Habitat for biological activity 

There are more species living below ground than above. Soils provide the living space for 
an enormous diversity of organisms, but in turn, are also formed by soil biota. 
The activity and diversity of soil organisms are largely affected by biotic and abiotic factors 
(e.g., climate, soil properties), but also by land use and management practices. Soil 
organisms play important roles in a number of soil processes such as nutrient cycling, 
mixing of soil material and development of soil structure. Due to the high diversity of soil 
organisms, many species are thought to be redundant, which means that they can be 
replaced by other species fulfilling the same function. However, certain species may play 
an irreplaceable role in soil functions. Soil structure provides a multitude of niches where 
different species can coexist with reduced competition for food and reduced stress of being 
caught by predators. This is a fundamental difference to the living space above ground.