Das Pantanal (Brasilien) - Artenreichtum zwischen Dürre und Vernässung

Mit einer Flächenausdehnung von 160.000 km² ist das Pantanal eines der größten saisonalen Feuchtgebiete der Erde. Es erstreckt sich zwischen 16-20° Süd und 55-58° West. Seine größte Flächenausdehnung befindet sich im westlichen Grenzgebiet der brasilianischen Staaten Mato Grosso und Mato Grosso do Sul (ca. 140 000 km²), kleinere Flächenanteile erstrecken sich über das Dreiländereck nach Südost-Bolivien (ca. 15 000 km²) und Nordost-Paraguay (ca. 5 000 km², vgl. Abb. 1/1a). With 160 000 km², the Pantanal is one of the world's largest inland wetlands. It is situated in a depression, which has been filled with sediments by the Paraguay River and its tributaries since Pliocene/Pleistocene times. Varying water discharge and sediment transport of the rivers during dry glacial and wet interglacial periods led to a small-scale mosaic surface relief. This results today in a large diversity of habitats, characterized by different length of inundation. The vegetation corresponds to the surrounding savanna (Cerradol belt). But there are also species from other adjacent biomes, such as the Amazon rain forest, the Atlantic forest, and the Chaco. About 1,900 species of higher plants are desc ribed, of which about 750 species are woody species. About half of them colonize terrest rial habitats. Most of the others have a broad ecological amplitude and tolerate flood and drought stress