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1.
Methods of geometric morphometrics have been used to estimate the influence ratio of nonselective elimination and drought factors on variation in the shape and size of the mandible in the population of bank vole (Clethrionomys glareolus Schreb.) in the southern taiga subzone. Nonselective elimination of rodent populations for medical and sanitary purposes was carried out in a felling site located in a focus of hemorrhagic fever, in the spring of a climatically normal year and of a dry year. The summer samples of mature young of the year from control bank vole colonies and impact colonies (i.e., recovered after deratization) in adjacent years have been compared. The results show that drought, nonselective elimination, and the interaction of these factors have significant effects on the size and shape of the mandible. Changes in its shape under drought conditions are largely due to allometry. Morphogenetic effects of nonselective elimination are highly repeatable between climatically different years. A significantly higher level of within-group morphological disparity (MNND) of the undisturbed control cenopopulation in a dry year has been revealed, which indirectly indicates a stronger destabilization of morphogenesis upon exposure to the autecological factor. Every ecological factor contributes to the development of specific configurations of the mandible; i.e., it induces certain changes in morphogenesis in response to aut- and synecological effects and their combination.  相似文献   

2.
Using methods of geometric morphometrics, significant differences have been revealed in manifestations of variability and morphological disparity in allochronous samples from the population of model species, the bank vole (Clethrionomys glareolus Schreb. 1780), in the Middle Urals at different levels of rodent community (taxocene) completeness in different years. Two states of the taxocene—oligospecific (two species) and polyspecific (five species)—and the level of relative abundance of bank voles (high or low) have been taken into account. Comparative analysis of variation in the size and shape of the mandible in same-aged (late-summer) young of the year has shown that significant morphogenetic differences exist between the animals sampled from the rodent taxocene at its different states (oligospecific and polyspecific) and, to a lesser extent, at high and low levels of abundance. The level of variation and the parameter of intragroup morphological disparity (MNND) in the mandible shape reach a maximum when the community has a reduced composition and decrease to a minimum when its composition is complete (i.e., in the oligo- and polyspecific taxocene). A parallelism is observed in the manifestation of morphofunctional changes of the mandible in male and female voles under conditions when the taxocene has high abundance and oligospecific composition or low abundance but polyspecific composition. Different morphogenetic responses of the population to oligo- and polyspecific composition of the community are considered as a compensatory increase of morphological disparity in the dominant species (the bank vole) under conditions of incomplete composition of the taxocene and low population density, in accordance with Chernov’s ecological compensation principle.  相似文献   

3.
Changes in the distribution and abundance of some game mammals have been analyzed over the past 100–150 years. Correlations between changes in the population density of species in slightly and strongly transformed habitats have been revealed, which show that the influence of anthropogenic factors on the population density of species has a highly complex pattern. Transformation of habitats leads to disturbances in the species composition of communities, changes in the population density of species, and disruption of functional relationships between them.  相似文献   

4.
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.  相似文献   

5.
Molecular genetic methods (AFLP and ITS1–5.8S–ITS2 rDNA analysis) have been used to study the level and structure of genetic diversity in relict populations of the Ural endemic Gypsophila uralensis Less. in the northeast of European Russia. Intraspecific genetic differentiation is most clearly manifested between G. uralensis Less. subsp. pinegensis (Perf.) Kamelin locally endemic to the north of Europe (Arkhangelsk oblast, locus classicus) the population of G. uralensis Less. subsp. uralensis on limestone outcrops along the Shchugor River, the Subpolar Urals. The cluster of Timan populations (on limestone outcrops along the Svetlaya, Pizhma, and Myla rivers) is autonomous and genetically heterogeneous. Genetic distances between model G. uralensis s.l. populations are correlated with geographic distances. The size and abundance of relict populations show a descending gradient in the forest zone, and parameters of their genetic diversity [1] and unbiased expected heterozygosity have been found to decrease along this gradient.  相似文献   

6.
The overgrowing of meadow-bog communities by shrubs and trees (age 5–40 years, crown closure 0.4–0.9) leads to a decrease in incident illumination. As a consequence, juvenile and generative plants disappear from D. incarnata population loci, their average ecological density decreases, and the loci enter the state of regression. The digging activity of wild boars disrupts phytocenotically closed groups of longirhizomatous herbs, thereby creating favorable conditions for seed reproduction of D. incarnata. The species begins to form population loci with a complete ontogenetic spectrum and high ecological density, eventually restoring the normal (definitive) population structure.  相似文献   

7.
Changes in the survival parameters of the red fox were analyzed at different phases of the population cycle. It was found that the survival rate in all age classes, including newborns, drastically increased at the phase of population growth. The relationship between the general mortality rate and population size was determined. A hypothesis concerning the mechanism of these changes in the general mortality rate is suggested.  相似文献   

8.
Experimental studies of interactions between two amphipod species (Gmelinoides fasciatus and Gammarus lacustris) showed that predation is the basic mechanism accounting for their mutual exclusion in nature. Mortality from predation among similar-sized specimens of both species at an equal abundance ratio was similar (24–25% in G. lacustris and 27–30% in G. fasciatus). The displacement of G. lacustris by G. fasciatus was observed when the latter was dominant. Adult G. fasciatus and G. lacustris successfully preyed on juveniles of their competitors and did not differ significantly in daily food consumption as a percentage of body weight: 6–24% at a fresh body weight of 18–24 mg in both species. The potential for rapid population growth under new conditions contributed to the success of the invasive Baikal species G. fasciatus in displacing G. lacustris from many water bodies of Russia.  相似文献   

9.
To estimate the response of tree vegetation to recent climate warming in the Western Caucasus, the population state of several tree species at the upper limit of their distribution has been estimated in three mountain massifs in the Belaya River basin. For this purpose, the average and maximum stem diameters, vitality, and age of trees have been determined in the transitional zone between middle-mountain and high-mountain beech-fir forests (1400–1700 m a.s.l.) and in crooked birch forests growing at the upper timberline (1810–2025 m). The upper limits of Acer platanoides, A. pseudoplatanus, Ulmus glabra, and Betula litwinowii have shown a tendency to rise. The upper limit of Abies nordmanniana has remained unchanged over the past few decades, which may be explained by a decrease in moisture supply during the warm season.  相似文献   

10.
Changes in the abundance and taxonomic and trophic structure of necrophilous invertebrates inhabiting mixed forests have been studied in the area polluted with the emissions from the Middle Ural Copper Smelter. It has been shown that the abundance of most taxa decreases by factors of 2 to 80 along the pollution gradient, but the trophic structure and composition of major groups vary insignificantly. Changes in the necrophilous assemblage can be caused by either direct (toxic) action of industrial pollutants or their indirect effect exerted through modification of habitats.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
Fluctuations in the abundance of insular groups of sea otters on the Commander Archipelago are analyzed with regard to changes in meteorological conditions. The main factors responsible for the abrupt decline of the Bering Sea group between 2002 and 2004 are discussed. A statistically significant correlation has been revealed between fluctuations of sea otter abundance and the cycles of solar activity in the period since 1992. Changes in the age and sex structure of the insular groups of sea otters are evaluated.  相似文献   

14.
The spatial distribution of 33 Arctic fox dens on Bering Island was studied, and a relationship between the burrowing activity of Arctic foxes and the pattern of vegetation near their dens was revealed. This activity was shown to change the structure of the plant cover, with the degree of change depending on the type of biotope.  相似文献   

15.
It has been shown that conditions formed in technozems of tailing dumps covered with a layer of chernozem are optimal for the development of soil microflora, including actinomycetes, as follows from their high abundance. The use of Leymus sabulosus (Bieb.) Tzvel in biological remediation of technozems formed in tailing dumps ensures an increase not only in the abundance of microorganisms in edaphotopes but also in their ecological diversity, compared to technozems planted with Rhus hirta (L.) Sudw, as confirmed by 1.2- and 1.9-fold increase in the Margalef and Berger–Parker diversity indices. Therefore, applying a layer of chernozem on technozems of tailing dumps provides for more efficient remediation of technogenic soils.  相似文献   

16.
The cyclicity of population dynamics of abundance has been analyzed in sympatric adult populations of three odonate species monitored for long time (1980–2010) in the Lake Chany basin (Western Siberia). The spectra of odonate population dynamics have been constructed for the first time and shown to be species-specific: each species has its own population cycles, and if the cycles are similar, interspecific differences manifest themselves in the relative power of these cycles. These differences provide for separation of species in time, reducing the stress of competition between them. The population rhythms of all studied species show synchronicity with natural rhythms that are important to them, such as fluctuations of climatic parameters (2–3 year cycles) and hydrological parameters of Lake Chany (2–4-year cycles).  相似文献   

17.
Long-term changes in the contents of heavy metals (Cu, Zn, Cd, Рb) in the food and liver of bank voles (Myodes glareolus) inhabiting areas exposed to pollution from the Middle Ural Copper Smelter (MUCS) in the period of reduction of its emissions (1990–2015). The results show that 50-fold reduction of emissions has not resulted in an equivalent decrease in the dietary and body concentrations of metals: in the impact zone (1–2 km from the MUCS), Cu, Zn, and Pb concentrations remain unchanged, while Cd concentrations have increased twofold by the end of the observation period; in the background zone (20 km), Cu, Zn, and Cd concentrations remain unchanged, while Pb concentrations have decreased by a factor of 1.7–2.5; and no directed changes have been revealed in moderately polluted plots (4–6 km). The accumulation of heavy metals in the animal body depends primarily on the contents of these elements in food and on the system of elementspecific homeostatic barriers providing effective protection from the toxic effect of heavy metals.  相似文献   

18.
The environment-forming role of desert tree plants has been studied in the light of A.A. Uranov’s concept of phytogenic field using the example of black saxaul, Haloxylon aphyllum (Minkw.) Iljin, in the Karnabchul Desert. It has been shown that the environment-forming influence of this species leads to considerable changes in the light regime, air and soil moisture and temperature regimes, and soil humus and salt contents within its phytogenic field. Consequently, pertinent changes take place in the dynamics of abundance and distribution pattern of the main plant species and wormwood–ephemeral vegetation.  相似文献   

19.
The effect of geographic origin on morphometric characteristics of ants has been studies by means of one-way ANOVA using 120 worker specimens of M. angulinodis from four population groups inhabiting different parts of the Baikal region. Similarity between the population groups has been evaluated using cluster analysis. The results show that worker specimens in populations from areas with lower air temperatures have significantly greater body size and that ants with an elongated head and more strongly curved frontal carinae dominate in the south of Irkutsk oblast, while ants with a wider frons prevail in the south of the Republic of Buryatia.  相似文献   

20.
The contents of the digestive tract in sables (Martes zibellina L.) of known sex and age from the Middle Kolyma basin were examined to assess the winter diet in general and the frequencies of particular types of food in different sex and age groups of these animals. No statistically significant sex-related differences in the diet were revealed. This is probably explained by a considerable overlap of size and weight parameters between male and female Kolyma sables, due to which probable differences in their diets are leveled off.  相似文献   

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