Russian Journal of Biological Invasions

2026, issue №2

CONTENTS

ALIEN SPECIES OF MACROZOOBENTHOS OF THE GORKY RESERVOIR - Belova A.P., Pryanichnikova E.G. - The taxonomic composition and abundance of non-native macrozoobenthos species of the Gorky Reservoir for 2021–2023 have been studied. A total of 10 alien species have been recorded in the benthic communities. The amphipod Dikerogammarus villosus (Sowinsky, 1894) was recorded for this reservoir for the first time. The bivalve mollusks Dreissena polymorpha (Pallas, 1771) and D. bugensis (Andrusov, 1897), as well as the polychaete Hypania invalida (Grube, 1860) associated with the dreissenid biocenosis, formed the basis of the alien species abundance and biomass. In the river part of the reservoir, abundance and biomass of alien species was significantly higher than that in the lake part. An increase in the abundance of bivalve mollusks Corbicula fluminea (Muller, 1774) and gastropods Lithoglyphus naticoides (Pfeiffer, 1828) was noted in comparison with early studies. The results obtained indicate the significant role of alien species in the formation of benthic communities of the Gorky Reservoir and the necessity for further monitoring of their distribution.

THE FIRST CASE OF A TERAPONTID (PERCIFORMES: TERAPONTIDAE) CATCH IN THE BLACK SEA - Guskov G.E. - In the waters of the Black Sea at the entrance to Gelendzhik Bay (coordinates: 44°33'3.7277" N; 38°2'23.8611" E), a specimen of a representative of the family Terapontidae (Perciformes: Terapontidae) Terapon cf. theraps (Cuvier, 1829) was caught on bottom tackle on December 2, 2025. The depth at the capture point was 15.5–16 m. Documentary photo and video footage was taken. This discovery is the first record of a species of this family in the Black Sea. A brief description of the coloration of the captured specimen is provided, and the findings of four species of the Terapontidae family in the Mediterranean Sea are discussed. The possible routes of this Indo-West Pacific species to the Caucasus coast are described.

PHENOLOGY OF HERACLEUM MANTEGAZZIANUM SOMMIER & LEVIER (APIACEAE) IN THE MIDDLE TAIGA SUBZONE OF THE KOMI REPUBLIC - Dalke I.V., Chadin I.F. - Long-term observations of the seasonal development of H. mantegazzianum in the middle taiga subzone of the Komi Republic revealed a diversity of phenorhythmotypes among different phenotypic classes within the species' populations. Juvenile individuals followed a spring-autumn-green phenorhythmotype with periods of summer and winter dormancy. Immature and virginal individuals were characterized by a spring-summer-autumn-green phenological type with a period of winter dormancy. Generative individuals exhibited a spring-summer-green phenorhythmotype, distinguished by the shortest growing season compared to other phenotypic classes. The generalized spring-summer-autumn-green phenological type with a winter dormancy period in self-sustaining populations of H. mantegazzianum ensured the species' dominance over herbaceous plants throughout the growing season. Seed dispersal of H. mantegazzianum in different parts of its secondary range commenced at a relatively constant level of environmental heat supply. The sum of active air temperatures ≥5°C (SAT5), averaging 1662 ± 176°C and 113 ± 12 SAT5-days, can be recommended as predictors for the onset of the generative diaspora dispersal period for invasive hogweeds. In urban conditions, the phenological phases of H. mantegazzianum occurred 1–2 weeks earlier than in the suburbs, a factor that must be considered when planning and executing plant eradication measures.

FIRST RECORD OF THE ALIEN SPECIES OTIORHYNCHUS ALBIDUS STIERLIN, 1861 (COLEOPTERA: CURCULIONIDAE) IN THE MIDDLE VOLGA REGION - Dedyukhin S.V. - An adventive population of the Eastern Mediterranean parthenogenetic weevil Otiorhynchus albidus has been recorded in the Middle Volga region (Samara Region, Tolyatti City) for the first time. This species was found more than 1000 km far from the northeastern boundary of its natural range in the Black Sea region. The beetles were collected overnight (August 4, 2022) in streets and residential areas in plantings of introduced trees and shrubs in the area of old buildings. The species presumably arrived to the city as a result of an unintentional introduction with seedlings. To determine the extent of its establishment and distribution in populated areas of the Samara Trans-Volga region additional studies are necessary.

START FEEDING OF JUVENILE PINK SALMON (ONCORHYNСHUS GORBUSСHA) IN RIVERS, ESTUARIES AND SEA OF NORTHWEST RUSSIA, AND FACTORS INFLUENCING IT - Efremov D.A., Rasputina E.N., Shulgina N.S. - Pink salmon smolts were collected during the 2024 downstream migration of the spawning season of 2023 odd-line spawners from rivers of the White and Barents seas, under various temperature conditions. Stomach fullness, prey composition and differences in their qualitative composition depending on the water body within the latitudinal geographic profile were analyzed. The experiment examined the start feeding patterns of pink salmon smolts from the 2022 downstream migration of 2021 the odd-line spawners, depending on water salinity (sea, estuary, river). Differences in the qualitative composition of food items were identified between pink salmon smolts in experimental cages located in areas with different salinity levels. The hypothesis of a catastrophic mortality of pink salmon smolts in the White Sea during the 2022 downstream migration due to a lack of food resources and depletion is confirmed. The reason for the low abundance of pink salmon spawners during the 2023 spawning run is substantiated. The qualitative and quantitative feeding characteristics of pink salmon smolts of the 2024 downstream run of the 2023 odd-line spawners were studied, and samples from 7 rivers were analyzed. A comparative analysis of the pink salmon smolts feeding patterns during the 2022 and 2024 downstream migrations from the Varzuga and Indera rivers was conducted.

SEASONAL DYNAMICS OF FEEDING OF AMUR SLEEPER PERCCOTTUS GLENII (ODONTOBUTIDAE) IN A FLOODPLAIN LAKE ON THE TERRITORY OF SAMARSKAYA LUKA - Kirilenko E.V., Shemonaev E.V. - The article analyzes the feeding dynamics of the Amur sleeper Perccottus glenii Dybowski, 1877, which entered the reservoirs of the Volga River basin more than seven decades ago. Information on the diets of different age groups is given in dependence of the season. A change in the nutrition spectrum in accordance with ontogenetic and seasonal patterns was revealed. The tendency in increasing consumption of their own young fish as well as that of other species tracing from spring to autumn is shown.

FRESHWATER JELLYFISH CRASPEDACUSTA SOWERBII LANKESTER, 1880 (CNIDARIA: HYDROZOA: LIMNOMEDUSAE) IN WATER BODIES OF BELARUS - Lipinskaya T., Semenchenko V. - Recently, a spread of naturalized alien species of invertebrates throughout the water bodies of Belarus is observing, but new species are also appearing. For the first time the freshwater jellyfish was revealed using environmental DNA, and then local residents observed the bloom in the summer, when mass accumulations of invertebrates lived in the water column of various water bodies. Taking into account the life cycle of jellyfish and their ability to live in the form of polyps, it is expected that this species will be found in other places because of increase in water temperatures of reservoirs and streams.

THRESHOLD CONCENTRATIONS OF CATIONS IN THE EXTERNAL ENVIRONMENT DETERMINING THE BOUNDARIES OF THE INVASIVE SPECIES DREISSENA BUGENSIS (ANDRUSOV, 1897) RANGE IN FRESH WATER BODIES - Martemyanov V.I. - This study demonstrates that the minimum concentrations of sodium, potassium, calcium, and magnesium in water required to maintain balance between D. bugensis and its environment are 0.022–0.026, 0.0021–0.0026, 0.43–0.47, and 0.0032–0.0039 mmol/L, respectively. Compared to D. polymorpha, D. bugensis requires slightly higher concentrations of sodium and calcium ions in water for survival. A comparative analysis showed that both mussel species are not found in water bodies where calcium ion levels in water are below the threshold values. To assess the further spread of mussels, it is necessary to determine the range of changes in the content of ions, primarily calcium, in different freshwater bodies. In any basin and region, mollusks will colonize those water bodies where the calcium level in the water is above the threshold values and will not be able to settle in fresh water with calcium content below the threshold values.

DYNAMICS OF DISTRIBUTION OF BROADLEAF CATTAIL TYPHA LATIFOLIA L. (TYPHACEAE), AN INVASIVE SPECIES IN THE MAGADAN REGION (FAR EAST RUSSIA) - Mochalova O.A. - Typha latifolia L. is a widespread plurizonal species. In the Magadan Region, it is an invasive species, appeared about 10 years ago in the vicinity of the Laryukovaya roadside cafe on the highway M-56, 383 km from Magadan. This is the most northeastern location in Russia. In recent years, active dispersal of broadleaf cattail has been observed in landscapes disturbed by gold mining. The area of water bodies in which cattail grows increased by approximately 7 times between 2017 and 2025. The rate of cattail dispersal has accelerated in the last 5 years. The most preferred habitats for cattail are heavily disturbed man-made water bodies formed after placer gold mining. T. latifolia is very rare in long-formed reservoirs at the site of quarry excavations, where natural restoration of vegetation along the banks has occurred. Broadleaf cattail grows in water bodies with high mineralization, averaging around 300 ppm, with a wide range of mineralization values – from 61 to 858 ppm. Acidity ranges from 6,7 to 8,0, most commonly pH 7,3–7,6. Water temperature in middle June ranges from 14° to 23°C. All water bodies are heavily polluted with dust and enriched with suspended particles of industrially origin. In the Magadan Region T. latifolia flowers and fruits later than in the European part: flowering in July–early August, and fruiting in September. The late maturation of seeds does not hinder the successful spread of cattail in the region. Communities dominated by cattail are rare in the region. Horsetail-cattail and sedge-cattail communities are more common; they are common in the shallows of small bodies of water, both heavily disturbed and long-existing, slightly disturbed reservoirs. The most likely vector of invasion of broadleaf cattail includes the transfer of seeds by wind from the first site of introduction to anthropogenically transformed ecotopes, primarily quarries and other damp habitats after placer mining, and roadside reservoirs. T. latifolia in Magadan region may be referred to the category of alien species settling and naturalizing in disturbed habitats, which further will be able to take root in seminatural and natural communities.

GROWTH DYNAMICS OF NORWAY SPRUCE (PICEA ABIES (L.) H. KARST., PINACEAE) IN STANDS OF SOSNOWSKY’S HOGWEED (HERACLEUM SOSNOWSKYI MANDEN., APIACEAE) IN THE MOSCOW REGION - Ozerova N.A., Osipov F.A., Petrosyan V.G., Krivosheina M.G. - This study evaluated the potential use of Norway spruce (Picea abies) to limit the spread of the invasive species Sosnowsky’s hogweed (Heracleum sosnowskyi) in an old fallow meadow. The study was conducted from 2018 to 2024 on a 0.58 ha experimental site in the Moscow Region. Spruce saplings aged 5–10 years were planted both within hogweed stands and in control habitats differing in light conditions (birch stand, spruce stand, and open meadow). Throughout the study, plant survival was regularly assessed, and tree height and annual height increment were measured. The effects of initial sapling height and habitat conditions on spruce growth were analyzed using a generalized linear mixed-effects model (GLMM) with repeated measurements taken into account. Spruce growth was shown to depend significantly on both the initial size of planting material and light conditions. Under shading beneath the hogweed canopy, growth suppression and increased variation in annual increment were observed; however, some individuals retained the capacity for sustained development. These results support the potential use of woody vegetation as a biological control factor against invasive plant species through modification of the light regime and formation of a closed canopy.

THE ALIEN SPECIES – SETARIA FABERI R.A.W. HERRM. (POACEAE) IN DONBASS - Ostapko V.M., Mulenkova E.G., Gnatyuk N.Yu. - The paper presents information on the unintentional introduction and spread of the alien species of East Asian origin, namely Setaria faberi R.A.W. Herrm. in Donbass, which is assessed as potentially invasive.

COMMUNICATION WITHIN AN INVASIVE TANDEM: FOUR-EYED FIR BARK BEETLE POLYGRAPHUS PROXIMUS (COLEOPTERA: CURCULIONIDAE) – PHYTOPATHOGENIC FUNGUS GROSMANNIA AOSHIMAE (ASCOMYCOTA: HYPOCREOMYCETIDAE) - Pashenova N.V., Demidko D.A., Pertsovaya A.A., Efremenko A.A., Aniskina A.A., Baranchikov Yu.N. - In laboratory and field experiments, the role of the fungus Grosmannia aoshimae − the specific fungal symbionts of the four eyed fir bark beetle Polygraphus proximus − in chemical communication of beetles within vector populations was investigated. The evidences of the attractiveness of volatiles produced by the G. aoshimae mycelium were obtained that affected adult vector beetles both at the stage of choosing trees for colonization and at the stage of determining the boring site during a direct contact with plant tissues. In addition, it was found that terpenes of Siberian fir (Abies sibirica) and volatiles produced by Leptographium mycoassociates of the black fir longhorn beetle (Monochamus urussovii) also demonstrated attractiveness during tree colonization by bark beetles. However, the influence of these substances on P. proximus beetles was less effective. It was supposed that semiochemicals produced by the G. aoshimae may be subdivided into two groups: 1) host monoterpenes chemically modified by the fungus; 2) volatiles produced de novo by mature mycelium that has reached the secondary biosynthesis phase. Volatiles of the first type may play a predominant role at the stage of primary selection and colonization of new trees during the mass flight of P. proximus beetles. Semiochemicals of the second type are important for the vector offspring, especially for young beetles to attract them for maturation feeding to the phloem areas colonized by the fungus, where the nitrogen content has increased and the concentration of host defensive substances has reduced. The importance of studying chemical communications between bark beetles, their fungal symbionts, and the host plant is noted, since this is necessary for developing methods for monitoring and control of xylophagous pest populations.

DETECTION OF POPULATION OF TOPMOUTH GUDGEON, PSEUDORASBORA PARVA (ACTINOPTERYGII: CYPRINIDAE), IN THE MOSCOW REGION, RUSSIA - Reshetnikov A.N., Pikel K.V., Petrovskiy A.B., Karabanov D.P. - The topmouth gudgeon (stone moroko), Pseudorasbora parva, is listed among the Top 100 most dangerous species for the natural ecosystems of Russia. This fish species was recently discovered in a water body in the Moscow region (Russia), an area located significantly north from its current main invasive range. Species identification of the collected specimens was confirmed based on morphological and molecular genetic features. The presence of individuals of different age groups, including numerous yearlings, confirms successful reproduction and naturalization in the water body. However, the long-term sustainability of the detected population, perspective of the secondary distribution, and, accordingly, the prospects for the dynamics of the northern range boundary remain unclear.

NEW DATA ON THE DISTRIBUTION OF IPS AMITINUS (EICHHOFF, 1872) (COLEOPTERA: CURCULIONIDAE, SCOLYTINAE) IN THE WEST SIBERIAN INVASION RANGE - Smirnov N.A. - The article presents the results of a reconnaissance survey of Siberian pine stands in the Tomsk and Kemerovo regions conducted in 2025 to monitor the spread of the invasive bark beetle Ips amitinus (Eichhoff, 1872). A slight northeastward shift in the boundaries of the invasive range was established in the Tomsk region, where a new locality of the pest was identified in the vicinity of Orekhovo (Pervomaysky District). In the Kemerovo region, the species was recorded for the first time in the mountain forests of the Tisulsky District (near Moskovka) and was also found in the Sheregesh urban-type settlement (Tashtagolsky District). Thus, over the past five years, the known distribution limit of I. amitinus in Western Siberia has shifted approximately 320 km southward. It is noted that there is a high risk of further naturalization of the small spruce bark beetle in the mountain Siberian pine massifs of the Kemerovo region, with potential of further expansion into the Altai Republic.

METACERCARIAE OF THE TREMATODE APOPHALLUS MUEHLINGI (JAGERSKIOLD, 1899) AS BIOLOGICAL INDICATORS OF MIGRATION ACTIVITY AND PHYSIOLOGICAL STATUS OF DIFFERENT AGE INDIVIDUALS OF THE BLACK AND CASPIAN SEA SPRAT CLUPEONELLA CULTRIVENTRIS (NORDMANN, 1840) IN TWO UPPER VOLGA POPULATIONS - Tyutin A.V., Shlyapkin I.V., Morozova D.A., Bazarov M.I., Medyantseva E.N., Tyutin V.A. - The authors used metacercariae of the trematode Apophallus muehlingi (Jagerskiold, 1899) to assess the migration activity of fingerlings and adults of the thermophilic freshwater form of the Black and Caspian Sea sprat Clupeonella cultriventris (Nordmann, 1840) naturalized in the upper Volga basin. In the limnic conditions of a large lake-like reservoir (the Rybinsk Reservoir), C. cultriventris showed relatively weak feeding migrations, which is probably due to the need to form local subpopulation spawning groups in small river reaches. This resulted to the minimal contacts with littoral settlements of the first intermediate host of the trematode, the Ponto-Azov prosobranch mollusk Lithoglyphus naticoides (C. Pfeiffer, 1828), in 2020 the prevalence of metacercariae in the central part of the Rybinsk Reservoir was only 1.75% in fingerlings and only 2.65% in adult individuals. In 2020, under lotic conditions of the upper section of the Gorky Reservoir, classified as a valley type, the prevalence of metacercariae in fingerling samples varied from 38.46 to 48.95%. This is partially explained by the fact that, in this reservoir, juveniles of C. cultriventris (relatively large dominant individuals) have the ability to make long-distance feeding migrations already in the first months of their life. Based on the example of the middle section of the Gorky Reservoir, this paper examines the possibility of using A. muehlingi as a biological indicator for identifying the physiologically weakest individual-outsiders in fish samples. In the largest foci of apophallesis, formed in the middle section of the reservoir, the prevalence of metacercariae did not exceed 68.97% in fingerlings, whereas it reached ~100.00% in adult individuals of C. cultriventris. Large age differences, in terms of the prevalence of metacercariae, can be associated with the selective consumption of the most infected and physiologically relatively weak fingerling-outsiders by pelagic ichthyophages. Maximally infected (>50 specimens of metacercariae) fingerlings of C. cultriventris were absent in pelagic trawl catches within the heated discharge water zone of the Kostroma State District Power Plant, but were found in samples collected on the water intake protective grates of the power plant, i.e. among the individuals least prone to migration and not subject to serious pressure from pelagic ichthyophagous fish.

GELATINOUS MACROPLANKTON OF THE NORTHWESTERN PART OF THE CASPIAN SEA AND ITS IMPACT ON THE ECOSYSTEM (2020–2023) - Ushivtsev V., Shiganova T., Kazmin A., Steponyan O., Sayapin V., Moskovets A., Galaktionova M. - The ecosystem of the Caspian Sea has been under the influence of non-native species since the late 1990s, primarily the harmful zooplanktophagous Mnemiopsis leidyi (Agassiz, 1865). Due to the absence of predators, feeding on M. leidyi, its number increased rapidly. The active depletion of zooplankton by M. leidyi was regulated only by abiotic factors (primarily temperature and salinity) and affected all the trophic levels of the ecosystem. However, in November 2019, a new non-native species was discovered in the southern part of the Caspian Sea for the first time - the ctenophore Beroe ovata (Bruguiere, 1789), a predator that feeds on zooplantophagous ctenophores. Observations in the northwestern part of the Caspian Sea in 2020-2023 showed that during the development of the Caspian population of B. ovata, the number of M. leidyi decreased and ecosystem restoration began. At the same time, the habitat of the harmful hydromedusa (also zooplantophagous) Blackfordia virginica Mayer, 1910, had expanded and spread to the Northern Caspian Sea. The paper presents field data on monitoring the state of populations of all three species of gelatinous macroplankton using standard catches with plankton net and an innovative underwater telemetry system. The influence of B. ovata on the population of M. leidyi was studied; information on the distribution of B. virginica and on the beginning of the restoration of the species composition and abundance of pelagic zooplantophagous fishes in the northwestern part of the sea after the introduction of B. ovata was obtained.

FLORISTIC SHIFT IN RESPONSE TO AGERATINA ADENOPHORA (SPRENG.) R.M. KING & H. ROB. (ASTERACEAE) INVASION IN A MIXED FOREST OF CHAMPAWAT, KUMAUN HIMALAYA - Khatri K., Shankar R. - Himalayan forests are dynamic ecological systems that regulate climate, soil, and water cycling, and sustain rich biodiversity. Yet, invasive plant species like Ageratina adenophora are progressively threatening their integrity. This study explores the ecological impacts of A. adenophora invasion on vegetation structure and composition of mixed forest in the Champawat region of Kumaun Himalaya. Comparative analysis between uninvaded and invaded sites revealed substantial alteration in community structure. While the invaded site exhibited higher tree density and basal area, this was primarily due to the dominance of few disturbance adapted species, leading to reduced species evenness and altered spatial distribution patterns. Significant decline was observed in frequency, abundance, and regeneration of the key native and non-native species such as Myrica esculenta, Quercus leucotrichophora, and Cedrus deodara, while opportunistic species like Alnus nepalensis and Betula alnoidea showed increment in these parameters. Shrub and herbaceous layers were similarly affected resulting in decline of local plant diversity and dominance of A. adenophora. Diversity indices demonstrated drop in diversity, and community imbalance in invaded areas. These findings emphasize the serious ecological consequences of A. adenophora invasion and underline the need for anticipatory management and restoration approaches to secure native biodiversity and uphold forest ecosystem functioning in the Himalayas.

A COMPREHENSIVE ASSESSMENT OF INVASIVE AND ALIEN PLANT SPECIES ALONG ROADSIDE CORRIDORS IN THE VALLEY DISTRICTS OF MANIPUR, INDIA - Ningombam R., Singh C.S., Singh P.K., Senjam J.S. - Biological invasions of alien plants present one of the most serious threats to long-term maintenance of ecosystem health, agricultural production, forest regeneration and biodiversity. Roadways have been identified as one of the major source-points facilitating the spread of invasive species as they tend to create edge effects, degrade soils, and drag winds generated by vehicular movements provided added force on further spreading of the seeds. The present study provides the first systematic inventory and quantitative assessment of invasive alien species (IAS) along roadside habitats in the five valley districts of Manipur, India. Vegetation sampling was conducted using stratified quadrat methods across national, state, and district roads between 2022 and 2024. A total of 146 alien plant species were recorded, comprising 107 herbaceous and 39 shrub species originating from 39 countries. The herb layer was dominated by fast-growing ruderal species with high frequency and turnover, whereas the shrub layer showed structurally dominant perennial species with greater biomass and long-term persistence potential. Frequency distribution patterns deviated from Raunkiaer’s normal distribution, indicating an actively spreading and non-equilibrium invasive community. Whitford’s Index of distribution further revealed contrasting spatial strategies between short-lived herbs and stress-tolerant shrubs. The results demonstrate that roadside habitats in Manipur function as active invasion corridors and early establishment zones for both herbaceous and woody IAS. These findings provide a baseline for invasion monitoring and emphasize the urgent need for early detection and targeted roadside management to prevent further landscape-level spread into adjacent natural and agricultural ecosystems.

ADVANCED STUDY OF BEROIDAE SPECIES AND RECENTLY DESCRIBED BEROE PSEUDOCUCUMIS SP. NOV.: MORPHOLOGY, GENETICS, GEOGRAPHY - Shiganova T.A., Abyzova G.A. - The present study extends a thorough investigation of the order Beroida Eschscholtz, 1829 species, performed earlier by the authors with a particular focus on Beroe ovata, B. cucumis, and recently re-described B. pseudocucumis sp. nov. The paper refines the description of this new species. The research focuses on the morphology, genetics, and worldwide distribution of Beroe pseudocucumis sp. nov., providing information on the holotype and paratype, required for compliance with ICZN regulations for new species registration. In the Mediterranean Sea, this species previously classified as Beroe ovata and subsequently as Beroe cucumis sensu Mayer has been re-identified based on the authors' morphological and genetic analyses as Beroe pseudocucumis sp. nov. Still, B. ovata, which initially invaded the Black Sea, stays there as the only recognized Beroida species. This study integrates field-obtained morphological traits of examined species with the historical data and genetic information derived from sequences, focusing on the ITS1-5.8-ITS2 nuclear ribosomal DNA cluster. Contrary to the widespread opinion that B. cucumis represents a one widely distributed species, our findings indicate significant genetic variation within its population. B. pseudocucumis sp. nov. was later also discovered in other parts of the World Ocean. Furthermore, the species' tolerance to water temperature was assessed. B. cucumis lives only in the cold waters, whereas B. pseudocucumis sp. nov. and B. ovata – in the warm and temperate waters. All three species mainly inhabit coastal areas. Geographic distribution of the two species, i.e., B. cucumis and B. pseudocucumis sp. nov. has been considered based on expert analysis of their photographs from various online sources.

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