The Influence of Precipitation Change on Spiders as Top Predators in the Detrital Community

Abstract

Spiders are significant top predators in the detrital system (Fig. 20.1) of the deciduous forest (Clarke and Grant 1968; Moulder and Reichle 1972; Petersen and Luxton 1982) and may influence decomposition through top-down trophic cascades (Lawrence and Wise 2000). Collembola (springtails) and oribatid mites dominate the detritivore and saprophage guilds of most ecosystems studied (Petersen and Luxton 1982), accounting for up to 95% of total microarthropod numbers (Seasted 1984). Numerous studies have shown that springtails have a significant impact on nutrient cycling in terrestrial systems, both directly by consuming and shredding litter and indirectly by consuming fungal decomposers (Ineson et al. 1982; Leonard and Anderson 1991; Parkinson et al. 1979; Visser et al. 1981). Spiders are significant predators of springtails. Direct collecting of prey found in webs or in the chelicerae of wandering spiders has shown that a variety of spider families prey heavily on Collembola (Nyffeler et al. 1994). Manley(1976) report that up to 55% of springtail mortality in Acer forest litter may be attributable to spiders.