Population Structure and Dynamics of Small Rodents and Insectivorous Mammals in a Region of the Middle Volga, Russia

Home , European pine vole, Striped field mouse, Ural field mouse, Volga Upland

BIHAREAN BIOLOGIST 15 (1): 33-38 ©Biharean Biologist, Oradea, Romania, 2021 Article No.: e201305 http://biozoojournals.ro/bihbiol/index.html

Population structure and dynamics of small rodents and insectivorous mammals in a region of the Middle Volga, Russia

Alexey ANDREYCHEV

National Research Mordovian State University, Saransk, Russia, E-mail: [email protected]

Received: 18. March 2020 / Accepted: 14. August 2020 / Available online: 18. August 2020 / Printed: June 2021

Abstract. Long-term dynamics analysis of small mammals in the Republic of Mordovia is given in this paper. Ecological studies on the small mammals at Republic of Mordovia were made during the years 2006-2019.There are altogether 17 species. Among the 23,780 captures. A 3-4-year cycle in population fluctuations was revealed for the conditions of this region. It is shown that in unfavorable years under the conditions of temperature and humidity (2010 and 2012), small mammals recovered their population numbers by the end of the growing season due to the existing areas of settlement and concentration centers. The sex ratio of most species over the research average period is almost always biased in the direction of males.

Key words: rodents, insectivores, population dynamics, reproduction, Russia.

Introduction ies from 3.5 to 4.0°C. The average temperature of the coldest month (January) is in the range of –11.5–12.3°C. Temperature drops down A review of the literature on small mammals, mostly ro- to –47°C occur. The average temperature of the warmest month, i.e. July, is in the range of +18.9+19.8°C. Extreme temperatures in the dents, suggests that average population levels are largely de- summer reach 37°C. The average annual precipitation in the territory termined by a positive effects balance of the resources and of Mordovia is 480mm. Over the course of observation lasting many the negative effects of predators of small mammals and that years, periods of more and less humidification were noted, ranging the strengths of these effects vary from habitat to habitat. between the minimum and maximum values of 120–180mm. Distri- Seasonal patterns of the population change largely occur bution of precipitation across the territory is not very diverse. The each year, because of the seasonal breeding, while the differ- average long-term value of evaporation is calculated to be in the ences among years occur because of theshifts in weather, re- range of 390–460mm (Water resource 1999). sources, and predators (Adler & Wilson 1987, Batzli & Le- According to the research of botanists (Water resource 1999), there are more than 1,230 species of vascular plants from 495 genera sieutre 1991, Batzli 2001). and 109 families in the modern flora of Mordovia. These include 4 The rodent cycle was first described in the scientific liter- species of plains, 8 horsetails, 18 ferns, 3 gymnosperms, and 1,197 ature by Charles Elton (1924). Since then, many regions and species of flowering plants. Herbaceous perennial and annual plants countries have been conducting multi-year counts of small predominate. The number of species of woody forms is relatively mammals. These studies are undoubtedly still relevant. The small: trees – 24, shrubs – 45, shrubs – 7, semishrubs – 5 (Water re- Republic of Mordovia has very few studies on the dynamics source 1999). of the small mammals’species number in the region. All The territory of Mordovia includes coniferous broad-leaf, broad- leaf forests, shrub steppes and meadow steppes. The main forest these works date back to 70years of the last century (Borodin forming species are the Scots pine (Pinus sylvestris L.), Norway 1966, 1974), which is why the interest in this ecological as- spruce (Picea abies (L.) Karst), European larch (Larix decidua Mill.), pect of natural ecosystems is actually due. English oak (Quercus robur L.), common ash (Fraxinus excelsior L.), The aim of the work was to study the dynamics and the Norway maple (Acer platanoides L.), Scots elm (Ulmus laevis Pall.), sil- population structure of small rodents and insectivores spe- ver and pubescent birch (Betula pendula Roth., B. pubescens Ehrh.), cies number in the Republic of Mordoviain the natural habi- black alder (Alnus glutinosa L.), small-leaved lime (Tilia cordata Mill.) tats. This work covers the study of long-term micro dynam- and black poplar (Populus nigra L.) (Water resource 1999). ics of the small mammals’ species number. The material was collected at two hospitals: in the Chamzinsky district (near the village of Chamzinka) and in the floodplain of the

Sura river in the Bolshebereznikovsky district (near the biological

Materials and Methods station of the Mordovian state University). The hospitals were selected in two geo-ecological districts typical for the area: the South- Region of research Eastern (landscape of broad-leaved forests and forest-steppes of ero- The Republic of Mordovia is located in the center of the European sion-denudation plains) and Surskiy (landscape of mixed forests of part of Russia. Its extreme points are defined by geographical coor- water-glacial plains and river valleys). The South-Eastern district is dinates 42º 11’ – 46º 45’ E and 53º 38’ – 55º 11’ N. The maximum dis- located in the axial part of the Volga upland. The arcuate crowned tance from west to east is 298 km and the distance from north to watershed massifs, dissect the upper left tributaries of the Sura – Big south is 57 to 140 km. The area of the republic is 26.2 thousand km2. and Small Kshi, Shtermy, Lasha, Cheberchinka folded siliceous- Features of the geological structure of Mordovia are determined by carbonate rocks with light gray and gray wooded gravelly soils with its location in the central part of the Russian Platform and the north- small tracts of deciduous forest (27.7%). At lower absolute levels, western slopes of the Volga Upland. In the western part of the Re- they are bordered by tracts of slopes composed byeluvial-deluvial public of Mordovia, the Volga Upland reaches the Oka-Don Low- deposits of the upper Cretaceous carbonate rocks with dark gray for- lands. est soils and chernozems under broad-leaved forests, mostly plowed The climate of the region is moderately continental with pro- (55%). On the slopes of the tributaries of the Sura, there are com- nounced seasons throughout the year. The influx of direct solar radi- pletely plowed meadow-steppe complexes. Forests have been pre- ation in Mordovia varies from 5.0 in December to 58.6 KJ/cm2 in served on slopes and beams that are inconvenient for plowing. The June. Total radiation throughout the year is 363.8 KJ/cm2; the radia- composition of woodlands in this group of natural complexes is very tion balance is 92.1 KJ/cm2. The average annual air temperature var- diverse. In addition to oak forests, the area of Linden trees and ash 34 Andreychev A. trees is significant. In the second tier of oak trees, there is an abun- three dominant rodents in the different biotopes showed that dance of shrubby growth. In the form of secondary forests, there are each species had its own optimal biotopes. Under unsuitable aspen trees, less often birch trees, the structure of which is close to conditions, or in the years of lower densities, the numbers of the native forests. The edges are strongly settled. Here you can find these rodents were generally higher in their optimal bio- thickets of briar and blackthorn with a steppe herbaceous cover of sage, bedstraw, tar, pea-shaped peas, and fence peas. The South- topes. The optimal biotopes of M. glareolus appeared to be in Eastern geo-ecological district includes the territories of the follow- the mixed forest, that of M. arvalis in the open areas (mead- ing administrative districts of the Republic: Chamzinskiy, Dubenskiy ows, fields), whereas that of S. araneus in the deciduous for- (Northern part), Bolshebereznikovskiy (Northern part), and Kochku- ests. The peaks of fluctuation curves occurred at different rovskiy (Central part). times in different biotopes. The numbers of rodents varied in Surskiy geo-ecological district occupies the valley of the Sura wide ranges from year to year. There are peculiarities in dif- River, whose tracts are characterized by poor agricultural and resi- ferent species. In the years of 2008, 2014, 2019 the numbers of dential development. The dominant tracts are above-floodplain- all the dominant species were high, while in 2009, 2015 all terraced slightly undulating surfaces composed of ancient alluvial deposits with light gray and gray forest soils under mixed forests were low. But in 2009, the numbers of M. arvalis and S. ara- (42%). Terrace complexes have been significantly reworked by Aeo- neus were particularly low, whereas for M. glareolus, it was lian processes (7%) and are heavily waterlogged. About 24% of the high in the optimal biotope. In 2014, the numbers of M. arva- landscape is floodplain. The structure of natural vegetation is domi- lis and S. araneus were extraordinarily high, while that of M. nated by pine-lichen, or white-mosses, cranberry-Heath, blueberry- glareolus was at an average level. In 2019, the density of the lingonberry, green-mosses, long-mosses and sphagnum. The overall yellow-necked mouse was higher than that of the redbank economic development of the territory is low. Surskiygeoecological vole. Based on our observations of the fourteen years, it is district includes the territories of Bolshebereznikovskiy, Dubenskiy (southern part) and Kochkurovskiy (Eastern part) municipal dis- believed that the yearly periodicity of rodents' numbers is tricts. closely related to the biotopes. In the years of especially high (2014) or especially low (2015) numbers, the indices of num- Study methods bers for the different biotopes were similar, but in the years Ecological studies on the small mammals in the Republic of Mordo- of average densities, high indices occurred in the optimal bi- via date during 2006-2019. The work is based on the materials of our otopes and low indices in the unsuitable biotopes. own surveys of rodents and insectivorous mammals conducted in The dynamics of the number of insectivorous in geo- the Republic of Mordovia, using trap lines and trap grooves using ecological districts during the research period was not cata- traditional methods (Karaseva &Telicina 1996, Ravkin & Livanov 2008). Field work was carried out during the snow-free period of the strophic, i.e. there were no ultra-high fluctuations over the year (from May to November). The snap traps were set in the typical years. The only species of small insectivorous mammals that habitatsof the small mammals for several days and then transferred had clearly defined dynamics were the Eurasian common to the next site.The number of snap traps in each line was 25. Traps shrew and lesser shrew (Fig. 1). were checked to collection material every morning. Bread soaked in sunflower oil was used as bait for trapping method. Within the geo-ecological districts, for the greatest coverage of the species composition, the following habitats were selected as har- vested: 1) mixed forest; 2) oak wood; 3) aspen; 4) meadow; 5) agricultural field; 6) swamp; 7) human construction. During the accounting period, 19255 trap-days (t-d) and 4525 cylinder-days (c-d) were worked, of which 9220 t-d and 2650 c-d were setting the traps in forest biotopes; 5340 t-d and 1875 c-d in open stations; 2950 t-d in swamps; 1745 t-d in human buildings.

Results

There are 17 species of small mammals present in the Repub- lic of Mordovia. Among the 23,780 captured specimens, the bank vole (Myodes glareolus), the common vole (Microtus arvalis) and the Eurasian common shrew (Sorex araneus), were the dominant species. 2106 individuals of small mammals were captured in the monitored hospitals, including five species of voles (the red bank vole, the ground vole, the common vole, the root vole and the short-tailed vole); five Figure 1. Dynamics of the number of Eurasian common shrew and species of mice (the striped field mouse, the Ural fieldmouse, pygmy shrew according to catch data. theyellow-neckedmouse, the house mouse and the harvest mouse); one species of dormouse (the forest dormice); four Eurasian common shrew is reported for the both geo- species of shrews (the common shrew, the least shrew, the ecological districts. It served as a dominant almost always. Laxmann'sshrew and the taiga shrew), one species of Lesser The average long-term population was 14.7 individuals/100 white-toothed shrew; and one species Eurasian water shrew. c-d. Highest relative number was observed in 2010. Trap- As a result, the average long-term number of small mam- ping results showed that female:male ratio is 42% to 58%. As mals captured was established at 8.1 individuals/100 t-d and well, our results showed that the age group ratio in the pop- c-d).An analysis of the numbers and their fluctuations of the ulation is as follows for summer: 39% ad: 48% sad: 13% juv. Population structure of small mammals 35

Pygmy shrew (Sorex minutus) is reported for the both geo-ecological districts. It served as a subdominant of the common borer in forest areas. The average number was 7.1 individuals/100 c-d. The dynamics of the S. minutus captured number was similar to the changes in the number of S. araneus. Our study showed that female:male ratio is 38% to 62%. For summer the age group ratio is as follows: 44% ad: 50% sad: 6% juv. Laxmann's shrew (Sorex caecutiens) is reported for the both geo-ecological districts. The species avoids agricultural fields. The average number was 3.1 individuals/100 c-d. Our trapping results showed that female:male ratio is 47% to 53%. For summer the age group ratio is as follows: 56% ad: 41% sad: 3% juv. Taiga shrew (Sorex isodon) isreported for the both geo- ecological districts. In geo-ecological districts in the Eastern part of the Russia, it shows a biotopic attachment to wet meadows in the border area in forests’ edge, in contrast to the Western part of the region, where it prefers to inhabit dark coniferous forests. The species was not found in human buildings or in agricultural fields. The average number was 5.4 individuals/100 c-d. The female : male ratio is 52% to 48%. For summer the age group ratio is as follows: 35% ad: Figure 2. Dynamics of the number of bank vole, Ural field mouse and yellow-necked mouse according to catch data. 47% sad: 18% juv. Lesser white-toothed shrew (Crocidura suaveolens) is reported for the Chamzinskiy geo-ecological district. It was d. during the species depression, the number falls to 3-4 in- registered in human buildings and near swamps on dis- dividuals/100 t-d. Mordovia is characterized by relatively turbed territories. It was caught in single specimens. The fe- frequent rises and shallow short-term depressions in the male:male ratio is 71% to 29%. For summer the age group ra- population number of the red bank vole. The largest increase tio is as follows: 52% ad: 56% ad: 2% juv. in population was observed in 2009. The entire cycle usually Eurasian water shrew (Neomys fodiens) is reported for the takes 3-4 years. The female:male ratio is 53% to 47%. For Bolshebereznikovskiy geo-ecological district. The average summer the age group ratio is as follows: 38% ad: 57% sad : relative abundance in wet biotopes was 1.3 individuals/100 5% juv. c-d. European water vole (Arvicola amphibius) is reported for Forest dormouse (Dryomys nitedula) is reported for the the both geo-ecological districts. The peak number was rec- both geo-ecological districts. It was mainly registered for the orded in 2014, when the catch was 8.1 individuals/100 t-d. in Bolshebereznikovskiy geo-ecological district. One of the re- other years, the catch had a small number. fugiums of this type in the region is located here (Grigorieva Root vole (Microtus oeconomus) is reported for the both et al. 2015, Andreychev & Boyarova 2020, Andreychev & Ki- the geo-ecological districts. It was caught in wet biotopes. yaykina 2020). The forest dormouse prefers to inhabit oak The average number was 0.7 individuals/100 t-d. trees, and is also periodically observed in human buildings Common vole (M. arvalis) is reported for the both geo- located in the forest floodplain of the Sura River. In 2013 and ecological districts. The female:male ratio is 47% to 53%. The 2018, there was an increase in population number of this age group ratio is as follows: 48% ad: 39% sad: 13% juv. M. species compared to previous years. Due to the rarity of this arvalis is a common species in the fields and meadows, species in the Russian Republic of Mordovia, it is recom- where it appeared as a dominant species among others. The mended to include it in the next edition of the red book of average long-term population is 8.4 individuals/100 t-d. The the region. maximum number reaches up to 15 individuals/100 t-d (Fig. It is known that the population number of the red bank 3). Peaks (2008, 2014, 2019) and depressions in the number of vole (M. glareolus), its’ population number correlates with common vole in different years are consistent with the re- the changes in average annual temperature level and there is sults obtained when analyzing the food spectrum of preda- a minus correlation. The red bank vole is more environmen- tors in the region, including species such as the Eagle Owl tally plastic compared to other forest vole species. However, (Bubo bubo), burial ground (Aqula heliaca), of the Ural Owl it is characterized by a manifestation of heat and moisture (Strix uralensis) in the diet of which M. arvalis plays a signifi- (Andreeva & Okulova 2009). It was registered for both geo- cant role (Andreychev et al. 2014, 2016a, b, Andreychev & ecological districts in the region. For all the Russian Republic Lapshin 2017). of Mordovia, M. glareolus is the most numerous species Field vole (Microtus agrestis) is reported in the Bolshe- among the microteriofauna in the forest area. The popula- bereznikovskiy geo-ecological district. The average number tion number dynamics of the red bank vole, as a dominant was 0.2 individuals/100 t-d. It prefers to settle near various species, it’s indicative for the forest communities (Fig. 2). The reservoirs in sparse forests. species was not captured in agricultural fields and mead- The European pine vole (Microtus subterraneus) is not re- ows. The maximum number reached 24.6 individuals/100 t- ported in our study. However, in 2019, it was captured and 36 Andreychev A.

Yellow- necked mouse (Apodemus flavicollis) is reported for the both geo-ecological districts. Among all forest biotopes, it prefers oak forests. It was not captured in meadows, agricultural fields, swamps. It is a permanent resident species of the human settlements buildings at the Mordovian University station. Broad-leaved and mixed forests are the preferred habitats for this species. The average number was 5.6 individuals/100 t-d. According to the trapping method, the female:male ratio is 26% to 74%. For summer the age group ratio is as follows: 62% ad: 31% sad: 7% juv. Harvest mouse (Micromys minutus) is reported in single specimens in the Chamzinskiy district. Its collection showed a predominance of females compared to males. This is a rare species for the Russian Republic of Mordovia. It is recom- mended to be included in the next edition of the red book of the region. House mouse (Mus musculus) appeared as an absolute dominant species inside the human settlements. The average number in our collection for this speciesis 8.8 individuals/100 t-d. In addition to human settlements in the Cham- Figure 3. Dynamics of the number of common vole and striped field mouse according to catch data. zinskiy district, it was recorded in a single specimen in meadows and agricultural fields. According to the trapping method, the female:male ratio is 36% to 64%. The age group reported for the first time in the Mordovia (Kirillova et al. ratio is as follows: 58% ad: 17% sad: 25% juv. 2019). An example of the European pine vole was a capture on 4 May 2019 in an abandoned vegetable garden in the village of Obrezki. This record is an evidence of the eastern- Discussion most occurrence of M. subterraneus. Previously, the Europe- an pine vole was recorded in neighboring regions of Mordo- It should be noted that, from year to year, small mammals via, namely in the vicinity of the village of Zhelannoe in the almost always increased their numbers by autumn and pop- Ryazan region (Zagorodniuk 1992) and in the Zametchinsky ulated suitable areas of habitat. This was not affected by district of the Penza region (Il'in et al., 2006). This species is some specific climatic conditions of each year (the hot sum- rare and included in many Red books of Russian regions: mer of 2010, high tide 2012). Small mammals filled the free Leningrad region, Tver region, Penza region, Moscow re- habitat areas due to the existing resettlement areas and con- gion, Pskov region, and Novgorod region. The appearance centration areas. In the floodplain of the Sura River, the fo- of a new species for Mordovia can be explained by expan- cus of concentration is the above-floodplain terrace, and pine sion into new territories. This is confirmed by the registra- forests act as a dispersal area. A similar situation was ob- tion of this new species also for the Smolensk region served by other authors for the Volga region, where flood- (Belyaev 2020). plains of steppe rivers, roadside, protective and other forest The striped field mouse (Apodemus agrarius) is reported belts play an important role in the resettlement of mesophilic for the both geo-ecological districts. It has a high population rodents (Oparin & Oparina 2009). Especially this trend of ef- in meadows and fields. This species was not captured in for- fective realization of reproductive potential in Mordovia was est biotopes. The average number was 5.5 individuals/100 t- observed for such biotopes as mixed forest and meadow. d. A. agrarius shows a high population number during the This can be explained from the position that by their nature years of the common vole population depressions (Fig. 3). representatives of microteriofauna from an ecological point The female:male ratio is 39% to 61%. The predominance of of view are mostly expressed r-strategists. Analyzing the av- males over females for the striped field mouse populations erage data on changes in the number of different species of was noted by other authors in the Central Chernozem region small mammals in the time interval, we should state a 3-4- (Okulova et al. 2012). For summer the age group ratio is as year cycle for the region. A similar trend was noted earlier follows: 37% ad: 45% sad: 18% juv. by scientists (Marcstrom et al. 1990, Hanski & Korpimaki The Ural field mouse (Apodemus uralensis) is reported for 1995, Tomášková et al. 2005). For Swedish, population dy- the both geo-ecological districts. It appeared as a subdomi- namics each species of small mammals is significantly posi- nant species compared to the red vole or yellow-necked tively correlated with the abundance of M. glareolus mouse in the forest biotopes. This appeared as dominant (Marcstrom et al. 1990). Fluctuations in most species the species in some of the disturbed meadows in the Cham- small mammals seem to occur in synchrony. One possible zinskiy district. It was not captured inside and around the explanation is that predation mortality caused by specialist human settlements. The average number was 5.6 individu- predators keeps all species in step (Hagen 1969, Angelstam als/100 t-d. The largest increase in the population number et al. 1984). The major alternative hypothesis is that food re- was observed in 2010 (Fig. 2). The female:male ratio is 67% sources change cyclically for all species (Kalela 1962, to 33% y. For summer the age group ratio is as follows: 39% Marcstrom et al. 1990). ad: 52% sad : 9% juv. Population structure of small mammals 37

Mauricio Lima and colleagues demonstratedin their Batzli, G.O. (2001): Dynamics of small mammal populations: a review. Wildlife. study an interesting approach explaining the rise in rodent Populations. 831-850. Batzli, G.O., Lesieutre, C. (1991): The influence of high quality food on habitat population number. In their opinion, reproduction and sur- use by arctic microtine rodents. Oikos 60: 299-306. vival during the breeding season contributed approximately Belyaev, D.А. (2020): Pine vole (Microtus subterraneus, Rodentia, Cricetidae) - a equally to population growth in the leaf-eared mouse, new species of mammals in the fauna of the Smolensk region. Zoologicheskii Zhurnal 99(2): 234-238. [in Russian] whereas the multimammate mouse is characterized by a Borodin, L.P. (1974): Materials to the fauna and ecology of the shrew of the more clearly defined seasonal structure into breeding and North-West of Mordovia. Proceedings of the Mordovian State Reserve 6: 5- non-breeding seasons and, that reproduction contributes far 22. [in Russian] Borodin, L.P. (1966): Comparative evaluation of the effectiveness of different more than survival during the breeding season (Lima et al. methods of fishing for small mammals. Proceedings of the Mordovian state 2003). reserve 3: 186-202. [in Russian] Other scientists attributed the population peaks to an in- Chitty, D. (1967): The natural selection of self-regulatory behaviour in animal populations. Proceedings of the Ecological Society of Australia 2: 51-78. crease in the mammalian food availability (Feliciano et al. Christian, J.J. (1978): Neuro-behavioural-endocrine regulation of small mammal 2002). There was a relationship between the seed production populations. In: Snyder, D.P. (ed.). Populations of Small Mammals Under of various forest trees and population dynamics of small ro- Natural Conditions. Pymatuning Laboratory Ecological Special Publications dents. Although, the effects on population dynamics may be 5: 143-158. Grigoryeva, O., Balakirev, A., Orlov, V., Krivonogov, D., Stakheev, V., caused by unknown related factors. The need for seed food Andreychev, A. (2015): Phylogeography of the forest dormouse Dryomys was very evident in the granivorous species, indicating a nitedula (Gliridae, Rodentia) in Russian Plain and the Caucasus. Folia causal relationship between fructification and dynamics Zoologica 64(4): 361-364. Elton, C. (1924): Periodic fluctuations in the numbers of animals: their causes (Hansson 1971). The rodent life cycle has been attributed to a and effects. British Journal of Experimental Biology 2: 119-163. large number of mechanisms (Krebs & Myers 1974, Hansson Feliciano, B.R., Fernandez, F.A.S., Freitas, D.D., Figueiredo, M.S.L. (2002): & Henttonen 1988,Henttonen & Hanski 2000), ranging from Population dynamics of small rodents in a grassland between fragments of Atlantic Forest in south eastern Brazil. Mammalian Biology 67:304-314. individual behaviour (Christian 1978) and the force of natu- Hagen, Y. (1969): Norske undersøkelser over avkomproduksjonen hos ral selection (Chitty 1967, Krebs et al. 1973) to proteinase in- rovfugler og ugler sett i relasjon til smågnagerbestandens vekslinger. Fauna, hibitors in the food (Seldal et al. 1994). 22: 73-126. Hanski, I., Korpimäki, E. (1995): Microtine rodent dynamics in Northern For insectivorous mammals, the results of our research Europe: parameterized models for the predator-prey interaction. Ecology are consistent with the results of scientists from Finland. 76(3): 840-850. Analyses revealed no regular multiannual cycles; seasonal Hansson, L. (1971): Small rodent food, feeding and population dynamics: fluctuations and erratic long-term fluctuations prevailed. acomparison between granivorous and herbivorous species in Scandinavia. Oikos 22(2): 183-198. The summer declines of shrews at low densities were often Hansson, L. Henttonen, H. (1988): Rodent dynamics as community processes. synchronous with declines the cyclicity of microtine rodents Trends in Ecology and Evolution 3: 195-200. (Henttonen et al. 1989). Henttonen, H., Hanski, I. (2000): Population dynamics of small rodents in Northern Fennoscandia. pp.73-96. In: Perry J.N., Smith R.H., Woiwod I.P., Morse D.R. (eds). Chaos in Real Data. Population and Community Biology Series, 27. Springer. Henttonen, H., Haukisalmi, A., Kaikusalo, A., Korpimäki, E., Norrdahl, K., Acknowledgement. I am grateful to E.A. Ilykaeva, A.V. Salaeva, Skarén, U.A.P. (1989): Long-term population dynamics of the common E.O. Levtcova, S.A. Yutukova, M.N. Suharnikova for support in shrew Sorex araneus in Finland. Annales Zoologici Fennici 26: 349-356. carrying out of field studies. Il’in, V.Y., Bystrakova, N.V., Dobrolyubov, A.N., Ermakov, O.A., Zolina, N.F., et al. (2006): Synapsis of mammalian fauna of the Penza oblast. Izvestiya

Penzenskogo Gosudarstvennogo Pedagogicheskogo Universiteta imeni V.G. Belinskogo 1(5): 73-89. [in Russian] Kalela, O. (1962): On the fluctuations in the numbers of arctic and boreal small References rodents as a problem of production biology. Annales Academiae Scientiarum Fennicae, Series A, IV, Biologica 66: 1-38. Adler, G.H., Wilson, M.L. (1987): Demography of a habitat generalist, the Karaseva, Е.V., Telicina,А.Y.(1996):Methods for studying rodents in the field. white-footed mouse, in a heterogeneous environment. Ecology 68: 1785- Moscow: 227 pp. [in Russian] 1796. Kirillova, N.Y., Kryštufek, B., Kirillov, А.А., Ruchin, А.B., Grishutkin, G.F. Andreeva, T.A., Okulova, N.M. (2009): Ecological preferences of forest voles. (2019): The first record of Microtus subterraneus (de Sélys-Longchamps, 1836) Russian Journal of Ecology 40(2): 137-142. (Rodentia, Cricetidae) for Mordovia, Russia. Acta Biologica Sibirica 5(4): 145- Andreychev, A., Boyarova, E. (2020): Forest dormouse (Dryomys nitedula, 149. [in Russian] Rodentia, Gliridae) - a highly contagious rodent in relation to zoonotic Krebs, C.J., Gaines, M.S., Keller, B.L., Myers, J.H., Tamarin, R.H. (1973): diseases. Forestry Ideas 26(1): 262-269. Population cycles in small rodents. Science 179: 35-41. Andreychev, A.V., Kiyaykina, O.S. (2020): Homing in the forest dormouse Krebs, C.J., Myers, J.H. (1974): Population cycles in small mammals. Advances (Dryomys nitedula, Rodentia, Gliridae). Zoologicheskii Zhurnal 99(6): 698- in Ecological Research 8: 268-389. 705. [in Russian] Lima, M., Stenseth, N.C., Leirs, H.,Jaksic, F.M.(2003): Population dynamics of Andreychev, A.V., Lapshin, A.S. (2017): Quantitative and qualitative small mammals in semi-arid regions: a comparative study of demographic composition of diet of the Ural Owl, Strix uralensi (Strigidae, Strigiformes), in variability in two rodent species. Proceedings of the Royal Society B 270: the central part of European Russia (the example of the Republic of 1997–2007. Mordovia). Vestnik zoologii 51(5): 421-428. Marcstrom, V., Hoglund, N., Krebs, C.H.J. (1990). Periodic fluctuations in small Andreychev, A.V., Lapshin, A.S., Kuznetsov, V.A. (2014): Food spectrum of the mammals at Boda, Sweden from 1961-1988. Journal of Animal Ecology 59: Eagle Owl (Bubo bubo) in the Republic of Mordovia. Zoologicheskii Zhurnal 753-761. 93(2): 248-258. [in Russian] Okulova, N.M., Kalinkina, E.V., Mironova, T.A., Sapelnikov, S.F., Egorov, S.V., Andreychev, A.V., Lapshin, A.S., Kuznetsov, V.A. (2016a): Breeding success of Mayorova, A.D., Vlasov, A.A., Mutnykh, E.S. (2012): To the ecology of the the Eurasian Eagle Owl (Bubo bubo) and rodent population dynamics. striped field mouse (Apodemus agrarius Pall.) in the forest- steppe Chernozem Biology Bulletin 43(8): 851-861. region. III. Population composition and reproduction. Povolzhskiy Journal Andreychev, A.V., Lapshin, A.S., Kuznetsov, V.A. (2016b): Diet of the Imperial of Ecology 3: 268-277. [in Russian] eagle (Aqula heliaca; Falconiformes, Accipitridae) in the Republic of Oparin, M.L., Oparina, O.S. (2009):The role of anthropogenic and natural Mordovia. Zoologicheskii Zhurnal 95(3): 343-352. [in Russian] factors in changes in mesophilic rodent distribution in steppes between the Angelstam, P., Lindstrom, E., Widen, P. (1984): Role of predationin short- Ural and Volga rivers. Biology Bulletin 36(4): 380-387. termpopulationfluctuationsofsome birdsand mammals in Fennoscandia. Ravkin, Y.S., Livanov, S.G. (2008): Factorial zoogeography: principles, methods Oecologia 62: 199-208. and theoretical representations. Novosibirsk: 205 pp. [in Russian] 38 Andreychev A.

Seldal, T., Andersen, K.-J., Högstedt, G. (1994): Grazing-induced proteinase Zagorodniuk, I.V. (1992): Distribution and abundance levels of Terricola inhibitors: a possible cause for lemming population cycles. Oikos 70: 3-11. subterraneus on the territory of the USSR. Zoologicheskii Zhurnal 71(2):86-97. Tomášková, L., Bejcek, V., Sedlacek, F., Šťastný, K., Tkadlec, E., Zima, J. (2005): [in Russian] Population biology of shrews (Sorex araneus and S. minutus) from a polluted area in central Europe, in Advances in the Biology of Shrews II, Special Publication of the International Society of Shrew Biologists, New York, 1: 189-197. Yamashkin, A.A., Safonov, V.N., Shutov A.M. et al. (1999): Water resources of Republic Mordovia and geo-ecological problems of their development. Saransk, 188pp. [in Russian]