Pantanal Wetlands

• Category: Inland Aquatic Biomes.
• Geographic Location: South America.
• Summary: One of the world’s largest wetlands, located in the heart of South America, is a seasonally flooded area hosting an amazing diversity of wildlife that is the subject of expanding ecotourism and protection efforts.

Known as South America’s Serengeti, the Pantanal Wetlands biome is one of the largest wetland areas in the world, extending some 66,000 square miles (170,000 square kilometers). The Pantanal is mostly located along the Paraguay River in Brazil, in the states of Mato Grosso and Mato Grosso do Sul; it also reaches into neighboring Bolivia and Paraguay. The southern edge of the Pantanal is near Fort Olimpo, Paraguay, where hills close in on both banks of the Paraguay River. The wetlands are flooded in the wet season but emerge as a vast grassland during the dry season.

Climate and Biodiversity

A summer rainy period from November to March deposits most of the annual rainfall of 39–59 inches (1,000–1,500 millimeters). The name Pantanal is from the Portuguese word pantano, for swamp, certainly an adequate descriptive term here. Winters are the dry season, and occasionally, the temperature drops to near freezing. The area is mainly flat, with minor changes in elevation resulting in big changes in the water coverage. In the low areas are thousands of lakes, ponds, and river oxbows; these support great spreads of floating aquatic plants.

At slightly higher elevations, sedges and seasonally-flooded grasslands, known as campos, may be found. Fish enter flooded areas during the wet season to breed; birds such as roseate spoonbill and wood stork are attracted to the flooded areas to feed on the fish.

To the north and on hills adjacent to the flooded grasslands are cerrado vegetation, a woodland savanna that bridges the area between the Amazon rainforest and more temperate forests. Because the cerrado is less frequently flooded, much of the vegetation is fire-adapted, with grasses, shrubs, and short trees. Along rivers are found riparian forests.

Large animals in the Pantanal include caimans (reptiles in the alligator family), anacondas, jaguars, giant otters, giant armadillos, monkeys, bats, anteaters, marsh deer, and pampas deer. The jaguars feed on the capybara, large rodents that are slightly bigger than a beaver, as well as other mammals, including livestock owned by local ranchers.

Notable bird life includes more than 650 species, such as macaws, roseate spoonbills, wood storks, rheas, and seriemas. Storks, herons, and ibises nest in large rookeries here. The jabiru, a type of stork, is the symbol of the Pantanal. There are an estimated 400 species of fish inhabiting the Pantanal waters. The richness of wildlife in this biome makes the Pantanal one of the world’s most critical wildlife areas, rivaling even the African savannas.

Threats

The surrounding plateaus include areas of extensive soybean, wheat, and rice plantations. These agricultural lands use large amounts of pesticides and herbicides, which wash downstream into the Pantanal and have caused fish kills. In the past, the Paraguay River was scheduled for large-scale channel constructions, which would have changed the hydrology of the area. However, this proposal, known as the Paraguay-Parana Hidrovia, is on hold in the upper Paraguay basin. The proposal is of concern because the Pantanal stores water and maintains the flow of the Paraguay River during the dry season, and reduces flood peaks during the wet season, thus playing a major role in the hydrological regime of southern South America.

Elsewhere in the region, smaller dredging projects have occurred in the Brazilian and Bolivian portions of the Pantanal. Overfishing is also a threat to the Pantanal Wetlands biome, as are hunting and poaching. Climate change threats faced by this biome include accelerated evaporation due to higher air temperatures, a dangerous trend that could severely unbalance an ecoregion evolved around very distinct seasonal moisture regimes. In carbon-rich systems like the Pantanal, any significant long-term drying could release a great quantity of greenhouse gas, which would act to advance the pace of global warming in Earth’s atmosphere. In 2019 and 2020, the area suffered a prolonged drought that resulted in subsequent fires that destroyed thousands of hectares. It was the worst drought in the Pantanal Wetlands in fifty years. A study attributed the drought to climate change. Extreme drought continued, with the country recording drier and hotter conditions in 2023 and 2024. During these years, the are experienced irregular rains and a deficit of precipitation. The rainfall patterns recorded were consistent with the long tail of El Niño.

Conservation

The Pantanal Matogrossense National Park, established near the center of the biome and along the east bank of the Paraguay River, protects a flooded habitat area of about 520 square miles (1,350 square kilometers), but little upland habitat. This area is listed as a Ramsar Wetland of International Importance and a World Heritage Site. The Pantanal Conservation Complex World Heritage site includes this park and Doroche Reserve, both in the Brazilian state of Mato Grosso, as well as the Acurizal and Penha Reserves, located in Mato Grosso do Sul. The reserves were private ranches that now have become part of a system of voluntary Private Reserves of Natural Heritage. Landowners participating in the private reserve system are offered tax breaks and management assistance.

The Brazilian extent of the Pantanal as a whole is also a Man and the Biosphere Reserve. This is a designation of the United Nations Educational, Scientific, and Cultural Organization (UNESCO), in which protected areas and adjacent buffer zones for human use are managed to maintain the cultural heritage of indigenous communities while also protecting ecological sustainability. The Pantanal Biosphere Reserve includes such features as the national park, Taiama Ecological Station, and other areas in the region. Ecotourism and recreational fishing are examples of sustainable natural resource use activities that are encouraged by the Biosphere Reserve designation. Across the Paraguay River in Bolivia is the San Matias protected area. Bolivia also protects an area along the Otuquis River, at the common border with Paraguay and Brazil.

Various parts of the Pantanal are being developed as ecotourism destinations for bird watching and wildlife observation. A number of outfitters offer jaguar-viewing tours, for example. In another, the Estrada Transpantaneira is a dead-end road in southern Mato Grosso that is used for viewing caimans and wading birds. Boat rides and tourist activities also embark from Corumba and Miranda in Mato Grosso do Sul.

Bibliography

Alho, Cleber J. R., et al. "Environmental Degradation in the Pantanal Ecosystem." BioScience, vol. 38, 1988, pp. 164-71.

"Early Fires in Brazil's Pantanal." NASA Earth Observatory, 2 May 2024, earthobservatory.nasa.gov/images/152925/early-fires-in-brazils-pantanal. Accessed 9 Nov. 2024.

Ghai, Rajat. "Arid Americas: Are Pantanal, Colorado in a 'Post-Drought' Stage?" Down to Earth, 19 Aug. 2021, www.downtoearth.org.in/news/climate-change/arid-americas-are-pantanal-colorado-in-a-post-drought-stage-78562. Accessed 9 Nov. 2024.

Gottgens, Johan F., et al. "The Paraguay-Parana Hidrovia: Protecting the Pantanal with Lessons from the Past." BioScience, vol. 51, 2001, pp. 301-08.

Lowen, James. Pantanal Wildlife: A Visitor's Guide to Brazil's Great Wetland. Bradt Travel Guides, 2010.

Marengo, Jose A., et al. "Extreme Drought in the Brazilian Pantanal in 2019-2020: Characteristics, Causes, and Impacts." Frontiers in Water, 23 Feb. 2021, doi.org/10.3389/frwa.2021.639204. Accessed 9 Nov. 2024.

Swarts, Frederick A., editor. The Pantanal: Understanding and Preserving the World's Largest Wetland. Paragon House, 2000.