The Spatiotemporal Structure of Rodent Populations in the Steppe Zone of Western Siberia

The spatial structure of populations has been studied in two rodent species inhabiting the subzone of meadow steppes of the steppe zone of Omsk oblast: the narrow-sculled vole (Microtus gregalis Pall.) and steppe lemming (Lagurus lagurus Pall.). Their populations are represented by combinations of territorial family groups whose structure and spatial distribution vary by season depending on population density, the phase of the population cycle, and the status of their members in the population. In the areas cohabited by M. gregalis and L. lagurus, the pattern of territory use and the rhythm of animal activity during the day depend primarily on their total density: under conditions of low density, the population groups of both species are spatially separated; at increased density, they are distributed with respect to the pattern of daily activity. Both species jointly use part of the territory but at different times of day: M. gregalis, mainly at night and in the morning; L. lagurus, in the daytime.     

Spatial population structure in forest voles of the genus <Emphasis Type="Italic">Clethrionomys</Emphasis> in the southern taiga of the Middle Irtysh region

A comparative analysis of spatial population structure in the northern red-backed vole (Clethrionomys rutilus Pall.) and large-toothed red-backed vole (Cl. rufocanus Sund.) has been performed in the middle taiga zone of the Middle Irtysh region (Omsk oblast). Populations of these species are represented by sets of territorial groups whose numbers and spatial distribution change from year to year depending on the ratio of these species in a biotope and their population density. There is no significant interspecific competition between cohabitant Cl. rutilus and Cl. rufocanus. In particular, this follows from the fact that the population density and distribution pattern of one species are independent of those of the other species. It has been found that the size of home ranges in Cl. rutilus inversely depends on its population density, with that in Cl. rufocanus remaining approximately the same at different population densities, and that the structure of the resident part of the population in both species changes during the season, as voles from neighboring habitats or dispersing voles settle in the study area.     

Demographic Parameters of the Tartarian Roe Deer Population in the Transural Region and the Main Factors Determining Them

The demographic parameters (sex and age structure, fecundity, and population growth) and the main environmental factors (legal hunting and poaching, predators, weather, and food supply) affecting the structure and dynamics of the large Tartarian roe deer (Capreolus pygargus Pall.) population of Kurgan oblast were studied. The question of the conformity between the population size and the carrying capacity of its range is considered.     

Population dynamics and changes in the population structure of a polymorphic colony of northern mole voles

Long-term (1985–1999) stationary observations on a polymorphic population of northern mole voles (Ellobius talpinus Pall.) in Kurgan oblast, Russia, using a mark-recapture method yielded original data on the population dynamics and population structure of a polymorphic colony consisting of animals of three color morphs (black, brown, and intermediate or transitional). The period when the northern mole vole population dynamics was studied (15 years) consisted of five distinct three-year population phases: depression, growth, peak (stabilization), decline to depression, and the next growth phase. It was shown that the population dynamics and changes in the population structure of northern mole voles in the Kurtamysh colony are cyclic.     

The phenomenon of spatial distribution of the citrine wagtail (<Emphasis Type="Italic">Motacilla citreola</Emphasis>) in the North of Western Siberia and its ecological interpretation

In the nominotypical subspecies of the citrine wagtail, M. c. citreola Pall., the density of nesting pairs in the northern part of its range in the central Yamal Peninsula reaches a peak in the moss-lichen tundra subzone, while similar biotopes (moist herb-moss willow scrub) are also present in the forest-tundra and shrub tundras. It is suggested that one of the causes of such an unusual distribution is that the birds feed on tipulid larvae, which dominate by biomass among invertebrates in moist moss-lichen tundras. The species is capable of successful existence in the northern Subarctic because of the brevity of its post-nesting period, determined by the endogenous control of the age at the onset of postjuvenal molt, rapid molting during the polar day, partial postnuptial molt, and early development of the migratory state, which provides for early departure.     

On Characteristics of Production and Destruction Processes in Lowland and Mountain Tundras of the Extreme North

Parameters of the production and destruction processes in different types of tundras are compared. It is shown that there is a fairly high degree of correspondence between the structure of tundra communities and the ecotopes occupied by them. On the other hand, typologically similar lowland and mountain tundras markedly differ in the functional respect. The rate of decomposition processes is higher under environmental conditions of the mountain tundra belt.     

Phenogenetic Analysis of Pygmy Wood Mouse (Apodemus uralensis Pall.) Populations in the Zone of the Eastern Ural Radioactive Trace (EURT)

Monitoring of A. uralensis populations in Kamenskii raion, Sverdlovsk oblast, in 1992–2002 and in Kaslinskii raion, Chelyabinsk oblast, in 2000–2001 revealed an increase in the proportion and diversity of minor morphogenetic aberrations and abnormalities in the structure of the cranium along the axis of the Eastern Ural Radioactive Trace (EURT). The samples from the southern and northern parts of the EURT (contaminated with ⁹⁰Sr to 500 and 4 Ci/km², respectively) were characterized by directed deviations from the control with respect to the frequencies of phenes of nonmetric cranial traits and an increase in the level of their fluctuating asymmetry in young females, which is indicative of epigenetic rearrangements in populations living in a radioactive environment.     

Coat color polymorphism in populations of the northern mole vole in the Ural Region

Collections made in the course of long-term field studies on ecology of the northern mole vole Ellobius talpinus Pall. in the Ural Region and neighboring areas (more than 2000 individuals from 24 points of the species range) were used to analyze geographic variation in its coat color (color morphs). On the basis of long-term observations (1985–1999) on marked animals from a polymorphic population (Kurtamyshskii raion, Kurgan oblast), the life spans of males and females and the dependence of life span on population density and structure were estimated in animals of different color morphs. Each color morph of E. talpinus was shown to have specific features of the seasonal dynamics of age structure and migrations.     

Composition of pied flycatcher (<Emphasis Type="Italic">Ficedula hypoleuca</Emphasis> Pall.) nestling diet in industrially polluted area

The composition of pied flycatcher (Ficedula hypoleuca Pall.) nestling diet was studied in the zone of strong pollution with emissions from the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast) and in the background area from 2005 to 2007. The results show that diversity of the diet decreases and prevalence in it of one insect taxon (Lepidoptera) increases near the source of emissions. The proportion of uncharacteristic food objects (orthopterans, herpetobiont invertebrates) and variation in the size of invertebrates brought by parents to their nestlings increase, which is explained by degradation of forest habitats in the polluted area. Pied flycatchers provide nestlings with sufficient quantities of food, but its quality in the polluted zone is lower than in the background area.     

Types of narrow-skulled vole (<Emphasis Type="Italic">Lasiopodomys gregalis</Emphasis>) colonies in Northern Kulunda and seasonal dynamics of their demographic composition

Demographic structure and its seasonal dynamics have been studied in colonies of narrow-skulled voles (Lasiopodomys gregalis Pall.) in Northern Kulunda. Three types of colonies have been distinguished: (I) true colonies (large, complex families), (II) simple families (nuclear or incomplete), and (III) all-male colonies. Changes in their sex, age, and functional composition (based on animal migration activity) during the breeding season have been analyzed.     

Juvenile Dispersal in the Colonies of Spermophilus majorand S. suslicus Ground Squirrels

Natural dispersal of young animals was studied in the colonies of Spermophilus major and S. suslicus ground squirrels in the Volga region. On the basis of data obtained, this process was modeled taking into account the spatial–ethological structure of the colonies. In both species, male dispersal was more active, whereas the degree of natal philopatry was higher in females. The results of the study do not confirm the aggression concept of juvenile dispersal and indicate that its causes are related to hereditary behavioral tendencies. These results are compared with data on juvenile dispersal in other species of the genus Spermophilus.     

Condition of the Soil Fauna near the Epicenter of an Underground Nuclear Explosion in the Northern Urals

Radioactive contamination affects soil organisms and causes profound structural rearrangements in soil zoocenoses, which are manifested in the decreased species diversity of invertebrate communities and low relative abundance of large soil invertebrates. However, these communities gradually recover their initial structure. The soil biota near the epicenter of an underground nuclear explosion performed 30 years ago in Perm oblast has been studied to reveal specific structural features of the soil macro- and microfauna. Its structural diversity is considered with regard to such components as species (taxonomic) composition, the structure of dominance, and the ratio of ecological and trophic groups.__________Translated from Ekologiya, No. 3, 2005, pp. 171–179.Original Russian Text Copyright © 2005 by Kolesnikova, Taskaeva, Krivolutskii, Taskaev.     

On the Classification of Aquatic Communities: An Example of Zooplanktonic Cenoses of Karst Lakes in the North of European Russia

Nine lakes in the Arkhangelsk oblast were analyzed with respect to their morphometry, hydrology, and hydrochemistry, and their zooplankton was studied for three years. The data on zooplankton abundance, biomass, the ratio of filter-feeders and predators, the Shannon index of species diversity, and average individual weight of zooplankters were obtained. Differences in the structure of zooplanktonic cenoses were revealed in lakes differing in morphometric parameters, prevailing ions (HCO₃ ^–, SO₄ ^2–), and their concentration.     

Structure of fouling communities formed by <Emphasis Type="Italic">Halichondria panicea</Emphasis> (Porifera: Demospongiae) in the White Sea

The structure of fouling communities formed by the sponge Halichondria panicea in the White Sea is described. On artificial substrates exposed in the sea for a long time, this sponge forms overgrowths on the colonies of long-lived organisms such as the mussel Mytilus edulis or the ascidian Styela rustica. The biomass of algae and sedentary animals (other than H. panicea) on the substrate is markedly smaller in areas colonized by this sponge than in neighboring sponge-free areas. Conversely, the biomass of both sedentary and errant polychaetes is greater in H. panicea colonies than in adjacent fouling communities.     

Spatial population structure of rare orchid species in rich fens in the central part of Murmansk oblast

The spatial structure of 10 populations of rare orchid species (Dactylorhiza incarnata, D. traunsteineri, Listera ovata) has been studied in rich fens sporadically occurring in Murmansk oblast. Two levels of plant aggregation within populations have been distinguished: (1) clusters of individuals and (2) isolated population subsets consisting of clusters. General spatial demographic features of orchid populations in the fens are small area (77 m²) and low ecological density (0.009 ind./m²). Characteristics of the population subsets (their number, area, composition, and distance to the neighboring subset) are species-specific and reflect the degree of species rarity in plant communities.     

Comparative analysis of the population structure of social vole (Microtus socialis Pall., 1773, cricetidae, rodentia) in different areas of its range

A comparative analysis of the spatial-ethological structure of social vole (Microtus socialis Pall.) colonies was made on the basis of studies performed in Dagestan (1987–1991) and the southern Kalmyk Republic (1993–1998). Notwithstanding differences in environmental conditions and the extent and forms of anthropogenic impact, the population structure of the species proved to be similar and stable. Irrespective of population density, its core consists of family groups. Specific features of social behavior (aggressiveness toward unfamiliar animals) provide for the protection of home ranges and help to maintain a stable population structure.     

Ecological Segregation of Bustards (Otididae) in the North of the Lower Volga Region: Evolutionary and Adaptive Aspects

Based on the concept of an ecological niche, the processes of segregation in the Lower Volga populations of great and little bustards (Otis tarda L. and Tetrax tetrax L). have been studied in the evolutionary and adaptive aspects. The results have shown that segregation of the ecological niches of the two species occurs mainly on a trophic basis, when bird specialization in the use of food resources provides the possibility of changing the nesting biotopes. Some trophic adaptations are temporary and do not modify a species-specific stereotype, whereas other adaptations lead to the development of new forms of behavior and their evolutionary stabilization. Spatial characteristics (biotopic preference, nest location, etc.) complement the identified hierarchical series of parameters characterizing the ecological niches of the species studied. In the Transvolga region of Saratov oblast, the total sizes of great and little bustard populations in the breeding season reach approximately 4100 and 5900 birds, respectively.     

Small mammals in undisturbed and restored tundra biogeocenoses

Small mammal communities have been studied in undisturbed and restored zonal biogeocenoses in the southern subzone of eastern European tundras. The results show that the consequences of anthropogenic disturbances to the environment have an adverse effect on parameters of abundance, spatial distribution, and population dynamics of species comprising zonal communities. Soil and plant components of the disturbed biogeocenosis recover more rapidly than its small mammal community.     

Reproductive parameters and disturbances of embryonic development in the fieldfare (<Emphasis Type="Italic">Turdus pilaris</Emphasis> L.) in the zone of impact from the nuclear fuel industry

The impact of emissions from the Siberian Chemical Plant (Tomsk oblast) on reproduction and embryonic development of the fieldfare was studied. Bird abundance, clutch size, and egg volume in the impact and background (control) zones were similar, but partial brood mortality in the impact zone proved to be significantly higher, and the frequency of embryonic pathologies (including developmental abnormalities) was also several times higher than in the control.     

Variability of the Flower Structure in European Starflower (Trientalis europaeaL.) in Natural Populations

Flower variability was studied in natural populations of European starflower (Trientalis europaeaL.). The results showed that the flower structure in this species is determined by two parameters: the multiplicity of primordia of flower components and the uniformity of flower meristem development. The frequencies of nonuniformly developing flowers differs depending on the habitat. It appears that both parameters are largely determined by random fluctuations.