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Acta Theriologica ISSN 0001-7051 Acta TheriolDOI 10.1007/s13364-013-0161-x

Habitat preferences in gray marmots(Marmota baibacina)

Věra Pavelková Řičánková, Jan Riegert,Eva Semančíková, Martin Hais, AlžbětaČejková & Karel Prach

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ORIGINAL PAPER

Habitat preferences in gray marmots (Marmota baibacina)

Věra Pavelková Řičánková & Jan Riegert & Eva Semančíková &

Martin Hais & Alžběta Čejková & Karel Prach

Received: 2 March 2013 /Accepted: 30 July 2013# Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland 2013

Abstract We examined habitat preferences of the SouthernAltai subspecies of gray marmots (Marmota baibacinabaibacina) both at the small and large scale. Considerable dif-ferences in habitat use among the gray marmot (sub)speciescomplex have been described; Marmota kastschenkoi possiblyrepresents the only forest-dwelling Palearctic marmot. Our re-sults show that habitat use in Southern Altai marmots is deter-mined mainly by vegetation type. The Altai marmots preferredgrasslands and shrublands and their distribution was limited tothe alpine zone above timberline. Marmots clearly avoidedwoodlands, even the forest edges and forest-steppe areas with atree cover greater than 10 %. Gray marmots occur rarely inhabitats occupied by alpine pikas, whereas presence of groundsquirrels had no effect on marmot distribution. Altai marmotspreferred mesic habitats with permeable subsoil layers.Livestock grazing and human disturbance did not affect marmotoccurrence. Habitat requirements of examined Altai subspeciesM. baibacina baibacina differ from the forest-steppe M.kastschenkoi; nevertheless, the ecological factors to which theforest-dwelling species responds remain to be analyzed. A recentspeciation process in gray marmot complex was followed by theevolution of ecological requirements resulting in adaptation toforest dwelling.

Keywords Forest-steppemarmots . Ground squirrels .

Habitat preferences .Marmota baibacina . Pikas

Introduction

Habitat use of the burrowing herbivores is usually determinedby vegetation and soil characteristics. Relative importance ofthe vegetation structure and soil type in species habitat choicedepends on the scale and varies temporally (e.g., Hoogland1996; Kinlaw 1999; Wang et al. 2003; Lombardi et al. 2007).Determining the relationship between the species occurrenceand environmental features is crucial for understanding differ-ences in distributions of closely related species.

The gray marmot (Marmota baibacina Kastschenko 1899)is considered to occupy the broadest range of habitats amongspecies of Palearctic marmots (Bibikov 2004). Gray marmotsare found in alpine steppes and meadows of the Altai and Tien-Shan Mountains, in dry steppes of the central Kazakhstan hills,as well as in woodlands of Southern Siberia (Galkina 1970).The species inhabits all altitudinal belts from 150 to 3,500 mabove sea level (asl; Galkina 1970).

The range of gray marmots was significantly reduced fol-lowing the Holocene (Gromov and Erbayeva 1995). Climaticchanges and subsequent habitat fragmentation resulted indiversification into the three main subspecies of gray mar-mots, the Altai (M. baibacina baibacina), Tien-Shan(Marmota baibacina centralis), and forest-steppe marmots(Marmota baibacina kastschenkoi) (Yudin et al. 1979;Gromov and Erbayeva 1995). Forest-steppe marmots (M.baibacina kastschenkoi) are now recognized as a distinctspecies M. kastschenkoi Stroganov et Judin 1956 (Brandlerand Lyapunova 2009; Steppan et al. 2011). The gray marmotcomplex thus consists of the two subspecies of M. baibacinaand recently derived M. kastschenkoi.

Palearctic marmots are associated with grasslands, exceptfor M. kastschenkoi which is believed to be the only forest-dwelling species (Brandler 2003a; Bibikov 2004). This adap-tation may have evolved as a response to changes in theHolocene landscape, when the cold-steppe was replaced byforest-steppe vegetation (Brandler 2003a). M. kastschenkoi

Communicated by: Andrzej Zalewski

V. P. Řičánková (*) : J. Riegert : E. Semančíková :M. Hais :A. Čejková :K. PrachFaculty of Sciences, University of South Bohemia, Branisovska 31,370-05 Ceske Budejovice, Czech Republice-mail: Ricankova@seznam.cz

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now occupies steppes as well as broad-leaved and pine forestsof the South Siberian lowland (Galkina 1970; Yudin et al.1979; Brandler 2003b; Taranenko 2011).

Nevertheless, the Tien-Shan marmot (M. baibacinacentralis) colonies are frequently found in the zone of spruceforest (Ismagilov 1956). Habitat use ofM. baibacina baibacinahas been predominantly examined in the forestless MongolianAltai, where the subspecies inhabits steppes and meadowson mountain slopes and foothills (Rogovin 1992; Brandleret al. 2010b). Habitat preferences of the Altai subspecies(M. baibacina baibacina) thus remain unclear with respect topossible forest dwelling.

Generally, marmot habitat preferences appear to be evolu-tionary conservative, closely related species tend to occupysimilar environments (Davis 2005). Much of the marmotintraspecific variation is phenotypic, which may be the opti-mal solution to living in a variable environment (Armitage2005). Yellow-bellied marmots (Marmota flaviventris) occu-py various habitats from semideserts at low elevations throughwoodland and forest openings to the alpine zone (Frase andHoffmann 1980). The common feature of these differenthabitats is the presence of rocks sufficiently large to provideshelter (Svendsen 1976).

In the contact zone with the tarbagan (Marmota sibirica),M. baibacina baibacina are associated with rock outcropswith bouldery screes (Rogovin 1992; Brandler et al. 2010b).Many factors were proposed to limit graymarmot distribution:presence ofmeadow and steppe vegetation, topographic relief,permafrost and soil layer depth, or spatially extensive viewsheds (Galkina 1970).

Southern Altai marmots (M. baibacina baibacina) repre-sent the population of from which forest-steppe marmots(M. kastschenkoi) have evolved during the last 20–12,000 years(Grosval'd and Kotlyakov 1989; Brandler 2003a, c; Brandleret al. 2010a). By examining the key factors that influencehabitat use of M. baibacina baibacina in Southern Altai, weattempt to reveal possible origin of forest dwelling in graymarmot complex.

We suppose that forest dwelling could be the outcome ofhabitat flexibility of gray marmots. Occurrence of gray mar-mots could be limited by other ecological factor(s) than veg-etation and observed differences could result from the abilityto use both forest and steppe habitats according to theiravailability. Altai marmots thus would not display preferencesfor either vegetation type.

Alternatively, gray marmots could be limited by vegetationtype. Affinity to the forest habitat observed inM. kastschenkoicould be a result of the general preferences for woodlandscommon in the gray marmot complex. In such case, Altaimarmots would display preferences for woodland habitat.Forest avoidance in the Altai marmots would indicatea major shift in ecological requirements in forest-dwellingM. kastschenkoi.

Methods

Study area

The study area is situated in the Altai Mountains in theRussian Federation on the territory of the Altai Republic alongthe borders of Kazakhstan, China, and Mongolia. The area isbetween latitudes 49°10′ and 49°55′ N and longitudes 86°50′and 88°30′ E (coordinate system WGS 84). The region ofstudy is delimited by the Southern Chuya Range in the north,the Tarkhata mountain pass in the east, the Ukok Quiet Zoneand the Tabon Bogdo Ula Mountain in the south, and by theKoksu and Argut River valleys in the west (Fig. 1). Researchwas conducted during the summers (July and August) of 2003through 2005.

The region represents a complete sequence of altitudinalvegetation zones, including semi-desert, steppe, forest-steppe,taiga, sub-alpine, and alpine-tundra, although steppe patchesoccur as high as the sub-alpine belt. The eastern part of thearea lacks the typical altitudinal pattern of vegetation belts.Elevations range from 1,200 to 4,120 m asl. The forest line isat about 2,200 m asl. The area is characterized by grasslands(cover 47 % of the study area), tall grass and forbs stands(13 %), woodlands (mostly larch taiga; 11 %), and shrubs(mostly Betula rotundifolia; 10 %).

The region's climate is strongly continental. The averageJuly temperature in the Ukok Plateau (2,300–2,500 m asl) is9.4 °C, whereas the average January temperature is −27 °C(Kharlamova 2004).Most of the area is underlain by perennialpermafrost; the active thaw layer is usually 30–70 cm thick(Chlachula 2001).

As with the annual temperatures, rates of precipitation varygreatly according to the particular topographic setting. Mostof the precipitation falls on the western and northwesternslopes (400–500 mm per year). The eastern part of the studyarea is semi-arid, with a precipitation approximately 200 mmper year (Kharlamova 2004). Traditional extensive livestockraising is the major land use.

Data collection

A total of 92 transects were established where terrain topog-raphy made it possible at random order. Each transect wasapproximately 1 km long. Position of transects to the slopevaried; most of them were established along the elevationgradient. Along each transect, six square 50×50 m plots wereestablished at 200-m intervals (following Allainé 1994).Intervals between plots were measured from the center ofthe plots.

During the 3 years of the study, environmental conditionsdid not vary substantially. Different places were sampled eachyear. The data collection on transects was carried out by asingle person (first author). Each plot was thoroughly checked

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for the presence of marmot burrows. Sites occupied by mar-mots were not previously known. Active burrows were dif-ferentiated from old and inactive ones by the presence of freshsoil deposits, feces, and runways (Ricankova et al. 2006).Only active marmot burrow systems were considered un-equivocal detections in the analysis.

The ecological parameters estimated in each plot wereassigned to five groups: (1) environment, (2) management,(3) vegetation, (4) geology, and (5) other burrowing mamma-lian herbivores. Environmental features measured at the smallscale included elevation, slope, and orientation (i.e., aspect) asdescribed in Table 1. At the large scale, we estimated climateparameters, elevation, and terrain ruggedness (Table 1). Themean annual temperature and precipitation within the tran-sects were obtained from WORLDCLIM (Hijmans et al.2004). This database is a set of global climate layers with aspatial resolution of 1 km2.

Human disturbance sampled at the small scale covers bothdirect anthropogenic disturbance and impact of livestock graz-ing. We recognized three categories of human disturbance—high, medium, and low. Human disturbance was consideredhigh when the plot contained evidence of intensive humanactivity (i.e., presence of tracks, yurt or chalet(s), and signs ofgrazing by domestic livestock), medium when the plotcontained only signs of grazing (without tracks, yurt, or cha-let(s)), and low when there was no evidence of human activityor livestock grazing. Land use category, used at the large scale,describes the seasonality of pastureland use by domestic live-stock (i.e., sheep, goats, cattle, horses, camels, and yaks).

Small-scale vegetation parameters include plant cover,height of herbs and shrubs, and vegetation units (Table 1).We defined plant cover as the proportion of the plot coveredby herbs and grasses, shrubs, trees, or by any combination ofthese life forms. Coverage of the different life forms is inde-pendent of each other and together may constitute more than100%. The average height of herbaceous and shrub cover wasdivided into three categories reflecting the height of the graymarmot (ca. 50 cm; Ismagilov 1956).

Vegetation units (Table 1) were delimited using the prevail-ing growth forms and habitat preference of plant species(Mueller-Dombois and Ellenberg 1974). We recognized wood-land, shrubland, tall grass, and grassland units. Grassland cat-egory includes short-grass steppes, short-grass alpinemeadows, and nonwoody vegetation of slope debris and screes.At the large scale, grasslands were divided to alpine grasslandsabove the timberline (~2,000 m asl) and grasslands bellow thetimberline. Tall grass vegetation category includes tall forb andsecondary meadows and vegetation of treeless wetlands.Woodlands consist of larch taiga and broadleaved vegetationof alluvial woodlands. Shrubs category includes mostly B.rotundifolia, Potentilla fruticosa, and Caragana sp. Large-scale vegetation units (Table 1) were estimated using land coverclassification from Landsat satellite ETM+ data acquired in2000 (two scenes, 144/26 and 144/25). Resulting classificationwas calibrated using our field knowledge of the area.

Geology variables used at the small scale describe soil type,subsoil layers, and the relative surface humidity of theplot (Table 1; for details, see Ricankova et al. 2006). Soil

Fig. 1 Location map of the studyarea in the Southern AltaiMountains, Altai Republic,Russia. Black circles transectswith gray marmots Marmotabaibacina, open circles transectswithout marmots

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characteristics were described according to the ExpertCommittee on Soil Survey (1987).

The presence of long-tailed ground squirrels (Spermophilusundulatus Pallas 1778), alpine pikas (Ochotona alpina Pallas1773), and steppe pikas (Ochotona pallasi Gray 1867 andOchotona daurica Pallas 1776) in each plot was recorded toestimate the possible influence of interspecific competition onhabitat use of marmots. The presence of the other burrowingherbivores was used for both small and large scale. Populationsof steppe pikas had been extirpated within our study areas a few

years before the start of our research and re-established 3 yearsafter the end of field research. We included the presence of thepika burrows in our dataset because of the possibility of pastcompetition between pikas and marmots.

Data analysis

To avoid autocorrelations of vegetation cover data, wecomputed principal component analysis (CANOCO for

Table 1 Explanatory variablesused to characterize habitat ofMarmota baibacina in SouthernAltai Mountains. The details ofsmall- and large-scale are de-scribed in text

Variable Description Smallscale

Largescale

Environment

Elevation Elevation (in meters above sea level) (limits, 1,231–3,084) X X

Terrain ruggedness Categorical variable: (1) low, slope<10° without verticalstructures; (2) medium, slope>10° without verticalstructures; (3) high, slope>10° with vertical structures

X

Slope Average slope (in degrees; limits, 0–45) X

Orientation to cardinalpoints

Categorical variable: (1) N, (2) NW, (3) NE, (4) S, (5) SW,(6) SE, (7) W, (8) E

X

Mean annual temperature Mean annual temperature (in degree Celsius; limits, −8 °Cto +0.1 °C)

X

Mean annualprecipitation

Mean annual precipitation (in millimeters; limits, 185–480) X

Management

Human disturbance Categorical variable: (1) low, (2) medium, (3) high X

Land use Categorical variable: (0) no grazing, (1) winter grazing, (2)summer grazing, (3) year-round grazing

X

Vegetation

Herb cover Areal percentage cover of herbs (nonwoody vegetation;limits, 2–100 %)

X

Bush cover Areal percentage cover of shrubs (woody vegetation <2 m inheight; limits, 0–90 %)

X

Tree cover Areal percentage cover of trees (woody vegetation, >2 m tall;limits, 0–80 %)

X

Vegetation units Small scale: (1) woodland, (2) shrubland, (3) tall grassvegetation, (4) grassland

X

Large scale: (1) woodland, (2) shrubland, (3) tall grassvegetation, (4) grassland (bellow timberline), (5) alpinegrassland (above timberline)

X

Height of herbs Average height of nonwoody vegetation. Categorical variable:(0) <10 cm, (1) 10–50 cm, (3) >50 cm

X

Height of bush Average height of woody vegetation <2 m in height.Categorical variable: (0) absent, (1) <50 cm, (2) >50 cm

X

Geology

Soil Categorical variable: (1) Brunisol, (2) Luvisol, (3) Regosol X

Subsoil layers Categorical variable: (1) Impermeable subsoil layers, (2)permeable subsoil layers

X

Relative surface humidity Categorical variable: (1) arid, (2) mesic, (3) humid X

Other species

Spermophilus undulatus Presence or absence of active burrows of S. undulatus withinthe plot

X X

Ochotona alpina Presence or absence of any evidence ofO. alpinawithin the plot X X

Steppe pikas Presence or absence of any evidence of Ochotona dauricaand/or O. pallasi burrows within the plot

X X

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Windows software; Braak and Šmilauer 1998, visualized inCANODRAW; Šmilauer 1992) for both small- and large-scaledata to uncover possible relationships among tested factors(Table 1). Categorical variables were implemented as supple-mentary variables.

On small scale, we found that bush cover and tree coverwere correlated. Bush cover variable was therefore removedfrom further analyses. We selected tree cover because wewanted to examine its possible ecological importance formarmots. On large scale, the land use was correlated with

Table 2 Factors affecting largeand small scale occurrence ofgray marmots in the SouthernAltai Mountains (GLM analysis,forward selection, small scale:n=554 plots, covariate=transect;large scale: n=92 transects)

M marmot occurrence, V vegeta-tion units, AP alpine pika, SPsteppe pika, T tree cover, H sur-face humidity, Her height ofherbs, SL subsoil layers

Scale Model d.f. Percent of explainedvariability

Chi P F

Small scale Null (M~+1, transect~random effect)

2

M~V 5 7.3 33.835 <0.00001

M~V+AP 6 4.4 20.541 <0.00001

M~V+AP+T 7 2.6 11.881 0.00057

M~V+AP+T+H 9 4.1 19.382 <0.00001

M~V+AP+T+H+Her 11 4.3 20.124 <0.00001

M~V+AP+T+H+Her+SL 12 2.0 9.151 0.00249

Large scale Null (marm~+1) 1

M~V 5 33.9 <0.000001 10.773

M~V+SP 6 4.0 <0.05 5.103

Fig. 2 Percentages of habitat categories of gray marmots Marmota baibacina in the Southern Altai Mountains. White bars percentage of habitatcategories, black bars percentage of each habitat category used by marmots

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elevation. Therefore, we excluded land use from further large-scale analyses.

We analyzed the preferences of gray marmots using Rsoftware (R Development Core Team 2008). Small-scale datawere computed with linear mixed effect model withrandom effects under formula: model<−lmer (marmotoccurrence~+factors+(1|transect)+(1|year), family=binomial,data=file name), where transect and year were defined asrandom effect. The factor transect was used to avert the occur-rence of spatial autocorrelation. Forward selection wasperformed manually by repeated comparing the null (or last)model with other possible models using ANOVA function andAkaike's An Information Criterion (AIC). This enabled us todefine the best final model. Large-scale data were computed bygeneralized linear models (GLM) with logit–link function un-der formula: model <−glm (marmot occurrence~+factors,family=binomial, data=file name), using factor year as a co-variate. Forward selection was computed using step functionwith AIC. Both the models were finished when no othervariables were recommended byAIC. Therefore, we show onlyfactors with significant effect on marmot occurrence. Factorsused for each analysis are shown in Table 1. Elevation dataused for the large-scale analysis represent the mean value of thedifferent plots of each transect (Table 1).

We plotted the used/available percentage within each hab-itat category on the small scale for the purpose of data visu-alization. These percentages were computed as the number ofplots where marmots occurred divided by the total number ofplots with this type of habitat. The ratio was converted topercentages. The relationships between the proportions ofcategory use and category availability were expressed byManly's standardized selection ratio Bi with 95 % confidenceintervals (Manly et al. 2002).

Results

Evidence of marmot habitation was detected in 42 (45.6 %) ofthe 92 transects and in 111 (20 %) of the 554 plots investigat-ed. Nine abandoned burrow systems were not included in ouranalyses.

At small scale, vegetation type explained most of the vari-ability of marmot occurrence (Table 2). Marmots preferredgrasslands (Bi=0.6091; 95 % CI, 0.3758–0.8424). Lower pref-erential coefficient was found also for shrubs (Bi=0.1690; 95%CI, 0.0459–0.2921) and they clearly avoided woodlands(Fig. 2a). Marmots also preferred sites where alpine pika wasabsent (Fig. 2b; Bi=0.8330; 95 % CI, 0.6403–0.1026).Simultaneously, marmots were present almost exclusively onsites with tree cover up to 10 % (Fig. 3c; Bi=1.0000; 95 % CI,1.000–1.0000), permeable subsoil layers (Fig. 2d; Bi=0.9894;95 % CI, 0.9748–1.0039), and mesic humidity (Fig. 2e;Bi=0.7190; 95 % CI, 0.4904–0.9476). Finally, the marmots

preferred height of herbs between 10 and 50 cm (Fig. 2f;Bi=0.7190; 95 % CI, 0.4904–0.9476). None of the other envi-ronmental factors influenced marmot habitat use.

On large scale, marmot distribution was significantly af-fected by the vegetation category of the transect (Table 2).Marmots preferred alpine grassland (Bi=0.5576; 95 % CI,0.7738–0.34145) and shrub vegetation (Bi=0.4424; 95 %CI, 0.6587–0.2262). Marmots did not occur in woodland, tallgrass vegetation, and grassland below the timberline (Fig. 3).Occurrence of steppe pikas was also significantly linked tothat of marmots (Table 2). Pikas invariably shared their habitatwith marmots, but the number of recorded transects withsteppe pika burrows was very small (n=6 transects of 42 totaltransects occupied by marmots; Bi=0.7049; 95 % CI, 0.4167–0.9932). Both marmots and steppe pikas were absent from 50transects. Occurrence of the long-tailed ground squirrels oralpine pikas did not affect marmot habitat utilization. Terrainruggedness, mean annual temperatures, mean annual precipi-tation, altitude, and presence of other burrowing herbivoresdid not influence marmot habitat use.

Discussion

Our results show that the habitat use of gray marmot inSouthern Altai is influenced mainly by vegetation type. TheAltai marmots prefer grasslands and shrublands of the alpine

Fig. 3 The projection scores of the significant large-scale data variablesof gray marmot habitat use. Principal component analysis, I and IIcanonical axes explain 91.4 % of variability. Black circles vegetationcategories, triangles presence (plus sign) or absence (minus sign) of graymarmots and steppe pikas

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zone, avoid forests and tall grass vegetation, and their distri-bution is limited to the alpine zone above timberline.

Altai marmots clearly avoided coniferous taiga forests andthe broadleaved vegetation of alluvial woodlands as well.They even avoided the forest edges and forest-steppe areaswith a tree cover greater than 10 %. Similar preferences werefound in the Alpine marmot (Allainé 1994; Lopez et al. 2010).M. marmota is found in nearly all types of vegetation abovethe timberline. The complexity of vegetation is very importantfor the Alpine (Müller 1992) and Altai marmots (Galkina1970) favoring mosaics of meadow-steppe vegetation foundparticularly on the Ukok Plateau.

Habitat requirements of the other (sub)species of graymarmot complex seem to differ from the examined populationfrom Southern Altai Mts.M. kastschenkoi occupies coniferousand broadleaved forests, tolerating high vegetation cover andspatially limited view sheds (Yudin et al. 1979). Galkina(1970) documented a marmot settlement in a pine forest withdense shrubs and herbaceous vegetation reaching a height of2 m. Nevertheless, key ecological factors to which M.kastschenkoi responds remain to be analyzed.

In contrast to the examined population of M. baibacinabaibacina, the Tien-Shan subspecies (M. baibacina centralis)occurs also in a spruce forest zone (Ismagilov 1956).However, it is not known whether M. baibacina centralistruly occupies forests or are restricted to grassland patches inthe forest zone.

The differences in the use of steppe or forest habitat prob-ably result from different evolutionary history of the(sub)species and consequent specialization to different habi-tats. The recent origin of the forest dwelling in gray marmotcomplex is rather unexpected because of the trend of relatedmarmot species to occupy similar environments (Davis 2005).Moreover, the sister species of the gray marmot is Marmotabobac, a species associated exclusively with a steppe habitat(Steppan et al. 2011; Bibikov 2004).

The examined population of the gray marmot complexdisplay habitat requirements characteristic for a mountainsteppe species. Besides their general preference for grasslands,Altai marmots seem to prefer similar habitat as steppe pikas(mostly O. daurica; Tupikova 1989) on the large scale.Abandoned burrows of steppe pikas were found solely onthe Ukok Plateau, an area occupied by the largest marmotpopulation. Unfortunately, the number of recorded transectswith steppe pikas was too low to allow any further conclu-sions. On the other hand, Altai marmots occur rarely inhabitats occupied by alpine pikas (O. alpina). The alpine pikasare found mostly in the talus and less in taiga forests(Tupikova 1989); both these habitats were not favored by graymarmots.

Gray marmots seemed to be constrained in their habitatchoice by soil humidity, a permeability of subsoil layersreflecting soil insulation quality, permafrost depth, and possibly

also the concentration of respiratory gasses in burrows. Betterdrainage and reduced humidity are expected to increase soilaeration preventing the formation of permafrost, decreasingCO2 concentration in the burrow atmosphere, and may alsoincrease the insulation quality of the hibernacula (Burda et al.2007). Similarly,Marmota monax burrow occurrence is closelyassociated with a specific “sandy loam” soil and a Marmotahimalayana settlement was found exclusively in a deep layer oflight soil (Moss 1940; Nikol'skii and Ulak 2006).

Our results show that vegetation is the most importantfactor determining gray marmot habitat use despite the pro-nounced differences in the vegetation categories occupied bythe other (sub)species. Recent speciation process in graymarmot complex was probably followed by the evolution ofecological requirements, resulting in adaptation to forestdwelling. Further research of habitat requirements in M.baibacina centralis andM. kastschenkoiwould help to clarifythe observed pattern.

Acknowledgments We are grateful to Yurii V. Antaradonov, Prof. YuriiV. Tabakaev, and Dr. Albert Kamenov for granting permission to work ina frontier zone and for logistic support. We thank all expedition partici-pants for their help with transect recording, guides for assistance, and ourhorses for their exceptional patience and endurance. Thanks to JiriChlachula for the estimation of geological parameters and organizationof expeditions. Oleg Brandler kindly provided fundamental literature andZdenek Fric created the location map. We thank Radim Sumbera, ErikBeever, Jan Zrzavy, Petr Smilauer, and anonymous referees for helpfulsuggestions to the earlier versions of the manuscript. This research wassupported by the Czech Ministry of Education (MSM 6007665801,MSTVPodpora 2003), the Czech Literary Foundation and Czech ScienceFoundation #P504/11/0454.

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