Analysis of rodent populations in technogenically transformed areas (with reference to <Emphasis Type=Italic>Apodemus</Emphasis> (<Emphasis Type=Italic>S.</Emphasis>) <Emphasis Type=Italic>uralensis</Emphasis> from the EURT zone)

It is shown that the response of rodent populations to acute and chronic irradiation depends on its functional structure, i.e., on specific features of animals with two alternative types of ontogenetic development. Upon acute irradiation, sexually immature young of the year (animals with the second type of ontogeny) are most radioresistant. Exposure to chronic irradiation, as in the zone of the Eastern Ural Radioactive Trace (EURT), leads to an increase in the proportion of mature young of the year (animals with the first type of ontogeny), which are the most radiosensitive part of the population. The abundance and fecundity of mice in the impact zone are consistently higher than in the background zone, which improves the adaptive potential of the population. The role of species ecological specialization and configuration of the contaminated zone in the formation of migrant rodent population is emphasized. It is concluded that a high migration activity allows the pigmy wood mouse (a radiosensitive species) to avoid long-term radiation exposure.     

Traditional management and conservation of shea trees (<Emphasis Type=Italic>Vitellaria paradoxa</Emphasis> subspecies <Emphasis Type=Italic>nilotica</Emphasis>) in Uganda

Traditional practices are universally recognised as a basis for conservation of biodiversity. However, such practices are often not included in natural resource conservation policies. This study assessed local conservation practices of shea trees (Vitellaria paradoxa) within different farming systems in Uganda and developed conservation guidelines for the species. The assessment involved 300 respondents, 15 focus groups and 41 key informants. Content analysis was used to identify the most important management and conservation practices. Local uses were categorised on the basis of shea tree products while differences in conservation practices were analysed using the Friedman test. The results show that eight shea tree products are used for 36 different purposes. Respondents’ age significantly influenced their knowledge about the shea tree. Traditional conservation practices include on-farm retention during cultivation and the use of folklore (mainly taboos), customs and rituals. Traditional management practices include weeding, bush burning, pollarding and pruning. Based on the current management and traditional conservation practices, a framework for the conservation of shea trees is proposed for integration into conservation policy decisions.     

Influence of intra- and interspecific competition on daily activity of common (<Emphasis Type=Italic>Microtus arvalis</Emphasis>) and East European (<Emphasis Type=Italic>Microtus rossiaemeridionalis</Emphasis>) voles in experiments

The influence of intra- and interspecific competition of common and East European voles on their daily activity was studied in 34-m² enclosures at the Chernogolovka Experimental Research Station (Moscow Region). Family groups of animals captured in the same biotopes were placed in enclosures and, 25 day later, their daily activity was observed. Thereafter, the animals were pooled and observations were repeated 25 days later. The experiment consisted of three stages. At the first stage, the daily activity, time budget, and social behavior of common voles were studied before and after pooling different family groups; at the second stage, the same was performed with East European voles; and at the third stage, with both species. The species proved to use different strategies for alleviating intraspecific competition: in common voles, this was segregation of ecological niches via desynchronization of daily activity; in East European voles, conversely, aggregation in groups and synchronization of activity. Under experimental cohabitation, the strategy of the common vole, a more aggressive species, was to force out the other species, ecologically similar but less competitive; the strategy of the East European vole was aimed at avoidance via segregation of ecological niches in time.     

Group effect on individual locomotor activity of common toad (<Emphasis Type=Italic>Bufo bufo</Emphasis> L.) and brown frog (<Emphasis Type=Italic>Rana temporaria</Emphasis> L.) tadpoles

Different components of group effect on the locomotor activity of single common toad and brown frog tadpoles have been studied by estimating the length of their trajectories, the speed of movement, the number of crossings of experimental field zones, and the number and duration of stops. The results show that toad tadpoles are more active than frog tadpoles. Conspecific metabolites added to the water do not change the pattern of their locomotor activity. Under conditions of visual contact with other tadpoles, locomotor activity of a toad tadpole decreases, whereas that of a frog tadpole increases. Thus, tadpoles of the two amphibian species show species-specific behavioral responses to changes in experimental conditions.     

Changes of leaf morphology in <Emphasis Type=Italic>Betula pendula</Emphasis> roth and <Emphasis Type=Italic>B. pubescens</Emphasis> Ehrh. along a zonal-climatic transect in the Urals and Western Siberia

Leaf size, shape, and parameters of venation in Betula pendula and B. pubescens have been studied along a 1600-km latitudinal zonal transect in the Urals and Western Siberia. The results show that leaf size and venation density depend on the geographic location of population, with these parameters in the two species changing in opposite directions along the transect. In its northern part (forest tundra-southern taiga), B. pubescens shows a positive correlation of leaf area with long-term-average air temperature, while this correlation in B. pendula is negative. In the southern part, correlations of leaf size with long-term average precipitation in the two species are also opposite in sign. Parameters of leaf shape in both species depend mainly on weather conditions in the current year rather than on long-term average climatic parameters. The conclusion is drawn that B. pendula and B. pubescens have different mechanisms of structural adaptation of leaves to climate and weather conditions that are based on changes in leaf size and shape.     

Ecological-demographic characterization of <Emphasis Type="Italic">Potentilla bifurca</Emphasis> L. cenopopulations

A discrete approach to the study of ontogeny has made it possible to reveal a high degree of age heterogeneity in P. bifurca cenopopulations. The basal ontogenetic spectrum of cenopopulations has been determined. The index of regeneration is higher in cenopopulations of the young type and decreases in cenopopulations of the old type, whereas the situation with the index of senescence is inverse. The density of cenopopulations depends mainly on parameters of the substrate (density, composition, and moisture), its slope, and the intensity of plant vegetative reproduction and spread.     

Specific ecological features of the brown bear (<Emphasis Type=Italic>Ursus arctos</Emphasis> L. 1758) in Yakutia

In Yakutia, the brown bear inhabits the forest and forest-tundra zones. Compared to bears from other regions of Russia, Yakutian bears have slightly smaller body and skull sizes and are mainly herbivorous, with their wood spectrum being relatively narrow. Their fecundity averages 1.68 cubs per parous female. The bears make their dens at a depth reaching 2.5–3 m. The denning period begins early and is 195–210 days long. An electroencephalographic analysis of the effect of a 1–10 kDa peptide fraction from the bear brain on Wistar rats has shown that wintering bears are in the state of sleep, or “superficial hibernation.”     

Variability of Demographic Parameters in a Cyclic Population of the Bank Vole (<Emphasis Type=Italic>Clethrionomys glareolus</Emphasis>)

Analysis of demographic parameters in a local bank vole population has shown that different relationships exist between them. The level of population abundance is directly correlated with the proportion of sexually mature juveniles, the length of the breeding season, and the age of overwintered individuals. The duration of the breeding season shows a delayed dependence on population abundance in the previous year. Variation in the average age of overwintered voles at different phases of the population cycle is characterized by a delayed dependence on the length of the breeding season in the previous year. Intrinsic factors generate the cyclic dynamics of parameters, while extrinsic factors can modify their dynamics.     

On the term <Emphasis Type=Italic>Station</Emphasis> used in Russian ecological and faunistic literature

The history of the term station (in Russian, statsiya) in the Russian ecological and faunistic literature, interpretation of its meaning by different authors, and relationships between the terms station, habitat, biotope, and ecological license are discussed. It is suggested that station should be interpreted as the entire set of all external conditions affecting a population, which is observable as a part of physical space possessing certain properties.     

Insularization and polymorphism in marginal island populations of <Emphasis Type=Italic>Pinus sylvestris</Emphasis> L.

Comparative allozyme analysis of 26 marginal island populations of Pinus sylvestris L. and 20 populations from the center of the species range has confirmed, at the species level, the Wright-Dubinin “island model” of automatic genetic processes and Mayr’s hypothesis about homozygotization of small isolated populations at range boundaries. It has been shown that the polymorphism of isolated populations sharply decreases when their area is reduced below 15–20 km² and increases to the level observed in the center of the range when the population area exceeds 50–100 km². A chorogenetic classification of marginal P. sylvestris populations is proposed.     

Factors influencing the duration of gypsy moth (<Emphasis Type=Italic>Lymantria dispar</Emphasis> L.) population outbreaks

For the first time, an attempt has been made to reveal possible causes of the relative “brevity” of gypsy moth outbreaks in the Russian Far East. The results show that major factors limiting these outbreaks include the weakly manifested seasonal drift of gypsy moth foci, oviposition habits, as well as specific weather conditions during the period of larval development and death that facilitating the dispersal of insect pathogens in components of the forest ecosystem.     

Effect of biotic factors on growth and survival of the Oriental river prawn <Emphasis Type=Italic>Macrobrachium nipponense</Emphasis> (De Haan) in warm-water aquaculture

Biotic factors such as intraspecific competition, stocking density, and parameters of feeding have been compared with respect to their effect on the growth and survival of monosex and mixed populations of the Oriental river prawn Macrobrachium nipponense (De Haan) in warm-water aquaculture. The results suggest that biotic factors—in the present case, social interactions and, to some extent, the efficiency of food assimilation—may be more effective than genetic factors in controlling differences in the size composition of the population.