
Spatial heterogeneity in nutrients may increase the relative competitive ability of species that are more able to concentrate their roots where nutrient levels are high; if so, heterogeneity should have little effect on intraspecific competition when no genotypic differences exist between individuals. Zhou et al.Β grow a clonal invasive herb, Alternanthera philoxeroides (Amaranthaceae), at different plant densities with homogeneous or hetergeneous availability of soil nutrients and find no interactive effects on growth, consistent with the suggestion that effects of heterogeneity on competition depend upon differences in plasticity between individuals.