XVI International Botanical Congess
We have studied intra- and interspecific competitive responses of wild barley plants originating from 4 habitats. Three population habitats represented two parallel gradients of rainfall amount and its predictability: desert, semi-steppe batha and Mediterranean grassland. The populations consistently differed in intraspecific competitive responses, but only for density increment from 0 to 4 neighbors. The plants from Mediterranean grassland showed significantly lower decrease in fitness than plants from other environments. Besides, they exhibited highest plasticity in reproductive allocation among populations under both intra- and interspecific competition. These results are largely consistent with Grime's triangular ordination model and the hypothesis that high competitive ability is achieved by morphological plasticity.