A general integrative model for scaling plant growth, carbon flux, and functional trait spectra
Nature, 449 (7159):
218--222 (Sep 13, 2007)DOI: 10.1038/nature06061
Abstract
Linking functional traits to plant growth is critical for scaling attributes of organisms to the dynamics of ecosystems1, 2 and for understanding how selection shapes integrated botanical phenotypes3. However, a general mechanistic theory showing how traits specifically influence carbon and biomass flux within and across plants is needed. Building on foundational work on relative growth rate4, 5, 6, recent work on functional trait spectra7, 8, 9, and metabolic scaling theory10, 11, here we derive a generalized trait-based model of plant growth. In agreement with a wide variety of empirical data, our model uniquely predicts how key functional traits interact to regulate variation in relative growth rate, the allometric growth normalizations for both angiosperms and gymnosperms, and the quantitative form of several functional trait spectra relationships. The model also provides a general quantitative framework to incorporate additional leaf-level trait scaling relationships7, 8 and hence to unite functional trait spectra with theories of relative growth rate, and metabolic scaling. We apply the model to calculate carbon use efficiency. This often ignored trait, which may influence variation in relative growth rate, appears to vary directionally across geographic gradients. Together, our results show how both quantitative plant traits and the geometry of vascular transport networks can be merged into a common scaling theory. Our model provides a framework for predicting not only how traits covary within an integrated allometric phenotype but also how trait variation mechanistically influences plant growth and carbon flux within and across diverse ecosystems.