Igapó
Igapó (Portuguese pronunciation:
Characteristics
Igapó is primarily characterized by seasonal inundation caused by abundant rainfall; in some areas, trees can be submerged for up to 6 months of the year.[2] These ecosystems are relatively open and feature over 30% canopy cover with an average canopy height ranging from 20–25 m (65–80 ft); sparse measurements of trees can reach 33–36 m (110–120 ft). Tree composition includes a varied mixture of leaf types and seasonality. Development of tree communities within the freshwater swamp forests rely heavily on microtopography and flooding intensity. Swamp forests can have harsh environments, in which only a few adapted species are able to sustain life or dominate over other tree species. One of the tree species mostly found in freshwater swamp forests are legume trees, in which most swamp forests have high single legume species populations. Legume trees in these forests are thought to be abundant in nitrogen fixation, which is most common in waterlogged locations and is thought to be a favorable trait when experiencing seasonal and/or constant waterlogging.[3]
Freshwater swamp forests can be classified into two categories of forested wetlands, which are permanently and periodically flooded forests. It is possible to find these two types because of the high microtopographic variation. Due to these topographic differences, tree communities are delimited and have a distribution over small continuous areas.[3]
These forests may be able to sustain a large number of
Soil chemistry
Igapó forests are characterized by sandy
Flora
Igapó and other flooded forests typically display a lower diversity of plants than that seen in terra firma forests. Similar to other forests found throughout the tropics, it is common to observe only a few dominant tree species[3] Distribution of trees and other plants is highly dependent on inundation tolerances of species causing a non-random distribution of plants where more flood-tolerant species are found at lower elevations and less flood-tolerant species are found on higher ground. Fabaceae (or Leguminosae) and Euphorbiaceae are the dominant families of plants observed in igapó forest.[2][4]
Seed dispersal
Tree species adapted to seasonal inundation have adapted to maximize
Fauna
Diversity of terrestrial wildlife and fishes in igapó is highly influenced by flooding. During periods of inundation, vast numbers of aquatic species migrate into the flooded forest in search of food. Fish populations are highest during maximum fruiting periods and
Larger terrestrial mammals have varied strategies of dealing with flooding:
Human occupation and use
Native Amazonians have been using and modifying the forests in which they have lived for thousands of years. Several studies suggest that the presence of nutrient-rich "black earth" in typically nutrient-poor igapó environments indicates intense fertilization and burning of these areas. Black earth is a modified soil characterized by high nutrient content from highly stable organic matter and high levels of phosphorus.[citation needed]
The highly fertile soils and the openness of these areas confirm that the native Amazonians have been using these fields for agriculture.[10]
However, the Amazonians have not only used these areas for crops; they have used their agricultural lands as a place to hunt as well. Many animals (rodents, tapirs and deer) are attracted to these areas for food. The Amazonians produce a surplus so that the animals do not over-consume their food resource. Though, if the animals do start to deplete their crops, they will then harvest higher numbers of animals. Additionally, Amazonians consume fish as a main source of protein. Indigenous peoples understand that, while flooded, the forest serves as an essential feeding ground that increases fish abundance. Because of this, many protect igapó forests from deforestation.[11]
Conservation
The greatest threat to igapó forests is the construction of
In protected areas, such as
Notable areas
Freshwater swamp forests are distributed in multiple climate zones throughout the world, such as boreal, temperate, tropical and subtropic zones. They are found in the Afrotropics, Australasia, Indomalaya, and the Neotropics. However, they are most notably found in Amazonian areas.
- Cantão
- Igapó forests are one of the distinct natural communities found in the Cantão State Park. They offer a rich bird fauna that includes some habitat specialists due to the unique ecosystem the blackwater inundation provides. The trees in the igapó bloom once the inundation season begins. They do this so they can drop their fruit into the water to be dispersed by the different fish taxa.[9]
- Jaú National Park
- The Jaú National Park was designated in 1980 and is the largest national park in the Amazon Basin and the second largest protected tropical forest. It is known for its high level of biodiversity and varying ecosystems within. The park protects the entire watershed of the Jaú River, which happens to be one of the best examples of a blackwater ecosystem where the water is colored by acidic decomposing organic matter.[9]
- Mamirauá Sustainable Development Reserve
- a 57,000 km2 (22,000 sq mi) near Tefé, Brazil
- Anavilhanas Ecological Station
- an ecological station that includes hundreds of islands in the Rio Negro
References
- S2CID 53046359.
- ^ .
- ^ S2CID 26045412.
- ^ .
- ^ JSTOR 2389108.
- ISBN 978-0-521-62967-6.
- S2CID 85725169.
- .
- ^ a b c d United Nations Environment Programme-World Conservation M. "Jaú National Park, Brazil." Jaú National Park, Brazil. The Encyclopedia of Earth, 17 Nov. 2008. <http://www.eoearth.org/article/Ja%C3%BA_National_Park,_Brazil>.
- S2CID 153566259.
- S2CID 59492640.
- ^ S2CID 23980684.
- S2CID 24889153.
See also