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The Pantanal ((:pɐ̃taˈnaw)) is a natural region encompassing the world's largest tropical wetland area. It is located mostly within the Brazilian state of Mato Grosso do Sul, but it extends into Mato Grosso and portions of Bolivia and Paraguay. It sprawls over an area estimated at between . Various subregional ecosystems exist, each with distinct hydrological, geological and ecological characteristics; up to 12 of them have been defined (RADAMBRASIL 1982).〔Susan Mcgrath, photos by Joel Sartore, ''Brazil's Wild Wet'', National Geographic Magazine, August 2005〕〔(【引用サイトリンク】title=''The World's largest wetland'' )〕 Roughly 80% of the Pantanal floodplains are submerged during the rainy seasons, nurturing an astonishing biologically diverse collection of aquatic plants and helping to support a dense array of animal species. The name "Pantanal" comes from the Portuguese word ''pântano'', meaning wetland, bog, swamp, quagmire or marsh. By comparison, the Brazilian highlands are locally referred to as the ''planalto'', plateau or, literally, high plain. == Geology, geography and ecology == The Pantanal is a huge, gently-sloped basin that receives runoff from the upland areas (the Planalto highlands) and slowly releases the water through the Paraguay River and tributaries. The formation is a result of the large, concave pre-Andean depression of the earth's crust, related to the Andean orogeny of the Tertiary. It constitutes an enormous internal river delta, in which several rivers flowing from the surrounding plateau merge, depositing their sediments and erosion residues, which have been filling, throughout the years, the large depression area of the Pantanal. This area is also one of the distinct physiographic provinces of the larger Parana-Paraguay Plain area. The Pantanal is bounded by the Chiquitano dry forests to the west and northwest, by the Arid Chaco dry forests to the southwest, and the Humid Chaco to the south. The Cerrado savannas lie to the north, east and southeast. The Pantanal has an average yearly rainfall of , but is fed by the upper Paraguay River. Its average temperature is , but temperatures can fluctuate from . During the rainy season, the water in the Pantanal basin rises between two and five meters. Just as the Nile delta is fertile, arable land, so too are the Pantanal plains. The dramatic increase of water during the rainy season nourishes the producers of Pantanal, which in turn nourishes all the other species, as well. Humans have taken advantage of this so much that it has become a problem. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pantanal」の詳細全文を読む スポンサード リンク
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