The participation of small mammals (SM) in the migration of essential (Cu, Zn) and toxic (Cd, Pb) trace elements (TEs) in forest ecosystems under conditions of severe industrial pollution of the environment (1990–2000) by a large copper smelter (Middle Urals, Russia) and after a significant reduction in its emissions (2010–2019) was considered. The peculiarity of transit food flows (TFF) in the pollution gradient was determined by the composition and abundance of animals of different trophic groups (phytophages, mixophages, zoophages), as well as the specifics of their diet. The reduction in emissions was accompanied by positive changes in the SM communities, expressed in an increase in the number and structural rearrangements of trophic groups (TG), which led to partial changes in the composition and amount of food consumed, as well as the content of TEs in them. By the end of the observation period in the background zone, the animal-controlled TFF remained stable for most TEs (Cu, Zn, Cd), for Pb it decreased by a factor of 2, but not as a result of reduced emissions. In contaminated areas, the value of TFF Zn has not changed, Cd has increased, Cu and Pb - decreased. It was concluded that in the taiga zone the main contribution to the dynamics of biogenic TEs flows over time and space was made by a group of mixophages that dominated the pollution gradient.

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Morphological alterations of cells and tissues usually occur in biological organisms exposed to environmental contaminants, there by acting as a biomarker of environmental pollution, thus, making this study highly pertinent. The effect of industrial pollution on the qualitative and quantitative morphological parameters of hepatocytes (through histological analysis and cytomorphometry) was studied in two contrasting species of small mammals ( Talpa europaea and Sylvaemus uralensis ), taking into account the animal age (young and adult groups) and liver concentrations of heavy metals (Cu, Zn, Cd, Pb). Studies were performed in the regions exposed to emissions from two currently operating copper smelters: Middle Ural Copper Smelter (Middle Urals, T. europaea catching area) and Karabash Copper Smelter (Southern Urals, S. uralensis catching area). Seven morphometric parameters of hepatocytes were measured, of which two key parameters were selected by the method of principal components—the cell packing density and nuclear-cytoplasmic ratio ( N / C ). It was found that cell packing density in T. europaea from the impact zone decreased relative to the background area in young animals. At the same time, the differences in this parameter between the age groups from the background zone were leveled in the impact area of catching. The N / C ratio in T. europaea hepatocytes showed no correlation with either animal age or site of capture (background or impact area). In S. uralensis , both parameters, even taking into account the age, were found to be insensitive to indicate an effect of industrial pollution. Dystrophic changes (tested through histological analysis) in the liver tissue were revealed in all animal groups, but their frequency did not depend on any of the factors (age, zone) as well as the level of accumulation of toxic heavy metals (Cd, Pb). Morphometric parameters of hepatocytes have proved to be more reliable indicators of pollution, compared to the frequency of liver histopathology, due to lower subjectivity in their evaluation.

The dataset contains records of small mammals (Eulipotyphla and Rodentia) collected in the background (unpolluted) areas in the vicinity of Karabash copper smelter (Southern Urals, Russia) and the territory of the Sultanovskoye deposit of copper-pyrite ores before the start of its development. Data were collected during the snowless periods in 2007 (18 sampling plots), 2008–2010 (13 plots annually), 2011 (30 plots) and 2012–2014 (19 plots annually). The capture of animals was carried out in different types of forests (pine, birch, mixed and floodplain), sparse birch stands, reed swamps, marshy and dry meadows, border areas, a household waste dump, areas of ruderal vegetation and a temporary camp. Our study of small mammals was conducted using trap lines (snap and live traps). During the study period, 709 specimens of small mammals were caught, which belonged to five species of shrews and 13 species of rodents. The dataset may be highly useful for studying regional fauna and the distribution of species in different habitats and could also be used as reference values for environmental monitoring and conservation activities.Our dataset contains new information on occurrences of small mammals. It includes the peculiarities of their habitat distribution in the background areas in the vicinity of the large copper smelter and the deposit of copper-pyrite ores before the start of its development (Chelyabinsk Oblast, Russia). All occurrence records of 18 mammal species with georeferencing have been published in GBIF.

The accumulation of 28 elements (Na, Ca, Sc, Cr, Fe, Co, Zn, As, Br, Rb, Sr, Ag, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au, Th, U) in a maternal organism (the liver), the placenta and fetuses of the bank vole (Clethrionomys glareolus) from the vicinity of a large copper smelter and from the background territories (Russia, the Middle Urals) has been analyzed. It was shown that the level of trace element contamination (TEC) of the environment had no significant effect on the levels of elements in different types of samples. The exception was Br: its concentrations in the liver, placenta and fetuses from contaminated territories exceeded twofold the respective background values. At the same time, the type of accumulation of most elements depended on the sample type: the maximum concentrations of Cr, Fe, Zn, Rb, Sb, La, Ce accumulated in the liver of maternal individuals; Co, Ag, Eu, Tb, Th accumulated in the placenta; Na, Ca, Br, Ba, Ta accumulated in fetuses, and the levels of As, Cs, Nd, Lu, U did not vary between the samples compared. It was concluded that the TEC components under consideration in effective concentrations had no significant negative impact on the bank vole offspring quality in the area of the copper smelter.

The long-term changes in the contents of heavy metals (Cu, Zn, Cd, Рb) in the food and liver of four shrew species of the g. Sorex, in the vicinity of the the Middle Ural Copper Smelter (MUCS) during periods of its high (1990–1997), reduced (1998–2009), and almost ceased (2010–2019) emissions. The minimum concentrations of all elements in the animal organism were noted in unpolluted areas (background zone), the maximum concentrations of Cu, Zn, and Cd were in the immediate vicinity of the plant (impact zone), Cd—at moderate pollution (buffer zone). The species specificity of the accumulation of the considered elements in the liver was determined by the composition of diets and was expressed in increased accumulation of Cu and Cd in the liver of S. araneus and increased accumulation of Pb in the liver of S. caecutiens. A multiple reduction in industrial emissions did not lead to an equivalent decrease in the content of heavy metals (HMs) either in the feed or in the body of shrews. Over 30 years, directed changes in HM concentrations in the liver were noted only in S. caecutiens: in the impact zone (1–3 km from the plant), the content of Zn did not change, the concentrations of Cd and Pb decreased by 1.2–1.5 times, while the concentration of Cu, on the contrary, increased by 1.5 times. In the buffer zone (4–10 km) Cu, Zn, and Pb concentrations remain unchanged, while the concentrations of Cd decreased by 1.5 times; in the background area (20–34 km), the content of essential elements (Cu, Zn) was maintained at the same level, while the concentration of toxic elements (Cd and Pb) decreased by 4–5 times.

Abstract Data on the dispersal of shrews are still rare, and for some species of Soricidae these are not available at all. Group marking with bait containing rhodamine B was used to study the dispersal of two species of shrews – Laxmann’s shrew (Sorex caecutiens) and pygmy shrew (Sorex minutus) in the Middle Urals (Russia). Twelve Laxmann’s shrews moved straight-line distances ranging from 80 to 4500 m. Five pygmy shrews dispersed from 475 to 2570 m. The are first field data obtained on dispersal distances of the pygmy shrew. The reported dispersal distances of the Laxmann`s shrew are the maximum known for this species.

The long-term dynamics of β-diversity of small mammal (SM) communities in the vicinity of a large copper smelter has been analyzed during the periods of high (1990–1997), reduced (1998–2009), and almost terminated emissions (2010–2020). The results show that the β-diversity of communities increases as the smelter is approached, with the level of pollution playing a key role in the formation of community structure (up to 25%). Throughout the 30-year observation period, the background communities have been less variable than the buffer and impact communities; i.e., the more unstable the environment, the higher the community variability. Structural rearrangements in the impact and buffer communities in the period of emission reduction have resulted in the progressive divergence between the communities of background and polluted areas.

The long-term dynamics of the composition, total abundance, and diversity (α- and γ-diversity) of small mammal (SM) communities is analyzed in the vicinity of a large copper smelter during the periods of high (1990–1997), reduced (1998–2009), and almost terminated emissions (2010–2019). It is shown that the response of SM communities to pollution has not fundamentally changed over 30 observation years. An increase in pollution caused a significant reduction in the total abundance and α-diversity of communities and their dominance index in each of the three periods; at the same time, the γ-diversity remained similar in the background (13 species) and polluted zones (12 species). The reduction of emissions had no significant influence on the SM communities in the background (conditionally clean) zone: the species structure fluctuated insignificantly, the dominance structure did not change, and the increase in the animal abundance by the end of observations (owing to forest voles but not insectivores) was due to successional changes in the vegetation. The reduction of emissions led to a succession of dominants near the smelter and the trends of changes in abundance in this area differed from those observed in the buffer and impact zones (increase and no change, respectively). The increase in the abundance of species of different trophic groups (phytophages, granivores, and zoophages) in the moderately polluted (buffer) zone can be considered a symptom of the initial stages of recovery due to the improvement of habitat quality. Positive shifts in the SM community from the highly polluted (impact) zone are less distinct, being expressed only as an increase in the proportion of shrews.

The paper presents data on the involvement of local populations of bank vole ( Clethrionomys glareolus ) in the biogeochemical cycles of Cu, Zn, Cd, and Pb at territories strongly chemically polluted by large nonferrous metallurgical plant in the Middle Urals (in 1990–1992) and after a significant decrease in its emissions (in 2015–2017). At maximally polluted areas (impact zone), the animal-controlled transit Cu, Cd, and Pb flows approached their background values by the end of the study period, and the Zn flow simultaneously twofold decreased compared to the background areas. At moderately polluted areas (buffer zone), no significant changes in the metal fluxed were detected for any of the elements. The specifics of the transit flows of the elements at variably polluted areas are controlled by the concentrations of these elements in the diet of the animals and by the abundance of voles. Thereby the manyfold (fifty-fold) decrease in the emissions did no result in an equivalent decrease in the concentrations of the metals in the animal rations at the polluted areas. The main reason for the changes was a structural transformation in the community of the small mammals, which led to a drastic decrease in the bank vole population in the impact zone. The simultaneous effects of the analyzed factors over the study period of time (25 years) resulted in intensification (in the background zone), retardation (impact zone), and stabilization (buffer zone) of the biogeochemical exchange of the elements.

Long-term changes in the contents of heavy metals (Cu, Zn, Cd, Рb) in the food and liver of bank voles (Myodes glareolus) inhabiting areas exposed to pollution from the Middle Ural Copper Smelter (MUCS) in the period of reduction of its emissions (1990–2015). The results show that 50-fold reduction of emissions has not resulted in an equivalent decrease in the dietary and body concentrations of metals: in the impact zone (1–2 km from the MUCS), Cu, Zn, and Pb concentrations remain unchanged, while Cd concentrations have increased twofold by the end of the observation period; in the background zone (20 km), Cu, Zn, and Cd concentrations remain unchanged, while Pb concentrations have decreased by a factor of 1.7–2.5; and no directed changes have been revealed in moderately polluted plots (4–6 km). The accumulation of heavy metals in the animal body depends primarily on the contents of these elements in food and on the system of elementspecific homeostatic barriers providing effective protection from the toxic effect of heavy metals.

Morphometric parameters of hepatocytes have been studied in five small mammal species with different ecological specificity from two taxonomic groups: a surface-dwelling insectivore (the common shrew, Sorex araneus), a subterranean insectivore (the European mole, Talpa europaea), surface-dwelling rodents (the bank vole, Myodes glareolus and herb field mouse, Apodemus uralensis) and a subterranean rodent (the northern mole vole, Ellobius talpinus). The results show that the hepatocytes of the European mole differ markedly from those of all other species, being characterized by smaller size and nuclear area, low anisocytosis and anisokaryosis, the almost complete absence of binuclear cells and, on the other hand, high nuclear–cytoplasmic ratio and packing density. The common shrew differs from the European mole containing a relatively high proportion of binuclear hepatocytes, and the size of hepatocytes in this species is smaller than in rodents. Differences in the parameters of these cells between rodents are minimal or absent. The differences observed in the characteristics of hepatocytes between the above species cannot be explained solely by either taxonomic or ecological specificity. Comparative research involving a greater number of closely related species (at the levels of families and orders) is needed to reveal and evaluate the taxonomic and ecological specificity of hepatocytes in greater detail.

Fluctuating asymmetry (FA) of the mandible shape has been analyzed in bank voles from the zones affected by pollution from three copper smelters in the Urals. It has been shown that there is the necessity for a detailed analysis of the material, since the level of FA may depend on population parameters. Regardless of the pollution level, FA of the mandible region including the lower part of the mandibular body, ramus and processes is higher than in the diastema region. A gradient effect of toxic exposure on FA has been revealed: an increase in its level under increasing technogenic impact is clearly manifested along local pollution gradients.

An attempt was made to estimate the dimension of direct toxic effects of exposure to Cd on the basis of researches on reproductive parameters in small mammals in natural populations ( on the example of red-backed vole) inhabiting localities of large-scale non-ferrous metal plants and comparison of results obtained with outcome of toxicological experiments ( chronic exposure of female rats to Cd) ). It was expected that at the existing pollution levels, embryonic losses caused by direct toxic effect of Cd shouldn’t exceed 7%; however actual losses significantly exceeded extrapolation results. Distinctions observed are caused by impact of external and internal factors influencing reproductive potential on fulfillment of reproduction of animals in natural populations.