Human influence on collembolan populations in Brazilian rainforests

In 3 habitats near each of Manaus and Belem the effects on ground fauna of clearing forests by burning and of cultivation of cleared soil were studied. The methods used were pitfall-traps and Berlese-Tullgren-funnels. The primeval forests near Manaus and Belem had a similar fauna. On the soil surface the Collembola were dominant whereas in the soil it was the mites. The dominant Collembola-group on the surface were the Hypogastrurids and in the soil the blind Isotomids (mostly Isotomiella spp.). One month after clearing by burning, the population density on the surface (as found with the pitfall-traps) was higher than in the primeval forest, but the mites were now dominant and the Collembola were not very numerous. Collembola were nearly completely absent from the soil. The pioneers amongst Collembola were the Hypogastrurids and the Isotomids. In a Cecropia -stand one year after burning the total arthropod abundance was similar to that in the primeval forest, but the respective collembolan populations showed distinct differences.