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The ecological significance of soil phosphorus in lowland tropical rain forests

Benjamin Turner1
1 Smithsonian Tropical Research Institute

Key Note 5 in Plenary Keynotes

17.07.2014, 09:00-09:45

 

Nutrient availability is commonly assumed to limit plant productivity in lowland tropical forests, but experimental evidence is scarce and equivocal. In this presentation I will explore the extent to which soil phosphorus influences the productivity, diversity, and distribution of plant species in tropical forests. First, I will highlight the range of soils that occur in tropical forests and the remarkable number of plant species that they support. I will argue that pedogenesis and associated phosphorus depletion is a primary driver of forest diversity over long timescales when controlling for climate, parent material, and topography. I will draw on data from a regional-scale network of forest dynamics plots to show that dry season intensity and soil phosphorus determine the distribution of tree species in hyper-diverse tropical forests, and will suggest potential mechanistic explanations for this pattern in relation to phosphorus acquisition. I will present evidence from long-term manipulative experiments in Panama that demonstrate how multiple nutrients, including phosphorus, nitrogen, potassium, and micronutrients, limit plant productivity and microbial communities on strongly-weathered soils in the lowland tropics. Finally, I will discuss the implications of these results for attempts to model the response of tropical plant communities and soil carbon stocks to climate change and increasing carbon dioxide concentrations in the atmosphere.

 



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last modified 2014-05-14