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.     

Determining the age of cyclomorphic rodents: Functional-ontogenetic determination,ecological aspects

Functional-ontogenetic determination of age-dependent dental changes (ADCs) in voles has been demonstrated. The relationship between ADCs and the functional state of animals has been analyzed. A scheme and a table for determining individual chronological and biological ages in the bank vole (Clethrionomys glareolus Sch.) are proposed, which markedly improve the accuracy of results. Cases of rodent maturation and breeding in winter are considered.     

Functional patterns of life activities of rodent populations in the winter season

The results of 37-year continuous monitoring of basic rodent population parameters (the example of bank vole) are reviewed and generalized using the functional-ontogenetic approach. The role of the environment in synchronizing changes in certain biological indices is demonstrated. A detailed analysis is made of the pattern of change in population parameters during overwintering, including minimization of most biological parameters in this period and its adaptive significance. It is shown that successful winter survival largely depends on the functional status of animals (the type of ontogeny) and also on photoregulation. Consideration is given to the phenomenon of winter breeding and its types in murine rodents. A scheme is presented that describes the integrated (generalized), unspecific adaptive reaction of the population in response to irregular, extreme impacts of natural factors and some (short-term) anthropogenic impacts.     

Effects of environmental factors and species identity on oxygen and carbon isotope composition of teeth in recent small mammals of the Urals

The variation of carbon and oxygen isotope composition in the carbonate group of carbonated hydroxyapatite from the incisor teeth has been studies in six recent rodent species trapped in different latitudinal regions of the Urals. Specific features of variation in the carbon and oxygen isotope ratios are discussed in dependence of animal’s species identity, typical environment, mode of life, dietary features, and ambient air temperature.     

Types of Ontogeny and Territorial Distribution of Small Rodents

In small rodents, differences in the average home range size, depending on the type of ontogeny and animal sex, have been revealed. The dynamics of changes in the spatial structure of populations during the breeding season are described.     

The Method of Morphophysiological Indicators and Functional-Ontogenetic Approach to Solving Ecological Problems (Based on the Example of Splenomegaly in Rodents)

The productivity of the combined use of the method of morphophysiological indicators (MMPI) and functional-ontogenetic approach in population studies is shown based on the example of analysis of the phenomenon of splenomegaly (SM) in rodents. A solution of the problem of analysis of spleen with a giant variation range is proposed, namely, to analyze the spleen index separately for normal spleen and spleen with SM. It is shown that there is no morphophysiological peculiarity in individuals with different functional statuses in the studied states. It is established that SM does not significantly influence the processes of animal vital activity. The maximum proportion of animals with SM was recorded in reproducing groups, which is due to a high intensity of metabolic processes. It is proved that SM is infectious in the study area. Feral herd infection agents are identified and the mechanism of SM development is considered. The criteria for the correspondence of organs to morphophysiological indicators, as well as the use of spleen as an ecological indicator, are substantiated. All the obtained materials suggest the adaptation of the studied bank vole population to a long-term effect of the infectious factor, which was historically formed in the process of the long-term coevolution of the parasite-host system.

     

Nonresident Activity of Shrews (Sorex araneus,Eulipotyphla): Group Marking

Russian Journal of Ecology -     

Evolutionary ecological analysis of adaptation strategies of rodent populations under extreme conditions

Adaptive strategies of cyclomorphic rodent populations (Rodentia) under extreme conditions of droughts (in 1975 and 2010) have been analyzed on the basis of functional–ontogenetic approach. The following features of these strategies have been revealed: minimization of metabolic processes, block of sexual maturation, intergenerational crossing, prolongation of breeding period, and species-specific features in the dynamics of intrapopulation processes. Profound changes in the level of long-term oscillations of abundance after the drought have been noted in different species. Evidence is provided for the possibility of extremely rapid population rearrangements on an evolutionary scale that are fixed in a series of generations.     

Ecological Analysis of Spleen Hypertrophy in Cyclomorphic Rodents Taking into Account the Type of Ontogeny

The functional approach at the level of physiological functional groups (PFGs) reflecting two types of ontogeny was used to analyze spleen hypertrophy in five species of rodents. In addition to a wide variation of spleen weight, its hypertrophy was observed: in bank voles (Clethrionomys glareolus), the spleen weight was as great as 3.5 g versus the normal value of 100–150 mg. The variation range of the relative spleen weight was estimated. For example, in the dominant species, C. glareolus, this range was considerable (from 2 to 125). A distinct relationship with the types of animal ontogeny was revealed. The genus specificity of the phenomenon—its occurrence in three species of Clethrionomys voles and absence in Microtus voles and mice—was determined in the study region. The animals with normal and hypertrophied spleens did not differ from each other significantly in their vital activity (at least, with respect to the parameters studied). The voles with hypertrophied spleens normally reproduced, and the hypertrophy was asymptomatic. These findings suggest that the populations have adapted to a damaging factor (or factors) in the course of a prolonged coevolution. This parameter is regarded as the indicator of the presence of a damaging factor in the population.     

Alternative Types of Ontogeny in Cyclomorphic Rodents and Their Role in Population Dynamics: An Ecological Analysis

Two alternative ontogenetic pathways regularly effected in the populations of small mammals are analyzed as a manifestation of developmental multiversality. The types of ontogeny in rodents are characterized. These data are reflected in the concept of the functional approach. Multiversality of development in plants and animals is considered. Based on the results of long-term (26-year) observations on the natural populations of six rodent species, the dynamics of relationships between the types of ontogeny, abundance, and basic population parameters are analyzed using an example of a background species (Clethrionomys glareolus). A trigger mechanism of switching to a certain type of ontogeny, the role of environmental factors in actuating this mechanism, and the role of the genotype as a basis of multivalence are discussed. The existence of two developmental variants is regarded as a basis for functional rearrangements providing for a high flexibility of population responses and as a mechanism of population regulation determining the dynamics of rodent fauna. An adaptive population response to a board spectrum of influences, including anthropogenic damage, depends not only on the type and strength of the influence, but also on the functional structure of the population. The concepts described in the paper may explain the significance of critical periods in the life of populations.