The phenomenon of forest invasion to steppe areas in the Middle Urals and its probable causes

Steppes at the northern limit of their distribution are a convenient object for studying climate-induced modifications of the environment, being sensitive to regional climate changes. Over the past 46–47 years, herbaceous vegetation in the study steppe areas has been replaced by shrubs and trees. Petrophytic steppes on hilltops and stony knolls, where conditions are not favorable for tree growth, has proved to be more resistant to such changes. In these habitats, however, the influence of surrounding forest phytocenoses has also resulted in a gradual decrease in the proportions of species from the steppe and forest–steppe floras in the structure of communities and the invasion by species typical of forest vegetation.     

The ecology of quaternary mammals in the Urals

Special aspects of solving certain key problems in the ecology of Quaternary mammals using materials from the Ural region are considered. Possibilities and limitations accounted for by specific features of the region are analyzed. The nature of “mixed” (mammoth, tundra-steppe, hyperborean) faunas and their diversity are considered in the context of questions related to trends in the dynamics of range boundaries and relative abundance of different mammal species during the Late Pleistocene and Holocene.     

Analysis of the long-term dynamics of bird population in forests of the Ilmen State Reserve,Southern Urals

The results of long-term bird censuses in the Ilmen State Reserve are presented. Analysis of dynamic processes in the forest ornithocomplexes has shown that factors influencing changes in the abundance of birds in multispecies communities have unequal effects on different species. It has been found that the abundance dynamics of some species is correlated with spring meteorological parameters and the timing of phenological phases.     

Trials of different provenances of white birches (section Albae) in population cultures in the Middle Urals

Periodic monitoring (by age stages) of the growth energy and health of trees has been performed in population cultures of white birches established on a half-sib basis (for the first time in Russia). The results show that the pattern of growth and development and the health (survival) of provenances tested in population cultures depend primarily on the ecobiological properties of birch species and also on the distance and direction of seed transfer.     

Dynamics of the timberline in high mountain areas of the nether-polar Urals under the influence of current climate change

Changes in the altitudinal position of the timberline in high mountain areas of the Nether-Polar Urals and basic factors that influence such changes have been revealed on the basis of comparison of the age structure of Siberian larch (Larix sibirica) and arctic birch (Betula tortuosa) tree stands and photographs made in different years. On the mountain slopes studied, an upward shift of the timberline took place in areas covered in winter with thick snow (in the late 18th century), with Siberian larch being the pioneer species. Larch began colonizing areas with a thin snow cover in the 20th century. Birch appeared later and has since strengthened its positions. The increase in winter temperatures and precipitation facilitated the expansion of the forest.     

The role of railroads in the formation of synanthropic flora in the Middle Urals

Consideration is given to the biological diversity and bioecological features of ruderal vegetation developing along railroads and to its role in the formation of synanthropic flora.     

The Holocene Dynamics of Vegetation and Ecological Conditions in the Polar Urals

Palynological, paleocarpological, and paleoentomological analyses of frozen peat deposits near Lake Pereval'noe, the Polar Urals, were performed to reveal the main stages of change in the pattern of vegetation over the period from the beginning of warming after the last Pleistocene glaciation to the late Holocene. Nine to four thousand years ago, the study region (at the present-day upper boundary of open larch forests) was covered with taiga forests, as the climate there was significantly warmer. These were larch–birch forests with an admixture of spruce and, later, spruce forests with larch and birch.     

The history of formation of recent small mammal communities in the Nether-Polar Urals

The results of studies on small mammal bone assemblages from seven cave-type sites on the Shchugor and Kozhim rivers are presented. Four stages in the development of small mammal fauna in the Nether-Polar Urals are described, which correspond to the Aller?d, Younger Dryas, Early Holocene, and Subatlantic periods. The moderately cryohydrophilic fauna of the Aller?d was replaced by an atypically ??mild?? xerophylic community in the Younger Dryas. In the Early Holocene, its structure still included considerable proportions of tundra species, which, along with forest species, were also found in the subfossil assemblage from the Subatlantic. It is shown that the transformation of the small mammal fauna in the above sites had a specific pattern, compared to that in other regions of northeastern Europe and to the dynamics of the natural environment and climate.     

The State of Populations and Selective Hunting of Game Ungulates in the Middle Urals

The population dynamics of moose, wild boar, and roe deer in the Middle Urals and changes in the proportion of females among the animals taken by hunters were analyzed. For all the three species, a tendency toward selective hunting for females was revealed. In this situation, the proportion of females in a population decreases with time, and its reproductive potential is impaired.     

Bioecological characteristics of segetal flora in the Middle Urals

The data on the biological diversity, bioecological features, and geographic variations of segetal plants in the Middle Urals are presented for the first time. It has been shown that apophytic and anthropophytic groups are equally represented among them. Each group is characterized, and the phytocoenotic activity of segetal plants is considered.     

The boundary between European and Asian freshwater ichthyofaunas in the Arctic part of the Polar Urals

The spatial distribution of ichthyofauna in water bodies of the northern Polar Urals is reviewed. Four lake types are distinguished according to the species composition of fishes. The faunistic ranking of water bodies has been performed. The zoogeographic boundary between the ranges of the European and Siberian ichthyofaunas in the freshwater part of the Arctic has been determined.     

Population structure of the Colorado potato beetle in the Southern Urals

The population structure of the Colorado potato beetle in the Southern Urals is discussed. This population is shown to be divided into two groups of local populations, in central and in peripheral parts of the study area, which differ in degree of intrapopulation diversity. The founder effect and insecticide pressure are regarded as probable factors that have contributed to this division.     

On the Distribution of Reindeer in the Middle and Northern Urals

Russian Journal of Ecology -     

The Effect of Soil Cultivation on the Humus State of Gray Forest Soil in the Middle Urals

The results of studies on the humus state of soils in agrosystems of the Middle Urals (1984–1997) are described. It is shown that the change of agricultural technologies (crop rotation, doses of organic fertilizers, etc.) transforms environmental conditions and the direction of humus formation processes. Parameters such as the concentrations of humus and water-soluble carbon and soil potential for humus accumulation reliably characterize the humus state of arable soil and allow the mobility and migration rate of humic substances to be monitored.     

The status of mammal populations in the middle Urals and factors determining their distribution and density

Changes in the distribution and abundance of some game mammals have been analyzed over the past 100–150 years. Correlations between changes in the population density of species in slightly and strongly transformed habitats have been revealed, which show that the influence of anthropogenic factors on the population density of species has a highly complex pattern. Transformation of habitats leads to disturbances in the species composition of communities, changes in the population density of species, and disruption of functional relationships between them.     

Radionuclides in terrestrial ecosystems of the zone of Kyshtym accident in the Urals

It was shown that along the Eastern Ural Radioactive Trace central axis, about 100 km in length, decrease of the ⁹⁰Sr and ¹³⁷Cs deposition densities in soil samples may be described as an exponential function. At the western and eastern periphery of the trace, ⁹⁰Sr contents in soils approached to the background level due to global fallout. ⁹⁰Sr and ¹³⁷Cs concentrations in seeds of some herbaceous plants have been determined. The radionuclide concentrations and the resulting dose loads upon plant seeds showed an excess over the background level of about two or three orders of magnitude.     

Plant matter decomposition in the upper timberline ecotone of the Polar Urals

A relatively high biological activity of soils has been revealed at the upper timberline in the Polar Urals. The role of the altitudinal gradient as a factor of destruction process has distinctly manifested itself upon comparing decomposition rates of flowering plant foliage and herbaceous plant roots in the forest and in the tundra. The qualitative composition of decomposing plant matter has also proved to play a significant role. The soil moisture regime of the ecotope is the leading factor of the destruction process.     

The holocene dynamics of vegetation and environmental conditions on the eastern slope of the Northern Urals

Consideration is given to changes in the vegetation and climatic conditions on the eastern slope of the Northern Urals in the second half of the Holocene as reconstructed on the basis of integrated palynological, botanical, paleocarpological, and radiocarbon analysis of material from a peat bog section in the floodplain of the Loz’va River. The results show that the northern taiga zone of the study region in the period between approximately 5000 and 700 years BP was occupied by forests of southern taiga facies, as the climate was significantly warmer than it is today.     

The Holocene dynamics of vegetation and climatic conditions on the eastern slope of the Subpolar Urals

Changes in the vegetation and climatic conditions on the eastern slope of the Subpolar Urals over the past 10000 years have been reconstructed on the basis of integrated palynological, botanical, and radiocarbon analysis of material from two sections of peat deposits in the floodplains of the Lyapin and Man’ya rivers (the Severnaya Sos’va basin). The dynamics of regional vegetation have been traced: from the herb–shrub tundra in the late postglacial time to the spruce–larch forest–tundra and sparse larch–birch–spruce stands in the Early Holocene, to birch–pine–spruce forests with an admixture of fir in the Middle Holocene, and to northern taiga forests with dominance of Scots pine and Siberian stone pine (similar to present-day forests) in the Late Holocene. The results show that the northern taiga zone of the study region in the period between approximately 5500 and 2500 years BP was occupied by forests of middle and southern taiga facies, as the climate was significantly warmer than it is today.     

Micronutrient composition of plants in the Polar Urals under contrasting geochemical conditions

Natural variation in the level of micronutrients in plants and soils of the Polar Urals depending on the types of bedrocks has been evaluated. The contents of Fe, Mn, Zn, Cu, Ni, Cr, and Co have been determined by the atomic absorption method in 156 plant species of 25 families and in 38 soil samples. It has been found that the mineral composition of plant species varies depending on edaphic conditions. Taxon-specific features in the accumulation of chemical elements in plants of the Polar Urals have been revealed for the first time on the basis of a large amount of data.