The paper presents the results of our comprehensive studies of the saline rivers of the arid Prieltonie region based on hydrobiological surveys of plankton and bottom communities. We have compared two tables of the specific structure according to the results of observations at 13 river sites in 2013 and 2018, which included the numbers of hydrobionts of 94 different taxonomic groups of macrozoobenthos, meiobenthos and zooplankton. Using the method of joint inertia analysis, we have revealed a high statistical consistency of the data matrices, due to objective laws of the spatial distribution of aquatic organisms. A randomization test of the Procrustean correlation coefficient showed the statistical significance (p = 0.00026) of the conjugacy of both specific structures in the space of latent variables. At the same time, a certain trend was noted in the changes in the taxonomic composition of communities at individual stations over time under the conditions of dynamic abiotic factors. We have analyzed the dependence of the taxonomic structure of hydrobionts on a set of 30 abiotic environmental factors obtained during hydrobiological and hydrochemical monitoring of the studied river sections. Using canonical correlation analysis and the projection method on latent structures, a set of ordination diagrams was plotted to allow revealing peculiar “ecological niches” for each group of species with a certain set of characteristics of their biotopes. The plankton and bottom communities were shown to correlate quite well with each other, which indicates a close relationship between them, due to both biotic interactions and a mutually agreed response to changes in aquatic factors.

The data of floristic studies of 40 spring tracts of the Mangistau, Aktobe, Atyrau and West Kazakhstan regions of the Western Region of the Republic of Kazakhstan are presented. We have found that the studied flora is represented by 252 species, 167 genera and 55 families belonging to Equisetophyta, Pinophyta, and Magnoliophyta divisions. Taxonomic characterization of the flora showing the predominance of the Asteraceae and Poaceae families is provided. The predominance of perennial herbaceous plants in the flora of spring tracts was identified by the system of I. G. Serebryakov’s life forms. The predominance of steppe plants and weeds was revealed. Horological analysis showed the leading set of species with the Eurasian range type. Ecological characteristics highlighted the predominance of xerophytes and mesotrophic plants. 20 protected plant species listed in the Red Data Book of the Russian Federation and the Red Data Book of the Republic of Kazakhstan were identified. Analysis of the distribution of plants in the areas adjacent to the springs identified four grades of occurrence, namely: common species – 7; uncommon species – 17; rare species – 100; and very rare species – 128. The most common species found within the spring tract territories are related to weeds, such as Tripleurospermum perforatum (Merat) M. Lainz, Polygonum aviculare L., Taraxacum officinale Wigg., Lappula squarrosa (Retz.) Dumort., Plantago major L., Arctium lappa L., Xanthium strumarium L., Capsella bursa-pastoris (L.) Medik., Chenopodium album L., Convulvus arvensis L., Poa annua L., Bromus squarrosus L., Elytrigia repens (L.) Nevski. The Jaccard index (Kj) for the analyzed floras in pairwise comparison varies from 0.02 to 0.5, which shows the extreme heterogeneity of the specific composition.

In the course of our model experiment, an attempt was made to falsify (refute) a consequence from the mathematical justification of the winter route counting of hunting animals (WRC) – the consequence of the mathematical expectation of the proportionality coefficient of this counting being equal to π/2. A simulation was carried out in the MapInfo program. The essence of our digital experiment was as follows: in several places of the model territory, which was a circle 5 km in diameter, daily tracks of animals were placed. Next, a grid of parallel routes oriented along 12 equally spaced directions relative to each other was applied to the model territory. The frequency of the route grid (the distance between parallel routes) for different tracks was chosen so that the total number of all intersections of a single track in all directions was not less than a thousand. In total, 19 electronic daily tracks of various animal species were used. 95 different actual values of the proportionality coefficient were obtained for various locations of the tracks in the model territory, no violations of the above mentioned consequence were found. The results of our experiment made it possible to formulate a corollary arising from the fundamental properties of Euclidean geometry on the directly proportional dependence between the number of intersections between the lines of daily animal tracks and route lines and the product of the total lengths of these lines. The mathematical justification of WRC has once again passed a simulation test, already using the means of geographical information systems and data from satellite navigators. At present, there are no grounds for abandoning the practical use of winter route counting for game animals. All possible discrepancies in the estimates of the numbers of game animals determined by the WRC method with their actual values should be attributed to shortcomings in the direct organization of this counting rather than to its mathematical justification.

In recent decades the interest to the study of Hedysarum has increased. Researchers touched upon the classical issues of morphology and variability of external features of Hedysarum grandiflorum and other species of Hedysarum (to clarify morphology, to more accurately separate existing species, to describe the morphology of new species, including rare ones) providing almost no detailed descriptions. The paper provides information about the morphology of external features of H. grandiflorum in the Southern Volga Upland. The study was conducted in 2007–2018. We have studied 23 H. grandiflorum cenopopulations in habitats with various environmental conditions, where more than 600 counting sites were laid, and concluded that the morphological features of H. grandiflorum are rather variable and the values of morphometric parameters are higher in the northeastern part of the study area. The well-being of the population is achieved due to some heterogeneity in the size of individual plants and by means of suppressing the growth and size of separate cenopopulations. The decrease in the parameters of signs is often associated with a higher anthropogenic load. Dimensional indicators of individuals from the cenopopulations of the species studied depend on the thickness of soil, which decreases from fescue-feather grass to petrophyte steppes. Cluster analysis has allowed us to divide the cenopopulations into southern, northern and northeastern ones, and those with anthropogenic impact. The least variable and most informative morphological features of H. grandiflorum (in the descending order of importance) are: the length of the standard, the diameter of the caudex, the plant height, the number of foliole pairs, the number of inflorescences, the number of leaves, the length of the unpaired foliole, the number of flowers on the inflorescence, the length of leaves and the width of the unpaired foliole. In the overwhelming majority of the plants encountered, all the petals of the corolla were of uniform light yellow color, turning into a white tint to the edges of the petals. In some cenopopulations, the corolla can be colored differently and unevenly, especially at the keel. Approximately 0.3% of individuals of the corolla petals and/or the lower part of the keel and/or veins are light blue or light pink, less than 0.07% has a light magenta or even light purple tint of the veins of the carina, edges of the petals or the whole corolla. Similar individuals are found in other regions. Many scientists noted this peculiarity a long time ago and had already described this phenomenon as a color variation (for example, H. grandiflorum var. violaceum) or less often, as a subspecies (for example, H. grandiflorum ssp. argenteum). Individuals with recessive coloring of the corolla from the area of study are called intraspecific color variations.

The transformation of hazardous pollutants in the environment usually results in formation of hard-to-identify compounds that may have a significant impact on ecosystems. They are difficult to identify by conventional methods of quantitative chemical analysis, but their detrimental effects can be detected by biological methods. The goal of this study was to develop novel methodological approaches to the express assessment of the state of the environment as well as toxicity of its components in the process of biological monitoring at hazardous industrial facilities. The article presents the results of comprehensive toxicity assessment of environmental objects using originally developed system of express methods. The objects of research were water fleas (Daphnia magna Straus and Ceriodaphnia affinis Lilljeborg), infusoria (Paramecium caudatum), preparation of lyophilized fluorescent bacteria based on recombinant Escherichia coli strain M-17 (Ecolum), algae (Chlorella vulgaris Beijer, Scenedesmus quadricauda (Turp.) Breb.), and mammalian gonads. The original methods for determining toxicity by changing the motor activity of water fleas at elevated temperatures of the studied environment are described. The description of the following original utility models is presented: “Method of bioassay for water samples and device for its implementation”, “Device for express assessment of natural environment quality” and “Device for comprehensive assessment of natural environment quality”, confirmed by the patents of the Russian Federation. Their use may significantly reduce the cost of ecotoxicological studies in terms of time and money expenditures. The effectiveness of the system of express methods was established during a biological monitoring of a sanitary protection zone of the Balakovo NPP. Toxicity of the samples of bottom sediments, soil, as well as water samples from the cooler pond and the adjacent water area of the Saratov reservoir were identified. The bioassay results were matched by both conventional methods’ results and originally developed system of express methods.

The considerable polarization of bird habitats has been formed in European Russia – extensive abandoned lands, of low suitability for nesting of typical meadow species, alternate with increasingly intensively cultivated fields. Though the abundance of most species is low in these fields, the polarization has resulted in their increasing exploitation by Eurasian Curlew, Black-tailed Godwit, Common Redshank, Black-winged Pratincole, Demoiselle Crane, Montagu's Harrier, Grey Partridge, Short-eared Owl and Mallard, apart from those more typical for fields: Lapwing, Common Quail, Eurasian Skylark, Calandra Lark and Western Yellow Wagtail. However, nesting of these species on most crop fields often results in low breeding success. The trends most unfavorable for nesting birds in European Russia are conversion of grasslands into arable lands, associated with the switching to indoor keeping of cattle, and increasing no-till farming.

Population approach to determination of the borders and number of natural plague foci implies the specialists’ acceptance of the concept that the existence of a natural plague focus is always provided by a single population of the main carrier. Motivation for our discussion of such an approach was the data of a long-term study of the Hissar natural plague focus (Tadzhikistan). The area of the focus was only 300 km2 and its functioning was maintained by a single, relatively small population of Microtus carruthersi (Thomas, 1909) – the main carrier of plague. The Hissar mountain range territories adjacent to the focus have been surveyed for plague for more than 20 years, however, no plague agent (Yersinia pestis Lehmann, Neuman 1986) has been found, despite the complete identity of the species composition of rodents and fleas. Many of the known natural plague foci are significantly larger in size than the Hissar focus and inhabited by several populations of the main carrier. For instance, in the East-Caucasian high-mountain focus, covering the area of 23,500 km2 , five groups of common vole populations (the main carrier of plague) are distinguished (Microtus arvalis Pallas, 1778). In the Tuva mountain focus, the plague agent was detected in six populations of the main carrier – the long-tailed souslik (Spermophilus undulates Pallas, 1778). In the territory of the Mojynkumsky desert natural plague focus that occupies 93,000 km2 , 17 populations of the great gerbil (Rhombomus opimus Lichtenstein, 1823) were singled out. Similar data are available for a number of other foci. Revealingly, in different populations of the main carriers, genotype differences were identified, both in rodents and the plague agent, as well as asynchrony in the plague epizooty development. Thus, the plague parasitic coenosis, operating within the boundaries and in the territory of a single population of the main carrier, constitutes an autonomous, standalone natural focus. Therefore, the foci with several populations of the main carrier are, in fact, groups of autonomous foci with a close, similar biocoenotic structure. There are many more natural (autonomous) foci within the natural plague focality zone than is widely assumed.

Small mammals are an active component of ecosystems that supports energy and matter flows and they are responsible for both construction of and maintaining their habitat. Such activity is vital for human prosperity, as it supports the chemical and physical quality of the environment where the human is adapted as a biological species. The contemporary human activity has resulted in destruction of a number of natural habitats and, as a consequence, in drastic changes in the species abundance. Some species have become so abundant that pose problems for human health, agriculture, and industries. Some formerly common and even pest small mammals, on the contrary, have reduced in distribution and numbers and now fall in the category of vulnerable species. In both cases, ecologically-based management of populations is required to maintain an optimal abundance of various species. Effective ecologically-based management of populations could be based on the basic principles of population ecology. It implies our understanding of both external and internal factors affecting the population abundance. Here, I review some fundamental principles which could be applied to operational management of populations. Also, I focus on some specifics of population reactions which have been elaborated in the Russian ecological school. Based on the well-known principles of supporting the numbers of populations, I propose a classification of species in terms of their ability to provide and change the type of functions in local populations. My classification allows distinguishing three groups of species with predictable resilience of population. Fitted to various environmental instabilities, the species of these groups require different conservation tactics.

In the modern world, increasing importance is attached to the formation and preservation of surface water quality, which is recognized as one of the leading factors in maintaining human health and well-being. In the 2000s the water quality in the Khoper river was considered as one of the best in Europe, but now the waters have become more polluted, and flow regulation (even with a low-pressure dam) may cause declension of their condition due to disruption of the water exchange process. The aim of the study was to evaluate the river flow regulation effect on the floristic diversity of vascular aquatic plants and the water quality in the vicinity of the Potlovskaya Dam near the source of the Khoper River (Penza region, Russia). The content of nutrients in water was estimated since their concentration and ratio determine the trophic status, water quality, and the state of aquatic vegetation, which is important in assessing the status of the environment of a particular region. Water chemistry and plants were sampled at two sites, one being upstream of the Dam, the other one being downstream. We have found that flow regulation by this small hydraulic installation causes some changes in the hydrochemical regime but does not affect the floristic diversity.