Intrapopulation spatial segregation in bream (<Emphasis Type="Italic">Abramis brama</Emphasis>) and roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis>) in the Rybinsk Reservoir

In the course of studies on mass fish species (bream and roach) in water bodies of the Upper Volga basin, intraspecific groups of individuals have been distinguished. Conditions and possible mechanisms of spatial differentiation of these groups are considered. The intrapopulation divergence of individuals by some adaptive characters, primarily behavioral, enables them to utilize alternative resources, which provides for more efficient use of the environment by populations.     

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.     

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.     

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.     

Salinity tolerance polygon of <Emphasis Type="Italic">Hydrobia ulvae</Emphasis> (Pennant, 1777) (Mollusca: Hydrobiidae)

To estimate the capacity of the White Sea littoral mollusk Hydrobia ulvae (Pennant, 1777) for adaptation to changes in ambient salinity, the range of its tolerance to increased and decreased salinity was determined experimentally. The results were used to plot the salinity tolerance polygon. On this basis, it was estimated that H. ulvae can live in a salinity range of 6–85‰.     

State of the population of the European pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> (L.) (Mollusca,Margaritiferidae) at the northeastern boundary of its range (Solza River,White Sea Basin)

Only two river basins in which the European pearl mussel has survived to date are known in Arkhangelsk oblast. These are the Solza and Kozha basins. The northeastern boundary of the European range of this species passes along the watershed between the basins of the Solza and the Shirshema (the Onega Peninsula) and then along the Onega-Northern Dvina watershed. The population density and the proportion of juveniles widely vary in different parts of the Solza Basin, and, therefore, the previously conclusion concerning the ageing of the population in the Kazanka River (Bolotov and Semushin, 2003) applies only to certain parts of this river. The highest density of the pearl mussel in the Solza Basin is 68 ind./m². Fish cultivation contributes to the conservation of this pearl mussel population, as the release of Atlantic salmon juveniles ensures reproduction of the mollusk under conditions of regulated river flow.     

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.     

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.     

Mating systems in the steppe lemming (<Emphasis Type="Italic">Lagurus lagurus)</Emphasis> and narrow-skulled vole (<Emphasis Type="Italic">Microtus gregalis</Emphasis>) from the Northern Kulunda Steppe

A comparative analysis of reproductive behavior has been performed in the steppe lemming (Lagurus lagurus) and narrow-skulled vole (Microtus gregalis). The results show that the species are similar in certain behavioral features indicative of the stability of mating pairs. However, in the narrow-skulled vole, unlike in the steppe lemming, mature males in olfactory tests show preference for receptive sibling females versus non-kin females. Probably, it is the absence of the incest taboo that allows the involvement of young of the year in reproduction within growing family groups and accounts for “coloniality” of the species.     

Uranium isotopes in groundwater from the “Jeffara coastal aquifer” (southeastern Tunisia)

The distributions of ²³⁸U and ²³⁴U in groundwater from the “Jeffara aquifer” were studied by using alpha spectrometric methods. The concentration ranges of ²³⁸U and ²³⁴U/²³⁸U activity ratios were 1.34 ± 0.17 to 3.43 ± 0.38 ppb, and 1.43 ± 0.23 to 1.82 ± 0.27 respectively. Variations in concentrations can be related not only to lithostratigraphic formations but also to different origins of groundwater. U content of Jeffara are found very similar to those of Continental Intercalaire aquifer in both El Hamma and Chenchou regions, indicating that the Continental Intercalaire is the dominant source of the groundwater.     

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.”     

Mitochondrial DNA variation pattern and postglacial history of the Siberian larch (<Emphasis Type="Italic">Larix sibirica</Emphasis> Ledeb.)

Mitochondrial DNA (mtDNA) variation has been studied in populations of the Siberian larch with the use of five PCR-based markers characterizing 29 haplotypes. The studied populations from the main parts of the Siberian larch range belong to several geographically isolated groups with their specific sets of haplotypes, which have probably originated from separate refugia for forest vegetation of the last glacial maximum. Conclusions concerning the possible location of these refugia and the ways and pattern of the postglacial recolonization of the recent Siberian larch range are drawn. The spatial distribution of haplotypes within individual populations is nonrandom. The typical size of the area occupied by a group of plants with the same haplotype is 50–100 m across.     

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.     

Intraspecific variation in the viability of soredia in <Emphasis Type="Italic">Hypogymnia physodes</Emphasis> (L.) Nyl. (Ascomycota: Lecanorales)

The contribution of morphological features of parent thalli, substrate and climatic factors, and their seasonal fluctuations to variation in the viability of vegetative diaspores has been studied on the model of epiphytic lichen Hypogymnia physodes. Seasonal trends in viability have been revealed only in certain types of biotopes. Hygrothermal conditions and substrate properties in the biotope have proved to have a significant effect on the viability of soredia.     

Winter ecology of the pine marten (<Emphasis Type="Italic">Martes martes</Emphasis> L.) in the Volga floodplain opposite Samara

The footprint tracking method has been used to study specific features of winter ecology of pine martens inhabiting the Rozhdestvenskaya Floodplain of the Volga River. Attention has been paid to the size and demographic structure of the population, the distribution of footprints by habitats, home ranges and shelters, features of foraging and territorial behavior, reactions to objects of natural and anthropogenic origin, and interactions with heterospecific animals.