Spatially differentiated restoration strategies optimize multiple ecosystem functions in tidal marshes after Spartina eradication

Invasive species eradication, while necessary for biodiversity conservation, frequently triggers loss of ecosystem functions previously provided by the invader, creating management dilemmas for large-scale restoration. China’s Spartina alterniflora removal program (68,000 ha, 2023–2025) exemplifies this challenge: despite degrading biodiversity, the S. alterniflora delivers substantial coastal protection and carbon sequestration services. Strategic post-eradication restoration requires explicit evaluation of which ecosystem functions to prioritize at which locations. We developed a spatially explicit framework integrating species distribution modeling with scenario-based optimization to identify optimal native vegetation allocation strategies for ecosystem function recovery following S. alterniflora eradication in the Yangtze Estuary. We modeled habitat suitability for functionally distinct native species (Phragmites australis and Scirpus mariqueter) and designed four restoration scenarios: Environmental Suitability (ES, baseline) and three optimization scenarios targeting Carbon Stock (CS), Coastal Protection (CP), and Biodiversity Protection (BP). Optimization scenarios achieved target ecosystem function improvements (CS: +15 % carbon stock; CP: +71 % wave attenuation; BP: +15 % biodiversity indices), incurred 7–14 % reductions in non-target functions. Carbon storage and coastal protection exhibited synergies through shared biomass dependence: the CS scenario achieved +43 % wave attenuation despite prioritizing carbon, while the CP scenario co-delivered +7 % carbon stock gains. In contrast, biodiversity enhancement through habitat heterogeneity traded off both biomass-dependent functions: the BP scenario reduced carbon stock by 7 % and wave attenuation by 14 % relative to the ES baseline. Given these trade-offs, we recommend spatially differentiated implementation: CP along erosion-prone shorelines, CS in rapidly accreting zones, and BP in areas adjacent to protected habitats. This framework provides a transferable approach for balancing multiple ecosystem functions in S. alterniflora post-eradication coastal restoration worldwide.