The Freshwater Project - Rio Negro Igapó

Igapó is a word used in Brazil for blackwater-flooded Amazonian forests. These forests are seasonally inundated with freshwater. They typically occur along the lower reaches of rivers and around freshwater lakes. 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. These forests may be able to sustain a large amount of bird, mammal, reptile, amphibian, fish and invertebrate species, however, biodiversity varies between wetland ecosystems and the species richness of the freshwater swamp forests is not entirely known.
Igapó forests are characterized by sandy acidic soils that have a low nutrient content. The color and acidity of the water is due to the acidic organic humic substances (e.g. tannins) that dissolve into the water. The acidity from the water translates into acidic soils. Igapó and other flooded forests typically display a lower diversity of plants than that seen in terra firme forests. Similar to other forests found throughout the tropics, it is common to observe only a few dominant tree species. 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.
Tree species adapted to seasonal inundation have adapted to maximize fruit production during periods of flooding in order to take advantage of newly available seed dispersal methods. Fish consume nearly all fruit that fall into the water, and species that are unable to digest the seeds eventually excrete and disperse them into the water. Dispersal by other vectors such as birds and monkeys is secondary to that of fishes in igapó. An important factor in seed survival is the presence of seed predators. Fishes that lack the strong jaws found in characins, such as catfish, digest the fleshy material of the fruit while the seeds pass through the gut unharmed. Because many catfishes are bottom-feeders, they are critical dispersers for seeds that sink upon entering the water.

Freshwater Ecoregion of the World : #314 Rio Negro
Major Habitat Type: tropical and subtropical floodplain rivers and wetland complexes

Produced in 2011 and 2019. Red dots indicate personal favorites.

Flooded Forest Underwater



U05-1001 Black caiman	U05-1002 Black caiman	U05-1009 Amazon river dolphin	U05-1010 Amazon river dolphin
U05-1011 Amazon river dolphin	U05-1012 Amazon river dolphin	U05-1013 Amazon river dolphin	U05-1014 Amazon river dolphin
U05-1015 Amazon river dolphin	U05-1016 Amazon river dolphin	U05-1017 Amazon river dolphin	U05-1018 Amazon river dolphin
U05-1019 Amazon river dolphin	U05-016 Amazon river dolphin	U05-017 Amazon river dolphin	U05-019 Amazon river dolphin



U05-1020	U05-1021	U05-1022	U05-1024
U05-1025	U05-1026	U05-1027	U05-1028
U05-1029	U05-1030	U05-1031	U05-1032


Animals and Landscapes


U05-517 Amazon river dolphin	U05-518 Amazon river dolphin	U05-520 Amazon river dolphin	U05-515 Amazon river dolphin
U05-516 Amazon river dolphin	U05-1554 Amazon river dolphin	U05-1555 Amazon river dolphin	U05-1557 Black caiman



U05-1538	U05-1539	U05-1540	U05-1541
U05-1542	U05-1543	U05-1544	U05-1545



U05-1546	U05-1547	U05-1548	U05-1549
U05-1550	U05-1551	U05-1552	U05-1553





U05-1502	U05-1503	U05-1504	U05-1505
U05-1506	U05-1507	U05-1508	U05-1509
U05-1510	U05-1511	U05-1512	U05-1515
U05-1517	U05-1518	U05-1519	U05-1520
U05-1521	U05-1522	U05-1523	U05-1524



U05-1525	U05-1526	U05-1527	U05-1528
U05-1529	U05-1530	U05-1531	U05-1532
U05-1533	U05-1534	U05-1535	U05-1536




U05-1537
U05-501 Archipelago Anavilhanas	U05-502 Archipelago Anavilhanas	U05-504 Archipelago Anavilhanas	U05-507 Archipelago Anavilhanas
U05-506 Archipelago Anavilhanas	U05-505 Archipelago Anavilhanas	U05-508 Archipelago Anavilhanas	U05-509 Archipelago Anavilhanas
U05-510 Archipelago Anavilhanas	U05-511 Archipelago Anavilhanas	U05-513 Archipelago Anavilhanas	U05-514 Archipelago Anavilhanas
U05-555 Clouds over Amazon	U05-557 Clouds over Amazon	U05-558 Clouds over Amazon river	U05-559 Clouds over Amazon river
U05-560 Clouds over Amazon river	U05-561 Clouds over Amazon river	U05-562 Clouds over Amazon river	U05-563 Clouds over Amazon river


The flooded Amazonian rainforest – Rio Negro Igapó, Brazil








Igapó is a word used in Brazil for blackwater-flooded Amazonian forests. These forests are seasonally inundated with freshwater. They typically occur along the lower reaches of rivers and around freshwater lakes. 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. These forests may be able to sustain a large amount of bird, mammal, reptile, amphibian, fish and invertebrate species, however, biodiversity varies between wetland ecosystems and the species richness of the freshwater swamp forests is not entirely known. Igapó forests are characterized by sandy acidic soils that have a low nutrient content. The color and acidity of the water is due to the acidic organic humic substances (e.g. tannins) that dissolve into the water. The acidity from the water translates into acidic soils. Igapó and other flooded forests typically display a lower diversity of plants than that seen in terra firme forests. Similar to other forests found throughout the tropics, it is common to observe only a few dominant tree species. 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. Tree species adapted to seasonal inundation have adapted to maximize fruit production during periods of flooding in order to take advantage of newly available seed dispersal methods. Fish consume nearly all fruit that fall into the water, and species that are unable to digest the seeds eventually excrete and disperse them into the water. Dispersal by other vectors such as birds and monkeys is secondary to that of fishes in igapó. An important factor in seed survival is the presence of seed predators. Fishes that lack the strong jaws found in characins, such as catfish, digest the fleshy material of the fruit while the seeds pass through the gut unharmed. Because many catfishes are bottom-feeders, they are critical dispersers for seeds that sink upon entering the water. Freshwater Ecoregion of the World : #314 Rio Negro Major Habitat Type: tropical and subtropical floodplain rivers and wetland complexes



Website Michel Roggo	Copyrights of all images, movies and other contents 2021 © Michel Roggo	The Freshwater Project Website