Ontogeny and individual and group parameters of Cirsium erisithales (Jacq.) Scop. (Asteraceae) in the Ukrainian Carpathians

The article deals with ontogeny and individual and group parameters of an infrequent mountain species Cirsium erisithales (Jacq.) Scop. in the Ukrainian Carpathians. Isolated populations of C. erisithales in a wide high altitudinal range of 1040–1730 m a.s.l. were studied. Four periods and 8 age stages are defined in the ontogeny of this species. Characteristics of different age states are established. The total life span of C. erisithales is long. Unfavourable conditions cause shortening of ontogeny due to reduction or skipping of some periods. Population recruitment is performed by seed reproduction. The species has high parameters of seed reproduction, particularly germination rate and potential seed productivity. Thin-tussock or barren loci are most favourable for the establishment and successful development of seedlings. It is one of the few species, which can inhabit the schist screes. Individual and group parameters of C. erisithales do not significantly depend on the altitude above sea level. It was established that C. erisithales mostly has a low density. It is the highest in the high-mountain population on Mt. Hoverla. The height of generative shoot, width and length of leaf are significantly higher in the population in the place of Babyna Yama. Number of leaves and inflorescences are similar in all of the studied populations. The height of generative shoot is most variable. Percentage of generative group varies within 20–45 %. It was determined that considerable anthropogenic impact (particularly mechanical disturbance of herbaceous vegetation) results in the shrinkage of the area of populations and significant decrease in individual and group parameters, namely height of shoot and width of leaf – by 2, length of leaf – almost by 3, number of leaves – by over 3, real to potential seed productivity ratio – almost by 4, real seed productivity – by 5, number of capitula – almost by 6, harvest of seeds – by 26 times. Factors, which adversely effect the replenishment of C. erisithales are: timber skidding, road laying, recreation, excessive sodding, large land- and rockslides, inflorescense consumption by animals etc.