A bizarre layer cake: Why soil animals recolonizing polluted areas shape atypical humus forms

During soil recolonization by macrofauna in areas previously defaunated by industrial pollution, non-typical humus forms are produced. Given that the evidence of zoogenic activity cessation with increased forest litter depth in these humus forms, we tested the hypothesis that the lower organic layers are more toxic than the upper ones. The studies were conducted in the southern taiga, near the Middle Ural Copper Smelter (Revda city, Russia), in spruce-fir and birch forests. We investigated the series of degraded humus forms at different recovery stages, including those without signs of regradation, as well as at the initial and advanced recovery stages. In the organic layers, each of which were 1-2 cm thick and 6-8 cm in total, we measured the following parameters: pH(water), total acidity, the content of exchangeable Ca2+ and Mg2+, acid-soluble and exchangeable metals (Cu, Pb, Fe, Cd, and Zn), organic carbon, and total nitrogen. Simultaneously, we diagnosed the degree of zoogenicity of the organic layers following the European morpho-functional classification of humus forms. Concentrations of the metals increased with forest litter depth, reaching a maximum at the boundary between the organic and organic-mineral horizons (the difference exceeded an order of magnitude). In the same direction, the acidity increased, but the saturation of the exchange complex with Ca2+ and Mg2+ decreased. Within a particular forest litter profile, metal concentrations and acidity were lower in the layer with the highest zoogenicity compared to the layer with the lowest zoogenicity. Based on the metals, pH(water), and exchange complex, the accuracy of the predictions of the degree of layer zoogenicity within the OF horizon in the discriminant analysis reached 100 %. These findings suggest that the vertical gradient of toxic burden persisting in the forest litter after pollution cessation can explain the recovery pattern of humus forms in the contaminated areas.

Morphological parameters of hepatocytes in the European mole (Talpa europaea) and herb field mouse (Sylvaemus uralensis) under industrial pollution: Qualitative and quantitative assessment

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.

Long-distance dispersal of two species of shrews (Sorex caecutiens Laxmann, 1788 and Sorex minutus Linnaeus, 1766)

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.

Diversity and abundance of soil macroinvertebrates along a contamination gradient in the Central Urals, Russia

BACKGROUND

Since the late 1980s, long-term monitoring of terrestrial ecosystems in metal-contaminated areas near the Middle Ural Copper Smelter has been carried out in the Central Urals. As a part of these monitoring programmes, the data on species diversity, community composition and abundance of soil macroinvertebrates continue to be gathered.

NEW INFORMATION

The dataset (available from the GBIF network at https://www.gbif.org/dataset/61e92984-382b-4158-be6b-e391c7ed5a64) includes a 2004 census for soil macroinvertebrates of spruce-fir forests along a pollution gradient in the Central Urals. The dataset describes soil macrofauna's abundance (the number of individuals per sample, i.e. the density) and community structure (list of supraspecific taxa, list of species for most abundant taxa and supraspecific taxa or species abundance). Seventeen sampling plots differed in the levels of toxic metal (Cu, Zn, Pb, Cd and Fe) soil contamination from air emissions of the Middle Ural Copper Smelter (heavily polluted, moderately polluted and unpolluted areas). The dataset consists of 340 sampling events (= samples corresponding to upper and lower layers of the 170 soil monoliths) and 64658 rows (2907 and 61751 for non-zero and zero density of taxa, respectively). Arachnida (Araneae and Opiliones), Carabidae (imagoes), Elateridae (larvae), Chilopoda, Diplopoda, Gastropoda, Staphylinidae (imagoes) and Lumbricidae were identified to species level. In contrast, Mermithida, Enchytraeidae, Lepidoptera larvae, Diptera larvae, Hemiptera, Hymenoptera and some other insects were identified to family or order levels. In total, 8430 individuals of soil macroinvertebrates were collected in two soil layers (organic and organic-mineral horizons), including 1046 Arachnida (spiders and harvestmen), 45 Carabidae, 300 Elateridae, 529 Myriapoda, 741 Gastropoda, 437 Staphylinidae, 623 Lumbricidae and 4709 other invertebrates. The presence-absence data on each taxon are provided for each sampling event. An overwhelming majority of such absences can be interpreted as "pseudo-absences" at the scale of sampling plots or study sites. The dataset contains information helpful for long-term ecotoxicological monitoring of forest ecosystems and contributes to studying soil macrofauna diversity in the Urals.

Small mammals of background areas in the vicinity of the Karabash copper smelter (Southern Urals, Russia)

BACKGROUND

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.

NEW INFORMATION

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.