Publicada en: 28/12/2011 a las 15:20
The Pantanal biome
Nasa WorldWind - P199/Wikipedia
Nasa WorldWind - P199/Wikipedia
If you don’t know much about this biome, you may think it’s just a wetland filled with swamps. Ok, we’ll give you that, a lot of Pantanal is flooded. But swamps and marshes are not all of it.
Since it is located near both the Amazon and the Cerrado, Pantanal harbors many plant and animal species from both biomes, besides housing many endemic species - that is, species that can only be found in that geographical area, that are native to the region.
Due to its rich biodiversity, Pantanal was considered by UNESCO (the United Nations Educational, Scientific and Cultural Organization) as a World Heritage Site. Let’s get to know more about this treasure.
Up until now, 122 species of mammals, 93 of reptiles, 656 of birds and 263 of fish were reported in the region. Birds and fish are the most exuberant animals of the biome.
Photo: Pierre Pouliquin/Flickr
Since water is quite abundant in this ecosystem, there are plenty of fish. There are more species of fish in Pantanal than in all rivers of Europe! Among those are thousands of spotted sorubins (P. corruscans) , characins fishes like pacus, golden dorados (Salminus brasiliensis) and jaús. Jaús (Zungaro jahu) are giant catfishes that grow up to 5 feet and weigh as much as 260 pounds.
Among mammals, the cougar, the jaguar, the ocelot, the capybara, the giant otter, the tufted capuchin monkey and the marsh deer should be mentioned. Most mammals in Pantanal live in riparian forests, that is, forests adjacent to rivers.
Maybe the most widely known reptile in Pantanal is the caiman, a type of alligator. Caimans with up to 8 feet 2 inches have been recorded. The most commonly seen is the Yacare caiman, the spectacled caiman and the black caiman. Can you guess what alligators eat? Calm down! Believe us: the diet of these large alligators are fish-based. They are not aggressive as movies make us think they are; they only attack humans when they feel threatened.
Besides the caimans, there are other reptiles in Pantanal, like different snakes - such as anacondas, lanceheads, the red tailed boa (Boa constrictor) - and the green iguana.
The vegetation actually comprises a series of different landscapes. We have already mentioned that the biome is near the Amazon and the Cerrado. The proximity causes Pantanal to share plant species with the Amazon, such as those from the wetlands, and others similar to those of the Cerrado, in the non-flooded areas and riparian forests.
Riparian forests, which are those at the margins of rivers, are denser and include species such as Genipa americana, fig trees, ingas, palm trees and the pau-de-formiga (Triplaris brasiliana). Of course, “Pau-de-formiga”, in Portuguese, means “ant wood”, because the tree is used as shelter by a kind of ant whose bite hurt a lot. For instance, when someone shakes the tree or tries to cut it down, the ants fall (or come out of it) and start biting anyone that’s near it. Naughty Pantanal ants!
There are fields of grass (of purpus’ carpetgrass, for example) that are similar to those of the on the grassfields of the Cerrado and appear more rarely on the wetlands. On areas that never get flooded, bigger trees settle in, such as the caranda palm (Copernicia australis), the moriche palm, and the ipês, which, in the months of July and August, color the Pantanal with their pink, lilac and purple flowers.
Floating aquatic plants, such as the water hyacinth and the water lettuce - besides fixed plants with submerges leaves, such as the dwarf sagitaria and submerged plants like fanworts and bladdenworts - can always be found on the wetlands.
In the Pantanal, there is a type of forest called “paratudal”. Thick-barked, wrinkled trees with twisted branches grow in it. The yellow ipê (called “paratudo” in the region) is widely disseminated, thus the name of the forest.
Bonito. Photo: renato saboya/Flickr
The soil in the Pantanal is formed by material that come from upstream. It’s not very permeable. Because of the constant flooding and the ensuing excess water, organic matter decomposes slowly, which decreases fertility.
The soil is only fertile after it dried. When the rain stops and the soil dries, a mixture of sand, animal and plant remains, seeds and humus are left over the ground, which makes the soil more fertile.
The soil in the higher and drier lands is sandy and acid. There, the water is absorbed and retained underground in the aquifers. The fertility in these soils is also restricted.
Plains are prevalent in the Pantanal. When the plains are flooded, sandy hills measuring up to 20 feet can be observed among the waters. These formations are called “cordilheiras” (“mountain ranges”).
Around the plains there are elevations such as plateaus, ridges and massifs. The most famous is the Urucum massif, in Mato Grosso.
In the great ecosystem called Pantanal, water regulates life. We’re talking about the largest floodplain in the world: it is estimated that around 45 million gallons of water enter the plain every day.
But where all this water comes from?
The plains flood in the rainy months. The discharge of rivers crossing the region thus increases. The plains, which have low declivity - that is, are not very steep - retain the waters as they pass by. Since the soil is not very permeable, it can’t absorb all the water and the plains flood. That’s how the lagoons, bays, bogs and marshes - which remain connected by the courses of the rivers - are formed.
Among the most important rivers in the region are the Cuiabá, the São Lourenço, the Itiquira, the Correntes, the Aquidauana and the Paraguay rivers. They are all part of the Rio de la Plata drainage basin, which encompasses part of the southwest of Brazil.
The climate in Pantanal is tropical, which means temperatures are very high there. The region has two distinct seasons: a rainy summer, from October to March - when the temperature fluctuates around 90º F (32º C) - and a dry winter, from April to September, when the average temperature is 70º F (21º C).
Heavy rains are also a determining factor for the Pantanal. They flood the plains, which changes not only the vegetation, but the lives of animals and men for a few months in the year.
* Photo:Marcelo Mendes de Oliveira/Flickr
** Photo: ROBINHO Y PACO/Flickr
Learn more about other biomes and ecosystems:
Linhares, S. & Gewandsznajder, F. Biologia Hoje - Vol 3. São Paulo: ed. Ática, 1998.
Vânia Rocha, biologist at Fiocruz’s Museu da Vida (Life Museum).
Museu da Vida - Casa de Oswaldo Cruz - Fiocruz