This article continues the series of publications devoted to the classification of communities with invasive plant species in the Southern Urals (Abramova, 2011, 2015; Abramova, Golovanov, 2016b). The information on communities with four aggressive neophytes of North American origin Solidago canadensis L., S. gigantea Ait., Lupinus polyphyllus Lindl. and Phalacroloma annuum (L.) Dumort. s. l. (Table 1) is given. All species are included in the «black list» of the Republic of Bashkortostan (Abramova, Golovanov, 2016a), and the «Black book of the flora of Central Russia» (Vinogradova et al., 2010).
The studies was conducted in the period 2016–2018 on the republic territory. The wide distribution of species and their naturalization in the meadow and semi-natural communities of the Southern Urals are noted (Abramova, 2011, 2014; Abramova et al., 2016; Abramova, Golovanov, 2018). In the centers of invasion of the studied species, 83 geobotanical relevés of communities were performed on sample areas of 10–100 mІ. Location, date, area of the described area, total cover, mean and maximum height of grass layer were indicated for each sample plot. The classification of communities involving these invasive species was carried according to Braun-Blanquet method with Kopecký–Hejný approach (Kopecký, Hejný, 1974). The identified syntaxa were compared with the units previously described in the studied area and other regions.
Ecological regimes of communities are determined using the weighted average of the Landolt’s optimum ecological scales by IBIS 6.2 software (Zverev, 2007). The weighted average values are calculated according to the following scales: moisture (F), acidity (R), soil richness with mineral nutrients (N), humus content (H), light (L) and continentality (K). The Detrended correspondence analysis (DCA-ordination) method was applied using the CANOCO 4.5 software package to identify the patterns of ecological differentiation of invasive communities.
Herbaceous perennials plants Solidago canadensis and S. gigantea left the decorative culture and now are naturalized in meadows along roadsides, forest edges, wastelands, fallow lands, around gardens near large cities. The most common species is S. canadensis, common in the vicinity of human settlements. S. gigantea is first recorded only in 2017 in the North-West of the republic, where it formed monodominant communities on the territory of abandoned garden plots.
The ass. Rudbeckio laciniatae–Solidaginetum canadensis Tüxen et Raabe ex Anioł-Kwiatkowska 1974 (Tables 2, 3) with 2 variants: Solidago canadensis (Fig. 1) and Solidago gigantea and the derivate community Solidago canadensis–Poa angustifolia [Molinio-Arrhenatheretea/Artemisietea vulgaris] (Table 4, Fig. 2) is described. Association variants reflect the dominance of Solidago canadensis or S. gigantea, the derivative community is characterized by the presence of two large groups of species: meadow species of the class Molinio-Arrhenatheretea Tx. 1937 and sinanthropic two- and long-term species of the class Artemisietea vulgaris Lohmeyer et al. in Tx. ex von Rochow 1951.
Lupinus polyphyllus is an ornamental herbaceous plant, also dissapeared fr om culture and naturalized in meadow communities. Within the studied area it is sporadically recorded in the Cis-Urals, but invasive populations of sufficiently large in size form only in the north-western districts of the republic on the territories of abandoned horticultural plots, along the roads on the meadows, occasionally on abandoned fields. A derivative community Lupinus polyphyllus[Arrhenatheretalia elatioris] (Tables 6, 7) with 2 variants: typica (Fig. 3) and Convolvulus arvensis, which represent meadow or ruderalized communities, has been identified.
The annual Phalacroloma annuum is confined to the areas of the northern Cis-Urals, wh ere it is widely naturalized in meadows, but has no a transforming effect on the meadow coenoflora. Thay is why var. Phalacroloma annuum as part of the association of low-grass meadows of the hay and pasture use within ass. Agrostio tenuis–Festucetum pratensis Yamalov 2015 (Table 9) as well as derivate community Phalacroloma annuum–Cirsium setosum [Arrhenatheretalia elatioris/Artemisietea vulgaris] (Table 10) for semi-natural communities in abandoned garden plots and fields with a large proportion of synanthropic species in floristic composition are suggested.
All four invasive species are intruded and naturalized in meadows of varying degrees of anthropogenic disturbance, as well as in semi-natural phytocenoses of the final stages of succession. The ordination analysis (DCA-ordination) confirmed the suggested floristic classification (Fig. 4). The first axis is associated with two differently directed factors — soil acidity (correlation coefficient — 0.10) and humus content (correlation coefficient — –0.29). The distribution of communities along the second axis is associated with the substrate moistening (correlation coefficient is 0.10) and the community light conditions (correlation coefficient is –0.57), these vectors also have different directions. All communities with these species are well differentiated in the space of the two main ordination axes, which indirectly confirms the correctness of the syntaxonomic decision, and also indicates the wide ecological amplitude of the species and their use of different ecological niches in similar types of meadow and semi-natural communities of the Southern Urals. The leading factors in the community distribution are both those characterizing the soil properties (moisture, acidity, humus content) and habitat ones (light conditions). The high invasive potential of these neophytes makes possible to predict their further distribution over the territory of the Republic of Bashkortostan.
Broad-leaved plants of the Southern Urals broad-leaved-conifer forests (some results of the studies)