THE EFFECTS OF PHYSICAL SUPPORT AND DENSITY ON BIOMASS PRODUCTION ANDSIZE HIERARCHIES OF GALIUM-APARINE POPULATIONS

We assessed the growth and size inequality of experimental populations of Galium aparine at different densities with and without physical su pport. Those plants for which support was provided gained more weight than those unsupported. The presence of support increased the relative growth rate of the plants and reduced mortality at the highest densit ies. The biomass of the population was also higher in the case of supp orted plants. The size inequality of the population was not affected b y the support-treatment but varied with density. Since density-depende nt mortality took place at higher densities, and the variation of the relative growth rate increased with density, dominance-suppression cou ld be assumed. This was not, however, reflected in an increase in size inequality before the period when mortality occurred, which suggests that size is not necessarily a good predictor of the use of resources by individuals of this species.