The ecological role of silicon in tropical forests: consequences of inter- and intraspecific variation of silicon accumulation for woody seedling regeneration in the forest understory (DFG) Silicon (Si) can contribute more than 10% of the dry mass of plants, and it is well-recognized that Si can alleviate stress due to drought, low nutrients and herbivory. These stressors play an important role for seedling regeneration, species distribution, forest dynamics and ecosystem function in tropical forests. Yet, the ecological role of Si in tropical forests, which harbor an enormous diversity and provide globally important ecosystem services, has hardly been addressed. In this study, we examine if and how inter- and intraspecific variation of leaf Si contents and spatial variation of soil Si availability affect seedling vital rates, i.e. growth and survival, in the understory - and how such effects change across environmental gradients. By integrating observational, experimental and trait-based approaches, the study will provide novel and important insights into the ecological role of silicon in tropical forests. At the same time, it addresses a main pending question in Si biology, if leaf Si accumulation in plants confers an inter- and intraspecific ecological advantage.
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