Igapó
[1] 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.
They also "carry less suspended inorganic elements and contain elevated concentrations of dissolved organic material such as humic and fulvic acids".
[2] Therefore, igapó forests support comparatively less life and the environment found within these areas tend to lack species diversity and animal biomass.
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.
Fish populations are highest during maximum fruiting periods and river dolphins and giant otters move in to prey upon them.
[6] Larger terrestrial mammals have varied strategies of dealing with flooding: red brocket deer and collared peccaries move into islands and shift diet from fruit to browsing woody plants.
White-lipped peccaries and tapirs are largely unaffected by seasonal inundation; both species take advantage of the greater abundance of fruit during these times.
[7] Arboreal mammals such as monkeys tend to be lower in species richness compared to terra firma forests due to the decrease in tree diversity and the resulting lack of variety of suitable food types.
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.
[citation needed] The highly fertile soils and the openness of these areas confirm that the native Amazonians have been using these fields for agriculture.
Indigenous peoples understand that, while flooded, the forest serves as an essential feeding ground that increases fish abundance.
The loss of these trees will likely affect populations of frugivorous understory birds, such as the blue-throated piping guan and some Amazona parrots that are restricted to igapó.
Due to soil chemistry and seasonal inundation, trees and other resources tend to grow back more slowly after harvest by humans than in other types of Amazonian forests, .
[13] In protected areas, such as Jaú National Park, the lack of indigenous inhabitants and a low population of rural families limits the potential for over-harvest of fish and turtle species.
In other unprotected areas that lack rangers, unregulated harvest of fauna by peoples that move into igapó forests to hunt and fish may adversely affect future stocks.
