IMPATIENTETUM NOLI-TANGERE-PARVIFLORAE ASS. NOVA – NEW SYNTAXON OF THE RUDERAL VEGETATION FROM THE LEFT-BANK FOREST-STEPPE ZONE OF UKRAINE

Abstract

During the geobotanical research of the ruderal vegetation of the Left-Bank Forest-Steppe zone of Ukraine in 2017 and 2019, in the northern part of this region within administrative borders of the Kyiv Oblast, interesting communities with substantive participation of two species from the genus Impatiens L. (Balsaminaceae) – autochthonous for the temperate zone of Holarctic region I. noli-tangere L. and alien for Ukraine I. parviflora DC. (native for Central Asia and Southern Siberia) were found and described by the author. Ecologically these communities are specific for openings and peripheral well-moistened areas in ecotone of hornbeam-oak, linden-oak and alder forests with light-grey sod-podzolic soils. Considering the absence of analogic data about these communities from other regions, they were described as a new syntaxon Impatientetum noli-tangere-parviflorae Davydov ass. nova. This association belongs to the alliance Impatienti noli-tangere-Stachyion sylvaticae Görs ex Mucina in Mucina & al. 1993, the order Circaeo lutetianae-Stachyetalia sylvaticae Passarge 1967 nom. cons. prop. and the class Galio aparini-Urticetea dioicae Passarge ex Kopecký 1969. This is the second association from the mentioned alliance on the territory of Ukraine. The newly described syntaxon differs from the already known association Stachyo sylvaticae-Impatientetum noli-tangere Hilbig 1972 by the highly persistent presence of Impatiens parviflora, as well as by a noticeably better presence of such ruderal plant species as Chelidonium majus L., Galium aparine L. and Urtica dioica L. The association Impatientetum noli-tangere-parviflorae is marked by a high general projective cover of the herb layer on all studied areas with noticeable dominance of both species from the genus Impatiens and by the absence of a moss-lichen layer. Most likely, such communities are formed at the initial stages of the diasporal penetration of I. parviflora into hygromesophilic phytocenoses of the autochthonous type with the dominance of I. noli-tangere, and will be replaced by other communities of ruderal vegetation during further succession processes.