The function of the soil macrofauna in decomposition processes in central Amazonian polyculture systems and forests.

A study of macrofauna and decompositon in three central Amazonian ecosystems (a primary and a secondary forest and tow polyculture tree plantations) has shown the high importance of the macrofauna for the litter decompostion. Macrofauna biomass was highest in the primary forest and lowest in the secondary forest. It differed strongly between the two polyculture areas, probably due to different microclimatic conditions near the ground as influenced principally by density of secondary vegetation (cover) and shading by the neighboring forest. Litter decompositon in the central Amazon polycultures follows the same principles than in primary forest, e.g. the macrofauna regulates the decompostion rates. However the structure of the decomposer community differs clearly and lower decomposition rates and higher C/N-ratios show that the fauna in anthropogenic systems does not reach the same efficiency in decomposition and nutrient transfer