XVI International Botanical Congess

Life-history strategies concept is very valuable for analysis of plant communities but difficulties arise in its application to definite plant assemblages. Competition ability, stress-tolerance and ability to establish in disturbed sites are inherent in any plant species. Relatively few species are characterized by preponderance of one strategy type features. The differences between competitors and stress-tolerators are very vague. There are not evidences that competition is less intensive in extreme environment. Plants in every habitat are influenced by biotic or abiotic environmental stresses. The ruderals are often strong competitors and exist during several generations in the community. They are not less stable as many species in climax vegetation. Regeneration of most part of plant species is not successful in closed vegetation. Every species needs in disturbances or gaps for seedling establishment. It is impossible to divide plant species into three primary strategy types. For understanding of plant community structure is more perspective to investigate plant species features that ensure their competition ability.