Relationships among net primary productivity, nutrients and climate in tropical rain forest: A pan-tropical analysis

Cory C. Cleveland, University of Montana
Alan R. Townsend, University of Colorado Boulder
Philip Taylor, University of Colorado Boulder
Silvia Alvarez-Clare, University of Florida
Mercedes M.C. Bustamante, Universidade de Brasília
George Chuyong, University of Buea
Solomon Z. Dobrowski, University of Montana
Pauline Grierson, The University of Western Australia
Kyle E. Harms, Louisiana State University
Benjamin Z. Houlton, University of California, Davis
Alison Marklein, University of California, Davis
William Parton, Colorado State University
Stephen Porder, Brown University
Sasha C. Reed, United States Geological Survey
Carlos A. Sierra, Max Planck Institute for Biogeochemistry
Whendee L. Silver, Department of Environmental Science, Policy, and Management
Edmund V.J. Tanner, University of Cambridge
William R. Wieder, University of Colorado Boulder


Tropical rain forests play a dominant role in global biosphere-atmosphere CO 2 exchange. Although climate and nutrient availability regulate net primary production (NPP) and decomposition in all terrestrial ecosystems, the nature and extent of such controls in tropical forests remain poorly resolved. We conducted a meta-analysis of carbon-nutrient-climate relationships in 113 sites across the tropical forest biome. Our analyses showed that mean annual temperature was the strongest predictor of aboveground NPP (ANPP) across all tropical forests, but this relationship was driven by distinct temperature differences between upland and lowland forests. Within lowland forests (<1000m), a regression tree analysis revealed that foliar and soil-based measurements of phosphorus (P) were the only variables that explained a significant proportion of the variation in ANPP, although the relationships were weak. However, foliar P, foliar nitrogen (N), litter decomposition rate (k), soil N and soil respiration were all directly related with total surface (0-10cm) soil P concentrations. Our analysis provides some evidence that P availability regulates NPP and other ecosystem processes in lowland tropical forests, but more importantly, underscores the need for a series of large-scale nutrient manipulations - especially in lowland forests - to elucidate the most important nutrient interactions and controls. © 2011 Blackwell Publishing Ltd/CNRS.