ABSTRACT
Soil serves as a permanent or temporary habitat for several faunal groups. Animals of different shapes, body sizes, and taxonomic classes dwell in both natural and human-managed agricultural soils. Terrestrial invertebrates are highly adapted to these living conditions. Inhabitants of the soil surface and topsoil rely on both food
and shelter in these environments. Body pigmentation, higher mobility, and a higher resistance to weather extremes distinguish epigeal arthropods (see Chapter 11) from the true inhabitants of deeper soil layers. In contrast to the surface fauna, there are other soil inhabitants that can build and shape their own living sites. In burrows, forming tubes, and stabilizing cavities, earthworms and enchytraeids are good examples of soil-building and soil-forming edaphic groups as they burrow channels, form tubes, and stabilize cavities. The contribution of these worms is not limited to soilbuilding processes alone but in addition to many other functions (Chapter 9) including the formation of the living sites for several soil animal groups. Unlike epigeal and burrowing species, true soil inhabitants-mostly belonging to the meso-and microfauna
—are entirely dependent on “prepared” pores, tubes, cracks, or channels as habitats. Highly diverse communities, including Protozoa, Nematoda, Myriapoda, Acarina, Insecta, and Oligochaeta, colonize air-filled spaces, aggregates, or waterfilled pores. Together with bacteria, fungi, actinomycetes, and algae they build up the large bulk of soil biota, also known as the Edaphon. Water films coating soil mineral particles and water-filled pores are centers of decomposition activity, driven mainly by microorganisms. The significance of bacteria, fungi, Protozoa, and nematodes for soil biological activity has been repeatedly emphasized
in other chapters of this book, and particular attention was given to microbial organisms in Chapter 3.
