Litterfall and nutrient dynamics in a mature Atlantic rainforest in Brazil

Abstract

We assessed litterfall and nutrient cycling in an old-growth Atlantic rainforest in southern Brazil. Plant litter collected monthly was separated into: leaves, twigs, reproductive organs, and fragments, and dried, weighed, and ground. Determination of carbon, nitrogen, phosphorus, potassium, calcium, magnesium, and sodium contents of different litter fractions was also performed. The total deposition was 8.44 Mg-1 ha-1 year-1, with a higher proportion of leaves fraction. Litterfall predominated in spring and summer, coinciding with the highest average temperature and rainfall in the study area. For leaves, twigs and fragments, the elements sequence of concentration was C>N>Ca>K>Mg>P>Na; whereas for reproductive organs it was C>N>K>Ca>Mg>P>Na. A higher concentration of nutrients was observed in spring and summer for the leaves fraction. The quantitative transfer of nutrients by litterfall fractions to the forest soil followed the same sequence observed for the concentration of nutrients.