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.

尽管微生物参与凋落物分解在陆地土壤中广为人知，但微生物在分解的空中站立凋落物阶段的作用和意义仍然很少研究。我们检查了长叶松稀树草原生态系统中寄生于Schizachyrium scoparium和Schizachyrium tenerum静置落叶的真菌，并估计了它们对凋落物分解的贡献。我们确定了与落叶相关的真菌系统型，并量化了叶片 C 质量损失、真菌生物量产生和分解过程中的微生物呼吸。这些数据用于构建预算，估计流入和通过真菌的 C 流量。S. scoparium (55%) 和S. tenerum的重大损失(67%) 在静置分解过程中观察到叶片 C 质量，同时真菌生物量增加，最高分别达到 36 和 33 mgC/g 碎屑 C。分解过程中累积的真菌产量总计为 99 ± 6 mgC/g S. scoparium的初始碎屑 C和 73 ± 5 mgC/g 的S. tenerum初始碎屑 C ，表明 18% 和 11% 的枯枝落叶 C 转化为真菌生物量，分别。S. scoparium和S. tenerum累积真菌呼吸的相应估计值总计为 106 ± 7 和 174 ± 11 mgC/g 初始碎屑 C， 分别。下一代测序确定了几种真菌系统发育型，其中大部分序列属于子囊菌门（Dothideomycetes）和担子菌门（Agaricomycetes）。凋落物物种之间的真菌系统型相似，并且随着时间的推移而变化，呈现出连续模式。这些发现将我们对真菌过程的理解扩展到陆地生态系统中的枯枝落叶，并强调了真菌在 C 循环过程中的定量重要性。