Table 1.

Examples of some of the taxa below ground, the functional groups within soil food webs and their role in ecosystem processes in plant-dominated ecosystems. (The biodiversity of each functional group regulates or influences various ecosystem processes and thus provides benefits or ecosystem service for human well-being. See Wall (2004) and the Millennium Ecosystem Assessment (2005).)

biodiversity	functional groups	ecosystem processes
vertebrates, invertebrates (oligochaetaes, polychaetaes, crustaceans, molluscs, ants, termites), plant roots	bioturbators, ecosystem engineers	soil alteration, soil structure, organic matter and microbes mixing laterally and vertical depths
plant roots, algae	primary producers	create biomass, stabilize soils and sediments, provide C and N at depth
millipedes, centipedes	shredders	fragment, rip and tear organic matter
bacteria and fungi, Collembola, mites, nematodes, rotifers, tardigrades, protozoa	primary decomposers and secondary decomposers	recycle nutrients, increase nutrient availability for primary production
symbiotic (e.g. Rhizobium) and asymbiotic bacteria (e.g. Cyanobacter, Azobacter)	nitrogen fixers	biologically fix atmospheric N2
methanogenic bacteria, denitrifying bacteria	trace gas producers	C, N2, N2O, CH4 transfer and denitrification
roots, soil organisms	CO2 producers	respiration, emission of CO2