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Modern status and importance of forest-agrarian landscapes of North-Eastern Yergeni. – Baktasheva N.M. and Dordzhieva S.G. – A survey was made in the North-Eastern Yergeni, the marginal zone of the Chernozemelsky nucleus of desertification, which nowadays endures considerable anthropogenous loadings. The paper contains data about agroecological division into districts and forest amelioration land arrangement. The dynamics of expansion of the plantation area, cereal crop capacity and climate aridity (NIA) was revealed. Afforestation techniques for degraded arable lands in the North-Eastern Yergeni are recommended.
Key words: Yergeni Hill, agroecological division into distrists, climate aridity, plowed field, pasture, Republic of Kalmykia.
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Seasonal dynamics of population density and biomass of Hemidiaptomus rylovi Charin, 1928 (Copepoda, Calanoida) in temporary water bodies in the Saratov region. – Yevdokimov N.A. and Yermokhin M.V. – The seasonal dynamics of the population density and biomass of Hemidiaptomus rylovi in temporary water bodies in the Saratov region with various hydrological modes is analyzed. Peculiarities of the dynamics of life-cycle stages are revealed. A low population density and a low mortality of copepodit stages are noted.
Key words: Hemidiaptomus rylovi, population density, temporary reservoirs.
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New data on the vegetative cover of the Samara region. – Lysenko T.M. – Earlier published data on the vegetative communities of the Samara region are critically analyzed. Defects of the nomenclature of resolved phytosociological units are corrected.
Key words: plant communities, phytosociological units, nomenclature, Samara region.
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Testate amoebae community structure in a sphagnum quagmire of a northern tundra bog (Karelia, Russian Federation). – Mazei Yu.A., Bubnova O.A., and Chernyshov V.A. – In a heterogeneous sphagnum quagmire in a hummock-lake bog of the northern taiga (near Chernaya Reka village, Louchi district, Karelia), 39 testate amoebae species have been identified. Two community types were distinguished, corresponding to different moisture contents. In the upper 0 – 3 cm sphagnum horizon in all the community variants, the mixotrophic species Hyalosphenia papilio, Archerella flavum, Heleopera sphagni predominate. In the lower horizons the dominant species in the communities are different: in the most wet biotopes – Phryganella hemisphaerica prevail, in medium moisture conditions – Hyalosphenia elegans, Nebela tincta major predominate. The maximal abundance (85,200 – 113,200 ind. per gram of absolute dry sphagnum) develops in the medium-moisture Sphagnum lindbergii biotope, the minimal one (36,000 – 65,100 ind. per gram) – in submerged Sphagnum riparium at the edge of the quagmire and in hollows.
Key words: testate amoebae, community structure, sphagnum bogs, northern taiga.
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The experience in many year dynamics of mammal number studying. – Okulova N.M. – The 4 types of periodes in many year dynamics of mammal number are displayed: 1) microdynamics (to 10 – 12 years), 2) mesodynamics (during some ten-years), 3) macrodynamics (some hundred years), 4) megadynamics (some thousand years and above). The methods of mathematical statistics and the method of «climatic fields» for factors dynamics studying and number cycles characterizing in mesodynamic scale on 20 – 70 years rows are proposed. The trends of number dynamics as a new quality in comparisons with microdynamics with the leading role of abiotic factors in trend formation are discerned. The method of «climatic fields» allows to reveal both the local and the specific characteristics of optimum and pessimum conditions for species existence.
Key words: many year dynamics, mammals, factors, statistical methods, method of «climatic fields», forecasting.
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On habitat distribution of three green frog species of the Rana esculenta complex in the Volga River basin. – Ruchin A.B., Lada G.A., Borkin L.Ya., Litvinchuk S.N., Rosanov Yu.M., Ryzhov M.K. and Zamaletdinov R.I. – The habitat distribution of three species of the Rana esculenta complex is considered. Rana ridibunda was recorded in water bodies of various size, origin, and character. However, the species avoids small water bodies situated deeply in a forest. In forest landscapes, the lake frog inhabits ponds, sand pits, and other water bodies. In contrast, R. lessonae prefers various forested water bodies of natural and anthropogenic types. In open anthropogenic water bodies, R. ridibunda predominates, whereas R. lessonae is not numerous. R. esculenta more often occurs in forest and edge sites; the species is common in anthropogenic water bodies as well. Despite its hybrid origin, the edible frog is characterized by the least diversity of habitats in both natural and urbanized landscapes, in comparison with both the parental species, R. ridibunda and R. lessonae.
Key words: complex Rana esculenta, Rana ridibunda, Rana lessonae, Rana esculenta, biotopes.
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Role of alien species in feeding of the piscivorous fishes in the Kuybyshev water reservoir. – Semenov D.Yu. – The paper is the first to present information on the changes in feeding for the most widespread piscivorous fishes in the Kuybyshev water reservoir. Special attention is paid to the role of alien species in feeding of the piscivorous fishes. All the piscivorous fishes studied consume alien species to a certain degree; mass piscivorous fishes use more alien organisms as prey than less common ones. Among these alien species the highest frequency of occurrence in the feeding spectrum is peculiar to caspian tyulka and round goby.
Key words: alien species, piscivorous fishes, Kuybyshev water reservoir, food chains, feeding spectrum, adaptation.
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Effect of salt and water stress on the germination of Alfalfa (Medicago sativa L.) seed. – Ghasem Ali Dianati Tilaki, Behzad Behtari, and Behnam Behtari. – The effect of three different levels of salt (NaCl) and polyethylene glycol 6000 on the germination of Medicago sativa L. seeds was studied. The electrical conductivity (EC) values of NaCl solutions were 0.0, 6.93, 11.55, and 16.94 µs/cm-1. Drought conditions were induced by PEG 6000 at the same water potential of 0.0, -0.2, -0.4, and -0.8 MPa. The object of the study was to determine factors responsible for germination due to salt toxicity or osmotic effect. Our results revealed that NaCl and PEG treatments had significant effect on all the investigated characters. A lower germination percentage was obtained from PEG compared with NaCl at an equivalent water potential in each treatment. Non-germinated seeds under various NaCl treatments when transferred to distilled water recovered significantly, indicating little ionic effect of salinity on seed germination and viability. Germination inhibition, therefore, appears to be osmotic. A similar recovery response was noted when seeds from a PEG solution were transferred to water. PEG had no toxic effect since all the seeds germinated when PEG stress was removed.
Key words: Germination, Medicago sativa, recovery, salt and drought stress.
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Duration of development of some species of Ceratoppia and Nanhermannia (Acari, Oribatida) at various temperature modes. – Ermilov S.G. – Three oribatid mites species (Acari, Oribatida) were cultivated to study their embryonic and postembryonic development. The cultivation was performed at a 100% humidity, two different temperatures, and a forage surplus. It was found that Ceratoppia bipilis development from egg to adult took about 64 – 65 days at 17°C, 43 – 44 days at 20°C, C. quadridentata development lasts about 88 – 89 days at 17°C, 57 – 58 days at 20°C, while Nanhermannia coronata development took about 148 – 149 days at 20°C, and 112 days at 22.5°C. The theoretical duration of development was calculated for each species at different temperature modes.
Key words: oribatid mites, Ceratoppia bipilis, C. quadridentata, Nanhermannia coronata, duration of development, temperature mode.
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On a find of Silene cretacea Fisch. ex Spreng., Caryophyllaceae in the Saratov region. – Nevski S.A., Davidenko O.N., Berezutski M.A., and Arkhipova E.A. – The paper is devoted to a find of Silene cretacea Fisch. ex Spreng., Caryophyllaceae in the Saratov region, which was not found in this region more than 150 years back. Data about the modern status of the population are given. Silene cretacea is recommended to be included into the Red Book of the Saratov region.
Key words: Caryophyllaceae, Silene cretacea, rare species, cenopopulation, Saratov region.
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