The hemiparasitic European mistletoe, Viscum album L. (Viscaceae), displays a rapid and remarkable expansion into natural and urban ecosystems in Ukraine. The monitoring and management of this rapidly spreading species is increasingly difficult as new plant species become hosts. Unlike other local mistletoe species, the European mistletoe has a broad distribution and thus requires a countrywide pest status assessment for control. This review outlines the major taxonomic and evolutionary issues pertinent to V. album with an emphasis on the characters used to distinguish its five currently recognized subspecies. The review also provides an updated distribution map and host range for the three V. album subspecies in Ukraine (V. album subsp. album, V. album subsp. abietis (Wiesb.) Janch. and V. album subsp. austriacum (Wiesb.) Vollm.), addressing the current knowledge of their biology and ecology. A significant portion of the paper is devoted to the diversity of V. album associated organisms including herbivores, endophytes, and parasites, drawing particular attention to major pollination and dispersal vectors as well as potential biocontrol agents of this mistletoe species.

The habitats diversity of Lviv Skansen was researched and it sozological value was estimated. On the territory of Skansen, 19 types of habitats belonging to 12 groups of 7 classes have been identified and described. Among them, 14 types have an anthropogenic origin, 3 – semi-natural, and only one – natural. On the territory of the museum were found 2 species of vascular plants listed in the Red Book of Ukraine – Allium ursinum L. and Epipactis helleborine (L.) Crantz, as well as naturalized populations of cultural Crocus sp. and Leucojum vernum L. From the sozological point of view, tree habitats – highly artificial broadleaved deciduous forestry plantations, coniferous forestry plantations and hard water source settlements on tuff and travertine formations – are of the greatest importance. The last one is a new type of habitat for region, barely studied. Currently, only one location is known in the vicinity of Lviv (Bryukhovychi). On the territory of the European Union, this habitat is included in the list of particularly valuable habitats of the NATURA-2000 environmental network. Highly artificial broadleaved deciduous forestry plantations habitats, although formed by non-native species, are currently ongoing through demutation proces. During the years of absence any cuttings or other forms of management, the plantations of Robinia pseudoacacia L. and Aesculus hippocastanum L. were replaced by semi-natural forests from young undergrowth of Betula pendula Roth, Acer platanoides L. and Picea abies (L.) H.Karst. The grass layer in these forestry plantations is represented by fragments of typical nemoral species. Thus, despite the anthropogenic origin of the habitats formed in Lviv Skansen, they play an important role in the conservation and distribution of biodiversity and help maintain the stability of green corridors of sub- and urban areas.

North-central part of the Svydovets Mts with adjacent upper Chorna Tisa river basin belongs to the most preserved and less disturbed mountain ecosystems in the Ukrainian Carpathians characterized by high biotic and landscape diversity. This area has been highly threatened lately because of the construction of a large recreation ski and spa resort “Svydovets” is being planned here. An unprecedentedly massive disturbance and transformation of natural complexes in the area about 15-20.000 ha is expected to happen on the territory, which is almost unpopulated and hardly accessible. This area is characterized by unique low-disturbed high-mountain glacial landscapes, valuable hydrological objects, old-grown and virgin forests of high conservation value, habitats and populations of dozens of threatened plant and animal species. At least 43 rare and threatened species of vascular plants, 14 – invertebrates, 4 – amphibians, 19 – birds, 14 – mammals included in the Red Data Book of Ukraine (2009) occur here. The high-mountain zone of the Svydovets Mts is exceptionally significant for biodiversity conservation in the Ukrainian Carpathians as one of the most important refuges of the relic boreal-alpine and endemic Carpathian biota. Implementation of the mentioned ambitious business project will lead to destructive consequences for natural ecosystems and landscapes of the whole Svydovets mountain range as well as deterioration of hydrological regime and contamination of the upper Chorna Tisa river basin. It will pose the threat of devastation to ecosystems of the unique glacial mountain lakes, mires and rocks, riverine and subalpine forests, habitats and populations of many rare plants and animals protected in Ukraine and in the European Union. In these circumstances, the need emerges to establish the “Central Svydovets Mts” Nature Protected Area of national importance which could protect the natural environment and biodiversity within the territory threatened by the unacceptable business project.

Some theoretical and practical aspects of reintroduction and repatriation of rare species into natural conditions (populations) are analyzed in connection with the proposed All-Ukrainian Creative Children Competition "Share snowdrops with the forest – 2022", initiated by the Kyiv Ecological and Cultural Center and the All-Ukrainian NGO Living Planet. It is demonstrated here that, although plant reintroduction may play some role in species conservation, the long-term viability of most reintroduced populations has not yet been properly assessed. This initiative is analyzed in the context of existing methodological and practical aspects of the reintroduction or repatriation process. It is concluded that such initiatives are harmful and unacceptable because they threaten the genetic identity of natural populations and create conditions for potential phytoinvasions and because they violate the Ukrainian legislation.