ONTOGENETIC STRUCTURE OF POPULATIONS PHALACROLOMA ANNUUM DUMORT. (ASTERACEAE) ON THE TERRITORY OF KAMIANETSKЕ PRIDNESTROVYA

Abstract

On the territory of Kamianetskе Pridnestrovya, the mass distribution of plants of the genus Phalacroloma L. was noted in biotopes formed by human economic activity of type "I". A significant number of plants were recorded in grass-herbaceous meso- and xerotic biotopes of type "E" dominated by hemicryptophytes, formed in conditions of moderate or insufficient moisture in meadows, steppes, wastelands – these are biotopes of hygromesophytic, mesophytic, and xeromesophytic grasses formed in under conditions of sufficient moisture (meadows) (Molinio-Arrhenatheretea, Nardetalia) and meadow-steppe biotopes on rendzins and chernozems (Festuco-Brometea), as well as "F" type biotopes formed by chamephytes (semi-shrubs, bushes and semi-shrubs) and nanophanerophytes. characteristic features of the ontogenetic structure of coenopopulations of Phalacroloma annuum Dumort. (s. str.) and analyzed the dynamics of ontogenetic states for the period 2016–2019. In order to study the ontogenetic structure of populations on the territory of Kamianetskе Pridnestrovya, 6 experimental plots, 10x1 m in size, were established in biotopes with different ecological and coenotic conditions and anthropogenic pressure. It was established that the ontogeny of Ph. annuum is represented by 7 ontogenetic states: p – j – im – v – g1 – g2 – g3. A decrease in the number of individuals in all studied populations was observed during 2016-2019 and a change in the share of different ontogenetic states, which was caused by a number of factors: ecological-cenotic, anthropogenic, individual features of plant ontogenesis. According to the ontogenetic structure, cenopopulations are characterized as normal, to varying degrees immature. In some of them, the incompleteness of the ontogenetic spectrum was noted due to the absence of a number of ontogenetic states (seedlings and juvenile, senile or subsenile individuals), which is due to ecological and phytocenotic conditions of existence. Ontogenetic spectra of all investigated coenopopulations of Ph. anuum are bimodal with one peak on juvenile or immature individuals and a second peak on young generative individuals or left-sided, with a predominance of progenerative plants. The exception is P1 in 2017, where the ontogenetic spectrum turned out to be centered, that is, with a predominance of generative plants. During 2016-2019, only P3 was found to have stable ontogenetic spectra, in other populations a change in the share of ontogenetic states was observed. During the study period, most cenopopulations were characterized as invasive: in 2016, all cenopopulations were invasive, in 2017 the same was true, except P1, which was characterized as normal. In 2018, P1, P3, P6 became invasive, and P2, P4, P5 became normal. In 2019, all populations are characterized as invasive, only P4 – as normal.