Impacts of Spartina Alterniflora Invasion on Coastal Wetland Ecosystems

Spartina alterniflora, known as smooth cordgrass, has spread beyond its native range to reshape coastal wetlands worldwide. Its robust growth and dense rhizome network accelerate sediment accretion and alter tidal hydrodynamics, leading to changes in marsh elevation and shoreline stability. Invaded zones often see displacement of native plant communities, with consequent loss of habitat diversity for invertebrates, birds and fish. At the soil level, invasion modifies organic carbon and nutrient budgets, elevating rates of nitrogen fixation and sulphur cycling while influencing greenhouse gas fluxes—particularly methane and carbon dioxide. Underpinning these shifts is a restructuring of microbial communities in the rhizosphere and bulk sediment, which drives biogeochemical processes critical to ecosystem function. Such transformations carry profound implications for ecosystem services, including carbon sequestration, flood protection and biodiversity support. Understanding these dynamics is essential for informed management interventions aimed at restoring native biodiversity and optimising blue carbon benefits in invaded wetlands.

Research from Nature Portfolio

Recent studies have revealed key mechanistic insights into the impacts of S. alterniflora on microbial–plant interactions and biogeochemical cycles. A 2024 investigation demonstrated that roots of S. alterniflora host a symbiotic consortium of sulfur-oxidising and nitrogen-fixing bacteria, thereby enhancing nitrogen availability under sulfidic stress and contributing to plant productivity in salt marshes. Complementary work has shown that invasion can shift soil carbon gas exchange, markedly increasing methane emissions while reducing carbon dioxide flux in coastal mangrove settings. Foundational research using chronosequence approaches has further documented that prolonged invasion leads to elevated soil organic carbon and microbial biomass, with sequential changes in community structure and respiration rates over decadal scales.

Impacts of Spartina Alterniflora Invasion on Coastal Wetland Ecosystems publication trend

The graph below shows the total number of articles in impacts of spartina alterniflora invasion on coastal wetland ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Sulfur oxidation: Microbial process of converting sulfide to sulfate, often linked to energy generation and detoxification in sediment.

Nitrogen fixation: Biological conversion of atmospheric nitrogen gas into bioavailable ammonia by specialised microorganisms.

Methanogenesis: Archaeal metabolic pathway producing methane through the reduction of carbon compounds under anoxic conditions.

Rhizosphere: Soil zone directly influenced by plant roots where complex microbial interactions occur.

Blue carbon: Carbon stored in coastal and marine ecosystems such as salt marshes, seagrass beds and mangroves.

Chronosequence: Sequence of sites representing different stages of ecological succession or invasion over time.

References

1. Sulfur oxidation and reduction are coupled to nitrogen fixation in the roots of the salt marsh foundation plant Spartina alterniflora. Nature Communications (2024).
2. Exotic Spartina alterniflora invasion increases CH4 while reduces CO2 emissions from mangrove wetland soils in southeastern China. Scientific Reports (2018).
3. Spartina alterniflora invasion alters soil microbial community composition and microbial respiration following invasion chronosequence in a coastal wetland of China. Scientific Reports (2016).
4. Continental‐scale plant invasions reshuffle the soil microbiome of blue carbon ecosystems. Global Change Biology (2022).
5. The core root microbiome of Spartina alterniflora is predominated by sulfur-oxidizing and sulfate-reducing bacteria in Georgia salt marshes, USA. Microbiome (2022).
6. Invasion by Cordgrass Increases Microbial Diversity and Alters Community Composition in a Mangrove Nature Reserve. Frontiers in Microbiology (2017).