Title: Faunal Activities and Soil Processes: Adaptive Strategies That Determine Ecosystem Function
Abstract: This chapter helps in understanding the role of soil fauna in soil function. Soils host an extremely diverse community of invertebrates that differ in their adaptive strategies and hence in the functions they fulfill in soils. The chapter illustrates the functional classification of soil organisms based on their adaptive strategies. Three major groups of invertebrates may be defined based on the nature of the relationship that they develop with soil microflora. The microfauna comprise invertebrates of less than 0.2 mm on an average, makes use of micro-organisms mainly through predation in micro-foodweb systems. Mesofauna and large arthropods comprise the group of litter transformers. Earthworms, termites and, to a lesser extent, ants, are “ecosystem engineers” that create diverse organo-mineral structures. It is suggested that the three systems defined, operate at nested scales of time and space and have decreasing overall effects on the determination of soil function in the order micro-foodwebs < litter transformers < ecosystem engineers. Modifications of soil fauna communities may lead to loss of diversity and result in loss of functions when specific structural patterns or regulation mechanisms are lost.