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.     

Simulation of Rabies Epizootic Process in Fox Populations at a Limited Carrying Capacity of Biotopes

To describe the epizootic process of rabies in fox populations, a model based on a cellular automata network (Toffoli and Margolus, 1991) was constructed. The cell state and the rules of transition from one state to another were determined in accordance with a modification of the previous model based on a differential equation system, which was proposed to describe the epizootics of fox rabies in Western Europe. The new model provides the possibility of simulating spatial heterogeneity and indices of animal mobility related, in particular, to the seasonal features of fox ecology. Calculations were made using population parameters characteristic of biotopes with a low carrying capacity (the steppe zone of Western Siberia). According to the model, the maintenance of rabies epizootics in these biotopes is possible on condition that the mobility of foxes in them is much higher than in the biotopes with a high carrying capacity. This model can be used for prognosis and epidemiological control in natural rabies foci.     

Influence of China''s Population Mobility on the Change of Regional Disparity since 1978

In this study, an econometric model about population mobility and economic growth is used to show the unbalanced distribution of population mobility in different region was remarkably related to that of regional economic growth and the large number of movers had a significant influence on regional economic growth and developing disparity. On the basis of this study, we conclude that China's population mobility also had a significant influence on the structure and tendency of regional disparity, and the population mobility enlarged the regional disparity of the whole nation, the East, and the West since the reform, besides the Midst during 1978 to 1987. Furthermore, the population mobility accelerated the increase of regional disparity in the whole nation, the Midst, and the West, but at the same time, retarded that in the East in the period of 1996–2003.     

The Toad-Headed Agama Phrynocephalus guttatus (Reptilia: Agamidae): The Correlates of Survival in a Translocated Population in the Southwestern Kalmyk Republic

Observations of a translocated population of toad-headed agamas (Phrynocephalus guttatus) in the south of the Kalmyk Republic (1998–2001) have shown that seasonal differences in animal survival are manifested only in juveniles and the survival rate of juveniles is higher than that of adult individuals. A significant correlation between survival rate and sex is also characteristic only of juveniles: survival rate is higher in females than in males. In adult males, survival positively correlates with the level of activity; in juvenile males, with body size. In adult females, survival inversely correlates with body size and weight.     

Relationship between the Population Dynamics of the Gypsy Moth (Lymantria dispar L., Lymantriidae: Lepidoptera) and the Genetic Polymorphism of the Nuclear Polyhedrosis Virus

The population dynamics of the gypsy moth and the genomic DNA of the nuclear polyhedrosis virus (NPV) pathogenic for this insect were simultaneously studied using nucleic acid molecular hybridization (NAMH). It was demonstrated that population outbreaks of the gypsy moth were accompanied by an increase in its sensitivity to NPV and in the genetic polymorphism of NPV strains circulating in the insect populations. The hybridization activity of the virus strains isolated at the phase of gypsy moth population growth was significantly higher (p < 0.001) than the activity of the strains isolated at the phase of population decrease.     

On Population Mobility in Market Economy

Abstract

Regular and extensive social population mobility in natural economy is neither necessary nor possible while in a planned economic system, social population distribution is necessary but social population mobility is unlikely. Modern market economy as a highly mobile economy has a free-mobile population characteristic of market economy, which is fundamental to optimize human resource distribution. The rule for the modern market-based population movement is as follows: If the mobile population is the rational behavior choosers, under the permissive developmental environment as arranged by the social system, they tend to move from low profit-making fields to high income fields when there exists comparable difference of income in different regions and different industries, and various potential and practical profit-making chances. The degree of difference in comparable income is positively co-relative to the velocity and flux of mobile population.     

Specific Features of the Population Ecology of Creeping Thistle, Cirsium arvense(L.) Scop. s. l.

Two populations of creeping thistle (Cirsium arvense) growing in a field uncultivated for many years and on the sloping bank of an artificial pond were studied with respect to the demographic and chemical composition. The results showed that the contents of some elements in plants depend on specific features of the soil and plant population parameters (abundance, biomass, and ontogenetic composition). Some indices of the content of mineral substances in the population and soil proved to be difficult to interpret unambiguously.     

Species-Specific Features of Inter- and Intrapopulation Variation in the Level of Chromosome Instability in Rodents

Studies on the common vole Microtus arvalis revealed a distinct cytogenetic response to the influence of ionizing radiation, a wide range of variation in the group average indices of chromosome instability beyond the zone of technogenic impact, and the influence of natural factors (viral infections and fluctuations of population size) on the frequency of chromosome aberrations. In the northern mole vole Ellobius talpinus, neither the mutagenic effect of ionizing radiation nor interpopulation differences in the level of chromosome aberrations in the absence of anthropogenic impact were detected. Variation of genome instability of the rodents is significantly contributed to by species demography and population cycles.     

Periphyton grazing and phosphorus excretion by mollusks

The physiological activity of grazers related to feeding, assimilation, and excretion may either increase or decrease the productivity of algae in a periphyton community, depending on the size of the consumer and its population density. Population data on the numbers and biomass of Anisus spp. have been used to calculate the amount of mineral phosphorus per unit area regenerated in the medium through animal metabolism. No difference in the rate of soluble reactive phosphorus (SRP) excretion has been found between pulmonates and the bivalve Sphaerium suecicum.     

Prognosis of the State of Aquatic Animal Populations under Conditions of Disturbed Ionic Composition of Water

In the crustacean Eudiaptomus gracilisSars, relationships between mortality (D) and the ratio of main cations (R, the ratio of the sum of potassium and sodium equivalent concentrations to the sum of calcium and magnesium equivalent concentrations) were studied. The calculated regression equation D= 315 – 355/Rwas used for predicting the state of E. gracilispopulation in Lake Poppalijarvi (Karelia) polluted with mining waste. At R< 0.47, the population will survive; at R> 1.53, its extinction should be expected. The results of hydrobiological observations on Lake Poppalijarvi confirmed the prognosis based on the equation.     

On Population Mobility in Market Economy

A general survey of the changing process of economic development of human society indicates three historical development stages: agricultural-oriented natural economy, industrial-oriented market economy and knowledge- oriented market economy. In the first natural economic era, the most important factor of production is the land and the land resource is the first resource in the economic era of agriculture. In the market economy era of industry, capital, especially material and monetary capital…     

Problems of Population Dynamics of the White-Eyed Pochard (Aythya nyrocaGuld., 1770) in the Eastern Sea of Azov Region

The long-term population dynamics of the white-eyed pochard (Aythya nyroca) in the eastern Sea of Azov region was analyzed. It was found that the local population of this species tends to decrease in size. Clutch size, egg size, reproductive behavior, intraspecific clutches, embryonic mortality, and hatching success in this population were studied. The contents of PCDD and PCDF in the eggs of waterfowl were estimated. The eggs of white-eyed pochard, compared to other waterfowl, proved to contain abnormally high concentrations of xenobiotics. Possible causes of A. nyrocapopulation decline, including the impact of superecotoxicants, are discussed.     

Gradient analysis of the chrogenetic structure of lowland and highland scotch pine populations

Gradients of genetic distances (GGDs) between 26 adjacent cenopopulations of Scotch pine (Pinus sylvestris L.) along the transects through the distinct landscape-ecotopic isolation borders were analyzed graphically. The results made it possible to reveal and quantitatively estimate gradients and borders of gene-pool structural patterns in populations of this species in the central part of Northern Eurasia. In lowland areas, the most distinct borders were found between pine populations growing on dry lands and bogs (Pineta sphagnosa) in the forest zone of the Transural region, as well as between the Arakaragaiskii and Amankaragaiskii island pine forests in the steppe zone (Northern Turgai). In highland areas (the Urals and the Carpathians), the greatest GGDs were observed between low-mountain (about 600 m above sea level) and middle-mountain (850–900 m) populations. Analysis of GGDs is a promising gene-geographic method for determining population borders and studying the chorogenetic structure of species.     

Externalities,Floating Population and Spatial Agglomeration

Abstract

With the further development of socialist market economy, the mobility of factor markets in China, especially the labor market, is strengthened. Externalities interacts with the agglomeration of productive factors. Under the framework of new economic geography, this article presents a theoretical model involving the endogenous population density affected by urban externalities. Results show that the population density is more concentrated around the center because the degree and extent of interaction between individuals intensifies when the distance from the center decreases. When there are several externalities resources, the aggregation of externalities changes the configuration of spatial factor allocation. These results fit well with the empirical facts about the decreasing density of floating population along the cities of Guangzhou, Dongguan and Shenzhen in Guangdong Province which is situated in the eastern coast of the Pearl River Delta. We find that under the impacts of externalities released from Hong Kong into the coast, floating population was more concentrated around Shenzhen and Dongguan, which are more adjacent to Hong Kong compared with Guangzhou City.     

Population cycles of the bank vole in the range optimum

Patterns of seasonal and long-term dynamics of the size and structure of the bank vole population were studied in the European subtaiga subzone, the optimum of the species range. The dynamics of this population proved to undergo complex fluctuations with cyclic components, which have periods of one year and about three years. The one-year fluctuations of the population size and structure are accounted for by animal adaptation to seasonal changes in environmental factors. The fluctuations with the three-year quasi-period are determined by intrapopulation density-dependent mechanisms.     

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.     

Fluctuations of Population Size and Structure in the Northern Mole Vole: Preliminary Analysis

Long-term stationary studies on the ecology of the northern mole vole (Ellobius talpinus Pall.), performed by the mark–recapture method from 1985 to 1997, have provided original data on population dynamics and structure. The analysis shows that, to reveal cyclic fluctuations of population size in this species, the period of three years should be taken as a unit of time for estimating the duration of one phase. The 12-year population cycle in E. talpinus has four distinct phases: an increase, a peak, a decline, and a minimum. At each phase, the population is characterized by certain features of family structure, age composition, birth and death rates, and the composition of migrants.     

Spatial Distribution of Sables in the Middle Ob Region

Results of stationary studies on the spatial location of sables (Martes zibellinaL.) belonging to different age and sex groups are summarized. Mapping the sites where 388 animals were taken, it was found that young animals tended to live near floodplains; adult animals, on watersheds. Analysis of sables taken by commercial hunters (n= 1833) made it possible to estimate the age composition and the degree and spatial distribution of the hunting pressure on sable populations in three areas of the Ob region. The spatial separation of young and reproductive animals is interpreted as a group adaptive response to the specific distribution pattern of different habitats typical of this species and to the pattern of animal elimination. It is proposed to use the specific pattern of animal distribution for maintaining the size of the population that is subject to hunting. Specifically, reserve (reproductive) territories should be organized in watershed areas.     

义乌市流动人口对区域土地利用格局的影响研究

随着城市化和工业化进程不断加快,我国的人口流动越来越频繁。流动人口特别是流入人口持续、大规模增长对城市资源的影响方式和影响程度,是中国未来社会发展和城市化过程中急需深入研究的重要问题之一。本文以城市综合竞争力居浙江省县级市首位的义乌市为例,利用遥感技术提取了该市2007年的土地利用信息,在GIS空间统计分析功能支持下,综合分析了义乌市社会经济发展、流入人口变化特征,重点讨论了净流入人口持续增长对区域土地资源利用格局的影响。结果表明:随着社会经济的快速发展,2001-2007年,义乌市总人口增加了近68万人,其中流入人口增加了63万人;建设用地从51.33km2增加到140.36km2;耕地面积减少了126.55km2.     

Dispersal of Land Snails of the Genus Xeropicta Monterosato, 1892 (Gastropoda; Pulmonata; Hygromiidae)

Data on the parameters of migration of two land snails of the genus Xeropicta are presented. In relatively homogeneous habitats, the locomotor activity of these mollusks is relatively high: they can travel for up to 300 cm per day, with neither the phenotype nor size of the shell having any significant influence on the level of dispersal. The snails prefer to travel westward and southward, but the distances covered by individuals moving in different directions are similar. No connection between the directions or distances of movement on two successive days has been observed.