Aims Leaf traits are closely related to plant light use efficiency and photosynthesis. They can indicate plant adaptation strategies to the environment. Spartina alterniflora is a major alien invasive plant in many coastal wetlands, and it seriously threatens coastal wetland ecosystems in China. Tidal flooding is one of the main limiting factors for the growth and distribution of S. alterniflora in coastal wetlands. However, there has been very little research directly examining the pattern and adaptation mechanism of leaf traits of S. alterniflora along a tidal gradient.
Methods In this study, a tidal elevation control platform was established in Zhangjiang Estuary, Fujian. We studied the response pattern and driving factors of leaf functional traits (length, width, length width ratio, area, dry mass, and specific leaf area) of S. alterniflora to the tidal gradient (relative elevation).
Important findings The results showed that: (1) The leaf length, leaf width, leaf area, and leaf dry mass of S. alterniflora decreased with increasing elevation, whereas the leaf length width ratio increased with increasing elevation. (2) The specific leaf area of S. alterniflora and elevation showed a hump-shaped relationship. (3) The effects of inundation frequency, soil porewater salinity, and soil water content on leaf traits were different. The leaf length, leaf width, leaf area, and leaf dry mass of S. alterniflora increased with increasing inundation frequency and soil water content, but decreased with increasing soil porewater salinity; the leaf length width ratio of S. alterniflora decreased with increasing inundation frequency and soil water content, but increased with increasing soil porewater salinity; the specific leaf area of S. alterniflora increased first and then decreased with increasing inundation frequency, and increased with increasing soil water content. In summary, the patterns and main driving factors of leaf traits of S. alterniflora differed along a tidal gradient, and this finding may be due to differences in the effects of leaf traits on plant physiological processes. Thus, S. alterniflora can adapt to changes in tidal elevation by adjusting leaf traits and their trade-offs. This study provides a new perspective for understanding and predicting the ecological adaptation of S. alterniflora to sea level rise in coastal wetlands.