Том 48, № 2 (2017)

The critical situation with traditional reindeer husbandry in the Yamal district of the Yamalo- Nenets Autonomous Area, indicated by an anthrax epizootic, is analyzed from an ecological viewpoint. The phenomenon of epizootic is regarded as an ecosystemic homeostatic mechanism operating to prevent excess population growth and maintain ecosystem integrity. The shutdown of this mechanism by means of vaccination, with the proportion of reindeer removed from slaughter remaining low, has resulted in an increased grazing load of rangelands and their consequent severe degradation. These events have been aggravated due to change in the type of ownership in reindeer husbandry during the reforms of the 1990s. The ecological situation is classified as critical, posing a real hazard to this particular ethnic form of economy. It is concluded that the period of extensive/expansive development of Yamal reindeer husbandry has come to an end. Sociopsychological attitudes of the Nenets, acquired when biological resources were abundant, contradict with the principles of ecosystem existence and functioning in the period of resource depletion. The maintenance of reindeer husbandry in the traditional form requires increasing material, labor, and financial investments, but positive results are unlikely to be obtained because of ecological constraints.

Trends in stem temperature of Scots pine trees in different life states are described. Any substantial disturbances of water flow in the roots, stem, or crown have an immediate effect on the stem temperature. This temperature shows a strong inverse correlation with the state of the tree, with the coefficient of determination ranging from 0.710 to 0.974. The method of assessing the physiological state of trees by temperature parameters allows early diagnosis of decline in the viability of conifers.

Total soil available nitrogen concentrations (NO^–3 + NH₄⁺) were determined underneath plants of the more-competitive Poa ligularis, mid-competitive Nassella tenuis and the less-competitive Amelichloa ambigua exposed to various combinations of controlled burning and defoliation treatments. Defoliations were at the vegetative (V), internode elongation (E) or both developmental morphology stages (V + E) during two years after burning in northeastern Patagonia, Argentina. Hypotheses were that (1) concentrations of total soil available nitrogen after burning are greater underneath burned than unburned plants. With time, these differences, however, will gradually disappear; (2) greater total soil available nitrogen concentrations are underneath plants of the more- than less-competitive perennial grasses; and (3) total soil available nitrogen is similar or lower underneath plants defoliated at the various developmental morphology stages in all three study species than on untreated controls at the end of the study. Concentration of total soil available nitrogen increased 35% (p < 0.05) on average after the first six months from burning in comparison to control plants. However, these differences disappeared (p > 0.05) towards the end of the first study year. Total soil available nitrogen concentrations were at least 10% lower underneath the less competitive N. tenuis and A. ambigua than the more competitive P. ligularis on average for all treatments, although differences were not significant (p > 0.05) most of the times. Defoliation had practically no effect on the concentration of total soil available nitrogen. Rather than any treatment effect, total soil nitrogen concentrations were determined by their temporal dynamics in the control and after the experimental fire treatments.

A view of pollination systems is that they tend to generalization. Here we show that patterns exist in pollination systems that suggest otherwise. We examine how specialization may be affected by latitude, species richness and plant life-forms in 33 plant-pollinator interaction networks. Connectance increases with latitude (P = 0.040), but specialization at the community level significantly declines with increasing latitude, with the strongest evidence in the Northern Hemisphere (P = 0.001). The relationship between specialization level and connectance is negative (P < 0.001). While plants are more specialized in tropical areas and are more generalized at higher latitudes, specialization level also increases with plant richness (P < 0.001), total species richness (P = 0.041) and network size (P = 0.009). Specialization level of life forms of 1129 species differ substantially (P < 0.001), with herbs showing the highest specialization (74%), and tree species the lowest (62%).

Using methods of geometric morphometrics, significant differences have been revealed in manifestations of variability and morphological disparity in allochronous samples from the population of model species, the bank vole (Clethrionomys glareolus Schreb. 1780), in the Middle Urals at different levels of rodent community (taxocene) completeness in different years. Two states of the taxocene—oligospecific (two species) and polyspecific (five species)—and the level of relative abundance of bank voles (high or low) have been taken into account. Comparative analysis of variation in the size and shape of the mandible in same-aged (late-summer) young of the year has shown that significant morphogenetic differences exist between the animals sampled from the rodent taxocene at its different states (oligospecific and polyspecific) and, to a lesser extent, at high and low levels of abundance. The level of variation and the parameter of intragroup morphological disparity (MNND) in the mandible shape reach a maximum when the community has a reduced composition and decrease to a minimum when its composition is complete (i.e., in the oligo- and polyspecific taxocene). A parallelism is observed in the manifestation of morphofunctional changes of the mandible in male and female voles under conditions when the taxocene has high abundance and oligospecific composition or low abundance but polyspecific composition. Different morphogenetic responses of the population to oligo- and polyspecific composition of the community are considered as a compensatory increase of morphological disparity in the dominant species (the bank vole) under conditions of incomplete composition of the taxocene and low population density, in accordance with Chernov’s ecological compensation principle.

The effect of rise in spring air temperature on the breeding phenology and reproductive success of the Song Thrush in the Voronezh Nature Reserve have been studied over the periods of 1987 to 1990 and 2008 to 2012. The results show that relatively high air temperatures provide for earlier arrival of the birds from wintering grounds, earlier and more synchronous breeding of the majority of nesting pairs, and an increase in clutch size and proportion of pairs producing two broods per season. Predation pressure on bird nests decreases under such conditions, which markedly improves reproductive success. Climate warming is conducive to increasing breeding productivity of the Song Thrush population as a whole.

The effect of bog water table on the species structure of sphagnobiontic testate amoebae communities has been studied in peatland ecosystems of European Russia. On this basis, a transfer function (model) for quantitative paleoreconstructions has been developed. This involved the formation of a training dataset, construction of models, and testing their performance. As a result, the model constructed by weighted averaging regression has been adopted as optimal.