Home – Home – Jornals – Contemporary Problems of Ecology 2015 number 3

The main distribution patterns of dryad tundras in high mountain regions, where they form a large cryophilic florocenotic system, were studied. The cenoflora of dryad tundras comprises 286 species of vascular plants, among which there are several marker groups that indicate dryad tundras in general and their regional features in particular. These groups also reveal floristic connections with other phytocenotic systems that form a unified mountain-tundra complex.

The comparative study of meadows on long fallow lands and natural meadows from the subtaiga subzone of the West Siberian plain was carried out using the species activity and occurrence indices. It was shown that floristic composition of grass communities depended on their previous agricultural usage. Groups of differentiative species for long fallow and natural meadows were determined. At the same time, a group of species showed similar occurrence and activity indices in all the variants of meadow communities. This fact proves the unity of meadow vegetation on the territory of the subtaiga subzone of the West Siberian plain.

The role of arboreous species in the functioning of lowland needle–fir broad–leaved forest landscapes of the southern Primorye was estimated. Forest stand structure as well as biocycle parameters (measured in main structure-functional points called parsells) of the needle–fir–broad–eaved forests and soils were investigated. The macroelemental composition of assimilating organs of trees (leaves and needles) and characteristics of leaf fall and litter were studied. It was established that broad–leaved trees with high ash content, especially hornbeam and Actinidia, significantly increase the capacity and speed of the biocycle. Therefore, such trees support the biological productivity and stable functioning of the studied landscapes.

Distributions of 20 aquatic associations in the Danube-Tisza-Danube hydrosystem were mapped using published data and personal field observations resulting in 562 georeferenced collection sites. The Maxent modeling software was used to estimate the current potential and future distribution of the associations by the year 2050 (2 x CO₂ climate conditions, CCM₃ model). Based on the Principal Component Analysis (PCA), climate data at the collection sites described climatic preferences of different aquatic associations. The central-eastern part of the investigated area showed the most favorable climatic conditions for aquatic vegetation growth and thus the highest potential for future biodiversity. The stands of Lemnetum trisulcae, Ceratophyllo-Azolletum filiculoides, Najadetum marinae, Salvinio natantis-Spirodeletum polyrhizae, Elodeetum canadensis and Potametum denso-nodosi associations displayed a marked invasive potential in the forecasted distribution scenarios. The results revealed that the stands of Nymphaeetum albae and Nymphaeo albae-Nupharetum luteae subass. nupharetosum associations are likely to be significantly less abundant in the future. As the key climatic factors used in the analysis were annual mean temperature, as well as mean temperature of the wettest and warmest quartile, the findings suggest that, if adequate protective measures shall not be taken, these provenances could become degraded in the next decade and some could even become extinct at the locations where they presently occur naturally.

The ecological features of snow buntings and horned lark were discussed. Their ecology has so much in common that they become the only representatives of the Passeriformes order in polar deserts and arctic tundra. Under the climate conditions of the Arctic there is no northern range limit for snow buntings. The northern range limit of the horned lark is determined by biotopic factors, food supply and temperature; these factors don’t allow the horned lark to occupy a considerably large part of the Arctic zone. Southern limits of distribution of horned larks and snow buntings are probably determined by the light regime in the region - outside the polar day zone the birds do not come into a state of breeding. An additional requirement of snow buntings to their breeding area is the mean July temperatures below 10 °С.

The manifestations of philopatry and dispersion of wolves at the family level, population groups level (Central Forest Reserve) and population level (Tver region) were studied. The importance of the wolf’s den location in territorial structure formation was shown. The phylopatric behaviour of 35 wolves from seven families was analyzed. In the course of the study 32 individuals (16 adults and 16 youngsters from different families), being encircled with flags, crossed the flag line towards the den and only 3 individuals chose a different direction. Such behavior was typical for all the population groups: for young individuals born and raised in the place and for adult wolves (both resident wolves and their children who had started new families here). The role of “dispersant” wolves in 1972–1982 was emphasized: the rapid increase in the population size was caused by young individuals who had traveled short distances. Analysis of the available field data and literature shows that dispersant wolves “transfer” ecological, behavioral, spatial-functional and structural features of their families, i. e. they are the bearers of family traditions.

The results of the study of Cladonia lichen post-fire growth rate dynamics in different zonal units of West Siberia were presented. Relative growth rate of lichens in forest-tundra and taiga zones was assessed with regard to the pyrogenic factor. The growth rate varied from 1.2 mm/year at the early stage of progressive succession to 11.9 mm/year at the stage with dense lichen cover. The variations in lichen growth rate at different stages of recovery were observed in southern and middle taiga communities. In open forests and forest–tundra communities of northern regions the growth rate of lichens was not characterized by significant changes.

In this work the influence of environmental factors (prevailing tree stands, intensity of the fire season, weather conditions) on the fire radiative power (FRP) was analyzed. The data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used to characterize the variations of fire radiative power. Our studies showed that during the periods of high fire activity the FRP was 10 % higher than during the periods of low fire activity. The correlation level between the FRP and weather fire danger was determined. In particular, the fire weather index (FWI) of Canadian weather fire danger assessment system showed a closer relationship with the FRP in comparison with the Russian PV–1 index. It was also found that the fires in Siberian forests with the predominance of larch trees generally had 20–25 % higher FRP values than the fires in deciduous and pine forests.

The peculiarities of adaptation of Siberian crabapple (Malus baccata) to the lack of humidity on the boundary between forest zone and dry steppe were studied. A significant decrease in the growth rate, eventually leading to dwarfing, was found out. In the course of such adaptation, there was reduction in the photosynthetic surface of the leaves and increase in the stomatal density. At the same time, the size of the stomata decreased. It helped to optimize the loss of water during transpiration. It was found that the decrease in the growth rate of Siberian crabapple cuttings was accompanied by a three-fold decrease in the content of endogenous indoleacetic acid in the tips (116±13 ng/g of dry weight for the dwarf forms vs. 350±39 ng/g of dry weight for the tall-growing forms). There was no significant difference in the content of ABA in the tips of both the forms studied (210±18 and 213±21 ng/g of dry weight for the tall-growing and dwarf plants respectively).

The morphostructure of the aboveground part of sprouts of Astragalus mongholicus Bunge s.l. in Altai, Buryatia and Irkutsk region was studied. A complex of adaptive morphological characteristics was determined for this species, and the influence of height above sea level on the plants was estimated.

The species composition, spatial distribution and structure coefficients of benthic communities in small mountain streams on the territory of the Ergaki nature park (the south of the Krasnoyarsk Krai) were characterized. The comparative analysis of biotic indices and metrics, some of which are used by the European Water Framework Directive to evaluate water quality, was carried out. It was determined that the EPT, BMWP and IBGN indices had greater sensitivity, therefore they could be recommended as the standard in the evaluation of water quality of small mountain streams of that region. The gradation of water quality was determined and the integrated index was introduced after the ranking of obtained biotic indices and metrics in comparison to the background value.

The data on the measurements of vertical methane fluxes in the meso-oligotrophic peatland of middle taiga subzone with the use of the eddy–covariance technique was presented. It was established that the rate of methane emission depended on water table level and soil temperature at the depth of 15 cm. The overall methane emission from April to October was 22.4 g m^–2, which is higher than the results of measurements made by other authors for peatland ecosystems of circumboreal zone.

Long-term (1997–2012) monitoring of agroecosystems on the agrogrey soil of the Baikal forest-steppe was carried out. The influence of climatic factors on CO₂ emission to the atmosphere in different seasons of the year was studied. There was a close correlation between the CO₂ flux and hydrothermal indicators in spring and autumn. The contribution of the summer season to the annual flux of CO₂ made up 67 and 72 % in the fallow and wheat crop respectively. On the basis of 16-year observations the average annual CO₂ emission was calculated: it amounted to 173 g C/m^–2 in the fallow and 229 g C/m^–2 in the wheat crop.

The abundance and production of planktonic viruses, frequency of infected bacterial cells, the number of mature phages in infected bacterial cells and virus-induced mortality of bacterioplankton were studied in two small rivers and the large Sheksna River (Cherepovets city) in April – October 2011. High positive correlations were determined between the abundance of planktonic viruses and bacteria and between the number of viruses attached to bacterial cell walls and the frequency of infected bacteria. The number of planktonic viruses and the mortality of bacteria caused by virus–induced lysis in hypertrophic and eutrophic small rivers were higher than in the mesotrophic Sheksna River.

The influence of Siberian strains of Bacillus spp. on the causing agent of grey mold of strawberry (the fungus Botrytis cinerea Pers ex Fr.) and the host plant’s resistance to the disease were studied during three seasons with different weather conditions. The bacterial strains B. subtilis, B. amyloliquefaciens and B. licheniformis suppressed the B. cinerea fungus in vitro and in vivo. In addition to the antifungal action, the bacterial strains positively influenced the strawberry plant growth. These results showed that the Siberian strains of Bacillus spp. revealed polyfunctional properties towards strawberry plants infected with B. cinerea.

Foliar damage to white birch (Betula pubescens) caused by leaf-chewing insects and miners was assessed in 2005–2006 and in 2008 in the vicinity of a large copper smelter in the Middle Urals (Revda, Sverdlovsk oblast). The following indices were considerably lower near the smelter than in the background and buffer zones: the total leaf area removed by the insects (3–11 times), the number of damaged leaves (1–4 times), and the average leaf area removed per damaged leaf (2 times). The effect size was similar for all the three parameters and remained stable with time. Both groups of insects showed lower trophic activity in the impact zone, but the impact of pollution was greater on leaf–chewing insects than on miners.