Periodization ontogenesis Stenactis (Phalacroloma) annua and study of ontogenetic structure of populations in conditions of economic using floodplain meadows

Abstract

The article represents the features of the stages of ontogenesis invasive species S. annua. Take into consideration the specific features of the ontogeny of S. annua there were allocated 7 ontogenetic states: p - j - im - v - g1 - g2 - g3. Each ontogenetic state was detailed written. The obtained data were used to study the ontogenetic structure of populations of S. annua. During the investigation have been fixed that the ontogenetic spectrums of S. annua on floodplain meadows of the river Psel, which are used as pastures and hayfields, are consistently higher degenerative individuals. It gives the opportunity to estimate populations, in most cases, as pasqualina and рenicillinum gradients, as young (L. A. the Jivotovsky) or invasive ones (T. A. Rabotnov). The anthropogenic degradation of natural grasslands are raising for years, because the irrational using  of hayfields and pastures, increases the number of free ecological niches, so there is the implanting of invasive species. S. annua is not eaten by cattle and has no feeding value in the hay, so there is a necessity to control the population of this species, because the one competes for resources supply valuable forage grasses. Our research has shown that one of the methods phytocoenotic control, which leads to the reduction of populations of alien species S. annua, is conducting a two-mowing, because this species reproduces only by seeds, but the ones can’t mature in such conditions