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Nutrient cycling in a high-altitude swamp forest

Swamp forests are ecosystems restricted to hydromorphic soils which are subject to the presence of surface water due to upwelling of groundwater. The diversity and establishment of plant communities depend on adaptability to conditions of flooding and low oxygen in the soil. This study aimed to characterize aspects of N and P cycling in a swamp forest in Itacolomi Park, Minas Gerais, Brazil, by measuring parameters such as litterfall, nutrient quality and decomposition of leaf litter during the period October 2006 to September 2007. Mean annual litter production was 5.7 t ha-1, with peak production in September. The leaf fraction accounted for 57% of total litterfall, and concentrations of N, P and K were 12.6, 0.616 and 3.07 g kg-1, respectively. Leaf-mass loss during litter decomposition was negatively correlated to soil water content, varying between 29.2 and 46.2%. The N:P ratio of leaf litter suggests that the vegetation grows under P-limitation. Taking into account the evaluated parameters, the swamp forest showed a slower rate of nutrient cycling, mainly due to low litter nutrient quality and slower litter decomposition rate when compared with other wet tropical forests.

hydromorphic soils; nutrient cycling; N:P ratio; swamp forests


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