Acroptilon repens (L.) DC. in the flora in the interfluve of the lower Dnister–Tiligul rivers

Abstract

Primary field floristic studies of synanthropic species with a high invasive capacity are an important basis for broad, generalizing analyzes of the problems of flora transformation of ecotopes of different levels of anthropogenic transformation. Acroptilon repens is one of the species that has a high invasive capacity and is a quarantine plant on the territory of Ukraine. The aim of the work was to identify the localities of Acroptilon repens in the in the interfluve of the lower Dnister–Tiligul rivers, to characterize the conditions for the growth of plants of this species. Acroptilon repens is a herbaceous perennial plant, a xerophyte and a heliophyte; comes from Central and Asia Minor. It reproduces well both generatively and vegetatively (by root sprouts). According to the degree of naturalization, it is an epecophyte, according to the chronotype, it is a kenophyte. According to the method of spreading, the seeds are anemochorous. It is able to grow in areas with a wide range of environmental conditions and different levels of anthropogenic transformation (from natural to fully transformed). Preventive, agrotechnical, chemical, biological control measures are used to combat this species. Ecotopes with different levels of ecotope transformation were examined. According to herbarium materials of the herbarium (MSUD) of Odesa National University named after I.I. Mechnikov the species had not previously been noted in the Odesa region. The author found four localities of Acroptilon. Three of them are on transformed sections of transport routes: the village of Avangard, on the side of the Odesa — Reni Road and in the vicinity of S. Yehorivka. These are sections of highways and abandoned railway tracks. Another one is on a natural steppe slope. On the transformed areas, the participation of other plant species in the «spots» with steppe mustard is small: up to four species. In the natural area (in the vicinity of the village of Kholodna Balka), a total of 44 species coexisted with steppe mustard. Among them, only 23 (or 52.27%) species are synanthropic and only three (Bromus squarrosus, Descurainia sophia, Sisymbrium loeselii) are invasive species. They are mainly represented by a small number of specimens, but among them there are two species of local protection level: Kohlrauschia prolifera, Ephedra distachya. In the spring, in the «contour of the spot» with Acroptilon repens, the following plants of state protection level were found: Gymnospermium odessanum, Crocus reticulatus. These plants are ephemerals, and the terms of their growth and the beginning of vegetation of Acroptilon repens do not coincide.