The diversity of alien species in the flora of the Western Ciscaucasia and the Northwestern Caucasus is considered in the article. The materials of the article are based on the authors' research conducted from 1996 to 2023 and data collected by a detailed route survey of the Sochi Arboretum, the arboretum "Southern Cultures", the territory of the city of Sochi, the landscapes of the Black Sea coast, the Northwestern Caucasus, and the Western Caucasus. The reasons for the current high level of alien flora in the region are discussed in the article. Intensive agriculture began to take shape in the region under consideration since the Neolithic, historically there has been a high level of plant introduction and naturalization and a long period of complex migration processes is characteristic.

The purpose of the research is to combine into a single regional list of alien species that are capable of self-renewal and distribution in natural, semi-natural, disturbed and anthropogenic plant communities.

A taxonomic and typological analysis of alien species has been carried out. The volume of families was adopted in accordance with the international APG IV system (2016), the volume of genera and species in accordance with the WFO (2023). The list of 587 taxa, including 563 species, 12 subspecies, 10 varieties, 3 varieties of alien flora, which belong to 356 genera of 106 families, has been established according to modern taxonomic nomenclature.

The list of alien species that are renewable and spreading on the territory of the Krasnodar Territory covers introduction points, residential zones and urbanocenoses, and the all natural landscapes of the region. To clarify the transformation of the distribution area of the species, the abbreviation was used: C – botanical gardens and arboretums, U – anthropogenic territories, N - natural territories. It has been established that the existing scales of invasiveness and potential invasiveness do not allow us to simultaneously assess such a heterogeneous set of plants characterized by a mass of nuances of their distribution.

Information about three new adventive species for the flora of Dagestan is provided. There are Cyclachaena xanthiifolia, Diplotaxis tenuifolia and Senecio vulgaris. The genus Cyclachaena not previously known in Dagestan. For each species a short description is given, including information about locality, population condition, associated species. According to the methodological recommendations and criteria used in maintaining regional “Black Books”, all species have been assigned invasive status. The fact that new adventitious species was found on the territory of Dagestan suggests that this group of plants is poorly studied. According to increasing of the tourist flow to the Republic, and the rapid growth of the building sector, the study of this group is of particular importance.

Identification and study of relict, endemic and rare plants is a great importance for knowledge of the history of origin and formation of flora and vegetation. The aim of the work is an estimation of the condition of broad-leaved and coniferous forests of Dagestan with Taxus baccata from their conservation significance in terms of the presence of endemics, relics and rare plants. The research was carried out in 2015-2022 in the Foothill and Inner-Mountain Dagestan. Information on 203 plant species identified in yew forests related to 68 families and 139 genera is given. Of these, 49 species (24% of the total species richness) are relict and represent 34 families and 45 genera. The prevalence of relicts of the Tertiary period was noted. Twenty-one endemic species of the East Caucasus and the Caucasus as a whole have been identified, which is 10.3% of the total list of the Dagestan yew forest flora. 12 species are rare (5.9 %), of which 11 species are included in the Red Data Book of the Republic of Dagestan (2020) and 9 species in the Red Data Book of the Russian Federation (2008).

Conservation assessment of five communities with T. baccata was carried out. Communities with very high indicators of floristic significance (F9) were identified. Based on the obtained results it is necessary to assign the status of protected areas to the studied communities with the involvement of the scientific community of the republic.

The main stages of the formation of the network of protected areas of the KabardinoBalkaria Republic, where the occupy leading positions in the Russian Federation in terms of area is provided. The chronology of the main events in the history of the republic's nature preservation is given. A number of archival materials were introduced into scientific circulation for the first time.

A new data to the area of the rare species Nitraria schoberi in Dagestan, listed in the Red Book of the Republic of Dagestan, is provided. The ecological and geographical characteristics of the places of growth and the role of N. schoberi in the phytocenosis are given.

The data on new locations of Rosa species in the mountainous Dagestan, discovered by the author in the period 2021–2022 are given. For Diklosmta-Dyultydag floristic region the species R. prokhanovii and R. tuschetica are provided for the first time. R. alexeenkoi, R. brotherorum, R. micrantha, R. prilipkoana and R. sachokiana were found in the Central Dagestan region.