Kokhan T. Ecological and biologacal principles of creation of many-functional herbareous phytocenoses on the south-east of Ukraine.

The objects are species of herbaceous plants from collections of natural flora, and new and incomplete of forage plants of a Donetsk botanic garden of NAS of Ukraine both natural and simulated vegetative assemblages. The aims are to study of the functional features of simulated of herbaceous phytocenoses on their full-scale models, to reveal of regularity of development of species in vegetative assemblages and to elaborate the "ideal model" of perennial high-performance herbaceous phytocenoses steady on a species composition in conditions of a southeast of Ukraine. Methods - geobotanic, field, mathematical-statistical, rated - comparative. The thesis is devoted to the development of ecological and biological principles of herbaceous phytocenoses creation by means of using various approaches to species combinations. The following approaches have been emplojed: empirical (ecological adaptation and bioeconomic characters of species) and ecologic - phytocenotic approach where apart from ecological adaptation and selection of the species according to bioecological characters, a significant importance also belongs to phytocenotic peculiarities of the species (speсies strategy, association, competitive capacity). Species properties were used in creation of three model plant communities. Functional regulations of three types of models (empiric, with natural combinations of ceveals and model with species subordination corresponding to their competitive capacity) according to species development in plant communities, dynamics of species composition. The regularities revealed facilitated the search of an "ideal model" of artificial herbaceous communities which is based on species subordination according to phytocenotypes where dominants and subdominants have to be cenotically equivalent species which would be able to create a dynamic equivalence depending upon the change of ecological conditions. Species composition has been selected for artificial plant communities, created under concrete ecologic conditions with a view of renewal and concervation of natural steppe phytocenoses. Spheres of use are the agriculture and renewal and concervation of natural steppe phytocenoses.