Leaf Litter Diversity Effects On Microbial Functional and Taxonomic Profiles.

Recent reviews and research have noted the importance of understanding the relationship between diversity, community assembly, and ecosystem functioning. However, few studies have examined simultaneous changes in functional activity and microbial community composition during decomposition. We assembled 1, 3, and 4 species litterbags using labile (Hamamelis virginiana, Acer saccharum) and recalcitrant (Fagus grandifolia, Quercus palustris) leaf types. Litterbags were periodically harvested over a one-year period from two habitats (upland and riparian forest) in Northeastern Ohio. Individual leaf species were analyzed separately in order to understand how specific characteristics of each leaf type impact decomposition. Early harvests indicated that increased litter diversity was associated with increased fungal biomass, and that litter diversity effects on decomposition, C:N ratio, and bacterial community composition depended on the leaf type in question. Accounting for spatial covariation at the meter (block) and centimeter (litterbag) scales resulted in the majority of variance being explained for ash-free dry mass recovered and C:N ratio, but leaves a substantial amount of variability in microbial communities to be explained by factors at other spatial scales or by more complex spatiotemporal dynamics. Ongoing analysis will determine if extracellular enzyme activities are associated with biochemical composition of litter, and if taxonomic profiles show a shift in community composition associated with changing functional profiles during decomposition.