Aim. The aim is to study bivalve mollusks of the Dagestan zone of the Caspian Sea as the main feed for all the fish fauna in modern conditions. Material and methods. For the study, are used the materials received in the period of spring-autumn 2015-2017. The collection of material and data processing was carried out according to traditional methods. For the study of nutrition, 30 specimens of each fish species were opened. Such feeding characteristics as the composition of food and the ratio of feed components are given. In the study of shells of bivalve mollusks, the following morphological parameters were measured: length (L), height (H), convexity (Con.), in accordance with the most common measurement technique. Were calculated the allometric coefficients for each year of the life of the individual: the coefficient of elongation (the ratio of height to length), the convexity coefficient (the ratio of convexity to the height). Results. At all periods of the level regime, mollusks are the main food resource of the Caspian Sea. At present they form the basis of the food bolus of the investigated commercial fish species. In June 2017, 25 km north of the city of Makhachkala, after a storm, we found 109 shells of Corbicula fluminalis (O.F. Müller, 1774) (a new invasive atypical species for the investigated aquatorium), the third part of which still had the remains of the ligament. The species was the third most abundant and represented by specimens of all age stages. Conclusions. At present, there are fluctuations in the biomass of the autocolonizers Cerastoderma lamarcki (Reeve), Mytilaster lineatus (Gmelin) and Abra ovata (Philippi), as well as a significant reduction in the range of autochthonous Caspian species, mainly Didacna Eichw. Bivalve mollusks are the main food resource of the Caspian Sea. In conditions of increasing anthropogenic load, further detailed studies of the Caspian's malacofauna are needed.

Aim. The main aim of the research is to study the conditions of existence and the timing of the development of the preimaginal and imaginal phases of blood-sucking mosquitoes, depending on the natural and climatic conditions. Methods. Adult species were collected at the roost sites and at the time of swarming with the use of scoop net every five days throughout the season. The larval phases of bloodsucking mosquitoes were taken into account in all given reservoirs of various types using a photocell. Discussion. The results of the study showed that in the study area, the largest region where mosquitoes are reproduced is mainly artificial reservoirs accounting for approximately 65%, natural water bodies (25%) and hollows of tree trunks (10%). The saturation of the larvae of the malarial mosquito of the genus Anopheles was 82 species/m2, non malaria mosquitoes of the genus Culex – 234 species/m2, while Aedes genus made up 105 species/m2. Conclusion. There are 19 species of mosquitoes inhabiting Dagestan. The development of preimaginal and imaginal phases of blood-sucking mosquitoes on the territory of Dagestan is ecologically diverse.

Aim. The aim of the research is to identify and characterize the current composition and state of the fish fauna of the Lake Bolshoe Toko. Methods. Age determination was conducted based on the annual rings on the scales, taken under the back fin above the lateral line; coefficient of fatness was determined on a six-point scale by Fulton and Clark, respectively. The rest of the material was also processed according to the generally accepted methods in ichthyology. Results. As a result of the research, for the first time was obtained updated data on age, height, sex ratio, spatial distribution of fish species in the lake, relative dominant species in this lake; some data on nutrition and helminth infection is also given in this article. Conclusions. Lake Bolshoe Toko is represented by fish of three faunal complexes, of which two species of fish are not typical representatives of the lake ichthyofauna; stuntedness and a high level of infection of the Siberian whitefish by helminthes is due to a high probability of overpopulation in the lake. Small and valuable breeds of fish that live in the lake need protection throughout the basin adjacent to the lake reservoirs.

Aim. The human factor has a significant influence on the development cycles of flora and fauna in the republic, including ticks, in which life cycles are associated with parasitization of agricultural animals, where biotopes are farm buildings, virgin and fallow pastures. Global changes in agriculture over the past two decades have led to an increase in natural pastures, reduction in the areas of sowing grasses, an increase in biotope areas and a number of parasitic ticks on animals. In this regard, we set a goal to study the ecological and biological features of the distribution of biotopes of arthropod parasites in the republic. Material and methods. The material of the study was ticks collected from cattle, sheep and horses in various zones. Collection of ticks was carried out by epizootic and regular methods. Observations, using the direct collection method, have been carried out for 7 years. Results. The researches revealed the presence of 4 genera of Ixodes ticks in the Republic: Hyalomma, Boophilus, Rhipicephalus and Dermacentor, and the genus Hyalomma occurs mainly in the Tersko-Sulak lowland, the rest can be discovered throughout the territory of Chechnya. Their species composition is represented by H. scupense, H. anatolicum, H. marginatum, H. plumbeum; B. annulatus; D. reticulatus, D. marginatus, D. daghestanicus and R. bursa. Conclusion. Through the infected eggs of the tick, further infection of the larvae takes place, which in turn, after molting, turn into the nymph and infect healthy animals, as well as the adult. The natural and climatic conditions of the Republic favor such a cycle of development of ticks.

The purpose of this work is to publish new data on the species composition of oribatid mites in the North Caucasus, which will make possible to clarify the destribution of the oribatids of the world fauna region. The material was collected in 2003-2009, according to generally accepted methods, in 23 habitats in the territory of Adygea, Dagestan, Kabardino-Balkaria and the Krasnodar Territory in various altitudinal levels: in alpine and subalpine meadows, in mountain forests of various types (birch, pine, beech or mixed), mesophytic meadows in the forest zone, in xerophytic shrubs and mountain steppes, floodplain meadows and salt marshes of the semidesert biotopes of the lowland zone. Results. There were found 349 species of the oribatid mites from 158 genera and subgenera belonging to 62 families. Forest habitats are characterized by the greatest species diversity, there are found 232 species of oribatids. In the alpine and subalpine meadows 158 species are noted, 71 species are found in the mountain steppe zone, 47 species in the salt marshes of the semidesert zone, and 7 species in the floodplain meadows. For the first time in the Caucasian region one genus Novosuctobelba Hammer, 1977 and 29 species of the oribatid mites are registered, founded earlier only in Japan, China, Somalia and some countries of the Mediterranean. There are 14 new taxa for science: 12 species and 2 subspecies. Conclusion. In 23 biotopes of 18 geographical points of the Northern Caucasus 349 species of the oribatid mites from 158 genera and subgenus and 62 families were found. The number of species found in the biotopes of different altitude zones corresponds to the basic patterns of distribution of oribatids in mountain ecosystems: the biotopes of the forest zone are characterized by the greatest species diversity, the number of species in the soils of alpine and subalpine meadows and biotopes of the mountain-steppe zone is somewhat lower, the smallest number of species is found in the semidesert zone. For the first time in the Caucasian region one genus and 29 species of oribatid have been recorded, which allows to expand the areology of some species of the oribatid mites. There are 14 new taxa for science.

Aim. The aim is to investigate the relationship between the content of micronuclei, destructive disorders in the nuclei of erythrocytes of peripheral blood of the goby fish and intensity of lipid peroxidation in fish tissues. Methods. Was used the method of quantitative accounting of morphologically altered red blood cells of peripheral blood of goby fish. Evaluation of cytogenetic disorders in fish blood cells was carried out based on a micronucleus test. Samples of muscle tissues and liver were sampled for biochemical analyzes. The rates of lipid peroxidation (LPO level) were determined by a method based on the reaction of malondialdehyde and thiobarbituric acid, the end product of lipid peroxidation. Results. A correlation was found between the rates of spontaneous LPO, ascorbate-dependant LPO and the accumulation of malondialdehyde in the liver of fish and changes in the nucleus of erythrocytes (R2 =0,8; R2 =0,6; R2 =0,7, respectively). Conclusions. We established the functional dependence which justifies the need to use cytogenetic markers to assess the impact of adverse environmental factors on the body of hydrobionts.

Aim. The work is devoted to the study of intrapopulation variability of the Sulak population of Nitraria schoberi L. Methods. The materials for this article were samples of vegetative and generative organs (shoot, leaf, fruit, seed) collected in 2015 in the natural population of N. schoberi in the Caspian lowland to the north-west of the village of Sulak. Results. The studied individuals of N. schoberi differ both in absolute indices of characteristics and in the degree of their variability, which is related both to micro growth conditions and to their genetic and age specific features. The prevalence of shrubs with a smaller diameter we associate with the relative youth of the population. In the semi-arid conditions of the Caspian lowland of Dagestan, N. schoberi bushes play a big role in the sand consolidation process, forming dunes and barrows, which is related to their ability to grow in diameter forming the beds during the rooting of lodging boughs. Conclusion. On the basis of discriminative analysis on the set of the characteristics of the leaf, the maximum self-identity of the 8th bush (80%) was determined, and the 5th bush (100%), on the basis of the fruit and seed, as confirmed by the Mahalanobis distances. The evaluation of signs of vegetative organs according to the results of dispersion analysis showed that the influence of the conditions of the year (h² – 20,8%) is higher than the influence of the characteristics of the bushes themselves (h² – 3,8%). Of generative characters, the greatest contribution is made by the length of the seed (h² – 63,6).

 

Aim. The aim of the research is to define the species composition of technical plants, to conduct its comprehensive analysis and identify useful properties of wild species of Chechnya for enriching the range of plants used for technical purposes. Methods. The object of the study was the flora and spatial localization of certain types of technical plants on the territory of Chechnya and adjacent territories. The material for the study was obtained as a result of observations in nature and collection of herbarium material during expeditionary researches from 2010 to 2017. Discussion. The article lists dyeing, essential oil-bearing, tannic, tar-bearing plants of the flora of Chechnya and adjacent territories. The main woodraw plants that provide valuable wood are also given special attention in the research; the qualitative properties of various woods and their intended use are briefly described. Are also descried many arboreal and herbaceous species which are widely used or are promising for tanning leather, fabrics, as well as species for obtaining essential oils and aromatic substances suitable for the use in liquor and vodka production, confectionery and other industries. Conclusion. The availability of large reserves of raw technical crops in the republics of the North Caucasus makes them very promising for industrial use. The study of the properties of biologically active substances, establishment of their structure, and creation of valuable herbal preparations on their basis is of great practical importance. On the territory of the Chechen Republic we have identified 157 types of technical plants belonging to 74 genera and 35 families. The problem of preserving the species diversity of valuable, economically useful, including technical plants in culture, becomes especially urgent in connection with the expansion of the use of new species as sources of biological substances.

Aim. The aim is to study the features of lateral and radial differentiation, as well as biological absorption of Mn, Zn, Cu and Mo in landscape-geochemical catena of the Lower Dniester valley. Methods. Sampling and sample preparation were carried out in accordance with generally accepted methods. Determination of the metal content in soils, soil extracts (acetate-ammonium buffer with pH = 4.8) and plants was carried out in accredited laboratories using atomic absorption spectrometry. Results. The differentiation of the total and mobile forms of the four indicator elements (Mn, Zn, Cu and Mo) in soils and plants in conditions of the steppe region of the lower Dniester valley was studied for the first time. Their lateral and radial differentiation in soils and the variability of the content and intensity of biological absorption by plants in different landscape-geochemical conditions are shown. Conclusions. It was found that preferentially, Mn weakly differentiates in soils on different relief elements, and Zn and Mo accumulate mainly in subordinate landscapes. For these three metals, the poor differentiation of the content in plants growing in different landscape-geochemical conditions is more typical, although the biological absorption of Zn appreciably increases in subordinate landscapes. Cu weakly migrates in the landscape and the content of its mobile forms is often higher in soils on terraces and watersheds and therefore its biological absorption is more active on slopes and in relief depressions.

The long history of development of deposits of lead-zinc ores of the Sadonsky mining region led to the formation of extensive halos of chemical pollution of surface watercourses. Aim. The aim of this study is to monitor surface watercourses in the area of the Unalsky tailing dumps and the Kholst deposit by points of sampling of 1992-2004. Sampling was conducted in the summer of 2016. Methods. The content of heavy metals of 2 and 3 hazard classes (Pb, Cd, Ni, Zn and Cu) was studied by atomic absorption. The contribution of the Unaldon River and Unalsky tailing dump to the pollution of the Ardon River. Results. The highest content of cadmium, lead and zinc, significantly exceeding the maximum permissible concentrations (MPC) in the water bodies of cultural and domestic use is found in the Ardon River down from the Unalsky tailing dump. The flow of heavy metals into the Unaldon River with adit waters compared with the observation period of 1992-2004 decreased noticeably. In conditions of a reduction in the production capacity of mining and processing enterprises, the leaching of heavy metals from mountain dumps and excavations make an insignificant contribution to the pollution of the Ardon River in comparison with the Unalsky tailing dump. Conclusion. The state of the Ardon River down from the discharge from the tailing dump corresponds to the "environmental disaster" category. The condition of the rivers Mayramdon and Unaldon according to the content of heavy metals corresponds to a "relatively satisfactory" type.

Aim. The aim is to study the modern and ancient basin of the Ural River and establish the cause of its shallowing, as well as the disappearance of small rivers and tributaries of the Ural River. Methods. The research method consists in the generalization and reduction to a single scale of all cartographic and space-survey documents, as well as the identification of elements of hydrography and relief created by ancient watercourses. Results. At present, many countries experience a shortage of fresh water. A person uses a huge amount of fresh water to meet his daily needs. In addition, contaminated waste technical waters are discharged into rivers and lakes. The Republic of Kazakhstan occupies most of the Caspian lowland, with the only full-flowing river, Ural (the Kazakh name is Zhayik). However, this river is becoming shallow, its level and spring floods are becoming lower. Cut-off lakes are also drying and disappearing. Small rivers that flew into the Ural river have almost disappeared and water level increases only during the melting of snow and after heavy rains. The studied territory is located in the arid climate zone, where there is little snow, and rains are rare. Conclusions. However, studying the cartographic and space imagery, we can say that there are many dry channels in the Caspian lowland. It must be assumed that this region was sufficiently moist, with a large number of rivers and lakes.

Aim. The article suggests research on biotransformation of sewage sludge from treatment facilities in the city of Ryazan into organomineral fertilizer. An ecological analysis of the efficiency of fertilizer use in oat cultivation is proposed. Methods. Determination of growth and development indices of plants, structure of the oats crop of the Skakun variety, agrochemical indices of the soil. Results. Analyzed the effect of sewage sludge and vermicomposts, which are the basis for the cultivation of oats (Avena sativa) on organic soils (peat-mineral soil) which forms favorable conditions for the development of plants and the formation of high productivity of the crop, ensuring the production of ecologically safe grain products. Conclusion. The effect of the dehydrated sewage sludge and vermicomposts from the biological treatment plant in the city of Ryazan on the productivity of the Skakun oat has been revealed. The use of sewage sludge and vermicomposts is marked by an increase in the elements of the crop structure of the grain crop, as a consequence, by an increase in the bioproductivity of the phytocenosis, which indicates the advisability of using sewage sludge as a fertilizer.

Aim. The aim of the research was to identify the effect of types of fertilizer on increasing soil fertility and corn yield of grain and sorghum in conditions of irrigation of the Tersko-Sulak subprovince. Methods. Carrying out some field experiments: conducting observations and laboratory tests, selection of soil and plant samples was carried out according to generally accepted methods: statistical processing of yield data was carried out by the method of variance analysis based on Kirov Federal State Unitary Enterprise and FSBSI Dagestan Agricultural Research Institute named after F.G. Kisriev. Results. Studies showed that in the post-harvest period after harvesting winter wheat, it is better to cultivate green manure with the presence of legumes. A valuable biological feature of them is the ability to absorb atmospheric nitrogen. The powerful root system of the seeding pea improves the physical properties of the soil, as well as microbiological activity. The most favorable conditions are created for the growth and development of maize and sorghum, after plowing of fertilizers in the stubble period in the conditions of irrigation of the Tersko-Sulak subprovince, by applying mineral fertilizers at a dose of N150 P75 K75, seeding peas, manure (30 t / ha), In these cases, on average, over two years, the highest yield of maize was 5.6-5.7-5.5 t / ha and grain sorghum, respectively, 4.7-4.8-4.5 t / ha. Conclusion. For the first time, in conditions of irrigation of the Tersko-Sulak subprovince, were obtained the results on the effectiveness of different types of fertilizers introduced into the soil.

The article discusses the land-use problem of mountain and semi-desert landscapes of Dagestan caused by the need to improve the ecologization of traditional pastures as well as perspective tourism and recreational land use. Aim. A comprehensive geographic study of land use in the republic is crucial for the formation of ecologically sustainable distillation and nomad livestock and tourist-recreational land use on the natural, zonal and high-belt mountain-semi-desert landscapes that are not fully developed and are not suitable for farming. Discussion. Ecological and economic effects are revealed due to the combined use of semi-desert-mountain pastures and tourist-recreational areas represented by the population carryng capacity, the ecologization of pasture land use and a significant increase in the total livestock production. Improved combined interzonal use of lands with different natural rhythms of vegetation development contributes, first of all, to maintaining the equilibrium and integrity of the regional ecological system; secondly, to the ecological orientation of pasture-livestock and tourist-recreational land use; and thirdly, to the restoration and the functioning of the quality of natural semi-desert and mountain pasture lands. Conclusion. Ecological and landscape improvement within mountain pasture land use is proposed on the basis of the ecological and economic efficiency of the annual cycle of high-altitude sheep keeping with the regular change of pasture lands of different productivity levels by different sex and age groups of pastured livestock.

Aim. The aim is to conduct an analysis of biodiversity of valuable breeds of animals, as well as to assess its condition, find ways of preserving domestic genetic resources and identify their economically valuable qualities. Discussion. The material is presented, which proves the need to preserve valuable, rare and endangered breeds of agricultural animals characterized by high quality indices of production, longevity, fertility, resistance to diseases, adaptive abilities to extreme environmental conditions. Importance of carrying out these measures is associated with the absorption of domestic flocks by foreign breeds, which led to a decrease in genetic diversity and the continuing trend in the displacement of rare and endangered breeds of animals. One of the ways of preserving animals that cause breeders' concern is the use of seed cryopreservation, which is actively pursued by a number of scientists and specialized institutions. Lack of effective legislative framework, as well as the lack of state support for conservation programs for these breeds, causes significant damage to the problem of preserving local breeds. Together with the listed benefits from breeding local livestock, their role in the biological diversity should be taken into account. Conclusion. Despite the invaluable contribution to the preservation of local breeds and animal populations made by the profile research institutes (the Federal Research Center for Animal Husbandry - L. K. Ernst Institute of Animal Husbandry, All Russian Research Institute Of Animal Breeding) and individual scientists, the given problem requires its inclusion in the legislative framework and effective state support.

Aim. The Republic of Kalmykia is rich in fossils minerals, the main of which are oil, gas, condensate, etc. The republic includes three main morphostructures: the Caspian lowland, the Ergeninskaya Upland and the Kuma-Manych depression. The Caspian lowland, in turn, is divided into the Sarpinskaya lowland and the Black Lands. Practically all hydrocarbon production fields are concentrated in the territory of the Black Lands. In this regard, the most acute for this area are issues of environmental management and problems associated with the seepage of petroleum products into the environment. In the present work, was investigated the problem of soil contamination within the Nadezhdinsky, North-Kamyshansky, Tengutinsky, Bairskoye and Sostinsky oil deposits. Methods. The soil composition of the deposits is due to the complexity and is characterized by a light granulometric composition and, in most cases, salinity. The soils were analyzed for the content of Са²⁺, Mg²⁺ and Na⁺ cations, НСО₃^- , CI^- and SO₄² anions as well as their pH values. Results. Contamination of soils with oil and petroleum products leads to deterioration of its physical and chemical properties, salinity increase, soil alkalinization; soils saturated with oil products, lose the ability to retain moisture, they are characterized by lower values of hygroscopic moisture, water permeability and moisture capacity. Conclusions. The study revealed that the oil pollution of the Black Lands leads to a change in the quality of salinity; the content of sodium and chlorine ions increases in the oil-contaminated soils.

Aim. Are considered the issues of distribution, the current state, and some ecological peculiarities of the Eurasian beaver Castor fiber in the Rostov region in the south of their range. Methods. The materials presented in the study were collected predominantly in the spring-summer months, based on the information from hunting specialists. Was used the method of counting the number of inhabited settlements. Was also considered the confinement of the animal to certain stations, as well as to the width of the river bed. Results. Over the past two decades, this species has significantly expanded its distribution in the region and settled along the right bank of the Don River up to its mouth. Currently, the number of beavers in the Rostov region is estimated at over 2300 individuals. At the same time, the overwhelming majority of them inhabit the administrative regions located in the north of the region and are more connected with the rivers of Seversky Donets, Kalitva, Chir, the middle course of the Don River. Conclusion. In the Rostov region, the beaver demonstrates the main elements of occupying the territories, which is expressed in the prevalence of construction of burrows over the construction of huts, as well as the absence of dams and canals. In the near future, there is a probable increase in the density of the population of the beaver in the lower reaches of the Don, as well as the colonization of the rivers of the northern part of the Azov Sea.

Aim. The aim is to study the ontogeny and structure of introduced populations of useful plants in Central Yakutia. Methods. Description of the ontogeny of the plants under study was carried out with the determination of ontogenetic states according to generally accepted methods. After planting, current measures were taken to care for plants with elimination of weeds and preservation of the undergrowth. The number of plants at the planting sites was calculated annually. Results. In plants, there is a polyvariety of the rate of development, in which the life cycle is shortened in individuals, the rate of development is accelerated or the ontogenetic states are missed, and there is also transition of plants to a temporarily non-flowering state. All studied introductory populations were left-sided and had different absolute maxima, which depended on the life form and duration of plant stay in culture. Conclusions. Among young monocentric plants we saw the development and attenuation of the population (Delphinium grandiflorum, Linum komarovii, Plantago major, Redowskia sophiifolia). In them, absolute maximums fall on juvenile, immitric, virginile and young generative groups. In populations of monocentric perennial plants, Lilium pensylvanicum and Adonis sibirica, absolute maxima fall on virginile groups. For studied years, the nature of the developmental spectrum in populations of Clausia aprica and Tussilago farfara has not changed with the absolute maximum in the virginal group.

Aim. The aim is to carry out the typification of faunas and biogeographical zonation of coastal and island ecosystems of the Caspian Sea. Methods. Revision of fauna of separate groups of invertebrate animals and vegetation cover of coastal and island ecosystems of the Caspian Sea was performed according to the modern taxonomy, unified collection technique and cameral processing of collected field material. Results. For the first time, solution for the actual biogeographical problem is found; the structure, composition and main regularities of the geographical distribution of several groups of invertebrate animals and plants of coastal and island ecosystems of the Caspian Sea have been identified. Conclusion. The data obtained make it possible to better assess the state of ecosystems and determine the impact on social and socio-geomorphological systems, largely determining the structure and boundaries of the latter, thereby predicting the consequences of anthropogenic activity for the nature and establishing the spatial limits of this impact.

Aim. The aim of the research is to consider the medical and social aspects of artificially terminating pregnancy in the Republic of Dagestan. Material and methods. To achieve this goal, we have created a database of the cases of artificial abortion in the Republic of Dagestan. Statistical processing of the results of the study was carried out using software packages like STATISTICA and Excel. Results. The total number of abortions for the study period was 157526 cases, of which 26% of cases were spontaneous abortions, 8.9% of cases were abortions for medical reasons. During the period under review, there was an increase in the number of spontaneous abortions and abortions due to medical indications by 170% and 108.6%, respectively. There is the prevalence of abortions of the pregnancy of up to 12 weekperiod, including mini-abortions, the average percentage of the total number of abortions for the study period was 90%. In the Republic of Dagestan, the average annual intensive standardized abortion rate was 14.67 cases per 1,000 women of childbearing age women of childbearing age (WCA). And among the urban population, this number is higher, and amounted to 25.57 ‰ against 6.25 ‰ in rural areas. The highest values of the average long-term intensive frequency of abortions are observed in the cities of Kizilyurt, Derbent, Makhachkala, Kaspiisk; in the countrysides: Dakhadayevsky, Tarumovsky, Laksky and Babaurtovsky districts. Conclusion. The problem of abortion, despite the steady tendency to reduce their number, still needs to be solved because it is the leading cause of maternal death in Russia, inflammatory diseases of the genitals, infertility, and it also adversely affects the course of subsequent pregnancies and births, increasing the frequency miscarriage, maternal and perinatal pathology.