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Free keywords:
Amazonia; várzea; aquatic macrophytes; biomass; flood pulse; potential utilization
Abstract:
Herbaceous species in the Amazon floodplains particularly C4 plants may exhibit NPP values about three times those of the floodplain forest. Although restricted to relatively small areas, they show high diversity and are very important in the carbon and nutrient budgets of the region, enriching the aquatic system and associated floodplains through their decomposition both during the aquatic and terrestrial phases of the hydrological cycle. Sustainable management systems for Amazon floodplains should consider the importance of herbaceous vegetation in the nutrient budget of the region. Because of favorable nutrient conditions várzea forests are frequently replaced by farms and pasture lands for cattle and buffalo ranching. The substitution of the forest by herbaceous plant communities has little effect on total primary production because these communities are often more productive than the forest itself, but it affects strongly biomass. On the other hand, massive removal of herbaceous plants for the introduction of less adapted crops will reduce species diversity and the fertility of the várzea, and will require additional fertilization. Susceptibility of these degraded systems to fire increases during the terrestrial phase, resulting in losses of crops and pastures, and leading to further degradation of the natural plant communities and associated animals of the floodplains, with fare reaching negative consequences for human life.
