Soil Fauna: Macroarthropods
The macroarthropods are those large enough to be sampled as individuals, in contrast to the microarthropods that are sampled by extraction from a fragment of habitat (Section 25.3; Dindal, 1990; Borror et al., 1992; Arnett, 1993). Although smaller macroarthropods overlap in size with the larger microarthropods (Figure 25.2), the distinction between them is a practical one, based on method of sampling. A functional difference lies in their impact on soils. Macroarthropods are capable of restructuring soil profiles or relocating large amounts of soil, whereas microarthropods typically inhabit (and do little to modify) the existing pore spaces in soil (Coleman et al., 2004). Two insect groups, ants and termites, are responsible for major disruptions of soil profiles and have thus been classified as ecosystem engineers (Jones et al., 1997; Jouquet et al., 2006), while other macroarthropods may cause some disturbance. Examples include emergence tunnels of periodical cicadas (Insecta: Homoptera) (Whiles et al., 2001), or chimneys made by terrestrial crayfish (Crustacea: Decapoda) in hydric soils (Welch et al., 2008).