Статьи

CHEMICAL SIGNALS OF CONSPECIFICS AND THEIR ROLE IN THE SEASONAL RELATIONSHIPS IN THE MONGOLIAN HAMSTER (ALLOCRICETULUS CURTATUS) (CRICETINAE, RODENTIA)

The hormonal response of males of the Allocricetulus curtatus hamster to the natural excreta (urine and midventral gland secretion [MVGS]) of conspecific females during several seasons of the year was studied when the animals were kept in the conditions of natural light and temperature. In the autumn, no significant changes in the testosterone level in the blood of males for any of the signals presented were observed. In the winter and summer, there was a trend of increasing this indicator in response to the smells of urine and MVGS of females in their diestrus state.

PERCULARITIES OF HYDROCARBON DEGRADATION BY BACTERIA ISOLATED FROM DRILL SLUDGE

Some microorganisms isolated from drill sludge (Bacillus circulans NSh, B. firmus OBR 1.1, B. firmus OBR 3.1, Solibacillus silvestris OBR 3.2, B. circulans OBR 3.3, Halomonas sp. OBR 1, and Erwinia rhapontici OBR 4.1) have been shown to be capable of degrading crude oil, mineral oil, and diesel fuel. It has been established that the B. circulans NSh and B. firmus OBR 1.1 bacteria degrade 62 and 32% of crude oil, respectively, in an alkaline medium (pH 9) for 14 days and degrade 42 and 22%, respectively, in a saline medium (10% NaCl).

ABUNDANCE OF TETRAX TETRAX L. 1758 (OTIDIDAE, AVES) IN THE SARATOV REGION

Based on the count data obtained by various methods and their statistical processing, the abundance of the autumn population of Tetrax tetrax in the Saratov Trans-Volga region was estimated from the late 1990s till now. From 2012 to 2016 it averaged about 30,000 individuals, and in the Right Volga Bank region it was one or two orders lower, the species’ distribution there was sporadic. When studying the T. tetrax abundance dynamics, an increase in its population on the studied territory in the first half of the 2000s was established.

TROPHOMETABOLIC POTENTIAL OF ESENIA FETIDA SAVIGNY, 1826 (OLIGOCHATA, LUMBRICIDAE) CAUSED BY COPPER NANOPARTICLES AND COPPER OXIDE IN THE SOIL

Depending on the concentrations of Cu and CuO nanoparticles (NPs) (50, 100 and 500 mg/kg dry matter) introduced into an artificial soil, the influence of Cu NPs upon E. fetida is much stronger than similar CuO doses. In particular, this was reflected in higher mortality (80%) and a 50% weight reduction of the worm (p ≤ 0.05) when the dose of Cu NPs was 500 mg/kg, whereas the validity limit of the test (20%) was not exceeded with a similar dose of CuO. Copper hyperaccumulation in the body of E.

SPECIFIC COMPOSITION AND ABUNDANCE OF THE WINTER ZOOPLANKTON IN THE RYBINSK RESERVOIR

The specific composition, seasonal dynamics, vertical and horizontal zooplankton distribution were studied in the pelagic zone and littoral of the Rybinsk reservoir in the winters of 2008 – 2016. The zooplankton abundance was found to be low (the abundance < 10,000 ind./m3, the biomass < 0.1 g/m3), by an order of magnitude lower than the values recorded in the 1970 – 1980s. As earlier, the abundance peak was observed in March. The cryophilic Cyclops kolensis prevailed among the crustaceans. A reproducing population of C.

VIRAL INFECTION OF PICOCYANOBACTERIAE IN THE RYBINSK RESERVOIR DURING THE FREEZE-UP PERIOD

The virioplankton and planktonic picocyanobacteria abundances in the deep and shallow waters of the Rybinsk reservoir during the freeze-up period (the water temperature within 0.3 - 0.9°C) varied within (37.1 - 84.1)×106 ((57.3±2.1)×106 on the average) particles/ml and (13.5 - 75.0)×103 ((48.7±3.4)×103 on the average) cells/ml, respectively. The fraction of picocyanobacteria with viruses attached to their cell surface was 6.5 - 29.0% (12.0±0.8% on the average). The proportion of visible infected cells was 0.7 - 7.6% (2.2±0.3% on the average) of the numbers of picocyanobacteriae.

REPRODUCTIVE BIOLOGY OF CYPRIPEDIUM GUTTATUM SW. (ORCHIDACEAE, MONOCOTYLEDONES) AT THE NORTHERN BORDER OF ITS HABITAT

The paper presents data on the reproductive biology of Cypripedium guttatum Sw. (Orchidaceae) in the Komi Republic, at the northern border of its habitat. Bees (Lasioglossum calceatum and L. brevicorne) are pollinators of C. guttatum in the region. The pollination efficiency is 21%. C. guttatum seeds are the largest ones among those of other orchid species in the region (1.11×0.22 mm). The size of seeds depends on the growing conditions of mother plants. The seed productivity of C.

ANALYSIS OF THE AFFORESTATION STATUS IN THE ARID CONDITIONS OF WESTERN KAZAKHSTAN

The current status of the forest fund is considered, the agroforestry melioration potential of the Western Kazakhstan region is assessed. The modern silviculture stage on the area studied is described. The biodiversity depletion is noted, the possibilities of conservation of the existing natural and artificial protective plantings in the extreme conditions of the Western Kazakhstan region are assessed. Floodplain forests, chopping sand massifs and estuary-type depressions, gully and ravine forests are considered as key botanical and landscape territories of the surveyed area.

ON THE CASTOR FIBER (CASTORIDAE, MAMMALIA) ACTIVITY INFLUENCE ON THE ECOSYSTEM BIODIVERSITY OF SMALL RIVERS IN THE FOREST-STEPPE ZONE

Preliminary data on the Castor fiber activity influence on the ecosystem biodiversity of small rivers in three steppe clusters within the State Nature Reserve “Volga forest-steppe” were obtained. With zooplankton, amphibians and fish as examples, it was shown that after beaver-made ponds had appeared, the abundance of all these groups increased. In old ponds, the fish abundance decreases whilst the amphibian one continues to increase. In drained ponds, the zooplankton and amphibian abundance decreases while the fishes become more numerous, due to the appearance of better flowability.

PARTICULARITIES OF THE GREAT SPOTTED WOODPECKER (DENDROCOPOS MAJOR) (PICIDAE, PICIFORMES) WINTER SPATIAL DISTRIBUTION IN SARATOV CITY

The spatial distribution of the Great Spotted Woodpecker in Saratov city was studied in the winter seasons of 2004-2012. The bird distribution was either aggregated or random. The multi-year wintering sites of the Great Spotted Woodpecker are associated with the gully network of the suburban woodland park, city parks, forest belts and old gardens. Dependence between the spatial distribution and pine harvest was found. The bird distribution was grouped in productive years and random in lean years, respectively, because of woodpeckers’ movements to the woodland park and built-up areas.

Pages