Microarthropods in decaying wood from temperate coniferous and deciduous forests

Decaying wood represents a large source of energy and nutrients in many forest ecosystems
(Game & LOGAN, 1977; Swnrr, 1977 a; Voar et al., 1982; HARMON at al., 1986), and provides
both a substrate and a food resource for a diverse assemblage of fauna (Etzon, 1966),Invertebratesassist-in the decomposition of wood in a manner similar to that observed in the decomposition offoliar litter (e. g. Ausatus, 1977; Swrrr, 1977:Sim-mar, 1984). Relatively little is known aboutthe fauna inhabiting decaying wood. PAGER (1968) reported on species composition and relativeabundance of arthropods on natural and artificial logs. flmueott at al. (1986) summarized thepatterns of decaying wood use by macroarduopods, while Waiwottx (1976), Anao•rAet a/. (1980)and Moor,* CROSSLEY (1982) documented population densities and effects of microarthropodsfound on decaying branch litter during the initial stages of decay. However, population densities ofmicroarthropods in larger pieces of decaying wood or in wood in advanced stages of decay have notbeen quantified.
The present study measured the densities of microarthropods in tree stems (boles) of variousstages of decay from a coniferous forest in the northwestern U.S. Numbers of microarthropods indifferent factions or different types of wood (e. g. sapwiiod vs heartwood) were recorded, and a listof mite (Acari) species was prepared. These results were compared with published information onmicrobial respiration and decomposition dynamics of this wood (SouaNs at al., 1987). A lessextensive data set was also collected at two additional sites, a coniferous forest site in the RockyMountain region. and a riparian forest site found in the tallgrass prairie biome.. Densities ofmicroarthropods from these samples were compared with similar results from samples obtainedfrom the forest floor of these sites. These findings allow us to generalize about patterns ofmicroanhropod abundance in decaying wood.