Increasing atmospheric nitrogen (N) deposition is an important driver of biodiversity change. In China, N deposition has been dramatically increasing for decades, and the forests have been receiving high levels of N deposition. However, the effects of N deposition on the plant diversity in China’s forests have rarely been reported, especially regarding sensitive ecosystems such as boreal forest. In this study, by conducting an eight-year N addition experiment (0, 20, 50 and 100 kg N ha-1 yr-1), we investigated the long-term effects of simulated N deposition on understory species composition and richness in a boreal forest, northeast China.
Results/Conclusions
We found that mosses cover decreased significantly with increasing N addition. N addition had no significant effect on vascular plants species richness but changed plant community composition. The relative coverage of evergreen shrubs decreased, while that of graminoids increased under high-level N addition (100 kg N ha-1 yr-1). Under the high-level N treatment, cover of Deyeuxia angustifolia increased significantly after 4 years, while that of Vaccinium vitis-idaea decreased significantly after 3 years and almost disappeared after 5 years. The negative effect of N addition on mosses and evergreen shrubs accumulated over time, while the positive effect on graminoids increased during the first four years and did not change significantly thereafter. Our results suggest that the effect of N deposition varies across functional groups and shifts over time.