Home – Home – Jornals – Contemporary Problems of Ecology 2015 number 2

Adaptive strategies of sporophytes of epilithic ferns were identified on the basis of research studies and literature data. Complex analysis of photosynthetic apparatus of the plants was carried out on different levels of its organization: frond, mesophyll cells and plastids. The sporophytes’ adaptation to the environment was also characterized on different levels of organization. Two morphofunctional (MFT) and two physiological-functional types (PFT) of ferns were isolated based on their adaptability to epilithic way of living. This division reflects the adaptive peculiarities of ferns in certain biomes.

Biological peculiarities of Matteuccia struthiopteris and Onoclea sensibilis (family Onocleaceae) corresponded to the dynamics of seasonal changes in temperate climates. It was established that the adaptive strategies of the studied species varied depending on the ecological and coenotic conditions. The range of these variations was wider for Matteuccia struthiopteris than Onoclea sensibilis.

Ontogenetic structure of eight Thymus mongolicus coenopopulations in Southern Siberia was studied and assessment of their state was done. It was established that the studied coenopopulations had left-hand, central and bimodal spectrum types. It was shown that the optimal state of coenopopulations was achieved in true petrophytic steppes. Organism optimum and population optimum did not coincide in the steppes on a moving substrate and under the influence of grazing.

Upon the study of geobotanical descriptions of steppe meadows and steppes of South Urals, ecological groups of plants were differentiated on the basis of their reaction to moisture factor. The analysis of the species activity index along moisture gradient allowed us to identify the plant species that are diagnostic for zonal types of steppes: meadow steppes (order Festucetalia valesiacae) and typical bunchgrass steppe (order Helictotricho-Stipetalia). Most plants had similar activity indexes both on West-Siberian plain and in South Ural. The regional differences were caused by geographic peculiarities of the habitats: petrophytic species are common in South Ural mountain landscapes, halophytic and sand species - on West-Siberian plain.

Meromictic lakes are interesting objects for paleolimnological study, and Lake Shira is one of such lakes. In May 2011 core samples were collected from the bottom of Lake Shira and the species composition of diatom algae, which serve as bioindicators of the state of the lake, were studied. Moreover, in the year 2012 seasonal water samples and material from sediment traps were collected and the species composition of diatoms in them was analyzed. The results of the analysis showed that the lake, as in previous years of research, was dominated by Cyclotella choctawhatcheeanа Prasad. Diatoms were found twice in the studied core, above the white carbonate layers and were absent in other layers. Down to the first white layer the species living in the lake at present time were observed, including the predominant Cyclotella choctawhatcheeana. This fact, presumably, proves the consistency of the species composition of diatoms and the overall stable condition of the lake since 1946 [Popova, 1946]. Down to the second white carbonate layer the dominant species were Aulcosira valida (Grunow) Krammer and Aulcosira italica (Grunow) Simonsen. Besides them, Nitzchia sigmodea (Nitzsch) W. Smith, Fragilaria construens var. venter (Ehrenberg) Grunow were also observed at these depths, dating approximately to 1655-1690. These are freshwater species that belong to the diatoms of arctic, alpine and temperate latitudes which develop in shallow waters under moderate temperature conditions. This fact suggests that Lake Shira was less salty in the middle and the end of the 17th century than today.

Cyanobacteria containing neurotoxic saxitoxin synthesis genes were found in the coastal zone of Lake Baiakl near the village Turka for the first time. Phylogenetic analysis showed that the sequences of saxitoxin synthesis genes belong to the genus Anаbaenа Bory. Saxitoxin concentration in the water according to ELISA was 1.93 ± 0.64 mg/l. Genetic and taxonomic composition of the bacterial community of the Central part (basin) of Lake Baikal was characterized using 16S rRNA gene pyrosequencing. It was established that phylum Cyanobacteria dominated in the composition of summer bacterioplankton in both littoral and pelagic zones of the lake, but higher species diversity was noted in the plankton of littoral zone.

Seasonаl dynаmics of the phenotypic structure of a natural Epischura baicalensis Sars population from Southern Baikal by reference to the bristles number on the 5^th and 6^th segments of antenna (BNA), the length of the 5^th and 6^th segments of antenna (5LAS and 6LAS), cephalothorax length (CL) and the length of the 5 ^th pair of swimming legs (SLL) was studied. The phenotypic structure in terms of BNA, 5LAS and 6LAS was characterized by presence of bimodality, and in terms of CL and SLL had normal distribution. Seasonаl dynаmics of the arithmetic mean of the whole population was determined by changing of the number of individuals in classes with low and high values of traits. Increasing of the arithmetic mean went along with decreasing of the variability. Influence of temperature parameters on quantitative morphological traits is being discussed.

The article is based on the original data obtained during the study of soil gamasid mites (Mesostigmata) in 24 typical habitats along an altitudinal gradient at 400–1860 m a.s.l. in physico-geographic province of North Altai. The changes of main sinecological characteristics — taxonomic richness, total abundance and index of b-diversity of populations — were discussed. Analysis of the distribution of species with different types of habitats along the altitudinal gradient with regard to their number and abundance was carried out. The spatial-typological structure of soil gamasid mites populations in North Altai was characterized as inhomogeneous, and the impact of the main environmental factors on it was evaluated.

Six shrew communities of ten shrew species from open landscapes of Northern Asia were studied. The communities were characterized by similar structure, poor species composition, low number and low abundance. It was shown that the structure of shrew communities depended on the areas occupied by prairie, forested and wetland microlandscapes. The composition and dominance structure of the communities was affected by the landscape and geographical features of the habitat area. The study of population dynamics in northern Kazakhstan and in the south of West Siberia showed that two species of shrews demonstrated synchrony of population dynamics.

The taxonomic and size structure of the community of twilight and nocturnal insects inhabiting the plains of Middle Trans-Urals was studied. The studied community was represented by insects of 10 orders, predominantly small (up to 5 mm) and middle-sized (up to 20 mm). This insect community was regarded as potential food supply for the bats - a potential trophic niche. The effect of food preferences on the possibility of distribution of the nemoral bat species in the region of study was discussed.

At the end of the first decade of the 2000s the community of birds in the agricultural landscape of south boreal forest in the Middle Urals demonstrated substantial changes as compared to the population studied in 1978-1980. The community density within the agricultural landscape area increased by 1.3 times, the species richness increased by 1.5 times, the number of nesting species more than tripled. The observed changes were caused by the wide-spread occurrence of a new type of habitat areas within the agricultural landscape - fallow lands that appeared because of the reduction in agricultural production and removal of plow-lands from the agriculture. At the first stages of demutational succession of vegetation, the fallow lands have characteristics that are similar to natural shrub-and-grassland habitat areas and are highly attractive for field, grassland, shrub-grassland and forest-fringe species of birds. Thus, the reduction in agricultural production intensified an important biospheric function of the agricultural landscape - preservation of landscape diversity and biological diversity. At the same time, the number of species that became dependent on the agricultural landscape and agriculture in general (rooks, grey crows, rock pigeons) decreased notably when the agricultural production was curtailed.

Composition of helminths and infestation indexes of two species of frogs living in Western Siberia — Ranа arvalis (n = 1082) и Ranа amurensis (n = 33) — were studied. Nine helminth species, including four species of nematodes, and five species of trematodes, were found. Nematodes Rhabdias bufonis, Oswaldocruzia filiformis, Cosmocerca ornаta and trematodes Haplometra cylindracea dominated and infected both species of frogs. The moor frog also hosted Dolichosaccus rastellus, Opisthioglyphe ranаe, Pharingostomum cordatum (larvae), Parastrigea robusta (larvae) and Neyraplectana schneideri. The moor frog had higher helminth species richness and diversity compared with the Siberian tree frog. The overall rates of helminth infestation were the same in the moor frog and the Siberian tree frog. The invasion extensity was 85-100 %; the index of abundance was 5.2–27.5. The differences in infestation rates with certain species of helminths were due to the peculiarities of biology of the frog species.

The relevance of studying how non-ionizing terahertz radiation (0.1–10 THz) affects the living organisms is determined by the recent development of modern technologies that use such radiation. The aim of our study was to establish the impact of terahertz radiation on successive generations of fruit flies. The effect of terahertz radiation on the survival ability and lifespan of the Oregon-R strain of Drosophila melanogaster proved to be divergent: at early life stage they were negative and neutral, at late stages - positive. The radiation-exposed female flies showed increasing survival capability during the second half of the life of imago. Males showed low-sensitivity to radiation. There was not noted any significant difference in developing dynamics and total number of offspring between the female flies that were exposed and that were not exposed to radiation. The results of the study practically did not depend on the gender and maturity stage of the irradiated oocytes.

The characteristics of the state of Scots pine individual trees and tree stands in the areas with different levels of urbanization, including areas inside Yekaterinburg, city parks and forests outside of the city were studied. In city parks the tree stands’ state did not differ much from the state of the trees growing outside of the city, but inside the city timber volume decreased. Statistical analysis showed that this effect was due to summation of changes in stand density and trees size. Deterioration of the sanitary state of the trees due to environmental pollution and recreation accounted only for a small part of the changes in the volume stock. It was shown that mature tree stands in the city stayed resistant to the influence of negative environmental factors for a long time.

Pollen quality and cytogenetic changes in seedlings of Scots pine (Pinus sylvestris L.) were studied. The pines growing on different sites in Krivoy Rog (on an iron ore dump, near a large metallurgical plant and in the arboretum of Krivoy Rog Botanical Garden) were compared to the plants from the forestry in Ternopil region, where there is no environmental pollution. It was established that the percentage of pollen with developmental abnormalities was 3 to 4 times higher in the plants from Krivoy Rog. The percentage of pollen with abnormalities of germinating pollen tubes was 4.5 to 18.2 times higher and the percentage of cytogenetic abnormalities in dividing cells of seedling roots was 2 to 4.2 times higher as compared to the plants from the forestry in Ternopil region.

Peculiarities of population ecology of ruderal species in the urbanized environment were studied on the example of Setaria viridis. The results of the comparative analysis of morphometric status, ontogenetic and vitality structures of plant populations in an urban area were presented. Plasticity and variability of plant individuals ranged from 7.5 to 133 %. In stressful urban conditions the structural organization of plant populations was rearranged, and the living condition of plant individuals decreased by 3–4 times. Normal mature and maturing vegetative populations were formed at the first stages of the urbanization gradient, and normal transition-type populations were formed at the final stage.