Effect of Structure and Nutritional Quality of Litter on Abundances of Litter-dwelling Arthropods

Abstract
Field manipulations of forest litter were conducted to measure effects of litter structure on abundances of forest floor arthropods in natural and artificial leaf litter. Artificial litter was made of nondecomposable vinyl. Both artificial and natural litter occurred in 3 structural treatments: flat, natural and complex. Using this design the interacting effects of litter as a trophic base and as a spatially heterogeneous environment on litter arthropods could be compared. In 1 of 4 mo. of the study, micro-Araneae were significantly (P < 0.05) more abundant in litter with complex structure: both natural and artificial. Collembola and Acari abundances were unaffected by structural complexity of litter but were significantly (P < 0.05) higher in natural leaves compared to artificial leaves. Abundances of dominant macroarthropod predators (Araneae) increased significantly (P < 0.05) with increased litter structural heterogeneity in 1 of 4 study-months. Non-Araneae predators showed weak or no responses to litter complexity. Diplopods and isopods were more abundant in natural litter; other nonpredatory macroarthropods were equally abundant in natural and artificial litter.