Global change such as altered precipitation patterns and increased atmospheric nitrogen (N) deposition will have significant impacts on seedling growth during plant recruitment. However, how interactive effects of increased precipitation and N deposition on forest seedling performance have not been well investigated. In this study, we conducted a two-year field experiment that manipulating precipitation amount (ambient rainfall and 25% increment during the wet season) and exogenous N addition (0 and 100 kg ha−1 yr−1) in a tropical secondary forest. Seedling growth, morphology and nutritional status of a dominant tree species (Cinnamomum burmanni) were measured. Results showed that increased precipitation had positive effects on seedling height, basal diameter growth, biomass production, height/basal diameter ratio (H/BD), and Dickson's quality index (DQI), but decreased N and phosphorus (P) concentrations in the stems and roots of seedlings. Interactive effects between precipitation and N treatments on seedlings were significant. N addition only enhanced height, total biomass, and H/BD ratio of seedlings with increased precipitation. These results indicated that increased precipitation during the wet season caused by heavy rainfall events, together with elevated N deposition, potentially have profound influences on seedling performances during the early recruitment stage and plant community regeneration in the tropical forest.
Jun Wang, Dafeng Hui, Hongfang Lu, Faming Wang, Nan Liu, Zhongyu Sun, Hai Ren, "Main and interactive effects of increased precipitation and nitrogen addition on growth, morphology, and nutrition of Cinnamomum burmanni seedlings in a tropical forest", Global Ecology and Conservation, Volume 20, 2019, e00734, ISSN 2351 9894, https://doi.org/10.1016/j.gecco.2019.e00734.