Density and vertical distribution of soil invertebrates were studied during September of 1990 and 1991 in three plots, namely one forest plot and two arboreal plantations (Dipteryx odorata = cumaru <Leguminosae> and Simaruba amara = marupá <Simarubaceae>) near Manaus (Brazil). Nineteen main fauna groups were found, and most of them had similar densities in the three plots. The most representative groups were Isoptera (40.1 %), Formicidae (25.2%), Araneae (6.7%), all together representing 62.4% of all soil fauna in the cumaru plot, 57.0% in marupa and 84.1 % in the forest plot. Density of soil fauna decreased from the top soil to 20 cm depth (excluding termites), with a subsequent increase until 30 cm depth. 45% of all fauna occurred in the top 0-5 cm, followed by 9.5% (5-10 cm), 9.1 % ( 10-15 cm), 2.7% (15-20 cm), 20.7% (20-25 cm) and 12.3% (25-30 cm). Isoptera, Diptera and other invertebrates did not present correlation with the pH and the humidity of the soil.
Soil invertebrates; density; vertical distribution; sandy soil; dry season; forest; arboreal plantaion; Central Amazonia