Bioclimatic map of Brazil after Rizzini and Maia Pinto (1964). Moisture zones according to Thornthwaite's moisture index (Im). Vegetation areas as delimited by Rizzini (1963). Observe that both superimpose quite well.
Roman numerals on the map idicate vegetation; Arabic numerals indicate localities.
Vegetation: I. Amazon forest; II. Atlantic Forest; III. Cerrado; IV. Caatinga; V. Cocais ( babacu zone); VI. Pantanal; VII. Restinga; VIII. Pinheiral; IX. Campos do Rio Branco; X. Campos do Rio Grande do Sul.
HUMID-PERHUMID CLIMATE. Under this type, which has no ecological dry season (although at times with short rainless periods of not more than three months) are found the greatest rain forest areas in the world, namely, the Amazon dominated by the giant Araucaria angustifolia or Parana pine, either alone or more or less intermingled with trees from the Atlantic Forest.
HUMID CLIMATE. This type, like the former, has no drought period of ecological significance, and is found in the temperate (i.e., in the far southern) portion of Brazil, covering most of the state of Rio Grande do Sul. It is amply dominated by the Campo Limpo (X), a sort of prairie rather similar to the boreal (North American) type, but of quite distinct floristic composition and sclerophyllous habit.
SUBHUMID-HUMID CLIMATE. This type is characterized by a well-defined, regular, dry period lasting some four to five months; its range almost equals that of the humid-perhumid climate in extent. Two vegetation complexes stand out in this climate: The Atlantic Forest (II), extending along the maritime range (Serra do Mar) and representing the largest rain forest body in Brazil after the Hylaea; and the cerrado (III), the extensive savanna which prevails over the central plateau. Less important are: The Cocais or babacu zone (V), characterized by immense palm groves and comprising the states of Maranhao and Piaui; and the Restinga (VII), coastal vegetation consisting of the low and sparse plant cover of the beach, the mangrove, and a kind of sclerophyll forest consistently resembling the cerrado; and the remote Campos do Rio Branco (IX), composed of shrubs as well as under shrubs, both sparsely settled.
DRY-SEMIARID CLIMATE. Under this heading is a type, which is sharply marked by a long (6-9 months) and irregular drought period. This limitation of the development of the vegetation is further aggravated by the poor water storage capacity of the shallow soil, whereas in a subhumid-humid climate the deep soil stores large amounts of water and has a shorter dry season.
Accordingly, the vegetation found on such tracts is made up of many scrubby trees, rich in thorny species, and interspersed with numerous succulent plants (chiefly Cactaceae). This vegetation is the remarkable Caatinga (IV). Along the coastal rain forest belt the caatinga is taller and denser than it is inland, on account of the more abundant humidity carried by the sea winds. Therefore, it may be looked upon as a xerophilous forest. The caatinga covers the northeast, but extends itself also somewhat to the south, to Minas Gerais, and to Maranhao in the north.
PANTANAL (VI) is a transitional area situated in the southwestern part of Brazil, where the dry Chaco (from Argentina, Paraguay, and Bolivia), the Cerrado, and the Atlantic Forest are intermingled. The country is subjected regularly both to prolonged floods by the Paraguay River and to long drought periods.
The restinga and the campos are more closely related to the particular soil types in wich they thrive, than to the climatic types observed in their ranges.
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