Litter C transformations of invasive Spartina alterniflora affected by litter type and soil source

Litter types and soil properties can affect litter decomposition rate and litter carbon (C) transformation, consequently regulating soil C cycling. Yet, litter C transformations of leaves and roots of invasive plants are poorly understood, which limits our understanding of the role of plant residues in soil C sequestration during plant invasion. In a laboratory incubation experiment lasting for 153 days, we used two types of soil which were collected from invasive S. alterniflora and native Phragmites australis marshlands, and traced the transformation of 13 C from leaf and root litter of invasive Spartina alterniflora into CO 2 , soil-dissolved organic C (DOC), microbial biomass C (MBC), and soil organic C (SOC). The leaf litter of S. alterniflora decomposed faster than root litter, resulting in higher soil respiration and higher transformation of litter-derived 13 C into CO 2 , MBC, and DOC. Although the root litter of S. alterniflora decomposed slowly, SOC comprised up to 24% of litter-derived 13 C. Furthermore, the litter C transformations of S. alterniflora showed a positive home-field advantage effect. Soil respiration, MBC, fractions of litter-derived 13 C in Gram-negative bacteria, 13 C recovered in CO 2 , DOC, and SOC were higher in the soil colonized by S. alterniflora than in the soil colonized by P. australis , with the home-field advantage effect being more pronounced in root than leaf litter treatments. Therefore, litter type and soil source had differential impacts on litter C transformation patterns of S. alterniflora and the root litter of invasive S. alterniflora played an important role in SOC formation and C sequestration in soils from its invaded ecosystems.