Home – Home – Jornals – Contemporary Problems of Ecology 2014 number 2

Among the major changes induced by human beings, biotic homogenization is gaining popularity at regional as well as global level. Biotic homogenization is a multifaceted process which results from species extinction, introduction and environmental modification often induced by human beings. This human mediated introduction of alien species and the extirpation of native species, either independently or in combination have caused loss of taxonomic regional distinctiveness among formerly disparate faunas and floras. Ample evidence reveals that extent of homogenization differed between various ecosystems and taxa, as well as in different regions. Although biotic homogenization leads to increase in species richness at local level but it also causes loss of diversity at global level (i. e., paradox of gaining species but loosing diversity). Potentially biotic homogenization could affect any of the many processes in communities that vary in space and time, such as spatial subsidies and food-web dynamics, and thereby have cascading effects elsewhere on the landscape. Biotic homogenization does have relevance to conservation as it has utility in reserve selection and management. Current knowledge pertaining to patterns, mechanisms and implications of biotic homogenization is highly variable across taxonomic groups, but in general is incomplete. This article is an attempt to review literature pertaining to patterns, mechanisms and implications of biotic homogenization.

For the purpose of faunal zoning of terrestrial vertebrates, the part of Northern Eurasia that belonged to USSR was divided into 245 mapping units in 1991. Mapping units were marked on the World Vegetation Map at a scale of 1 : 20 000 000. Each mapping unit occupied a territory within the limits of a natural subzone with a latitudinal distance of 10°. Lists of vertebrate species were compiled for each unit. Jaccard similarity coefficients were calculated for these lists; the coefficients were used as the basis for performing cluster analysis of fauna of the mapping units. The results of calculations were used to create a hierarchical classification, which includes five faunistic regions and seven subregions, 18 provinces and 14 districts. Environmental factors that correlate with faunistic heterogeneity on the studied territory were described. The proposed zoning was 2-2.5 times more informative than previously developed schemes; it took into account 57 % of the variance of the similarity coefficients of the faunas of specific regions (coefficient of multiple correlation was 0.75). Connection with environmental factors and natural conditions may explain 83 % of the heterogeneity of the fauna (correlation coefficient is 0.91). Having compared the results of zoning that were carried out for different classes of terrestrial vertebrates (amphibian, reptilian, birds and mammals), we found significant similarity between the causes of fauna heterogeneity (zonal features, provinciality, heat availability, and their combined effect). However, the differences in tolerance to the environment among the studied animal classes resulted in substantial discordance of the boundaries of the described taxa and their hierarchy. Classification of 1243 species of terrestrial vertebrates living on the site was compiled according to similarity of their occurrence (the average in the lower taxon faunistic zoning). It contains three types of distribution: Northern, Middle and Southern. These in turn are divided into 7 subtypes and 13 classes. Informative presentation of the classification is equal to 53 % of the variance (correlation coefficient - 0.73).

For proper evaluation of data received during the ecological monitoring of space-rocket activities it is necessary to take into account the natural variability of the chemical properties of soils common for the territories used for landing of launch vehicles’ separated parts. The paper presents the results of the soil-geochemical studies in mountain tundra in the Altai Republic which have been carried out in the impact zone where launch vehicles’ second stages fall. Based on the data obtained during the research and the results of laboratory experimental investigations the ecological buffer capacity of soils in relation to the rocket fuel has been quantified for one of the monitoring sites.

Peculiarities of forming and growth of post-fire larch (Larix sibirica Ledeb.) forests at the southern range of their distribution in Northern Mongolia were studied. Regularities of the stand structure and dynamics of biological productivity were analyzed and discussed in the paper. It was proved that the structure of the organic mass of the post-fire herb-carex type larch forests at the southern border of forest vegetation distribution is closely related to their biometric indices: age, density and productivity. In comparison to tree stands from other areas of forest vegetation the total phytomass stock of larch phytocenoses increases by zonal gradient from forest-tundra border to Transbaikalian southern taiga and northern regions of Mongolia. Regeneration of forest cover by the edificator and formation of the original larch coenopopulation are positive trends from the ecological point of view, because Siberian larch forests in the area have sufficiently high growth energy and rate of phytomass production during young and middle-age periods, absorbing twice more carbon from the atmosphere than mature forests. It also has positive values of carbon balance and total decomposition of organic matter (“in-out” parameters).

The paper presents the results of studies of the anthropogenic factor (hunting) influence on the population dynamics of the red fox in Western Siberia in the XVII and XX centuries. The relatively stable population rate which has not changed significantly for the last 400 years was noted.

The spatial-temporaldistribution of the dragonfly Coenagrion armatum on the lake Fadiha (Barabinskaya forest-steppe) with border type of overgrowing was studied. It was shown that the local population of this species is divided into two topical groups. In one group dragonflies develop in the water area and do not migrate to the shore after metamorphosis. In the other group dragonflies develop in the reeds and migrate to the shore for additional feeding after metamorphosis.

Legacy effect of land use history on the contemporary state of the plant cover in the southeast of Belarus was studied. Forest ecosystems formed on arable lands, meadows and other non-forest lands are characterized by: few forest species and many synanthropic species, high level of invasion, low occurrence of late successional species, braking of successions.

The paper deals with the peculiarities of steppe biocenoses soil algae grouping makeup with various post-pyrogenic development periods after one- and two-fold fire effect on the territory of “Askania Nova” Biospheric National Park natural core set. It was determined that pyrogenic factor had essential impact on steppe algo-groups formation stimulating their ability to quickly adapt to changing environmental conditions. Number of species, major segments relationship, dominant complex compound as well as life-form spectrum were different in post-pyrogenic algo-groups. In steppe biocenoses, that had been twice exposed to pyrogenic effect, the increasing of total amount of algae species, especially heliophilous Cyanophyta, was observed. Among the dominant species of the studied biocenoses, specimens with various degrees of resistance to pyrogenic factor were noted. The most saturated ones in all researched biocenoses were formed in summer and spring on the basis of apparent algae community structure. In summer the most variable species were Cyanophyta, Chlorophyta, Baccilariophyta. In spring the amount of Cyanophyta increased in communities, while in autumn these were Eustigmatоphyta and Xanthophyta varieties. The largest amount of algae varieties was registered on the surface of 5-cm soil layer. At the deeper layer (up to 15 cm) the amount of species of Cyanophyta variety decreased dramatically in contrast to other species, especially Baccilariophyta.

Assessment of ecogeographic variability and differentiation of Japanese dwarf pine Pinus pumila (Pall.) Regel (Pinaceae) populations on the Kamchatka Peninsula and Koryak was carried out using morphological and phenotypic characters of mature seed cones. In the sample of cones from 10 сoenopopulations viability of seeds was determined using radiographic method. Latitudinal phenotypic differentiation between сoenopopulations was revealed. Lower seed viability due to high percentage of seeds without embryos or with underdeveloped embryos was recorded in north-eastern populations. The average proportion of viable seeds in the region wass 52 %, while in the north-eastern populations this parameter was lower - 6-24 %.

Influence of different doses (100 mg/kg, 300 mg/kg, 450 mg/kg, 600 mg/kg) of pharmaceutical antibiotics (benzylpenicillin, pharmazin, nystatin) on the number of microorganisms of the chernozem was studied through model experiments. All studied doses of antibiotics have certain inhibitory effect on the number of soil microorganisms. Linear dependence between doses of antibiotics and changes in the number of soil microorganisms was established. As for resistance to pharmaceutical antibiotics the studied groups of soil microorganisms formed a row (high concentration): Azotobacter > amylolytic bacteria > ammonifying bacteria > micromycetes.

Morphological variability of leaf apparatus in response to different light intensity is determined not only by the available solar radiation, but also by the complex of adaptations to other environmental factors. There is still not enough information about the possible effect of the natural habitats climatic characteristics on the differences between shadow and light leaves. In this paper we investigated lamina form differences of 15 species of the genus Ficus L. The relationship between plasticity and climatic conditions of the natural habitats was established. We also found a positive relation of phenotypic variability with the annual precipitation amount and amplitude and with temperature seasonality.

As a result of phytopathological investigation of birch (Betula pendula) stands in Krasnoyarsk group of areas (south of Middle Siberia) the newly appeared and existing nidi of bacterial dropsy were discovered. The influence of growth conditions on infection rate in birch forests and the relation of disease prevalence with characteristics of forest inventory were observed. The patterns of tree affection within the limits of phytocenoses and the influence of disease on sanitary state of birch forests were discussed.

The composition and content of groups of phenolic compounds (free flavonol aglycones, flavonol glycosides, free and bound phenolic acids, hydroxycinnamic acids and their esters) and individual components (quercetin, kaempferol, rutin, hyperoside, isoquercitrin, avicularin, gallic, protocatechuic, chlorogenic, p-coumaric, o-coumaric and cinnamic acids) in the leaves of Spiraea media Fr. Schmidt, S. chamaedryfolia L. and S. hypericifolia L. growing in Novosibirsk in the areas with high and background levels of industrial pollution were studied. The differences in the phenolic composition and content were revealed. Total phenolic content in the leaves of the studied species in polluted areas was 1,6 (S. hypericifolia) and 2,4 (S. media , S. chamaedryfolia) times lower compared to the plants studied under baseline conditions. Decrease in the phenolic content of S. media was due to flavonol glycosides (mostly rutin). As for S. chamaedryfolia and S. hypericifolia, decrease was due to hydroxycinnamic acids and their esters.

Plant communities that included Astragalus sericeocanus were studied. The data on ontogenetic structure, quantity of cenopopulations and seed productivity of individuals were given. It was also revealed that the habitats on the northern shore of Lake Baikal are characterized by high phytocoenotic diversity with codominating and dominating of A. sericeocanus . The state of cenopopulations and parameters of seed productivity showed that northern habitats have considerably favourable climatic conditions which are optimal for the growth of the studied species.

Communities of small mammals of Eravninskaya forest-steppe in the south of Vitim upland (Western Transbaikalia) were studied. Fourteen species of shrews and rodents were detected. Communities of small mammals in the cold forest-steppe conditions of Vitim upland were characterized by low indices of species diversity and evenness, and also by simplified dominance structure.

The storing of Siberian pine nuts by Nucifraga caryocatactes is a key factor of Pinus sibirica distribution and restoration at the East Sayan. The amount of Pinus sibirica young generation and murine rodent number were determined in drying stands, in burnt-out forests and in cut-over lands of different age to assess the zoochoric activities of the nutcracker and to define the impact of small mammals on the process of Pinus sibirica regeneration. A complex analysis of the received data allows us to update the known information about nutcracker activity and preferences in distribution of nut stocks and their influence on the development of Siberian pine seedlings.

Morphostructure and biochemical parameters of Scots pine (Pinus sylvestris L.) Northern taiga population under permanent excess soil moisture conditions were studied in estuary region of Northern Dvina River. Variational distribution curves were built. Levels of endogenous and individual variability were assessed.

Comparative assessment of eco-geochemical condition of the soils of Ulyanovsk city park territories was given. Some physical and chemical indicators of soil environment (рН, exchange bases, humus, sulfates, chlorides, etc.) were defined. The main problems of the ecological state of the parks under the conditions of urbanization were revealed.