A rapid survey of invertebrate and vertebrate groups reveals that at least ¼ of described
living species are strictly soil or litter dwelling. The greatest diversity is observed in systems
where equilibrium exists between the productivity level and the perturbation rate, whereas
local species extinctions may occur through lack of demographic recuperation when
perturbations increase or through competitive exclusion when productivity increases. Land
use changes and the intensification of agriculture also generate severe habitat degradation
or destruction of soil biota. The environment of soil organisms in managed ecosystems can
be influenced by any combination of land use factors, such as tillage, pesticide and fertilizer
application, soil compaction during harvest, and removal of plant biomass.