Although microbial participation in litter decomposition is widely known within terrestrial soils, the role and significance of microorganisms during the aerial standing litter phase of decomposition remains poorly investigated. We examined the fungi inhabiting standing leaf litter of Schizachyrium scoparium and Schizachyrium tenerum in a Longleaf Pine savanna ecosystem and estimated their contribution to litter decomposition. We identified fungal phylotypes associated with leaf litter and quantified leaf C mass loss, fungal biomass production, and microbial respiration during decomposition. These data were used to construct budgets estimating C flow into and through fungi. Significant losses in S. scoparium (55%) and S. tenerum (67%) leaf C mass were observed during standing decomposition along with concomitant increases in fungal biomass, which reached a maximum of 36 and 33 mgC/g detrital C, respectively. Cumulative fungal production during decomposition totaled 99±6 mgC/g initial detrital C in S. scoparium and 73±5 mgC/g initial detrital C in S. tenerum, indicating that 18 and 11% of the litter C was converted into fungal biomass, respectively. Corresponding estimates of cumulative fungal respiration totaled 106±7 and 174±11 mgC/g initial detrital C in S. scoparium and S. tenerum, respectively. Next generation sequencing identified several fungal phylotypes, with the majority of sequences belonging to the Ascomycota (Dothideomycetes) and Basidiomycota (Agaricomycetes). Fungal phylotypes were similar between litter species and changed over time, showing a successional pattern. These findings extend our understanding of fungal processes to standing litter in terrestrial ecosystems, and highlight the quantitative importance of fungi in C cycling processes.

This Excel document includes the raw data for all analyses presented in the manuscript and supplemental materials including: litter mass loss, fungal biomass (from ergosterol), glucosamine, fungal production rates, microbial respiration, bulk litter nitrogen and phosphorus concentrations, and carbon:nitrogen and carbon:phosphorus ratios.  The Excel document also includes relative sequence abundance for the major fungal groups presented in figure 5 within the manuscript, the antibiotic data presented in the supplemental material and the raw model data used in the Monte Carlo Simulation Analysis presented in Table 1.  Oecologia_Schizachyrium_Grass_Decay_DryadData.xlsx