Effects of Smooth Cordgrass Spartina alterniflora Invasion on Macrobenthic Fauna in the Yellow River Delta

Smooth cordgrass Spartina alterniflora, as a species for ecological engineering, was introduced to the Yellow River Delta (the YRD) in 1990. However, it expanded rapidly due to its strong compatibility and competitiveness in recent years. It would inevitably present severe threats to native plants and local macroinvertebrates. This study aimed to test the abiotic and biotic responses to the S. alterniflora invasion by analyzing the samples of pore-waters, sediments, and macrobenthos collected in different sites following the invasion chronology in August 2018. Results showed that with the invasion time, the contents of dissolved inorganic nitrogen (NOx- and NH4+) and phosphate (PO43-) increased, while the content of silicate (SiO32-) decreased in pore-water; the content of total organic matter (TOM) decreased firstly, and then increased in the sediment; the species composition of macrobenthos also changed significantly prolong invasion time, Crustacea disappeared, and Chironomidae occurred gradually; the values of the abundance, biomass, and biodiversity of macrobenthos decreased firstly and increased subsequently with invasion history. Our findings reflect the chronological effects of S. alterniflora invasion on the benthic environment and macrobenthic community, which contribute to establishing the linkage between the exotic plant invasion and benthic ecosystem, providing a scientific basis for wetland biodiversity conservation and resource management in the YRD.

Automated summary

The study aimed to test the abiotic and biotic responses to the S. alterniflora invasion in the Yellow River Delta. Results showed changes in pore-water composition, sediment organic matter content, and macrobenthos species composition with invasion time. The invasion had both negative and positive effects on the benthic environment and macrobenthic community, providing insights for wetland biodiversity conservation and resource management in the area.