The key strategy for controlling the alien component in natural and natural-anthropogenic communities is an inventory of species, including those in the territories of botanical gardens as sources of invasive plants. A total of 56 invasive species from 34 families of flowering plants was identified in the botanical garden of Vyatka State University. These are mainly perennial herbs. Species of the 1at (35.7 %), 2nd (28.6 %) and 3rd (28.6 %) invasive statuses predominate among them. Potentially invasive species (the 4th status) account for only 7.1 % of the species. Plants from Europe and Asia (39.3 %), Asia (25.0 %) and North America (21.4 %) dominate the invasive component.

Naturalization of alien plant species in secondary habitat conditions is one of the important areas of research for the conservation of species diversity. Invasive species and transforming species deserve special attention. Research of the population of Quercus ilex L. in various ecological and cenotic conditions of the «Cape Martyan» Specially Protected Natural Area was carried out according to modern, generally accepted methods and approaches. The characteristics of communities with Q. ilex is given. It has been revealed that over the past 30 years the number of individuals of the species has increased.

Emerald ash borer (Agrilus planipennis Fairmaire, 1888) was found on common and Pennsylvania ash trees in the streets of Pyatigorsk and in forest belts in its immediate vicinity. Judging by the number of infested ash trees with exit holes in the lower part of trunks, foci of mass reproduction of the pest have been active in the city for at least 5 years.

Forest communities with the Berberis aquifolium Pursh in the territory of the «Yalta Mountain Forest» Nature Reserve are described. As a result of cluster analysis, five phytocenons were identified, differing in structure and composition (species richness- 29-65). The first group includes communities belonging to the Quercetea pubescentis class, distributed at 300 460 and 200-320 m above sea level. The second group includes communities growing at 320-530 m above sea level, belonging to the Erico-Pinetea class.

Since 1975 we have been monitoring the biodiversity of macromycetes by a stationary method in the Perm Krai southern taiga subzone. No alien fungi have been found naturally. However, 15 species of fungi have been found in the Perm Krai that could be caused by: 1) specific habitat conditions (greenhouses — fungi of the genus Leucocoprinus Pat.); 2) cultivated plant species of the genera Populus L., Salix L. and related genera Tricholoma populinum J.E. Lange, Pluteus aurantiorugosus (Trog) Sacc., Volvariella bombycine (Schaeff.) Singer, Pholiota populnea (Pers.) Kuyper & Tjall.-Beuk., Laetiporus sulphureus (Bull.) Murrill and Cerioporus squamosus (Fr.) Quél.; 3) climate warming at large over the past few years; these are unusual species Mycenastrum corium (Guers.) Desv., Mutinus ravenelii (Berk.) E. Fisch. and local thermophilic fungi Phallus impudicus L., Suillellus luridus (Schaeff.) Murrill and Volvariella surrecta (Knapp) Singer. In general, alien fungi are not a threat to indigenous mycobiota. More likely, they are temporary and can become dormant again.

The appearance of two phytopathogenic fungi in the Donbass is predicted: Hymenoscyphus fraxineus (T. Kowalski) Baral, Queloz & Hosoya (Ascomycota: Pezizomycotina: Leotiomycetes) and Cryptostroma corticale (Ellis & Everh.) P.H. Greg. & S. Waller (Ascomycota: Pezizomycotina: Sordariomycetes). These species have already been registered in adjacent territories and in case of invasion into the region, they can cause serious damage to forest, shelterbelt and urban plantings involving ash and maple. Descriptions of disease symptoms and brief ecological and biological characteristics of pathogens are provided.

A grid mapping of the distribution of Impatiens glandulifera Royle in settlements near the source of the Angara River (Lake Baikal) has been carried out. The uneven participation of the invasive species in the composition of plant communities was noted, the projective coverage ranges from 30–40 % to 10 %. The total area of invasion is 578.5 hectares, the share of physiognomically and coenotically transformed sites accounts for 318.76 hectares. The data obtained can serve as a starting point for monitoring the state of plant communities and assessing the invasive activity of I. glandulifera.

Alien species have become a major environmental problem worldwide. They affect local biodiversity and ecosystem functioning. The invasion of Quercus rubra L. into forest communities of the Central Russian forest-steppe is considered against the background of current trends in reforestation and climate change. The work uses data from long-term observations in conditions of introduction and forest phytocenoses. The results of the study show that Q. rubra is invasively active in the forest-steppe region. Further climatic fluctuations and priorities in forestry may lead to an expansion of its secondary forest-steppe habitat.

Invasive weeds often pose a significant threat to agriculture. As a countermeasure, quarantine measures are used, the effective implementation of which requires methods for identifying diaspores (seeds, fruits) of plants in transported products. The use of molecular genetic identification methods as reliable and objective is highly promising.At present, there are practically no developed methods for use in laboratories, including for the listed quarantine objects Bidens bipinnata L. and B. pilosa L. A study was carried out of the genetic diversity of weeds of the genus Bidens L., section Psilocarpaea DС. at chloroplast (NdhF-rpl32) and nuclear (ITS1-5.8S-ITS2) loci. A conclusion is made about the practical inapplicability of identification by chloroplast loci and the suitability of identification by nuclear ones.

The study of phytophages and phytopathogens adapted to invasive species Solidago canadensis L. and S. gigantea Aiton (Asteraceae) was carried out in 2021–2023 in the Moscow, Tver and Kaluga regions. Identification of the collected samples was carried out in the plant protection laboratory of Main Botanical Garden named after N.V. Tsitsin of Russian Academy of Sciences. It was revealed that polyphages with a wide floral spectrum in the feed base predominate among phytophages. On S. canadensis and S. gigantea, 11 phytophage species were noted, occurring sporadically and not causing serious damage to plants. Both invasive species of Solidago L. are affected by powdery mildew Golovinomyces asterum f. solidaginis U. Braun, which is a synonym of Erysiphe cichoracearum f. solidaginis Jacz., noted earlier in Russia. The causative agent of rust was not found.