Literature data on the chromosomal characteristics of Soricidae, genera Crocidura and Sorex are analyzed. The importance of karyological studies for shrew taxonomy at the species level in the Russian Far East is shown. For each species, information on taxonomy, distribution, collection site of studied samples and the structure of karyotypes is provided. The intraspecifi c variability of shrew karyotypes in the Russian Far East is discussed based on a comparison of chromosomal characteristics from diff erent populations located in Russia and other geographical regions.

Heavy metal content in long-lived bivalves of the family Mytilidae in the Vostok Bay, Modiolus kurilensis and Crenomytilus grayanus is considered. These species prefer diff erent types of substrate, soft and hard, respectively. It is shown these mytilids contain metals in quantities close to the background concentrations of metals in the same species from the Peter the Great Bay. An increase in Cu concentrations and a decrease in Pb concentrations in both species is recorded at several stations compared to the background concentrations established according to 1990 data. From the standpoint of sanitary regulations of the Russian Federation, no excess levels of metal content are observed in these mytilids. The results obtained indicate the need to continue ecological monitoring of the bay using the indicated methods to obtain comparable data and observation of noted trends.

An overview of geometrid moth species (Lepidoptera: Geometridae) of the Kronotsky Nature Reserve is presented. Additionally, materials from the Bystrinsky and Nalychevo Nature Parks, the Yuzhno- Kamchatsky and Kol River protected natural areas, as well as from the Bering Island (Commander Islands National Park). An annotated list has been compiled, including 79 species, of which Biston betularia (Linnaeus, 1758) and Scotopteryx chenopodiata (Linnaeus, 1758) are listed for the fi rst time for Kamchatka. Seventy species have been recorded in the Kronotsky Nature Reserve, 39 of which are new to the reserve. About 80% of geometrid moth species known on the peninsula inhabit the reserve. For all 79 species, we provided data on the collected material, distribution in the reserve and Kamchatka Krai, relative abundance, food plants for caterpillars and other ecological features.

Nadezhda Konstantinovna Khristoforova was an Honored Scientist of the Russian Federation, Professor, Doctor of Biological Sciences, a recognized expert in the fi eld of biogeochemistry and ecology of aquatic ecosystems. She worked at the Pacifi c Institute of Geography, Far Eastern Branch of the Russian Academy of Sciences, for 50 years, and at the Far Eastern University for almost 40 years, having helped to establish 65 candidates and 14 Doctors of Science. This paper briefl y outlines her creative biography and analyzes her scientifi c and pedagogical heritage.

The fi rst data on spring macroinvertebrate fauna of the Southern Russian Far East are presented. Macrobenthos of a small forest spring classifi ed as helocrene includes at least 21 species from 20 genera and 17 families in Arthropoda and Platyhelminthes. Main groups of benthic organisms are amphipods, planarians, larvae of dipterous insects, caddisfl ies, stonefl ies and mayfl ies, small water beetles. The following invertebrates are defi ned to the species level: planaria Phagocata sibirica, stonefl y Skwala compacta, caddisfl y Glossosoma angarensis, aquatic beetles Hydraena riparia (imago) and Heterlimnius gapyeongensis (larvae), amphipods Gammarus koreanus and hypogean Procrangonyx primoryensis. The macrobenthos of the spring is also ecologically diverse. Here, rheo- and stagnophiles, highly specialized stygo- and crenobionts, and species with wide ecological niches, sharply diff ering in their preferences, closely coexist.

For the fi rst time, unifi ed types of zonal vegetation are established for the early Eocene in east of Asia and their changes in space are traced. The reconstruction is based on the analysis of 48 palynofl oras from the early Eocene localities situated from 75 to 19° N using Integrated Plant Record (IPR) vegetation analysis. In the results, quantitative parameters of the relative proportions of vegetation components are obtained. According to our data, along the latitudinal gradient from north to south, there is an increase in evergreen plants and herbs, but a decrease in conifers and deciduous plants, and no changes in the proportions of xerophytic plants. Mixed mesophytic forest is a widespread and dominant type of zonal vegetation. In general, the main changes in plant biomes show a very shallow and weakly pronounced diff erentiation into two plant zones: mixed mesophytic forest, north of ~50° paleolatitude, and warmer types of zonal vegetation (broadleaved evergreen forest and an ecotone between mixed mesophytic and broadleaved evergreen forests), in addition to mixed mesophytic forest, south of ~50° paleolatitude. The resulting spatial patterns of vegetation are consistent with climatic inferences.

The ash fallout of Shiveluch volcano (April 11, 2023, Kamchatka) is the most intensive volcanic ash fallout of the last 60 years. We present the results of the reconnaissance fi eld investigations supplemented with analyses of satellite images of the area for estimations of deposits distribution and area aff ected by the ash fallout. We also estimated the properties of fi ne grained ash of andesitic composition and its infl uence on the forest vegetation composed by Picea yezoensis (Siebold et Zucc.) Carrière, Larix cajanderi Mayr и Betula ermanii Cham. As a result of moderate- scale ash fallout in the forest (thickness of freshly deposited ash is 5–8 cm), the negative impact on vegetation was minimal because the ash was fi ne-grained and was deposited on a thick snowpack, and the leaves were not formed yet. The forest vegetation on lower elevations was not damaged at all but strong changes occurred in grass and bush vegetation. We have observed the diminished density of plant coverage, decreased size of grass vegetation and a decreased number of plant species. Calamagrostis purpurea (Trin.) Link. s. l., a broadly represented dominant species among grass vegetation, became less common, but Chamerion angustifolium (L.) Holub became more widespread. The possibility of small plants to grow through the ash layer turned out to be strongly reduced. Mosses and lichens in the forest have been buried under the ash, the recovery could take several decades. We have found a notable impact on plants by ash remobilized by strong wind, this impact is the strongest in the open areas and on forest edges. This process can continue for many years due to the large volume of the deposited ash covering the open spaces of the volcano foot.

This paper briefl y describes the interdisciplinary biogeographical expedition to the Garhwal Himalaya, Uttarakhand state (India) in May 2023. It was organized by the Center for Himalayan Research of the St. Petersburg Association of Scientists & Scholars (SPASS) and took place under the fl ag of the Russian Association of Researchers of the Himalaya and Tibet. This was the 7th expedition of SPASS to the Western Himalaya and the 2nd expedition of SPASS to Garhwal. Participants explored the eastern part of this region west of the Nanda Devi mountain from the Indo- Gangetic Plain to the southern foot of the Transhimalaya (Zanskar Range, 4330 m). Observations were made and materials were collected in the fi elds of botany, zoology (entomology, herpetology), hydrobiology and microbiology.

Widespread in nature, hybridization between species has a wide range of consequences, and hybrid zones have long been viewed as “windows into evolutionary processes”. The discovery and understanding of the role of hybridization has led to tremendous success in the study of evolution and speciation. Genomic studies make a major contribution to elucidating the role of hybridization in the evolution of modern and extinct taxa. Based on genomic data, the article briefl y reviews modern methods for detecting hybrids, various aspects of the formation and dynamics of hybrid genomes during separate crosses and in the interspecifi c hybridization zones, as well as the genetic and evolutionary consequences of natural hybridization, and highlights current tasks for further research.

Taxonomic and trophic structure and quantitative development of polychaetes are examined in the marine coastal areas of the Karadag Nature Reserve in 2021–2022. 40 species belonging to 30 genera and 15 families are discovered. From 1938 to 2022, 75 species have been recorded in this area. According to the nutritional spectrum, polyphages are the most represented, phytophages are the least represented. The average number of polychaetes in 2021–2022 is 100 ± 53 ind./m2, the average biomass is 3.55 ± 0.023 g/m2; S. papillocercusthe prevails in the total abundance and biomass, 98 and 99%, respectively. The change in the species composition, abundance and biomass of marine polychaetes of the Karadag Nature Reserve, inhabiting hard bottom substrates (1984–2022) and soft soils (1938–2021), is considered. From 1984 to 2021, 29 species of polychaetes have been recorded on soft substrates, and only two species in 2021–2022: Namanereis littoralis and Saccocirrus papillocercus. In underwater rock assemblages, on the contrary, the largest number of species (38) has been found in 2021–2022, and the smallest (14) in 1938–1940 (a total of 65 species found during 1938–2022). A transformation of the species composition and trophic structure of polychaetes occurred in the coastal biotopes of soft and hard bottom substrates in the marine area of the Karadag Nature Reserve from 1938 to 2022, with a decrease in the number of phytophages, as well as a decrease in quantitative characteristics. Presumably, the de crease in the number and diversity of polychaete worms on soft substrates is associated with a decrease in the macrophyte algae biomass. The results obtained, supplemented by data on the structure of phytocenoses and characteristic of bottom substrates, can be used in environmental monitoring of protected water areas of the Black Sea.