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Estimate of the vegetation dynamics in the Volga-Akhtuba floodplain (with a transection near the Bolkhuny village as an example). – Bondareva V. V. and Golub V. B. – Our repeated observations (1955, 1971, 1982, and 2013) on the transection crossing the Volga-Akhtuba floodplain near the Bolkhuny village (the Astrakhan region) are analyzed. The highest degree of xerophytization of the vegetation was noted in 2013.
Key words: Volga-Akhtuba floodplain, water stream regulation, xerophytization of vegetation.
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Status of the Calophaca wolgarica (L.) Fisch. ex DC. (Fabaceae, Angiospermae) cenopopulations in the Volgograd region. – Kashin A. S., Petrova N. A., Shilova I. V., Grebennikov K. À., and Kulikova L. V. – The cenopopulations of Calophaca wolgarica in the Volgograd region were monitored. They are confined to areas with light-brown soils and a horizontal surface, or (sometimes) to more or less steep slopes of various exposure beams. The communities with C. wolgarica are shown to be sparse (crops and bushes). The numbers of C. wolgarica individuals per a unit area in the cenopopulations vary from 14 to 122 ind/100 m2. The cenopopulations are predominantly mature, with low self-renewal. They are characterized by a mosaic and aggregated spatial structure. The main factors threatening the existence of these cenopopulations are: overgrazing, fires, direct destruction of plants while road works, an increased degree of the projective cover of the related plants in phytocenoses, adverse (for seed reproduction) weather conditions during dissemination. The presence of sites with a disturbed top soil layer contributes to effective seed reproduction.
Key words: Calophaca wolgarica, monitoring, age structure of populations.
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Statistical analysis of the inhomogeneity of the spatial distribution of trees. – Kislov D. E., Prilutsky A. N., and Brizhataya A. A. – A new method for local highlighting of trends of the spatial development of forest cenopopulations is proposed. On its basis, a statistical criterion to verify hypotheses of the character of spatial distribution of the constituent objects has been developed. An effective algorithm for computing the statistics of this criterion has been designed, and a physical interpretation of this statistics is given, opening opportunities of the use of our approach to build models and heuristic forecasts of the vegetation cover development.
Key words: vegetation cover dynamics, randomness criteria, spatial distribution.
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Structure dynamics of the breeding population of larks (Alaudidae, Aves) in a semi-desert of the Saratov Trans-Volga region. – Oparin M. L., Kondratenkov I. A., Konyushkova M. V., Oparina O. S., Mamayev A. B., Trofimov I. A., and Trofimova L. S. – According to our data of the density of breeding pairs of five lark species obtained from route accounting, the dynamics of their population in the Mezhuzensky and Uzensko-Dyurinsky landscapes of the semi-desert in the Caspian lowland is considered. Our five-year accounting was carried out in key sites of a 25 km2 area, with mapping and description of soils and vegetation using remote sensing techniques. Our comprehensive works on these key areas have revealed the dynamics of individual lark species characteristic of the north-west part of the Trans-Volga part of the Caspian lowland and related it to changes in the level of vegetation of the plant component of separate landscape tracts as depends on the moisture level in certain years. It is shown that in the monotonous plain conditions, an important role in the distribution of the specific population of larks is played by the meso and micro-relief, which determines the soil salinity, the distribution of moisture and vegetation groups (which predetermine features of bird habitats). The interannual variability of the population structure of larks is shown, which, in the modern conditions of consistently low anthropogenic pressure, is determined by the specific weather of certain years, which causes the level of vegetation and, therefore, changes in the nesting conditions of birds in specific habitats.
Key words: Caspian lowland, Alaudidae, soil, vegetation, habitat, remote sensing, population dynamics.
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Phytoremediation potential of some higher aquatic plants in Saratov Region water bodies. – Paydulova J. A. and Turkovskaya O. V. – A comparative analysis was made of the numbers of microbial plankton, benthos and periphyton in several plants growing in the Volga and Latryk rivers (the Saratov region). The highest microbial density was found on the surface of plants in both water bodies. Four strains were isolated from the periphyton of higher aquatic plants, which were highly degradative to phenol (95 – 99%). The activity of some enzymes able to oxidize phenolic compounds was revealed in the examined plants. On the basis of the characteristics studied, the highest potential for use in the remediation of water bodies polluted with phenolic compounds was shown by fennel-leaved pondweed (Potamogeton pechinatus), hornwast (Ceratophyllum demersum), and mealein (Myriophyllum spicatum).
Key words: higher aquatic plants, periphyton, hydrocarbon-oxidizing microorganisms, phenol-oxidizing microorganisms, plant oxidative enzymes.
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Radionuclide accumulation in mushrooms over the territory of the «Pleshcheyevo Lake» National Park. – Pelgunov A. N. and Pelgunova L. A. – The paper presents data on the accumulation of radionuclides (of both natural and anthropogenic origin) in five mushroom species. According to our data, the area can be considered environmentally pure, and the man-made radionuclides found mainly belong to the global nuclear fall-out from nuclear weapons tests and the Chernobyl accident traces.
Key words: radionuclides, mushrooms, «Pleshcheyevo lake» National Park.
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Climate changes and the virgin vegetation dynamics in the Northern Caspian Lowland. – Sapanov M. K. and Sizemskaya M. L. – A wavy trend of the increasing phytomass productivity of the desert, semidesert and steppe communities growing on the soils of the solonetzic complex was discovered in the Northern Caspian region during the 60-year observation period (1952 – 2013). The trend is mostly caused by the winter season warming (which has changed the soil moisture redistribution mechanisms) and the improved hydrothermal conditions in the spring months (the intense plant growth period).
Key words: arid territories, climate changes, productivity of plants.
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Influence of the genesis of stands of trees on the wood-destroying fungi biota in the «Buzuluksky Bor» National Park. – Safonov M. A. – The Buzuluksky Bor is a unique coniferous forest massif located within the steppe zone of the Trans-Volga region. Peculiarities of its genesis have an impact on all components of its ecosystems, including the wood-destroying fungi biota. The mycobiota is characterized by the high specific diversity, the proximity of its specific composition to the mycocomplexes of the forest-steppe part of the region, and the presence of some relict species. This allows the Buzulukskyi Bor to be considered as the southern outpost of the zonal forest-steppe mycocomplex and as a refuge of a number of fungi species, including those not trophicaly connected with pine wood.
Key words: wood-destroying fungi, relict species, Buzuluksky Bor, genesis of stands of trees.
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Importance of the biogenic element form ratio for assessing the current status of the Rybinsk Reservoir. – Stepanova I. E. and Bikbulatova E. M. – Various ratios of the biogenic element forms in the Rybinsk Reservoir are analyzed and the ecological status of this reservoir is assessed on the basis of our materials collected in 2001 – 2011. The total nitrogen (TN) to total phosphorus (TP) ratio is the most informative parameter with an average value of 17.0 for all stations during the observation period, which indicates both the elements not limiting the phytoplankton development in the reservoir. The high values of the absolute concentration of nitrate nitrogen and its fraction in the total mineral nitrogen (which are important indicators of the increasing eutrophication) as well as the percentage of inorganic phosphorus in the Volga part and the upper reaches of the Sheksna part, allow us to characterize their status as eutrophic.
Key words: nitrogen, phosphorus, reservoir.
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American mink – Neovison vison Schreber, 1777 (Carnivora, Mustelidae) in the floodplain and right-bank ecosystems of the Volgograd reservoir: seasonal changes in its spatial structure, nutrition and temporal activity. – Filipechev A. O., Belyachenko A. V., and Savonin A. A. – As a result of our long-term research (1978 – 2013), regularities of the spatial structure of some American mink (Neovison vison Schreber, 1777) populations, its nutrition, daily and seasonal activity in the floodplain and right-bank ecosystems of the Volgograd reservoir have been revealed. The average sizes of minks’ home ranges are 22.4 ha for females and 34.7 ha for males on the islands. On the reservoir’s right bank, they are significantly larger, namely, 51.3 and 75.5 ha, respectively. The mink’s diet is based on three forage groups: mammals (primarily mouse-like rodents) (18.8 – 42.7% BIO), fish (5.6 – 39.1% BIO), and amphibians (17.1 – 51.7% BIO). Other food could be significant in single seasons only. On the floodplain islands, the mink is most active in the spring and autumn, while its summer activity decreases, and in the winter the daily rhythm clearly have two peaks, the morning and evening ones. On the right bank, due to the food scarcity in some seasons, the activity peaks are smooth.
Key words: distribution, home range, occurrence frequency, biomass, trophic niche, daily activity, Saratov region.
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Social structure of the Siberian roe deer – Capreolus pygargus Pall., 1771 (Cervidae, Mammalia) in the north-east of its habitat. – Argunov A. V. – The composition of groups of the Siberian roe deer population inhabiting the northern limit of its habitat was investigated. The sex-age pattern was identified in the groups. Seasonal specific features and the dynamics of changes in the social structure of the species in this region are given. The size of groups of the Yakut roe deer is shown to be similar, in general, to the indices of flocking in other populations of the species. This indicates the uniformity of the social organization of this species population over the whole range.
Key words: females, males, calves, groups, index of flocking.
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Lead phytotoxicity in the presence of humate. – Kirdey T. A. – The influence of a humic peat preparation on wheat (Triticum aestivum L.) adaptation to high concentrations of lead nitrate (1 and 2 mmol/L) under vegetation experiment conditions in an aquatic culture was studied. Our humic peat preparation was found to accelerate the wheat plant growth by 1.5 – 1.8 times. An increased phytotoxicity of lead nitrate in the presence of the humate was found. The lead content in the plant overground organs increases by 4.5 – 10 times. The property of our humic preparation to increase lead accumulation in the plant overground organs can be used for the phytoremediation of contaminated soils.
Key words: heavy metals, phytotoxicity, humates, humic preparations.
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