Fungi rather than bacteria explain home‐field advantage for decomposition of litter carbon fractions

Abstract The home‐field advantage (HFA) hypothesis proposes that specific interactions between litter and microbial communities can accelerate litter mass loss in home habitats relative to away habitats. However, the role of HFA in regulating the decomposition of individual carbon (C) fractions with distinct chemical structures remain largely unexplored. In particular, it is unclear to what extent litter‐layer microbial communities—shaped by interactions between litter and soil microbial communities—drive the fraction‐specific manifestation of HFA during litter C decomposition. A 480‐day reciprocal litter transplant experiment was conducted across forest and cropland ecosystems. The effect of HFA on the loss of four C fractions (dissolved organic carbon, cellulose, hemicellulose and lignin) with varying chemical qualities, as well as the role of litter‐layer microbial communities in this process, were assessed using four litter types: two forest litters ( Schima superba and Castanopsis fargesii ) and two cropland litters ( Zea mays and Eleusine indica ). HFA significantly accelerated the loss of both total litter mass and individual C fractions, with particularly strong effects on the recalcitrant lignin fraction. Litter‐layer microbial communities were the key drivers of HFA, as microbial community dissimilarity between home and away sites showed a significant negative correlation with HFA for lignin loss. Moreover, a higher abundance of specific fungal taxa at home sites accelerated C fraction decomposition, whereas specific bacterial taxa suppressed decomposition. These findings suggest that HFA differentially affects the decomposition of individual C fractions, likely mediated by specific litter‐layer microbial communities at home sites. Overall, this study underscore the critical role of recalcitrant C substrates and litter‐layer fungal taxa in shaping HFA and advance understanding of the microbial processes underlying litter decomposition in terrestrial ecosystems. Read the free Plain Language Summary for this article on the Journal blog.