A comparison of plant communities on the basis of their clonal growth patterns

This study was performed to analyse how a vegetative propagation pattern of plants affects the coexistence of species and subsequent species richness of the community. We compared community average clonal growth in the herbal communities of forests, wooded meadows, and open meadows in Laelatu, Estonia. The parameters used for the calculation of the community averages and measured for each species were ramet life span, rhizome branching, and clonal mobility. We also examined the intrinsic (i.e. independent of the environment) relationship between community clonal growth and plant species density. We found strong correlations between the environmental factors (productivity, light availability, and mowing regime) and community averages of clonal growth parameters, while species density was (negatively) correlated only with community average of rhizome increment. The community average of ramet life span decreased with the increasing biomass of the herb layer. No evidence was found to support the hypothesis that species-rich communities may consist of species with more contrasting mobility compared with species-poor communities. Independent of the effect of the environmental factors, species density was positively correlated with ramet density. There was intrinsic positive relationship between species density and community average of ramet life span at open meadow sites and intrinsic negative relationship between species density and community average of rhizome increment at wooded meadow sites. We conclude that in forest communities the capability of clonal plants to forage for light is favoured, while in unmown meadows a competitively strong phalanx growth form is advantageous. We established that ramet turnover increases and vegetative mobility decreases with increasing species diversity, although these two relationships depend strongly on the type of the studied community.