Earthworms: Functional Traits and Soil Properties

Earthworm populations are often vulnerable to physicochemical qualities, soil drying and wetting in different ecosystems, i.e., cultivated or noncultivated soils, that influence directly or indirectly their survival. The creation of various population patches for earthworms’ species is supported by differences in soil qualities at diverse sites (i.e., croplands, forests, rangelands, and urban soils) or locations (e.g., catena landscape, pit and mound microtopography, gilgai position, single tree, deadwood, and canopy gap). The extent of the observed changes in earthworm populations is influenced by the ecosystem’s characters, as well as by topographically and climatically controlled processes like redistribution of litter and creep of soil. Anyway, the soil environment can be deemed as a mosaic of soil earthworm activity in different locations that are influenced by site factors. Soil physicochemical features like texture, moisture, temperature, pH, and organic matter (OM) affect the distribution of earthworms in the soil. Soils with a neutral pH are usually preferred by most species of earthworms. Soil moisture can play a vital role in the survival of earthworms, as their bodies have 75–90% of water by weight. There is a strong positive correlation between the soil organic matter and earthworm numbers and biomass. Earthworms are also recognized as soil managers due to their activities and alter the soil’s physicochemical and biological properties.