Size symmetry of competition alters biomass-density relationships

Authored by J Weiner, P Stoll, H Muller-Landau, E Muller, T Hara

Date Published: 2002

DOI: 10.1098/rspb.2002.2137

Sponsors: Japanese Society for the Promotion of Science (JSPS)

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

As crowded populations of plants develop, the growth of some plants is accompanied by the death of others, a process called density-dependent mortality or `self-thinning'. During the course of density-dependent mortality, the relationship between total population biomass (B) and surviving plant density (N) is allometric: B = aN(b). Essentially, increasing population biomass can be achieved only through decreasing population density. Variation in the allometric coefficient a among species has been recognized for many years and is important for management, assessment of productivity and carbon budgets, but the causes of this variation have not been elucidated. Individual-based models predict that size-dependent competition causes variation in the allometric coefficient. Using transgenic Arabidopsis with decreased plasticity, we provide experimental evidence that morphological plasticity of wild-type populations decreases the size asymmetry of competition for light and thereby decreases density-dependent mortality. This decrease in density-dependent mortality results in more biomass at a given density under size-symmetric compared with size-asymmetric competition.

Tags

geometry Mechanisms Asymmetry Neighbors Stands Plant-populations Phytochrome Arabidopsis Signal