Abstract:Since 2007, the unique anthropogenic hydrological regime of the Three Gorges Dam has had significant negative impacts on the reservoir riparian ecosystem. These include changes in the local climate pattern, habitat fragmentation, generation of methane gas, loss of biodiversity, and inundation of cities and highly productive agricultural land. The functional traits of plants in a particular area can reflect the eco-physiological processes that are specific to that environment, and can serve as crucial indicators of the structure and function of the local ecosystem. These functional traits play a key role in adaptation to anti-seasonal flooding, and might reveal clues about the adaptation mechanisms of plants in this area. Therefore, two years after the formation of the reservoir riparian region in the Three Gorges Area, we investigated six leaf functional traits of 42 species growing in the the reservoir riparian region in 2009. As a reference, we also investigated these functional traits in 33 species in an upland non-flooding belt, to determine variations in physiological processes associated with anti-seasonal flooding. The six leaf functional traits were leaf mass per area (LMA), maximum net photosynthesis rate (Amax), leaf stomata conductance (Gs), leaf nitrogen content per mass (Nmass), leaf phosphorus content per mass (Pmass) and leaf potassium content per mass (Kmass). A standardized major axis analysis method was used to determine the relationships among these traits. We compared these results with data in the global plant trait network to determine how the leaf traits relationships for plants in the the reservoir riparian region compare with those in the worldwide leaf spectrum. For species that coexist in the reservoir riparian region and non-flooding belt, we used paired-sample T-tests to compare differences in leaf functional traits between the two areas, to determine which physiological processes are important for growth in the the reservoir riparian region environment. The results showed that: 1) although there were slight differences in the standardized major axis slopes/elevation of some paired traits, there were similar patterns of leaf functional trait relationships between the reservoir riparian region and the global plant trait network, indicating convergence of leaf traits in the the reservoir riparian region ecosystem. 2) Amass, Nmass, Pmass, and Kmass of the reservoir riparian region species were significantly higher than their corresponding values in the global plant trait network, but the LMAs of the reservoir riparian region species were statistically lower than LMA values in the global plant trait network. The traits of the reservoir riparian region species were constrained to the lower-investment and faster-return end of the global leaf spectrum, and were consistent with typical fast-growing species. 3) When the 33 species common to both the reservoir riparian region and non-flooding belt were compared, we found that those in the the reservoir riparian region showed significantly higher Amax. The results of the present study suggest that enhanced photosynthetic capacity is one of the key physiological strategies for growth in the the reservoir riparian region environment. However, there are many uncertainties that remain after this study, because the the reservoir riparian region area is only two years old and plants are likely to be in the response or acclimation stages rather than the adaptation stage. Therefore, long-term investigations and observations should be continued in this area to identify and monitor adaptive changes in plant species.