The Russian Arctic supports wild sympatric ruminants and their data-deficient helminths. In this study, we: (1) collected fecal samples of wild and semiwild reindeer (Rangifer tarandus), muskoxen (Ovibos moschatus), and snow sheep (Ovis nivicola) across Palearctic North territories: Arkhangelsk Oblast (including Novaya Zemlya archipelago), Karelia and Sakha Republics, Kola, Yamal, Taimyr, and Chukotka Peninsulas, Bering, Svalbard, and Wrangel Islands; (2) conducted a coprological survey (noninvasive life-time method preferable for protected animals) to obtain eggs and larvae of helminths inhabiting digestive, respiratory, nervous, and muscular systems; (3) identified helminths according to their morphology and DNA sequences; (4) estimated parasite load per host; (5) analyzed our findings. Varestrongylus eleguneniensis (in reindeer) was reported for the Palearctic for the first time, while Orthostrongylus sp. was reported both for R. tarandus and for the Palearctic for the first time. Capillarid-type eggs were reported for snow sheep for the first time. The question of the role of wild Arctic ruminants as vectors for rotifers was raised.

—Blood cells of harbor seals, Phoca vitulina Linnaeus, 1758, from the Commander Islands population have been characterized in detail for the first time. Data on the composition, size, and ratio of red blood cells (RBCs), white blood cells (WBCs), and platelets in the peripheral blood of immature and mature seals are provided. A micrograph library for all types of peripheral blood cells of harbor seal is presented. The blood cell morphology of this seal generally corresponds to that of other pinniped species; however, neutrophils with Döhle bodies, reactive lymphocytes, and hypersegmented neutrophils have been found in blood films. Increased numbers of eosinophils (10–25%) have been recorded from the WBC differential counts of all examined seals. Mature seals had higher numbers of eosinophils (p = 0.04) and large lymphocytes (p = 0.005); immature seals had higher numbers of monocytes (p = 0.04) and Howell–Jolly bodies in RBCs (p = 0.03). Microfilariae and nucleated RBCs were observed in blood films of two mature seals.

Recently extinct species can provide important clues for understanding crucial aspects of human–environment interactions, including those that may lead to irreversible ecosystem transformations and...

The article presents the results of the pathological examination of the corpse of an arctic fox delivered from Copper Island (Commander Islands). Due to the sharp depression of the unique population of the Mednovsky (commander) Arctic fox – the only predator of Medny Island and the key element of the local ecosystem, the preservation of this subspecies is an urgent task for researchers. Parasitic diseases are widespread in arctic foxes and researchers consider arctic fox helminthiasis as one of the possible limiting factors in population depression. In this connection, the purpose of our study was to analyze pathological changes in organs and tissues, including parasitological research, which entailed the cause of death of the animal. The work was carried out at the departments of pathological anatomy and forensic veterinary medicine, pathological physiology and parasitology named after V.L. Yakimov FSBEI HE SPbGUVM. According to the results of the postmortem autopsy of the animal, signs of alimentary dystrophy, as well as acute catarrhal erosive gastritis with hemorrhage to the stomach cavity were found. According to the results of parasitological research, 11 adult nematodes of red color, 40–60 mm long, were found in the tumor-like granuloma of the gastric wall and in its cavity. Morphological data and localization of nematodes gave reason to identify them up to the river. Spirocerca. Previously, about the finds of helminths p. Spirocerca in arctic foxes Copper Island did not communicate.

Treeless oceanic islands in the North Pacific preserve important postglacial records of vegetation, climate and biotic exchange, but modern pollen-rain reference data from these settings remain scarce. We analysed annual pollen rain from modified Behling traps and paired vegetation surveys on Bering and Toporkov islands, Commander Archipelago.Modern pollen spectra differentiated the main vegetation contrasts but did not reproduce plot-scale plant cover in detail. Clustering and non-metric multidimensional scaling (NMDS), together with Mantel and Procrustes analyses, indicated a statistically detectable correspondence between vegetation and pollen structure. Regional arboreal pollen formed a persistent background signal despite the absence of trees from the islands. Highly productive wind-pollinated taxa, especially Poaceae and some meadow herbs, locally swamped finer floristic signals. A Quadrant Plot combining the coefficient of variation and Spearman's correlation identified several taxa with more interpretable local or extralocal behaviour, including Betula nana, Ericaceae, Cyperaceae, Apiaceae, Artemisia and Asteraceae.Absolute pollen concentrations added information not captured by percentage data alone: low-productivity tundra plots had weak local pollen production and were more strongly diluted by extralocal pollen, whereas high concentrations marked productive meadow settings, including ornithogenic grasslands. These results suggest that fossil pollen spectra from the Commander Islands are best interpreted as integrative records of broad island-scale tundra-meadow mosaics, regional pollen transport and local productivity contrasts, rather than as direct reconstructions of small local plant communities.

The biology and history of the decline of the Arctic fox population on the Mednyi Island, Commander Islands, North Pacific, are considered. Currently, this is the smallest and possibly the most ancient island population of canids on Earth. Among the endemics of island faunas, carnivores are generally very rare, and among the canids only the California island fox (Urocyon littoralis) is listed in taxonomic and conservation databases. Questions regarding the species status and phylogenetic history of Commander Arctic foxes, Vulpes lagopus beringensis (Merriam, 1902) and V. l. semenovi (Ognev, 1931), remain open until genomic studies are conducted. Over thousands of years, Commander Arctic fox populations have evolved in an environment radically different from that of the continental Arctic foxes: under conditions of complete isolation, ecological stability, and a mild climate, with neither predators nor competitors from other species. The behavioral ecology of the island Arctic fox has been adapted to life in a super-dense population, where severe intraspecific competition and the risk of inbreeding are prevalent. This adaptation has led to a complete restructuring of the social, reproductive, territorial, and spatial behavior of the island Arctic fox. Historically, the viability of the Mednyi population has been supported by its stable and relatively high population size (over 1000 individuals). Since the discovery of the Commander Islands in 1741, intensive fox trapping on Mednyi Island continued for over two centuries. In the last 40 years, trapping has been accompanied by supplementary feeding. After the cessation of fox trapping and supplementary feeding in 1965, the population size began to be determined solely by the island ecosystem’s natural capacity, which decreased significantly during the second half of the 20th century. The long-term decline in effective population size and artificial selection have led to a significant loss of genetic polymorphism. Genetic degradation and a decrease in the carrying capacity of the island ecosystem have placed the population in a critical state. A sudden outbreak of ear mange in the late 1970s, which killed 90% of cubs, demonstrated the enormous risk associated with the emergence of new pathogens. In recent years, the abundance of food sources (such as deposits of storm-cast macrophytes, the seabird colonies, and the sea otter population) has noticeably diminished, and the Mednyi Arctic fox population has declined to fewer than 60 individuals. The National Park protection regime and the inclusion of the Mednyi Arctic fox in the Red Data Book of the Russian Federation are not sufficient to prevent the population from going extinct. The situation requires targeted conservation measures to protect this disappearing island endemic.