Multiple competitive superiority made a great successful invasion of Spartina alterniflora in Eastern China: hints for management

Numerous case studies indicate that the successful invasion of alien species involve multiple mechanisms. Spartina alterniflora (Poaceae) has rapidly and extensively encroached on China's coastline over the past decades, however, limited studies have explored multiple invasion mechanisms. Using a combination of greenhouse experiments, field survey, and literature investigations, a cross-scale study of S. alterniflora in Eastern China was conducted to link the multiple invasion mechanisms against the dominant native species, Phragmites australis (Poaceae) and Scirpus mariqueter (Cyperaceae) at high and low coastal habitats, respectively. The results revealed that S. alterniflora was competitive superior to native species at the seed/seedling scale, with a higher seed yield and germination rate, and low risk of seed hunting by crabs. At the individual scale, S. alterniflora showed a stronger tolerance to changing environmental factors impacting photosynthesis, growth parameters, and root architecture, compared with the native P. australis. S. alterniflora were also resilient to insect pests. At the community scale, S. alterniflora showed shading effects on the native S. mariqueter. The multiple competitive advantage led to the successful invasion of S. alterniflora in Eastern China, broadening our understanding of why the exotic species can achieve dominance in whole China's coast. We suggest that the multiple competitive superiority of S. alterniflora can be integrated from the perspectives of the organizational level of life systems to efficaciously forecast invasion trajectories and design control strategies.