Leaf litter quality and composition as a determinant of invertebrate diversity, order richness, density, and abundance.

Abstract

To better understand how leaf litter amount and composition affect the diversity, richness, density and abundance of invertebrate communities, our study compared samples from differing treatment plots within the University of Michigan Biological Station’s Detritus Inputs Removals and Transfers (DIRT) experiment. We hypothesized that due to the effects of leaf litter on invertebrates, there would be a positive correlation between the amounts of leaf litter and invertebrate diversity, richness, density and abundance. We also hypothesized there would be a negative correlation between woody litter and invertebrate diversity, richness, density and abundance due to the limited nutrients available. We sampled control, woody litter, double litter and no litter treated plots from the DIRT experiment using three different sampling techniques to target differing invertebrate communities. The samples were processed, classified and tabulated by order. We found that typically, order richness was greater in the O-horizon samples than the other sample techniques. Invertebrate abundances were generally not related to amounts or compositions of litter of the plots in which they were collected. However, we found a positive correlation between litter volume and order diversity in the leaf litter and O-horizon samples. Litter volume was also positively correlated with abundance of macro invertebrates collected in the pitfall traps. While our interpretations were constrained by a small sample size, we saw trends supporting our hypothesis that invertebrate diversity, richness and abundance increase as litter amounts increase.