Vol 146, No 5 (2026)

The probable genetic consequences of global warming are considered. An increase in temperature within limits that allow organisms to maintain viability and reproductive capacity should lead to an increase in the frequency of mutations and meiotic recombination. Such effects have been demonstrated in laboratory experiments, but they are very difficult to observe in natural conditions and have not yet been described. Warming triggers animal migrations, which leads to the coexistence of individuals of related species capable of interbreeding in the same territory. The emergence of interspecific hybrids as a result of warming-related migrations has been described for a pair of closely related bear species (Ursus maritimus and Ursus arctos horribilis) and coccinellids (Adalia bipunctata and Adalia frigida). Another effect of warming is a change in population structure as some genotypes gain or lose advantages in changing conditions. Two carefully analyzed examples of such rearrangements over the past four decades are changes in chromosome inversion frequencies in Drosophila subobscura populations in Western Europe and changes in morph frequencies in several Adalia bipunctata populations in the Netherlands, Norway, and Russia. Identifying such genetic effects requires long-term observations of the same populations.

Chloroplast DNA variation was studied in 67 populations of all roburoid oak species (sect. Quercus) in Bulgaria and adjacent areas using chloroplast microsatellite markers (cpSSRs) and sequencing of five chloroplast DNA fragments. In the Balkans, 12 haplotypes were identified, geographically isolated in specific areas, including putative glacial refugia of temperate forests – the Rila-Pirin region, Strandzha and the Black Sea coast. A common geographic structure of chloroplast DNA is observed in all widespread species (Q. robur, Q. petraea, Q. pubescens and Q. frainetto), indicating gene flow between the species. A clear differentiation of populations (F_ST = 0.9160) was revealed, primarily due to profound differences between geographic regions in haplotype composition and frequencies (F_CT = 0.8814). Endemic haplotypes confined to the Black Sea coast are absent from inland areas, supporting the hypothesis of a postglacial oak dispersal along the sea. The areas of primary refugia are associated with the occurrence of unique endemic species and intraspecific taxa of Quercus. A phylogenetic analysis of chloroplast DNA and a comparison of the Balkans with other regions were conducted. Comparison with haplotypes in Eastern Europe revealed several identical or phylogenetically related ones, suggesting postglacial migration routes and confirming the contribution of Balkan refugia to the genetic diversity of the northeastern part of the oak range in Europe. However, many northern haplotypes do not match those of the Balkans, suggesting the existence of more northern secondary refugia (the Carpathians) or more western sources of dispersal. Several endemic Balkan haplotypes have no relatives in other regions; their distribution is confined to the primary refugia of the Strandzha region, and they are distributed only slightly northward along the Black Sea coast. Thus, the contribution of eastern Balkan refugia to the postglacial recolonization of more northern regions is limited. No common or related haplotypes were found for the Balkans and the Crimean-Caucasian region.

Global spread of plant pathogenic fungi, including powdery mildews, has become a major threat to woody plant diversity. Many species of the powdery mildew fungi are rapidly expanding their geographical and host ranges. In the Southern Urals the biota of the powdery mildew fungi associated with woody plants so far remains understudied. Here, we present a checklist of the powdery mildew fungi infecting woody plants in the Southern Urals. The checklist includes 37 species of five fungal genera, associated with 42 species of woody host plants. Ten fungal species are new to the Southern Urals. The number of alien species is 17, which are mostly of East Asian origin. The number and share of known alien powdery mildew species increased from 4 (22.2%) in the 1910–1980s to 17 (46%) in the 1990–2020s. The presence of alien species Erysiphe corylacearum, E. palczewskii and E. sambucina in the Southern Urals is confirmed using ITS sequence data. The main reasons behind the increase of alien fungal species in the Southern Urals are the live plant trade and climate change. Alien powdery mildew fungi may pose a threat to native woody plants, although the degree to which they have established in the Southern Urals is yet to be evaluated.

The article reports the results of studying the mycobiota of north-boreal pristine forests of Karelia. Surveys in four operating and two planned protected areas (PAs) in the northern taiga subzone detected 550 species of agaricoid, aphyllophoroid, and gasteroid basiomycetes. The number of fungal species varied among the PAs depending on their size, diversity of habitats, forest types and tree species, as well as coverage by studies. Only 50 species (9%) were shared by all the PAs, while each one contained 16 to 48 fungal species unique to that area. The greatest similarity was exhibited by mycobiotas of the Kostomukshsky Nature Reserve and Kalevalsky National Park (Ksс = 0.69). The areas surveyed feature 26 species listed in the Red Data Book of the Republic of Karelia, 28 indicator and 32 specialist species of biologically valuable forests of European Russia. Preservation of north-boreal forest landscapes is essential for maintaining the fungal species diversity of Karelia, Green Belt of Fennoscandia, and northwest Russia.

The species structure of the mycobiota was studied on the parental generation of Tomicus piniperda and T. minor beetles colonizing pine trees, the young generation at the end of development in pupal cradles, and during additional feeding in the shoots of healthy pine trees. Beetles were collected from natural substrates using sterile instruments. Pure fungal cultures were then isolated from each beetle under sterile conditions and identified using molecular genetics. The species composition of transmissible fungi was revealed to differ significantly both at different stages of the life cycle and within these species of bark beetles. Most of the isolated fungi species – Leptographium lundbergii, L. piceaperdum, Ophiostoma floccosum, O. minus – were found on beetles located under the bark. Only two species of phytopathogenic fungi, Ophiostoma canum and Sydowia polyspora, were present at all stages of the life cycle in both species. Pine bark beetles Tomicus spp. undergo supplemental feeding in the crowns of healthy pine trees. The presence of phytopathogenic fungi on young beetles during supplemental feeding on shoots of healthy trees creates the possibility of infection before the tree is colonized by the parent generation. The association of the fungi Ophiostoma canum, Sydowia polyspora, and the beetles Tomicus piniperda and T. minor can be considered a protocooperation, as the fungi introduced during supplemental feeding can weaken the tree long before the bark beetles attack, while the bark beetles, in turn, ensure rapid delivery of the fungi to the substrate. The epiphyte Aureobasidium pullulans and the endophyte Microsphaeropsis olivacea were also detected at all life stages, but only on Tomicus minor. It is highly likely that these fungi participate in the nutrition of the larvae.

Wood-destroying fungi are considered as an object of the functional structure of the heterotrophic complex of native spruce forests of the taiga of European Russia, performing the tasks of forming a biomass balance in the succession dynamics of spruce forests. The objects of the study are native spruce forests located in three subzones of the taiga of European Russia on the territories of nature reserves, national parks, and nature reserves unaffected by anthropogenic impact. The functional characteristics of wood-destroying fungi are studied using statistical methods for assessing the synergistic potential of fungi of the biotrophic and xylotrophic groups in forming the biomass balance of spruce biogeocoenoses in various succession states: demutation, digression, and climax. Wood-destroying fungi of these trophic-topic groups, having an important functional feature of facultative food specialization in the structure of the heterotrophic consort, are combined into a single “mechanism” for forming the biomass balance of forest communities. For the first time, an experiment has demonstrated a link between the accumulation of forest biomass and the decomposition of woody debris biomass based on the ratio of time periods per unit of time. This equates the processes of reproduction and destruction of forest biomass in volumetric terms, thereby establishing a balance between biomass and the stability of the biogeocoenosis. Using statistical methods, previously noted trends of increasing tree infestation with increasing age in generations of age series have been confirmed. For the first time, the relationship between growing stock and deadwood volume in biogeocoenoses of different successional states was determined using regression equations and the R² determination coefficient, which determine