Home – Home – Jornals – Contemporary Problems of Ecology 2018 number 4

The survey considered an ecological mechanism that transformed a population of psychrophilic (cold-like) sapro-zoobiontic pseudotuberculosis microbe Yersinia pseudotuberculosis O:1b into a population of obligate “blood” microbe of plague Yersinia pestis in the host-parasite system Marmot - Flea ( Marmota sibirica - Oropsylla silantiewi ). This mechanism corresponds to the evolutionary principle of “quantum” speciation. The most significant population-genetic microbial transformations took place in hibernating populations of the Mongolian marmot. The main factor of rapid speciation was the heterothermal and heteroimmune status of marmots during hibernation. During winter, the body temperature of marmots fluctuates within a short period of time (from 10 minutes to several hours) by S-form in intervals from 5 to 37 ºC. In the temperature range 20-30 ºC, a sharp acceleration of metabolic and immune processes takes place. Fast adaptation to the explosive rise of immune activity of the primary host (the Mongolian Marmot) in its regular winter awakenings was the essence of the process of speciation of Y. pestis.

The aim of study was to test the assumption that the relationship between degree of dominance and local species richness in herbaceous communities with different productivity may be dissimilar. As objects of the study, we used alpine, subalpine and low-mountain meadows, subalpine mires, alpine communities of the habitats with little snow and those with long-term snow cover, steppe communities, layer of low-mountain forest communities of the Western Caucasus and Ciscaucasia. The analytical material included 419 plots of herbaceous communities of 0.25 m² in the area with the data on the phytomass of vascular plant species. The results showed that the higher was the average productivity of communities, the closer was the relationship between the degree of dominance and species richness, and the closest one was in meadow communities. Possible causes of such relationships are considered. It is suggested that this may be due to the peculiarities of the organization of plant communities with high and low productivity (high or low intensity of competition).

We compared three approaches to study climatic signals of Pinus sylvestris and Larix sibirica tree-ring width chronologies from the forest-steppe zone of South Siberia, where both temperature and precipitation limit the conifer tree growth: paired correlation of chronologies with monthly climatic variables; paired and partial correlations with monthly and seasonal series of primary and secondary climatic factors, calculated in the Seascorr program; paired correlation with a 15-day moving average series of climatic variables. The comparison showed that simple paired correlation with monthly series as the simplest approach could be used for a wide range of dendroclimatic studies, both as the main procedure and for preliminary analysis. The Seascorr analysis is the most suitable for assessing climate-growth relationship in the extreme growth conditions and for reconstructions of extremes, e.g. droughts, and of their impact periods. The application of a 15-day moving average series is limited by the availability of daily climatic data, but describes the seasonal window of climatic response with high precision. Altogether, the combination of three approaches allowed to explore the spatial-temporal pattern of the conifers radial growth climatic response in South Siberia.

Variability of physiological and biochemical indicators and radial growth of different forms of Pinus sylvestris L. (f. (var.) sulfuranthera Kozubow and f. (var.) erythranthera Sanio) under flooding conditions was investigated. It was shown that the dynamics of the content of some biochemical characteristics such as photosynthetic pigments (chlorophylls and carotenoids), proline, proteins, ascorbic acid, peroxidase activity and light harvesting complex in the pine needles depended on meteorological factors and phenophase. Forms with different color of anthers differ in the seasonal dynamics of the content of stressful metabolites and age variability of radial growth of wood. Our results indicate that different forms of Pinus sylvestris L. have nuances in adaptation to stress conditions.

The influence of climate changes on larch radial increment (Larix sibirica Ledeb.) in conditions of a limited (forest-steppe) and sufficient (highlands of Kuznetsky Alatau, floodplain stands) humidification was considered. The relationship between growth index of larch trees (N = 257) and ecological-climatic variables was analyzed. In the forest-steppe, with the onset of warming, decrease in climate aridity, and increase in duration of growing season (1980s), an increase in larch growth index followed by its depression in the 1990s was observed. Radial increment depression was caused by an increase in vapor pressure deficit and arid climate due to rising air temperature. In the 2000s, radial increment fluctuations occurred with average values not exceeding those before the beginning of the current climate warming period. In the highlands, since the 1970s, there has been a general trend of increasing the larch radial increment, closely associated with the main limiting factor of growth - air temperature. At the same time, in arid years, radial increment depression was also noted in high-mountain and floodplain larch forests. When implementing «hard» climate scenarios (RCP 6.0, RCP 8.5), it is likely that larch growth index in the forest-steppe will decrease further and increase in areas of sufficient moisture.

A new method of approach to the determination of "upper forest border" (UFB) as the border of the "rootclosed" stand and regrowth ones as its potential vaniguard is suggested. The mass scale of Pinus sibirica populations dispersal by the nutcracker (Nucifraga caryocatactes) in the UFB ecotone in the Northern Urals (Pavdinskii Kamen and Third Hillock mountains) from the middle-mountain taiga to the mountain forest-tundra and tundra at distance up to 1 km has been established. It was performed on the basis of original reconstruction method of the number dynamics of P. sibirica annua seedlings and the analysis of the relations with the dynamics of the seedbearing and population number of the nutcracker. The trustworthy consortive relations of the generations number of Pinus sibirica in the mountain fortundra and tundra zones with its seedbearing and the nutcracker number in the previous year in the middle-mountain taiga zone have been revealed. A trustworthy increase (2.6 times) of seedling generations number during the last 49 years has been established in connection with the increase of the summer air temperature in Subarctic up to 2.0 ^oC. A hypothesis of the formation of the united genetical metapopulation of P. sibirica in the mountain ecotone zone "forest - tundra" in consequence of its seed ornitochory from the high-different populations has been formulated. A prognosis of the mosaical formation of the vaniguardal "thin forests" in 20-25 years and the rootclosed curtains of the "forest" in 40-50 years in the mountain tundra in the Northern Urals by current speed of the rise in temperature is made.

The territory of the new mass breeding of Dendrolimus sibiricius is the northernmost of the previously known in Siberia. The increase in pest numbers began in 2011-2012, 14 years after the previous mass outbreak. As a result, the area of damage to dark coniferous forests exceeded 1.4 million hectares. The reasons for the emergence of the pest population from a depressive state were insufficient moisture availability in May 2011, a severe drought in June-July 2012, and an increased average monthly temperature. A significant decrease in the vegetation index of SWVI in 2011-2012 was established. The hydrothermal regime of the spring-summer period in these years promoted the transition of the majority of the pest population to development over a one-year generation. An exceptional feature of the current outbreak is the low damage to D. sibiricus caterpillars by diseases and parasites. Favorable weather conditions and small number of natural entomopathogens contribute to the rapid spread of the pest in the northern and eastern directions. This creates a high risk of mass reproduction of D. sibiricus in dark coniferous forests, since the area of nearby dark coniferous stands that are suitable for the structure, climatic and forest-growing conditions for pest distribution is more than 2.7 million hectares. Pure cultures of the entomopathogenic fungus Beauveria bassianа were isolated from dead caterpillars of D. sibiricus . Multistage screening made it possible to select a promising strain for the creation of a long-acting bioinsecticide for preventive treatment of forests. The main selection criteria are: high virulence; high entomopathogenic activity at low temperatures (7-10 ^oC) and ability to solid-phase fermentation of plant waste.

The results of the analysis of thermal field dynamics on post-fire areas performed using remote satellite imagery are presented in the paper. The presence of a characteristic "background" was observed in the thermal range (10.780-11.280 μm) for the post-fire areas in the permafrost zone caused by changes in the parameters of the stand, ground cover and litter. The average surface temperature of post-fire areas in larch forests is characterized by increasing up to ΔT = 7.2 ±1.3 ^oС relative to the background values in summer, which is 20-40 % higher than the temperature of background undisturbed areas. Anomalies of the temperature background remain more than 10 years in the conditions of natural restoration of the ground cover. It is estimated that the rate of temperature anomalies recovery is 2.5 times lower than the dynamics of the vegetative index NDVI. It was evaluated numerically that temperature anomalies on the surface could lead to an increase in thawing depth of the soil layer by up to 20 % more than the average statistical rate.

The paper deals with phytomass of herbaceous phytocenoses growing on anthropogenically impacted areas in the Middle Urals at different stages of succession along heavy metal pollution gradient. Cenoses of young soils of dumps have less resistance and higher sensitivity to changes in weather factors, in contrast to the phytocenoses of the deposits. It is shown by the method of general regression models that the epiterranean and subterranean biomass of cenoses in technozems depends on the Selyaninov’s hydrothermic coefficient for September and the amount of precipitation in October - November of the previous year and in January - May of the current year. The degree of this dependence for cenoses under study is determined by edaphic conditions that affect the species diversity and dominance structure.