La fauna del sòl i les xarxes tròfiques edàfiques

Soil is home to an extraordinary quantity and diversity of organisms of equally varying sizes and lifestyles. Microorganisms (bacteria and fungi), protozoa, plants and animals interrelate in complex edaphic food webs, fueled by organic detritus and ultimately resulting in decomposition and mineralization of these detritus. Animals play a key role in these food webs and, according to their functional characteristics, can be grouped into three main guilds operating at different time and size scales. The “micro predators” guild are comprised of smaller-sized animals, working on a microscopic scale and controlling microorganic communities. The “litter transformers” guild consist of medium- and large-sized animals; they mechanically fragment organic detritus, rendering it more accessible to microflora decomposing processes. The “ecosystem engineers” guild is formed by large animals that collaborate in maintaining the physical and chemical properties of soil through their mechanical and chemical activities. The large taxonomic diversity and functional redundancy of soil fauna may aid soil in withstanding disturbances. Some species may disappear as a result of such disturbances, while the survivors continue to maintain the ecosystem’s functionality