Статьи

VITALITY DYNAMICS OF TULIPA GESNERIANA L. (LILIACEAE, LILIOPSIDA) POPULATIONS IN THE LOWER VOLGA REGION AND ADJACENT TERRITORIES

The vitality of 38 Tulipa gesneriana populations in the Lower Volga region and adjacent territories was monitored during four agricultural seasons (2013 - 2016). A significant variability of this parameter, correlated with certain geographical trends, is shown within the territory surveyed. Two population clusters were revealed, differing by oppositely directed responses to external factors. A similar variability character was also obtained from ordination of the studied cenopopulations using the average values of morphological traits by means of the principal component analysis.

ON THE DISTRIBUTION OF CAULINIA MINOR (ALL.) COSS. ET GERM. (HYDROCARITACEAE, LILIOPSIDA) ON THE TERRITORY OF THE NIZHNY NOVGOROD REGION

The results of our analysis of the Caulinia minor distribution in the Nizhny Novgorod region on the basis of published sources, herbaria samples and the authors’ original data are presented. The species preferring water bodies with well-warmed shoals and high mineralization levels was revealed. The species entering the Red Data Book is justified due to its location on the border of the habitat. It is proposed to promote the rarity status of the species in the region; recommendations on its conservation are given.

SALINITY INFLUENCE ON CHIRONOMID LARVAE (DIPTERA, CHIRONOMIDAE) IN THE CRIMEAN HYPERSALINE LAKES

The paper summarizes the results of our long-term research (2007 - 2015) of chironomids in 38 saline and hypersaline lakes in the Crimea. Chironomid larvae were found at salinities up to 340 g/l, and their occurrence frequency decreased as salinity rose above 30 - 50 g/l. Four species, namely, Baeotendipes noctivagus, Cricotopus gr. cylindraceus, Tanytarsus gr. Mendax, and Paratanytarsus gr. quantuplex were identified.

HISTORY OF BIRD STUDIES IN THE VOLGOGRAD REGION

On the territory of the contemporary Volgograd region, bird studies began in the second half of the 18th century. First ones were conducted by the heads of large academic expeditions, namely: S. G. Gmelin (1771, 1777), I. I. Lepekhin (1771, 1795), and P. S. Pallas (1788). Therefore, this period of ornithological research can be called the “academic period”.

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.

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