Spartina alterniflora invasion decouples multiple elements in coastal wetland soils

Deciphering the biogeochemical coupling of multiple elements in soils could better mechanistic understanding of ecosystem stability response to the alien invasion. The coupling of 45 elements in soils from wetlands covered by Spartina alterniflora (Sa) was compared with that in soils covered by native Phragmites australis (Pa) in coastal regions of China. Results showed that S. alterniflora invasion not only significantly reshaped geochemical enrichment and dispersion states, but also decoupled the coupling of multiple elements in soils compared with Pa. Atomic mass emerged as the primary factor governing the coupling of multiple elements, of which a significantly positive correlation exhibited between atomic mass with elemental coupling in Pa, but no such relation was observed in SaThe coupling of lighter elements was more susceptible to and generally enhanced by the invasion of S. alterniflora compared to the heavier, of which carbon, iron (Fe), and cadmium (Cd) had the highest susceptibility. Besides atomic mass, biological processes (represented by soil organic carbon, nitrogen, phosphorus, and sulfur), interactions between sea and land (represented by salinity and pH), and their combination explained 17 %, 10 %, and 13 % variation in the coupling of multiple elements, respectively. The present work confirmed that S. alterniflora invasion was the important factor driving soil multi-element cycling and covariation in coastal wetlands. S. alterniflora invasion not only significantly redistributed geochemical enrichment and dispersion but also decoupled the coupling of soil multiple elements. The coupling of lighter elements proved to be more susceptible to and generally enhanced by the invasion of S. alterniflora compared to heavier elements. [Display omitted] •S. alterniflora invasion alters elemental geochemical enrichment and dispersion.•The mean MEC value in Sa, 0.351, was lower than that in Pa, 0.372.•S. alterniflora invasion decoupled the coupling of 45 elements in soils.•The coupling of lighter elements is more susceptible to S. alterniflora invasion.•Atomic mass and biological processes are main factors governing elemental coupling.