Ecocenotic differentiation between Thalictrum minus L. and Thalictrum simplex L. in the Southern Urals

442 The Southern Urals are a unique region for research on ecocenotic differentiation between closely related species that often grow together in the same plant communities. Analysis of such differentiation makes it possible to reveal the ecocenotic strategies of the species and predict changes in their proportions in plant communities under the effects of climatic and anthropogenic factors. Meadow rues Thalictrum minus L. and T. simplex L. are an example of such spe� cies. They are of interest as producers of isoquinoline alkaloids, which serve as the active ingredients of vari� ous effective drugs (Yunusov, 1997). Thalictrum minus is a holarctic species occurring throughout Eurasia and in North America, while T. simplex is an Eurasian species (Bagdasarova, Barykina, and Luferov, 1993). They often grow together in various habitats. This study was performed to analyze ecocenotic principles of differentiation between these species in the South� ern Urals. The bulk of material for the study was collected during expeditions over the Southern Ural region (2007–2011). Standard geobotanical descriptions made in habitats of the two species were referenced to the system of units in the ecofloristic classification of Southern Ural plant communities made by the Braun� Blanquet method. To assess the cenotic ranges of these species, we also used a database of Southern Ural plant communities compiled of our own geobotanical descriptions and those published by other authors. This allowed us to analyze the presence and propor� tions of the two species in plant communities belong� ing to 363 associations of 83 unions, 52 orders, and 32 classes of forest, meadow, steppe, synanthropic,