Effects of initial density, nutrient, and water level regime on the seedling survival and growth of Typha orientalis Presl

Abstract

Seedlings' successful establishment is of importance in the preemption process of pioneers in wetlands. Although Typha orientalis Presl has been reported as a pioneer in Asia countries, studies on the seedling phase of T. orientalis are not available yet. A mesocosm experiment was conducted to understand the effects of biotic (initial density) and abiotic (nutrient and water level regime) factors on the seedling survival and growth of T. orientalis. Most seedlings survived under low initial density (93.8%) and eutrophic (95.5%) rather than high initial density (64.3%) and ombrotrophic (62.5%). Seedlings under low initial density, eutrophic, and flooded conditions showed relatively higher growth in shoot height. The final number of ramets showed an adverse tendency compared to the survival rate and shoot height particularly depending on the water level regime. T. orientalis compensated its biomass production with producing less but longer shoots under the flooded condition, indicating the phenotypic plasticity of T. orientalis as a deep water species. However, the compensation seemed to be guaranteed only under the condition of sufficient nutrients. Asian T. orientalis seemed not to be a pioneer but a weak-competitor not only in mature plant stage but also in juvenile seedling stage unless sufficient nutrients are guaranteed.