Abundance and community structure of forest floor spiders following litter manipulation.

We conducted a field manipulation of forest litter to determine effects of litter structure (flat vs curly leaves) on forest floor spiders in natural and artificial leaf litter. Artificial litter made of vinyl, was nondecomposable and non-nutritive. In this way, we separated interactions of effects of litter as a nutritional base and as a spatially heterogeneous environment on litter-dwelling spiders.Structural complexity of litter significantly affected abundances of some forest floor spiders. In particular, abundances of web-building spiders were lower in treatments of flat leaves. Litter nutritional content and structural complexity only slightly affected spider species composition and richness. Results suggest that litter depth is more influential than are litter structural complexity or nutritional content, in organizing forest floor spider communities.