Vol 50, No 2 (2019)

This paper is dedicated to the 100th anniversary of the birth of Stanislav Semenovich Shvarts, an outstanding Soviet ecologist. Consideration is given to his role in the establishment of ecology in the Soviet Union, its development at national and international levels, and the evolvement of special fields of ecological science currently pursued in Russia, namely, population, evolutionary, and human ecology. Special attention is devoted to the influence of Shvarts’ theoretical concepts on the development of ecological forecasting and ecological foundations of nature conservation and effective natural resource management. It is concluded that Shvarts was the one who gave rise to population-oriented thinking in ecology.

In this review, we describe karyotypic, morphological, and genetic structuring of population in the common shrew Sorex araneus (Lipotyphla, Mammalia), and try to explain some unclear and contradictory aspects of this structuring on the basis of population approach. The subdivision of this species into more than 76 parapatric chromosomal races does not correspond to its morphological and genetic structuring. Chromosomal hybrid zones are formed in the areas of contact between the races. The frequency of interracial F1 hybrids is low in nature, but we have shown that mating between different races in captivity occurs quite readily, although the postnatal survival of hybrids is reduced. We suggest that this species is subdivided into relatively small populations characterized by the unity of functioning, which is ensured by the predominant dispersal of individuals from each of the populations within their population space. It should also be emphasized that the main provisions set forth by Stanislav S. Shvarts in his conceptual monograph The Evolutionary Ecology of Animals are still relevant today.

This study estimates the dependence of the duration of the downstream migration of burbot larvae in the Voikar River (the Lower Ob basin) on the relative condition factor of semianadromous spawners migrating upstream to the spawning tributary in autumn; the estimates are based on 20 years of observations (from 1999 to 2018). The observed (11 years) and calculated (9 years) values of the hepatosomatic index were used to estimate the relative condition factor of spawners. The values of the hepatosomatic index were calculated using the median quantile regression based on estimates of the maximum level of floodplain flooding and sum of daily average water temperatures during the open channel period in summer feeding areas. A strong, highly significant negative dependence of the duration of downstream migration of juveniles and of the number peaks of abundance larvae on the values of the hepatosomatic index of spawners has been revealed. It is assumed that there is a relationship between the relative condition factor of spawners and the timing of their upstream migration to spawning grounds. In turn, the upstream migration time determines the accessibility of river spawning areas for spawners, which then determines the timing of hatching of burbot larvae.

Tendencies in the dynamics of harvested northern fur seal (Callorhinus ursinus) population on the Tyulenii Island have been analyzed in detail. The results show that retardation of reproduction (decrease in the numbers of pups) and decline in the survival of young females (up to 3 years of age) by the late 1980s resulted in a reduction of the total number of females and a significant increase in the proportion of older females. This tendency changed during the later observation period (after 1988–1989) due to increase in the survival of young females: the female population has gradually recovered, with the proportion of young females increasing at the expense of old females (aged over 10 years). The age composition of males has also changed: the proportion of young animals has decreased, while that of large mature males (bulls) has increased. Moreover, the number of bulls continues to increase and has already exceeded the level that formerly provided for the well-being of the population. This, a paradoxical situation has arisen: the numbers of females and bulls are increasing, whereas pup production remains at a low level.

Larix chinensis Beissn forms a subalpine timberline on Taibai mountain, Shaanxi, China. Seed emergence and survival of seedlings were studied by seed sowing experiments across an altitudinal gradient (3150–3400 m a.s.l). Three main factors were considered: seed addition, shrub shadowing and disturbance. In three different habitats (from low altitude to high: the Abies fargesii forest, the Larix chinensis forest and the shrub meadow), seeds emergence was examined and the seedling number and growth in every plot were recorded continuously over 4 years. Kruskal-Wallis ANOVA was used to analyze the relationship between seedling emergence/recruitment and the explanatory variables in every stand. The results showed that seed addition in disturbed plots always caused significantly increased seedling emergence and recruitment in the A. fargesii forest and the L. chinensis forest, but not in undisturbed plots under the canopy of forests. It demonstrated that recruitment of L. chinensis was limited by seed and microsite availability under closed forest, and litter is one of the factors leading to microsite limitation. However, in the shrub meadow, no treatments improved recruitment, indicating that the shrub meadow was not suitable for seedling establishment because of more intense light and lower temperature. In the L. chinensis forest and the A. fargesii forest, more recruited seedlings indicated that these two forests are safer for L. chinensis seedling establishment, though seeds limitation and the litter obstacle had seriously constrained the regeneration of L. chinensis.

The dynamics of nest-dwelling mites from the nests of the great tit in the protected area of Kamchia Mountain in Northeastern Bulgaria was investigated. The mite fauna inhabiting the nests of great tit differs significantly in terms of the degree of infestation, species richness, abundance and structure of communities in study years. There are statistically significant differences in the specimens’ number between 2014 and the other years 2012, 2013 and 2015. The mite species such as Dermanyssus gallinae, Androlaelaps casalis and Ornithonyssus sylviarum demonstrated significant changes in the abundance over the study years. A relation between the abundance of a species and the species diversity in the nests was not registered. Comparison of the annual dynamics of mites in the nests of great tit and the nests of semi-collared flycatcher for the same period of time and for the same environment, showed similarities—a significant fluctuation in the abundance of mites over the years and differences—in the species richness. Regarding the structure of the communities, both similarities and differences were recorded.