A new soil-dwelling mite species, Zerconopsis sibiricus sp. nov., is described from Russia based on the females, males, and nymphs. It occurs in plain and mountain areas of Siberia and the Far East (27 localities), in tundra (Low Arctic) and taiga landscapes, including the area of the Cold Pole of the Northern Hemisphere. Another species, Zerconopsis michaeli Evans & Hyatt, 1960, is first reported from Denmark, Russia, Georgia, Turkey, Azerbaijan, and California, USA (23 new records). Its male, nymphs, and larva are first described, and the female description is corrected with illustrations. The range of Z. michaeli in the Old World can be considered as an Amphi-Palaearctic one, excluding areas with very cold and/or continental climates. This species dwells in forest litter, rotten wood, and bracket fungi; however, in Northern Europe almost all records are from arboreal (woody, fungal) habitats. The genus Zerconopsis Hull, 1918 now includes 19 described species from all continents except Africa and Antarctiсa. A revised generic diagnosis is provided, and three morpho-ecological species groups are recognised. A key for the five Zerconopsis species residing in Siberia is given.

Siberia occupies vast areas underlain by permafrost, and understanding its land cover changes is important for ecological environmental protection in a warming climate. Based on the land cover and climate datasets, we analyzed the land cover changes and their drivers in Siberia from 1992 to 2020. The results show that ① From 1992 to 2020, the areas of evergreen needleleaf trees and deciduous needleleaf trees in Siberia decreased by 9% and 2.5%, and the areas of grassland, shrub, cropland, and construction land increased by 1.5%, 14.2%, 2.8%, and 39.2%, respectively. Cropland expansion had the fastest rate of 1.85% in the continuous permafrost zone, and construction land expansion had the fastest rate of 3.07% in the non-permafrost zone. ② The center of gravity of agricultural land continues to migrate to the northeast, and the center of gravity of construction land continues to migrate to the southwest. ③ The primary drivers for the land cover changes were temperature and precipitation, and active layer thickness also affected grassland, cropland, and deciduous needleleaf trees. The correlation coefficient between active layer thickness and cropland area is 0.74 in the continuous permafrost zone. The interaction between factors is mostly manifested as a two-factor enhancement, with the highest q-value of the interaction of temperature and precipitation for explanatory power. Our results suggest that climate change and permafrost degradation significantly changed land cover in Siberia. This finding deepens our understanding of the mechanisms of land cover change under the influence of permafrost degradation and provides a new perspective on the land cover changes in permafrost regions.

Access to salmon resources is vital to coastal brown bear (Ursus arctos) populations. Deciphering patterns of travel allowing coastal brown bears to exploit salmon resources dispersed across the landscape is critical to understanding their behavioral ecology, maintaining landscape connectivity for the species, and developing conservation strategies.

Setaria spp. are vector-borne parasitic roundworms commonly found in the abdominal cavities of wild and domesticated ungulates globally. The objective of this study was to conduct a morphological and molecular analysis of Setaria tundra Issaitshikoff et Rajewskaya, 1928, collected from roe deer Capreolus capreolus Linnaeus in Lithuania. The morphological characteristics of S. tundra described and illustrated. The amplification of the 12S rRNA and 18S rRNA genes confirmed the presence of S. tundra. This is the first case report of S. tundra in roe deer in Lithuania.

Climate warming can alleviate temperature and nutrient constraints on tree growth in boreal regions, potentially enhancing boreal productivity. However, in permafrost environments, warming also disrupts the physical foundation on which trees grow, leading to leaning trees or "drunken" forests. Tree leaning might reduce radial growth, undermining potential benefits of warming. Here, we found widespread radial growth reductions in southern latitude boreal forests since the 1980s. At mid latitudes, radial growth increased from ~1980 to ~2000 but showed recent signs of decline afterward. Increased growth was evident since the 1980 s at higher latitudes, where radial growth appears to be temperature limited. However, recent changes in permafrost stability, and the associated increased frequency of tree leaning events, emerged as a significant stressor, leading to reduced radial growth in boreal trees at the highest latitudes, where permafrost is extensive. We showed that trees growing in unstable permafrost sites allocated more nonstructural carbohydrate reserves to offset leaning which compromised radial growth and potential carbon uptake benefits of warming. This higher allocation of resources in drunken trees is needed to build the high-density reaction wood, rich in lignin, that is required to maintain a vertical position. With continued climate warming, we anticipate widespread reductions in radial growth in boreal forests, leading to lower carbon sequestration. These findings enhance our understanding of how climate warming and indirect effects, such as ground instability caused by warming permafrost, will affect boreal forest productivity in the future.

Long-distance migrations are a striking, and strikingly successful, adaptation for highly mobile terrestrial animals in seasonal environments. However, it remains an open question whether migratory animals are more resilient or less resilient to rapidly changing environments. Furthermore, the mechanisms by which animals adapt or modify their migrations are poorly understood. We describe a dramatic shift of over 500 km in the wintering range of the Western Arctic Herd, a large caribou (Rangifer tarandus) herd in northwestern Alaska, an area that is undergoing some of the most rapid warming on Earth. Between 2012 and 2020, caribou switched from reliably wintering in maritime tundra in the southwesternmost portion of their range to more frequently wintering in mountainous areas to the east. Analysis of this range shift, in conjunction with nearly 200 documented mortality events, revealed that it was both broadly adaptive and likely driven by collective memory of poor winter conditions. Before the range shift, overwinter survival in the maritime tundra was high, routinely surpassing 95%, but falling to around 80% even as fewer animals wintered there. Meanwhile, in the increasingly used mountainous portion of the range, survival was intermediate and less variable across years compared to the extremes in the southern winter ranges. Thus, the shift only imperfectly mitigated overall increased mortality rates. The range shift has also been accompanied by changes in seasonal patterns of survival that are consistent with poorer nutritional intake in winter. Unexpectedly, the strongest single predictor of an individual's probability of migrating south was the overall survival of animals in the south in the preceding winter, suggesting that the range shift is in part driven by collective memory. Our results demonstrate the importance and use of collective decision making and memory for a highly mobile species for improving fitness outcomes in a dynamic, changing environment.

Plant phenological dynamics have been well studied in relation to abiotic conditions and climate change, but comparatively poorly studied in relation to herbivory. In contrast, plant abundance dynamics have been well studied in relation to abiotic conditions and herbivory, but poorly studied in relation to phenology. Consequently, the contribution of herbivory to plant phenological dynamics and therefrom to plant abundance dynamics remains obscure. We conducted a 9-year herbivore exclusion experiment to investigate whether herbivory might link plant phenological and abundance dynamics in arctic tundra. From 2009 to 2017, we monitored annual green-up timing and abundance of nine plant taxa, including deciduous shrubs, forbs, and graminoids, on plots that were either grazed or experimentally exclosed from herbivory by caribou () and muskoxen (). In 62% of cases, green-up occurred earlier under herbivory, and in 75% of cases abundance was greater under herbivory, compared to green-up and abundance under herbivore exclusion. Moreover, taxa that responded to herbivory with earlier green-up also had comparatively greater abundance later in the growing season. Conversely, taxa that responded to herbivory with delayed green-up exhibited comparatively lower abundance later in the growing season. Hence, well-documented influences of large herbivores on plant abundance and community composition in arctic tundra may relate, at least to some extent, to influences of herbivory on plant phenology. We recommend that ongoing and future assessments of the contribution of herbivores to plant abundance and community responses to climate change, especially in the Arctic, should also consider impacts of herbivores on plant phenology.

Present and future Köppen-Geiger climate maps and time series of particulate matter (PM10) at continental scale were used to investigate the relationship between spatial patterns of PM10 and climate zones. Five main patterns (spatial clusters) of PM10 were found over the European continent, which show a good spatial overlap with the main Köppen-Geiger climate zones. The map of future climate, which shows a poleward movement of the warmer climate zones, an expansion of the (semi-)arid zones and a shrinking of the polar and tundra zones, indicates a higher PM10 concentration, especially in the northern part of Europe. The results also show that there is a temporal shift (later/earlier) of PM10 extremes in the period 2013-2022. This insight into the relationship between climate zones and clustered PM10 time series and the use of high-quality future climate maps based on different scenarios can be used to estimate possible changes, such as annual averages or seasonal cycles, in PM10 concentrations.

Previously, differences in the thyroid profile of Arctic residents were shown depending on the vitamin A blood level. However, dietary habits and metabolism peculiarities in the aboriginal and Caucasian representatives of the North population may be the cause of different retinol supply and therefore be one of the reasons for changes in their thyroid activity. of the research was to assess vitamin A and thyroid blood levels in the aboriginal and local Caucasian population representatives of the Russian Arctic territories. . In the single-center observational cross-sectional study, apparently healthy residents of villages in the Arkhangelsk region were examined (n=281): 145 representatives of the local Caucasian population and 136 representatives of the aboriginal population, with the proportion of tundra nomadic aborigines at 34%, village aborigines at 66%. Vitamin A blood serum level was determined by the fluorometric method, and the thyroid content [thyroid stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), free T4, free T3] was determined by enzyme immunoassay. The integral thyroid index (ITI) as well as the index of peripheral conversion of iodothyronine (IPC) total and free fractions were calculated. . The level of retinol in the indigenous population of the Arctic was lower than that in the local Caucasian population (1.84 [1.26; 2.56] versus 2.10 [1.70; 2.42] μmol/L, p=0.014). However, its deficiency was found only in village aborigines (20.5% of women and 11.8% of men). At the same time, they have the maximum tension of the pituitarythyroid system: lower level of free T3 and free fractions' IPC than in the nomadic and Caucasian population, and TSH levels were higher than in the Caucasian population. Increased vitamin A levels prevailed among the nomadic population: in 60.7% of men and 11% of women retinol level exceeded the norm. At the same time, they have increased metabolic activity of thyroid hormones: higher levels of free T3 and free fractions' IPC compared with sedentary aboriginal population. No pronounced features of the thyroid profile were found in local Caucasians at normal blood concentrations of vitamin A. . The lowest retinol levels are observed in settled aborigines (especially young women) living in villages and experiencing the greatest transformation of traditional lifestyle and nutrition, which is combined with higher TSH blood levels and decreased thyroid hormone metabolism. The highest retinol levels were found in nomadic aborigines (especially young men), which increase the reserves of antioxidant defense and support high metabolism of thyroid hormones. However, the high percentage of people with excessive vitamin A blood level in this group raises concerns due to the possible negative consequences. Therefore, it is necessary to monitor fat soluble vitamin levels among Arctic aboriginal populations. Social support measures should be taken for settled residents of villages, enabling them to consume more traditional foods rich in vitamin A. The causes of excessive blood retinol in nomadic aborigines require further study and control.

Despite their genetic adaptation to local conditions, plants often achieve ecological success through symbiotic associations with fungal endophytes. However, the habitat-specific functionality of these interactions and their potential to drive plant adaptation to new environments remain uncertain. In this study, we tested this using the vascular flora of the Antarctic tundra (Colobanthus quitensis and Deschampsia antarctica), an extreme environment where fungal endophytes are known for playing important ecological roles. After characterizing the root-associated fungal endophyte communities of both species in two distinct Antarctic terrestrial habitats-hill and coast-we experimentally assessed the contribution of fungal endophytes to plant adaptation in each habitat. The field reciprocal transplant experiment involved removing endophytes from a set of plants and crossing symbiotic status (with and without endophytes) with habitat for both species, aiming to assess plant performance and fitness. The diversity of root fungal endophytes was similar between habitats and mainly explained by plant species, although habitat-specific endophyte community structures were identified in D. antarctica. Endophytes significantly influenced C. quitensis homeostatic regulation, including oxidative stress and osmotic control, as well as plant fitness in both environments. By contrast, the effect of endophytes on D. antarctica was particularly evident in coastal sites, suggesting an endophyte-mediated improvement in local adaptation. Altogether, our results suggest that the two Antarctic vascular plant species follow different strategies in recruiting and developing functional symbiosis with root-associated fungal communities. While C. quitensis is more generalist, D. antarctica establishes specific interactions with habitat-specific microbial symbionts, predominantly in the most stressful environmental context.