This article analyzes the evolution of plant cover of the Northern Black Sea region resulting from the anthropogenic factor. It gives the dynamics of processes of humus formation, biogeochemical transformations, and soil erosion. The twin evolutionary phases are distinguished, lasting 2600, 7550, 90-110, and 40 years, which reflect the polyclimax nature of steppe ecosystems.
The effect of oil pollution of the soil on the fauna and ecology of small mammals was studied in various accidental spills in the Central Ob' region. Characteristic structures of populations and morpho-physiological indicators of dominant species in controls and in polluted territory were deduced in various phases of population dynamics. A conclusion is made about species specificity of reactions to oil pollution.
This paper summarizes data on various aspects of the ecology of the brown bear in North-Eastern Siberia. It is shown that the main foods of the bear in this region are Pinus pumila, berries and other plants. In places migratory fish (salmon family) are of significant but secondary importance. The brown bear does not form separate subspecies in this territory, but there is considerable individual variation, especially among young animals.
The author studied the trophic effect of susliks (ground squirrels) on vegetation with increased population density of little suslik, and the vegetation's reaction to this action. It was established that little suslik uses food stores only up to a certain level, which does not exceed 30-40% of the plants' yield of aboveground material. Appropriation of this amount of vegetation by susliks does not reduce the plant cover's overall productivity. Under the influence of susliks, new groupings of plant species develop, which well withstand repeated appropriation of their plant material and produce a large aftermath.
An investigation of the trophic structure of an experimental on-farm field crop rotation has shown its completeness as a unique agrobiocenose. During crop rotation in the fields, the differentiation of fields by biomass of cultivated plants and phytophages as well as of entomophages becomes negligible. The directing action of the anthropogenic factor (the choice of crops and management) reduces the natural biocenotic relationships between the components. Support is given to the hypothesis advanced by the author on the development of a complete agrobiocenose on the whole or the greater part of the area of field crop rotation.
The dependence of the parameters of digestion and energetics of the willow grouse on the composition of the diet was investigated in caged experiments. The variations of the digestive parameters in free populations are analyzed on the basis of the relationships detected.
Results are presented for three-year investigations into downstream migration of whitefish larvae. A detailed study of the dynamics of downstream migration and spatial distribution of larvae in the stream make it possible to reduce error in absolute counts of abundance of young in the spawning areas. The role of the Voikar River in reproduction of chir, pizhyan (Ob' whitefish"), peled, and tugun is demonstrated.
A short characterization of the vegetation of two areas located in regions containing polymetallic ore manifestations to the north of Lake Balkhash is presented. The data from an x-ray fluorescence analysis of the metal content of soil samples and the above-ground parts of plants are analyzed. The general regularities of the accumulation by a number of dominants of the metals in question and the individual reaction of particular varieties to each of the metals and its concentration in the soil are established.
Data are set forth on the feeding of American mink acclimatized in the plains part of Western Siberia. The author investigated peculiarities of the species' feeding for the region as a whole, as well as differences in the use of foods with the population's habitat distribution. The results obtained indicate trophic plasticity of mink.
On areas 45 x 45 m in size, the author set out 100 break-back traps on a grid of 5 x 5 m, which made it possible to conduct prolonged observations of the mobility of bank voles and field mice in Moscow, Kostroma, and Amur Oblasts. It was established that the animals' movements over a location are not disorderly, but are confined to clearly expressed "ecological channels."
On the basis of six years of research, data are given on the number, biomass, and commercial reserve of whitefish (peled, muksun, broad whitefish, and Siberian whitefish) in one of the floodplain bodies of water of the Lower Ob: the Khanty-Pitlyar sor. The reasons determining variations in ichthyomass are discussed. In fish biomass (7.79-17 72 kg/ha), continental sors of the Lower Ob are close to lakes of the oligotrophic type. A conclusion is drawn about the need to create a fishery classification of the sor system in the Ob basin.
Changes in distribution of natural zones connected with climatic changes in Russian territory are examined. Changes of areas of natural zones as a result of warming by 1.4-2.2-degrees-C are cited. These are illustrated by distribution maps comparing natural zones in Russian territory, at present and after warming by 1.4-2.2-degrees-C.
The author investigated structural features of the earthworm population and seasonal changes in the number of them in two biotopes in conditions of the Northern Caucasus. The ratio of species was shown in the overall complex and in complexes of sexually mature and sexually immature individuals.
The relationship of general and local mechanisms regulating the red-blood system when an organism adapts to acute and chronic action of cold is significantly determined by the power of Its cell membranes, sodium-potassium pump. A state of animals' adaptation to cold is characterized by a balance of these mechanisms at a higher functional level. The adaptation effect has a high physiological cost to the organism on account of a sharp reduction in cellular immunity.
Results are given from investigation of the effect of feeding peculiarities on alpha-amylase characteristics in the intestinal mucous membrane of fish in the Pechora River basin (on the example of the Shchugor River). Differences were revealed in the level of enzyme activity, which were determined by the fishes' feeding spectrum. In a number of cases, adaptive changes were discovered in the characteristics of alpha-amylase for fish of different species.
Results are given from determination of the plant mass of eight phytocenoses of a typical halohydrogenic series of the Baraba forest steppe. It was established that the main store of phytomass is formed in the underground sphere, providing for stability in conditions of climatic instability, salinization, and hay-cutting. Characteristics of the fractional composition and vertical structure of underground phytomass were determined, and also the aboveground and underground mass of communities in different types of solonetz soils.
Nest groupings of obligate-colonial species of seabirds on Wrangel and Gerald Islands are characterized by extremely diverse ratios of thick-billed murre and black-legged kittiwake. This is determined by differences in these species' use of different forms of micro- and nanorelief of rocky surfaces, which, in turn, depends on structural characteristics and bedding of rocks composing the shore. Besides that, nesting of murre depends on the ratio of the height of rocky surfaces to their distance from the waterline. The suitability of habitats for nesting is a consequence of peculiarities of the species' nesting biology: the presence or absence of nest building, the number of nestlings, and the age of the young birds when they fly off.
By morphometric and histological methods, the authors investigated the condition of sex glands of sea urchins inhabiting three polluted regions of Amur Bay (the most polluted part of the Gulf of Peter the Great) and at two control stations. They found significant changes in the gonadal index and distribution of volumes of ovocytes, and histopathological changes in the gonads of sea urchins caught at Cape Egershel'd (station 1) and Skrebtsov Island (station 2). The article discusses the relation between these parameters and such environmental factors as temperature degree of provision with food, and pollution.
