Abstract
Flooding throughout the Pantanal is seasonal. The complex vegetative cover and high seasonal productivity support a diverse and abundant fauna. A gradient in flood level supports a range of major habitats in a complex mosaic with annual seasonality. The rivers and streams are lined with gallery forests, and other arboreal habitats exist in the more elevated areas. The remainder is either grasslands or seasonally flooded grasslands. The regional flora and fauna are adapted to annual water fluctuation. However, an inter-annual series of higher or lower rainfalls has caused either severe floods or drastic dry seasons. Large scale climate phenomena such as greenhouse gases, El Niño and La Niña influence the seasonality of floods and droughts in the Pantanal. Knowledge of severe floods and droughts, which characterize natural disasters, is fundamental for wildlife management and nature conservation of the Pantanal. Plants and wild animals, for example, are affected by tree mortality in riparian forest after extreme flooding, with consequent habitat modification for wild animals. In addition, human activities are also affected since cattle ranching and ecotourism are economically important in the region, and when seasons with unusual floods or droughts occur, areas with human settlements are impacted.