Updated Octover 30th, 2002
Amazon Ecosystems - Floodplain Ecosystems
Encyclopedia of Biodiversity Vol. 1 p. 145-157
Almost 10 percent of the Amazon region is region is subjected to periodic flooding due to the rise and fall of river levels in most of the region and backup of the rivers from high tides in the delta region.

River levels are very seasonal and the magnitude of change is considerable. (ex. annual change in water level = 10m in central Amazonia)

Forest beside the river flooded to a depth of several meters for five to seven months each year.

Two main flooded ecosystems:

General Characteristic Fauna/Flora of this region

Varzea Forest formed on soil that is flooded by the alluvail rich white water rivers, therefore the soils are much more fertile; in the lower Amazon, the varzea forest is often accompanied by large meadows of grassland known as canarana genrally tall and physiogonomically quite similar to terra firme forest but it is much less diverse in species; in the canarana, there are extensive grass meadows on the lower, more flooded ground farther away from the river margins and when the water recede and the lakes dry up, the open ground quickly becomes covered with grass, increasing the area of the meadows.

Igapo formed on soil that is flooded by black water and clear water rivers (which has less sediment compared to white water rivers and the water is acid and nutrient poor) the banks are usually gradually sloping sandy beaches with trees but in the rainy season they are transformed into an inundated igapo forest where only the canopy is above water; physiognomy of the igapo forest is usually rather different from that of the terra firme and varzea forests - lower stature and the tress are more scattered; species characteristic to these region are - Astrocaryum jauari, Calophyllum brasiliense, Eschweilera albiflora, gustavia augusta, Hevea spruceana, Parinair excelsa, Vatairea guianensis
The seeds of these species are often light and have many different flotation mechanims. On the other side of the river, there are trees with fleshy fruit that is often green which are dispersed by fish.

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	General Characteristic	Fauna/Flora of this region
Varzea Forest	formed on soil that is flooded by the alluvail rich white water rivers, therefore the soils are much more fertile; in the lower Amazon, the varzea forest is often accompanied by large meadows of grassland known as canarana	genrally tall and physiogonomically quite similar to terra firme forest but it is much less diverse in species; in the canarana, there are extensive grass meadows on the lower, more flooded ground farther away from the river margins and when the water recede and the lakes dry up, the open ground quickly becomes covered with grass, increasing the area of the meadows.
Igapo	formed on soil that is flooded by black water and clear water rivers (which has less sediment compared to white water rivers and the water is acid and nutrient poor)	the banks are usually gradually sloping sandy beaches with trees but in the rainy season they are transformed into an inundated igapo forest where only the canopy is above water; physiognomy of the igapo forest is usually rather different from that of the terra firme and varzea forests - lower stature and the tress are more scattered; species characteristic to these region are - Astrocaryum jauari, Calophyllum brasiliense, Eschweilera albiflora, gustavia augusta, Hevea spruceana, Parinair excelsa, Vatairea guianensis The seeds of these species are often light and have many different flotation mechanims. On the other side of the river, there are trees with fleshy fruit that is often green which are dispersed by fish.