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LABORATORY OF POPULATION ECOLOGY
MAIN GOALS AND TASKS
Professor S.A. Shilova
Kalmykia. Meriones tamariscinus. Feed reserving
Ground squirrels, labeled with collars for individual recognition
The laboratory is working according to the program of the Biological Sciences Department of the RAS "Ecology of organisms and communities". The main direction of the work is the study of the patterns of formation and dynamics of populations as a basis for adaptations to the changes of natural and social environment. The basic models for research were small mammals and some sparrow birds. Long-term field observations on the key areas of different landscape zones (the regions of expedition works are described in section 12) served as the main method of studies. Field investigations are conducting annually in subzones of middle and south taiga, mountain forests (Krasnoyarsk Region, Komi Republic, Tver Region and Mongolia), in dry steppe and semi-desert zone (Kalmykia, Saratov Region), in steppe meadows (southern districts of Moscow Region) and in tropical forests of southern Vietnam.
Dynamics of grazing ecosystems in semi-desert of Kalmykia was studied. It was shown that as a result of economical reconstructions, a reduction in pasture occurred that led to transformation of the primary semi-desert into "anthropogenic steppe" with severe grass and predominance of mat-grasses. A rapid restorative succession of vegetation didn't induce corresponding changes in the structure of rodent community. An "inertness" of the populations in response to environmental changes was observed (S.A. Shilova, A.V. Tchabovsky, V.V. Neronov). These materials were defended in the thesis work of V.V.Neronov "Dynamics of vegetation and rodent populations in the south of Kalmykia in changing environment" SIEE RAS, 2002.
The materials on specific character of rodent communities in the deserts of different continents were generalized. It was shown that structural organization of communities of little mammals in the desert was formed under the influence of exogenous and endogenous factors, at that in different deserts different combination of the factors determined a high degree of variability in community structure. These materials were defended in the thesis work (Doctor of Sciences Degree) of K.A. Rogovin "Ecological and geographical aspects of organization in communities of small mammals in deserts" SIEE RAS, 1997. The possibilities of non-invasion evaluation of the stress level as an index of population group stability were shown on the model of great gerbil Rhombomys opimus (K.A.Rogovin).
The peculiarities of individual and social behavior of rodents of arid zones were studied. On the model of gerbils and ground squirrels (g. Meriones, Rhombomys, Spermophilus etc.) a new concept of divergent evolution of sociality in the rodents of open areas was suggested, which implied two ways of social adaptation depending on ecological conditions: the strengthening of social dependence or the increase of social indifference (A.V. Tchabovsky). These materials were generalized in the thesis work (Doctor of Biological Sciences) of A.V.Tchabovsky "Evolution of sociality in the rodents of open areas: ecological aspects" (SIEE RAS, 2006) and in the thesis work (Candidate of Sciences Degree) of A.F. Babitskiy "Life history regulation in Speckled ground squirrels (Spermophilus suslicus Guld. 1770)" (SIEE RAS, 2008).
In the subzone of the South Taiga (Tver Region), the structure and functions of populations of small mammals (common shrew, red-backed mouse) were studied. Ecological populations of common shrew were determined and it was shown that the borderline between populations was defined by interpopulation mechanisms, basically by specific character of displacement and dispersion. The principle importance of signal fields in provisioning of population autonomy was revealed. Classification of the small mammalian species with different functional organization of populations was suggested. In the course of this direction of research, the thesis work (Doctor of Sciences Degree) of N.A.Shchipanov "Functional organization of populations" (SIEE RAS, 1996), the thesis work (Candidate of Sciences Degree) of T.B.Demidova "Spatial-ethological structure of populations of four common shrew species (Sorex araneus, S.caecutiens, S.isodon and S.minutus)" (SIEE RAS, 2000) and the thesis work (Candidate of Sciences Degree) of A.V.Kouptzov "Non-resident behavior in four common shrew species - Sorex araneus, S.caecutiens, S.minutus, S.isodon" (SIEE RAS, 2004) were defended. On the basis of the obtained data, the studies on chromosomal races distribution of common shrew in different parts of the areal have been evolved together with the Laboratory of microevolution since 2002. The zones of hybridization between the races were revealed. It was shown that a limited migratory activity of the common shrew acted as a mechanism, preventing hybridization (N.A.Shchipanov, A.A.Kalinin, B.I.Sheftel), and the thesis work (Candidate of Sciences Degree) of Pavlova Svetlana “Population and genetic aspects of interactions between the chromosome races of the common shrew Sorex araneus L. in a hybrid zone” (SIEE RAS, 2007) was defended.
In the Krasnoyarsk Region (middle taiga), the previously started studies on dynamics of population structure in the model species of small mammals and sparrow birds were continued. Density assessment for 54 species of sparrow birds and the dynamics of this index for 25-year period was made. The specific character of forage behavior in 7 species of leaf warbler species (g. Phylloscopus) was studied and the role of foraging behavior in formation of morphological adaptations was revealed. A possible role of sparrow birds of the middle taiga in transferring of the avian flu virus was studied. According to this part of research, the thesis work (Candidate of Sciences Degree) of O.V.Burskiy “Population structure and dynamics of passerine birds in Central Siberia” (SIEE RAS, 2007) and the thesis work (Candidate of Sciences Degree) of O.N.Batova "Foraging behavior and its role in ecological segregation of seven sympatric old-word leaf warbler species (g. Phylloscopus)” (SIEE RAS, 2007) were defended.
The comparative studies of long-term dynamics of the number of small mammals in the middle Yenisei taiga and in the mountain forests of Western Khentei (Mongolia) were carried out. It was shown that the character of number dynamics was dependent on environmental conditions. In stable conditions of flat ground taiga, well defined cyclic fluctuations in number were formed, and acyclic fluctuations in number depending on meteorological factors were characteristic for the periphery of taiga zone (Western Khentei) (B.I.Sheftel). Long-term data, concerning population cycles of small mammals, in different natural zones are generalized. On the basis of these materials, the thesis work (Doctor of Biological Sciences Degree) of B.I.Sheftel is preparing for defence.
In tropical forests of southern Vietnam, long-term studies on species diversity, number and population structure of rodents were carried out and their role in nidus of plaque was studied out. On the basis of zoological and parasitological analysis of the niduses of this infection, a new hypothesis of the plaque agent origination was suggested. The most important ecological precondition of the plaque origin became the behavior of Mongolian marmot as an adaptive response to living in cold climate. On the basis of obtained data, the thesis work (Doctor of Biological Sciences Degree) of V.V.Suntsov "Ecological aspects of plaque bacillus evolution and nature nidus genesis" (MSU, 2001) and the thesis work (Candidate of Sciences) of O.N.Shekarova "Population ecology of the red spiny rat Maxomys surifer Miller 1900" (SIEE RAS, 1998) were defended.
For the period of 1996 - 2007 12 dissertations were defended (4 of Dr. Biol. Sci. and 8 of Cand. Biol. Sci.)