Overview
The Tereré River (also spelled as Tererê River) is a fundamental watercourse for the hydrological dynamics of the Southern Pantanal, located entirely in the state of Mato Grosso do Sul. This river plays a vital role as one of the tributaries on the left bank of the Paraguay River, situated in an ecological transition region of extreme importance for Pantanal biodiversity. Its basin is inserted in an area of floodplains that house a rich variety of wildlife and preserved ecosystems.
The river's name is a direct tribute to regional culture, referencing tereré, the typical yerba mate-based drink consumed cold, which is a symbol of the South Mato Grosso and Pantanal identity. Geographically, the Tereré River is one of the axes that define the landscape of the municipality of Porto Murtinho, serving as an essential biological corridor that connects different conservation areas and rural properties focused on ecotourism and sustainable cattle ranching.
Geography and Course
The Tereré River has its origins in the transition areas between the plateau and the Pantanal plain in Mato Grosso do Sul. Its course runs approximately 307 kilometers through low-gradient terrain, a striking characteristic of the Upper Paraguay depression. The river flows predominantly in an east-west direction until it flows into the left bank of the Paraguay River, north of the city of Porto Murtinho.
During its journey, the Tereré meanders through areas of dense vegetation, including riparian forests and Pantanal Chaco formations. Its main tributaries are smaller streams that drain seasonal rainwater. The region is characterized by sedimentary soils and a topography that favors lateral overflow during flood periods, creating vast areas of vazantes (drainage channels) and temporary bays that are fundamental for the life cycle of countless species.
Hydrological Role in the Pantanal
The Tereré River is an active component of the complex flood pulse of the Pantanal. During the rainy season (November to March), the river's water volume increases significantly, but it is the phenomenon of "reflux" or damming caused by the rise of the Paraguay River that defines its hydrology. When the Paraguay River reaches its maximum levels, it prevents the drainage of the Tereré's waters, forcing them to spread across the adjacent plain.
This seasonal flooding process is what ensures soil fertility and the renewal of nutrients in aquatic ecosystems. The Tereré River acts as a water regulator, retaining water on the plain for months and releasing it slowly as the level of the Paraguay River drops. This dynamic creates an environment of calm waters rich in organic matter, essential for fish reproduction and the maintenance of wetlands that sustain terrestrial fauna during the dry season.
Fauna and Ecology
The biodiversity along the Tereré River is exuberant and representative of the Southern Pantanal. In its waters, fish species of great ecological and sporting value stand out, such as the Pacu, the Pintado, the Dourado, and the Piraputanga. The river serves as an important natural nursery, where fish larvae find shelter and food in the flooded areas of the riparian forest.
On the banks and adjacent areas, the presence of the jaguar (Panthera onca) is frequent, using the fluvial corridor for hunting and movement. Other mammals such as the giant otter, the capybara, and the marsh deer are commonly sighted. The avifauna is equally rich, with the jabiru, the roseate spoonbill, and various species of kingfisher using the river as a primary food source. The preservation of the Tereré's riparian forests is critical for the survival of these species, serving as a refuge against anthropogenic pressures.
Tourism and Experiences
The Tereré River is a privileged destination for contemplative tourism and sport fishing. Due to its more remote and preserved location, it offers an authentic experience of immersion in Pantanal nature. Several ecological inns and ecotourism farms in the Porto Murtinho region use the river for river photographic safaris, where visitors can closely observe wildlife in its natural habitat.
Sport fishing in the Tereré River is regulated and follows strict closed seasons (Piracema) to ensure the sustainability of fish populations. Fishing enthusiasts seek the river especially for the quality of its waters and the abundance of species such as Pacu and Pintado. Additionally, canoeing and sunset boat trips are popular activities that allow for the appreciation of the unique landscape where the Pantanal meets the influences of the Chaco.
Connection with Other Rivers
The Tereré River is intrinsically connected to the vast hydrological network of the Upper Paraguay Basin. Its main connection is with the Paraguay River, of which it is a direct tributary. Through this connection, the Tereré integrates into the system that receives water from other large rivers such as the Cuiabá River and the São Lourenço River further north.
In the southern region, its water dynamics are influenced by the proximity to the Miranda River and the Aquidauana River, whose basins share similar geological and climatic characteristics. During major floods, the waters of these systems can interconnect through corixos and vazantes, forming an immense continuous mirror of water that characterizes the Southern Pantanal in its fullness.
References
[1] ALHO, C. J. R. (2008). *Biodiversidade do Pantanal*. Editora UNIDERP.
[2] EMBRAPA PANTANAL. (2020). *Hidrografia do Pantanal*. Embrapa Pantanal. Available at: https://www.embrapa.br/pantanal/publicacoes
[3] POTT, A.; POTT, V. J. (1994). *Plantas do Pantanal*. Embrapa-SPI.
[4] SOS PANTANAL. (2023). *The importance of rivers for the Pantanal*. SOS Pantanal. Available at: https://sospantanal.org.br
[5] IUCN. (2023). *Pantanal*. The IUCN Red List of Threatened Species. Available at: https://www.iucnredlist.org/regions/south-america/pantanal
[6] ICMBIO. (2022). *Plano de Manejo do Parque Nacional do Pantanal Mato-Grossense*. ICMBio. Available at: https://www.icmbio.gov.br
[7] SILVA, J. S. V. (2000). *O Pantanal: Natureza, Homem e Cultura*. Editora da UFMS.
