Invertebrates as Webmasters in Ecosystem: New York: CABI Publishing, 2000. Paper abstract bibtex
At practically any terrestrial site, the vast majority of the animal species are invertebrate members of the decomposer community. In temperate forests, these animals, primarily arthropods and nematodes, are concentrated in the decomposing organic layers that make up the top few centimeters of the soil. As thin and fragile as this layer is, it is the zone through which most of the productivity of the system, as leaves, roots, wood and animal debris, passes and is transformed. Through their activity as microbial grazers and saprophages, the decomposed fauna is the gate-keeper to the flow of material through the system. In ecosystem-level models of nutrient cycling, this zone and its inhabitants are most commonly represented by several compartments through which nutrients flow, entering as a large pulse input at litterfall and leaving through plant uptake, leaching, denitrification and respiration. But the mechanisms that regulated decomposer interaction webs, their structure and biotic diversity, are nested on a finer scale of resolution, one that discerns structure within the litter profile and the dynamics of its annual fluctuations. A mechanistic understanding of the organization of soil assemblages and their mediation of processes will require study on this scale. In this chapter, I will focus on the most diverse of the litter-dwelling mesofaunal groups, the non-astigmatic oribatid mites, and how the morphology and dynamics of the litter profile determine their diversity, species composition and their functional impact. As a case study, I will discuss an experiment that compared the oribatid assemblage in profiles developed form monotypic litter, the typical medium for studying litter dynamics and a common consequence of human activities, with those in profiles developed from natural, mixed litter.