Background Enzymatic stoichiometry reflects microbial relative resource limitations by linking microbial nutritional demands with soil nutrient availability,yet how plant invasion-induced changes in vegetation,soil pr...Background Enzymatic stoichiometry reflects microbial relative resource limitations by linking microbial nutritional demands with soil nutrient availability,yet how plant invasion-induced changes in vegetation,soil properties,and microbial communities modulate these limitations and metabolic efficiency remains undetermined.Here,we employed enzymatic stoichiometry and vector modeling to assess microbial relative resource limitations in invasive Spartina alterniflora salt marsh in comparison to those in bare flat and in native Suaeda salsa and Phragmites australis salt marshes,and systematically linked these limitations to microbial carbon(C)and nitrogen(N)use efficiencies(CUE and NUE,respectively)across coastal wetland ecosystems of eastern China.Results Our analyses showed predominant phosphorus(P)limitation of soil microbial metabolism in bare flat and native S.salsa and P.australis salt marshes,contrasting with dual C-P co-limitation observed in invasive S.alterniflora salt marsh.S.alterniflora invasion intensified microbial P limitation compared with bare flat,while simultaneously inducing the most pronounced C limitation among all plant communities.The microbial C limitation induced by S.alterniflora invasion drove reductions in microbial CUE,whereas microbial NUE increased,establishing an antagonistic relationship between these metabolic efficiencies.Microbial resource constraints and nutrient use efficiencies(CUE/NUE)in soils were coordinately controlled by plant traits,soil properties,and microbial attributes.Partial least squares path modeling analysis identified soil organic C(SOC)chemical fractions(e.g.,aromatic C,alkyl C,dissolved organic C)as predominant positive drivers of microbial C limitation and NUE,while simultaneously suppressing microbial CUE.Simultaneously,plant traits were identified as the foremost contributor to microbial P limitation,followed by microbial attributes as the second-most influential positive factor.Conclusions This study revealed that S.alterniflora invasion fundamentally shifted microbial nutrient limitation from predominant P limitation in bare flat and native salt marshes to dual C-P co-limitation,while simultaneously inducing the strongest microbial C limitation among all communities.This invasion-induced microbial C limitation drove a reduction in microbial CUE but an enhancement of NUE.SOC accumulation increased with decreasing microbial CUE following S.alterniflora invasion,a tradeoff potentially linked to divergent nutrient limitations across ecosystems.This study provided empirical evidence for microbially-mediated soil C sequestration mechanisms underlying plant invasion-induced ecosystem transformations.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.32071632,31600427)the National Science Foundation of Shaanxi Province,China(Grant Nos.2022JM-114,2019JQ-666)
文摘Background Enzymatic stoichiometry reflects microbial relative resource limitations by linking microbial nutritional demands with soil nutrient availability,yet how plant invasion-induced changes in vegetation,soil properties,and microbial communities modulate these limitations and metabolic efficiency remains undetermined.Here,we employed enzymatic stoichiometry and vector modeling to assess microbial relative resource limitations in invasive Spartina alterniflora salt marsh in comparison to those in bare flat and in native Suaeda salsa and Phragmites australis salt marshes,and systematically linked these limitations to microbial carbon(C)and nitrogen(N)use efficiencies(CUE and NUE,respectively)across coastal wetland ecosystems of eastern China.Results Our analyses showed predominant phosphorus(P)limitation of soil microbial metabolism in bare flat and native S.salsa and P.australis salt marshes,contrasting with dual C-P co-limitation observed in invasive S.alterniflora salt marsh.S.alterniflora invasion intensified microbial P limitation compared with bare flat,while simultaneously inducing the most pronounced C limitation among all plant communities.The microbial C limitation induced by S.alterniflora invasion drove reductions in microbial CUE,whereas microbial NUE increased,establishing an antagonistic relationship between these metabolic efficiencies.Microbial resource constraints and nutrient use efficiencies(CUE/NUE)in soils were coordinately controlled by plant traits,soil properties,and microbial attributes.Partial least squares path modeling analysis identified soil organic C(SOC)chemical fractions(e.g.,aromatic C,alkyl C,dissolved organic C)as predominant positive drivers of microbial C limitation and NUE,while simultaneously suppressing microbial CUE.Simultaneously,plant traits were identified as the foremost contributor to microbial P limitation,followed by microbial attributes as the second-most influential positive factor.Conclusions This study revealed that S.alterniflora invasion fundamentally shifted microbial nutrient limitation from predominant P limitation in bare flat and native salt marshes to dual C-P co-limitation,while simultaneously inducing the strongest microbial C limitation among all communities.This invasion-induced microbial C limitation drove a reduction in microbial CUE but an enhancement of NUE.SOC accumulation increased with decreasing microbial CUE following S.alterniflora invasion,a tradeoff potentially linked to divergent nutrient limitations across ecosystems.This study provided empirical evidence for microbially-mediated soil C sequestration mechanisms underlying plant invasion-induced ecosystem transformations.
