Invasive Plant Species of Recreational Zones of Kharkiv (Ukraine) ^†

Abstract

The formation of synanthropic flora of any territory occurs in two ways: the penetration of anthropophytes (anthropophytization, adventization) and the transition of native plant species from natural phytocenoses to anthropogenic ecotopes (apophytization). The article highlights the results of the study of synanthropic flora and vegetation of recreational zones of Kharkiv (abandoned parks, recreational areas, and green areas) for 2018–2020. The classification of synanthropic vegetation was performed on the basis of processing geobotanical releves in programs Turboveg 2.91 and Juice 7.0.127. Ecological amplitudes of syntaxons were determined by ecological scales of Ya.P. Didukh. The study of invasive plant species was carried out according to the classification of D. Richardson et al. As part of the synanthropic vegetation of recreational zones of Kharkiv, we have found 15 invasive plant species. Most of them, according to the degree of invasive potential, belong to the group with high invasive capacity (11 species). Among them there are dominate species of the family Asteraceae (eight). The results of biomorphic analysis show that there are dominate therophytes (8 species), ecological analysis shows the domination of mesophytes (14 species) and geographical analysis shows the domination of species of North American origin (13). The structural analysis of the alien fraction of flora shows the dominance of kenophytes (15 species), xenophytes (6 species), and ergasiophytes (5 species), and epecophytes (7 species). Woody phytocenoses of the class Robinietea are sensitive to soil acidity and carbonate content in soil, thermal, and cryo-climate. In their composition, we have found eight invasive species. In plant communities of herbaceous annual vegetation of classes Bidentetea and Galio-Urticetea, which are adapted to the variability of damping and nitrification of the edaphotope, nine invasive plant species are growing. Ruderal phytocenoses of classes Artemisietea vulgaris and Stellarietea mediae are formed with the participation of 10 invasive plant species. These communities are sensitive to the variability of damping, soil acidity, total salt regime, nitrogen content in soil, thermal climate, humidity, and the continentality of the climate.

1. Introduction

The formation of synanthropic flora in any territory occurs in two ways: (1) the penetration of anthropophytes (anthropophytization, adventization) and (2) the transition of native plant species from natural phytocenoses to anthropogenic ecotopes (apophytization) [1]. Urban flora is a type of anthropogenically transformed flora and forms in the conditions of urban agglomerations. It has a specific structure, as well as its own characteristic florogenetic processes. The need to study urban flora is determined by the fact that in this type of anthropogenically transformed flora, different types of flora “coexist” (flora of man-made ecotopes, recreational areas, agrophytocenoses, cultivated flora, etc.) [2].

Gardens and parks form a special type of urban landscape. The peculiarities of urban flora largely depend on city location and landscaping. The landscape design of gardens and parks has its own patterns: the alternation of closed and open areas, flat places and elevations, dry slopes and ponds, and compliance with the natural basis of the created complexes [2].

The aim of the work is to study invasive plant species in the flora and vegetation of recreational zones of Kharkiv (abandoned parks, recreational areas, green areas) for 2018–2020.

2. Materials and Methods

We studied the synanthropic flora and vegetation of abandoned parks, recreational areas and green areas for the period of 2018–2020 (Figure 1). The study of invasive plant species was carried out according to the classification of D. Richardson et al., and taxonomic and biomorphic analyzes by Tolmachev [3] and Raunkiaer [4]. The classification of synanthropic vegetation was performed by the ecological-floristic method. Selection of syntaxons was based on the processing of geobotanical releves in the programs Turboveg 2.91 [5] and Juice 7.0.127 [6]. Syntaxonomy follows to the “Prodrome of the Vegetation of Ukraine” [7]. Ecological amplitudes of syntaxons were determined by ecological scales of Ya.P. Didukh [8].

3. Results and Discussion

In the composition of the synanthropic vegetation of recreational zones of Kharkiv, we found 15 invasive plant species. Most of them, according to the degree of invasive potential, belong to the group with high invasive capacity (11 species) [9]. Invasive plant species of the family Asteraceae (8) dominate in the taxonomic spectrum, which is characteristic of the synanthropic flora of Ukraine [10]. The families Balsaminaceae, Vitaceae, Fabaceae, Aceraceae, Amaranthaceae, Portulacaceae, and Nyctaginaceae are represented by one species. The biomorphic analysis shows the dominance of therophytes (eight species), which is typical for recreational zones of Kharkiv. Hemicryptophytes take the second place (four species) and phanerophytes the third (three species). Among the invasive plant species, there are dominate mesophytes (14), species of North American origin (13), kenophytes (15), xenophytes (6), ergasiophytes (5), and epecophytes (7). Using ecological scales, we calculated the tolerance zones of the identified plant communities in the hyperspace of 12 ecological factors. The class Robinietea Jurko ex Hadač et Sofron 1980 is represented by plant communities of unions Balloto nigrae-Robinion pseudoacaciae Hadač et Sofron 1980, Chelidonio majoris-Robinion pseudoacaciae Hadač et SofronexVítková in Chytrý 2013, Chelidonio-Acerion negundi L. Ishbirdina et A. Ishbirdin 1991 nom. inval. (art. 3o, 5), Geo-Acerion platanoidis L. Ishbirdina et A. Ishbirdin 1991nom. inval. (art. 3o, 5), which include invasive species Acer negundo L., Robinia pseudoacacia L., Parthenocissus inserta (A. Kern.) R. M. Fritsch, Conyza canadensis (L.) Cronquist, Erigeron annuus (L.) Desf. (Phalacroloma annuum (L.) Dumort), Grindelia squarrosa (Pursh) Dun., Impatiens parviflora DC., and Solidago canadensis L. The studied synanthropic woody phytocenoses are distributed in recreational zones of the city and along roads and streams. They have narrow tolerance zones to soil acidity and carbonate content in soil, as well as to thermal and cryo-climate (Figure 2).

In the composition of vegetation of unions Bidention tripartitae Nordhagen ex Klika et Hadač 1944 and Chenopodion rubri (Tx. in Poliet J. Tx. 1960) Hilbig et Jage 1972 of class Bidentetea Tx. et al. ex von Rochow 1951, we found Bidens frondosa L., Ambrosia artemisiifolia L., Acer negundo, Impatiens parviflora, Erigeron annuus, and Parthenocissus inserta. This pioneer vegetation near bodies of water have fairly wide tolerance zones and can withstand fluctuations in edaphotope damping and slight shading (Figure 3). Similar environmental parameters have ruderal communities of the remains of oak forests and wetlands along watercourses (rivers, streams) of class Galio-Urticetea Passarge ex Kopecký 1969. These cenoses include Ambrosia artemisiifolia, Grindelia squarrosa, Erigeron annuus, Solidago canadensis, and Iva xanthiifolia (Nutt.) Fresen. The vegetation of both classes is adapted to the variability of damping, nitrification of the edaphotope.

The vegetation of class Artemisietea vulgaris Lohmeyer et al. in Tx. ex von Rochow 1951 is represented by unions Onopordion acanthi Br.-Bl. et al. 1936, Convolvulo arvensis-Agropyrion repentis Görs 1967, and Arction lappae Tx. 1937, in which Grindelia squarrosa, Solidago canadensis, Helianthus tuberosus L., Ambrosia artemisiifolia, Erigeron annuus, Oxybaphus nyctagineus (Michx.) Sweet, and Conyza canadensis grow. Ruderal xerophytic communities of the class are distributed along roads and paths and in places of active recreation on nitrified soil, have narrow tolerance zones of variability of damping and soil acidity, and are sensitive to changes in thermal climate and humidity (Figure 4).

Ruderal vegetation of dry roadside areas and dumps in park zones of class Stellarietea mediae Tx. et al. in Tx. 1950 demonstrates sensitivity to soil acidity, total salt regime, nitrogen content in soil, and continentality of climate (Figure 5). In the unions Panico-Setarion Sissingh in Westhoff et al. 1946 and Sisymbrion officinalis Tx. et al. ex von Rochow 1951, we noted Ambrosia artemisiifolia, Amaranthus retroflexus L., Conyza canadensis, Grindelia squarrosa, Erigeron annuus, Iva xanthiifolia, and Portulaca oleracea L.

4. Conclusions

As a result of the study, we identified 15 invasive plant species in 5 classes of synanthropic vegetation of recreational zones of Kharkiv. Analysis of the taxonomic and biomorphic structure revealed a predominance plant species of Asteraceae family and herbaceous annuals. Woody phytocenoses the class Robinietea are the center of growth of eight invasive plant species. According to the results of ecological analysis, these plant communities are sensitive to soil acidity and carbonate content in soil, thermal, and cryo-climate. There are nine invasive plant species in the communities of herbaceous annual vegetation of classes Bidentetea and Galio-Urticetea, which are formed under conditions of variability of damping and nitrification of the edaphotope. Ruderal phytocenoses of classes Artemisietea vulgaris and Stellarietea mediae are formed with the participation of 10 invasive plant species. These communities are sensitive to the variability of damping, soil acidity, total salt regime, nitrogen content in soil, thermal climate, and humidity, as well as to the continentality of climate.