The study of the contribution of soil animals to the flow of nutrients (SO42-, NH4+, NO3-, Cl-, K+, Ca2+, and Mg2+) through soil columns was done in a Pinus merkusii (Jungh. & De Vriese) forest plantation at two altitudes (600 and 800 m a.s.l.) along an active stratovolcano, Mount Merapi, in Central Java. A field experiment using closed and open mesocosm systems was carried out in the wet season from October 1990 till April 1991. Litter percolate was collected using vacuum tube lysimeters. The results showed that the open systems, containing soil animals such as ants and earthworms, collected about 25-30 % more percolate than the closed systems, in which these animals were absent. The dynamics of percolate volume and most of the nutrients showed more or less the same pattern in both plots except for SO42-, Cl-, and K+ which originated from the volcano via rainfall. It seemed that the effects of macrofauna i.e. Araneae, Oniscoidea, Julidae, Formicidae, and Lumbricidae were evident for elements found in high amounts in the percolate, such as SO42-, Cl-, and K+.
