Using leaf nutrient stoichiometry as an indicator of flood tolerance and eutrophication in the riparian zone of the Lijang River

摘要

Leaf carbon (C), nitrogen (N), and phosphorus (P) concentrations and corresponding ratios are indicators of ecological processes. How plant C, N and P stoichiometry responds to environmental stresses under variable flooding regimes in riparian systems is presently unclear. In this study, we evaluated the characteristics of C, N and P stoichiometry of riparian plants across different seasons and inundation zones along the Lijiang River in China. Our analysis revealed that leaf C, N and P concentrations and C: N: P ratios varied extensively. Leaf N and P concentrations were lower in spring than in autumn, whereas leaf C concentration and C: N, C: P and N: P ratios were higher in spring. Total leaf N and P concentrations were significantly higher and C: N and C: P ratios were significantly lower in the severe inundation zone than the mild inundation zone. Among different plant functional types, grasses in the severe inundation zone had relatively higher N and P concentrations. In general, plants in the Lijiang River riparian zone used a quiescent strategy to cope with flooding stress. Herbaceous plants showed the greatest adaptation to flooding environments. A tendency towards N limitation of plant growth may exist due to anthropogenic eutrophication. Our findings, which highlight the influence of season and flooding on plant leaf stoichiometric characteristics, may help guide the rehabilitation and conservation of riparian ecosystems.