Impact of the Black-Capped Marmot (Marmota camtschatica bungei) on Floristic Diversity of Arctic Tundra in Northern Siberia

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  • The Regents of the University of Colorado, a body corporate, contracting on behalfof the University of Colorado at Boulder for the benefit of INSTAAR

    Impact of the Black-Capped Marmot (Marmota camtschatica bungei) on Floristic Diversity ofArctic Tundra in Northern SiberiaAuthor(s): Youri Semenov, Raymond Ramousse, Michel Le Berre and Youri TutukarovSource: Arctic, Antarctic, and Alpine Research, Vol. 33, No. 2 (May, 2001), pp. 204-210Published by: INSTAAR, University of ColoradoStable URL: http://www.jstor.org/stable/1552221 .Accessed: 18/06/2014 19:26

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  • Arctic, Antarctic, and Alpine Research, Vol. 33, No. 2, 2001, pp. 204-210

    Impact of the Black-capped Marmot (Marmota camtschatica bungei) on Floristic Diversity of Arctic Tundra in Northern Siberia

    Youri Semenov, Raymond Ramousse, * and Michel Le Berre Equipe de Socioecologie et Conservation, Laboratoire de Biom6trie et Biologie Evolutive UMR CNRS 5558, Universite Claude Bernard Lyon 1, 43 bd du 11 Novembre 1918 bat. 403, 69622 Villeurbanne Cedex, France. * Author for correspondence. ramousse @biomserv.univ-lyon 1 .fr

    Youri Tutukarov Faculty of Biology, Yakutsk State University, 58 Belinsky Prospect, 677891 Yakutsk, Russia.

    Introduction

    In any ecosystem, dynamic relations between plants and an- imals influence vegetation in many different ways. Selective feed- ing can affect plant populations directly by reducing growth (Ar- cher et al., 1987) and survival of preferred plant species and there- by indirectly benefit other less preferred species (Archer and De- tling, 1984; Pacala and Crawley, 1992; McKendrick et al., 1997). Herbivores may also affect the availability of resources that limit plant development. Animals can alter soil physically and chemi- cally by burrow digging, trampling, and depositing urine or feces. Studies have shown that burrowing animals have significantly af- fected plant communities (Marmota bobac and M. baibacina

    [Zimina and Zlotin, 1980]; M. monax [Swihart, 1991]; M. olympus [Del Moral, 1984]; Cynomys ludovicianus [Archer et al., 1987]; Geomys bursarius [Reichman and Smith, 1985; Inouye et al., 1987]; Thomomys bottae [Koide et al., 1987; Hobbs et al., 1988]; Taxidea taxus [Platt, 1975]). There is reason to believe that ani- mals have similarly affected plant communities in the Arctic.

    Arctic tundra is characterized by severe environmental con- ditions, including low temperatures and permafrost. Tundra eco- systems are generally limited by low availability of nutrients, often nitrogen; productivity increases when nutrients are added (Shaver and Chapin, 1980, 1986). The typical flora includes li- chens, bryophytes, shrubs, and herbs. Some plant species are listed as endangered (Labutin et al., 1985). Mammalian species in particular appear to have substantial effects on soil nutrients and vegetation in arctic tundra: arctic ground squirrel (Spermo- philus parryii) mounds (McKendrick et al., 1980; Mallory and Heffernan, 1987) and caribou (Rangifer tarandus) carrion (McKendrick et al., 1980) significantly alter the floristics of the

    plant community, with increasing importance of graminoids and decreasing importance of lichens and shrubs.

    In some areas of the arctic tundra of Northern Siberia, black- capped marmots (Marmota camtschatica bungei Kastchenko 1901) are found between 100 and 1500 m above sea level (a.s.l.). Two

    Abstract The impact of black-capped marmots on arctic tundra vegetation was examined by descriptive and quantitative methods in three marmot home ranges. Vegetation in the home range core area (main burrows) differed from the peripheral zone

    (secondary burrows, paths, scratching areas) or from marmot-free tundra area. In main burrow plots species richness, diversity, and equitability were low. In the same places graminoid abundance were increased, whereas dominance of shrubs and presence of cryptogams (bryophytes and lichens) were declined. Some forbs were more often found around marmot main burrows. Some of these are rare and listed as protected species in Siberian Arctic tundra. This suggests that through activities such as burrowing, trampling, and excretion black-capped marmots

    modify microrelief and soil properties, which influence the floristic structure and

    composition of the arctic tundra.

    endangered populations (Kondakovskaya and Ioujno-Yakoutskaia) are listed in the Red Book of the Sakha Republic (Yakutia, Russian Federation; Revin et al., 1987). These are medium-sized, ground- dwelling animals, which as adults average 2-4 kg (Kapitonov, 1978); they are well adapted to the harsh arctic environment. They are active during the polar day and hibernate from mid-September to May. Marmots are sedentary animals living in family groups on home ranges which they often occupy for very long periods, some- times centuries (Zimina and Zlotin, 1980). Home ranges extend on 10-15 ha including a core area and a peripheral zone (Kapitonov, 1978; pers. observ.). The core area is centered on a main burrow system with large mounds and latrines on top of the tundra surface. The main burrow consists of several meters of galleries and one or two rooms at a depth of 0.25 to 0.6 m, where the family group hibernates and where the female gives birth. The peripheral zone is characterized by several paths on the tundra surface, secondary bur- rows, shelters, and scratching places (Kapitonov, 1978).

    Kapitonov (1960, 1978) emphasized visible changes in veg- etation growth and greenness always associated with marmot core areas, strongly contrasting with the usual brown aspect of the tundra. Sofronov (1997) suggested that floristic composition differed between marmot-active and marmot-free areas. Quan- titative analysis and direct evidence for these conclusions, how- ever, are not available.

    The black-capped marmots develop extensive burrow and path systems, which disturb soil and vegetation. The objective of this study was to test the hypothesis that black-capped mar- mots have a substantial impact on certain characteristics of arctic flora. We compared floristics and plant cover between marmot- active areas and marmot-free areas. Results are discussed in re- lation to vegetation-animal interactions in the arctic ecosystem.

    Methods STUDY AREA

    This work was conducted in the Lena Delta Nature Reserve near the Arctic Ocean coast (71?57'N, 127?17'E, 250 m a.s.l.),

    204 / ARCTIC, ANTARCTIC, AND ALPINE RESEARCH

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  • in Sakha Republic (Yakutia, Russian Federation). In this region the mean temperature varies from 34.0?C below zero in winter to 8.9?C in summer (Spravochnik po klimatu SSSR, 1967). The permafrost layer reaches 400 to 600 m in depth (Kudryavtsev et al., 1978). The summer melting depth varies from 0.1 to 1.0 m depending on several factors including plant distribution, soil moisture, slope aspect, and topography (Karavaeva, 1969). In- vestigations took place on shrub tundra with high abundance of Dryas punctata and Cassiope tetragona (Labutin et al., 1985). During July and August 1998, three black-capped marmot home ranges located on southwest-facing rocky hills were chosen as three sample sites: HR1, HR2, and HR3.

    SAMPLING METHODS

    Two perpendicular transects, each 100 m long, were cen- tered on the main burrow of the marmot home ranges (HR1, HR2, and HR3). One-square-meter plots were established every 5 m on both sides of the transects for a total of 80 plots per marmot home range. Characteristic activity marks of marmots were recorded: burrows, scratching areas (5 to 10 cm depth, 10 cm diameter), temporary shelters (one entrance only), paths, and outside latrines (30 cm depth, 15-40 cm diameter). Three plot categories were defined based on evidence of marmot activity: (P1) heavily impacted plots (core area of marmot home range with main burrows and outside latrines); (P2) lightly impacted plots (peripheral zone of marmot home range including second- ary burrows, path or scratching area); (P3) marmot-free tundra plots (tundra area without marmot marks). Vegetation (lichens, bryophytes, and vascular plant species) was sampled in each plot by estimating number of floristic species (species richness), height, and the cover of each plant species. Median species di- versity and equitability were calculated for each plot and each home range using the Shannon-Weaver diversity index (H; log base 10) and the equitability index (J; log base 10; Begon et al., 1990).

    STATISTICAL ANALYSES

    Because data failed to meet normal statistical assumptions, nonparametric statistics were used with a significance level of 0.05. Frequency of vegetation species in the three plot categories (P1, P2, and P3) was tested using Fisher's exact probability (Sie- gel, 1956). Kruskal-Wallis one-way analysis of variance and multiple comparisons of medians (smallest significant difference; Sprent, 1992) were used to test for significant differences be- tween medians in floristic species richness, percent cover, aver- age height, species diversity (H), and species equitability (J) be- tween the three plot categories.

    Percent cover was ranked among six classes: 0, 0-

  • TABLE 2

    Mean percent cover of dominant species and cryptogams in three plots categories

    HR1 HR2 HR3

    P1 P2 P3 P1 P2 P3 P1 P2 P3

    N 10 16 54 12 14 54 12 4 64

    DOMINANT SPECIES

    Poa arctica 24.6 0.2 0.4 24.7 1.5 0.4 21.3 0.1 0.4

    Cassiope tetragona 0.1 4.1 10.0 0.2 12.6 14.6 0.7 23.0 13.7

    Dryas puncata 5.3 43.1 24.0 4.7 31.6 19.5 19.8 19.0 21.7

    CRYPTOGAMS

    Bryophytes Aulacomnium turgidum 0.0 2.4 7.7 0.8 6.0 8.2 0.6 7.9 4.9

    Dicranum acutifolium 0.1 0.9 2.1 0.2 0.7 0.9 0.4 3.1 2.2

    Hylocomium splendens 0.0 0.8 1.1 0.0 7.6 11.8 0.0 2.6 9.1

    Pohlia cruda 0.0 0.1 1.4 0.0 0.8 0.7 0.0 0.4 0.9 Lichens

    Alectoria ochroleuca 0.0 0.1 0.3 0.0 0.3 0.3 0.0 0.1 0.6 Cetraria chrysantha 0.0 0.1 0.5 0.0 0.0 0.1 0.0 0.1 0.5 Cetraria juniperina 0.0 0.7 4.9 0.0 3.6 2.6 0.0 2.8 4.8 Cetraria laevigata 0.0 1.2 2.0 0.0 0.9 1.0 0.0 1.8 2.7 Cladonia chlorophaea 0.0 0.1 0.1 0.0 0.1 0.1 0.0 0.3 0.1

    Cladonia sylvatica 0.0 0.8 1.8 0.0 0.1 0.3 0.0 0.3 1.5

    Dactylina arctica 0.0 0.3 1.0 0.0 0.7 0.6 0.0 0.5 0.8

    Peltigera aphthosa 0.0 0.2 0.2 0.1 0.6 0.2 0.0 0.1 0.2

    Stereocaulon alpinum 0.0 2.6 9.1 0.1 1.8 3.1 0.0 1.3 5.1

    Thamnolia vermicularis 0.0 1.0 2.8 0.0 1.4 1.2 0.0 0.4 2.2

    HR: home range; N: total number of plots; P1: heavily impacted plots (main burrows and latrines); P2: lightly impacted plots (secondary burrows and paths); P3: marmot-free tundra plots.

    absolute and relative contributions to Fl. For every home range, in factorial plans Fl and F2 the points corresponding to P2 and P3 plots are grouped near the center of gravity of the graph.

    In the second graph for each home range (Fig. lb, 2b, 3b) floristic points were projected. The limited dispersion of these

    points indicated a high floristic homogeneity within P2 and P3

    plots. Conversely, the great dispersal of P1 data indicated im-

    portant floristic heterogeneity among heavily impacted plots. A common effect was observed in the home ranges (Fig.

    1, 2, 3). On F1, P1 data were different from P2 and P3 data clustered near the origin of the Fl and F2 axes. This may have resulted in differences in species composition among the plots. For some species, which for a great part were common to the three home ranges, the points were projected in the vicinity of the P1 plots (Fig. 1, 2, 3). This suggested a particular abundance

    or even the exclusive presence of these vegetation species in the P1 plots.

    VEGETATION SPECIES FREQUENCY

    The number of plots containing species associated with P1

    plots (Fig. 1, 2, 3), indicated their frequency in core areas (P1) was significantly higher than P2 or P3 for any of the three home

    ranges (Fisher's exact probability test, Table 4). Comparisons of

    species frequency between P2 and P3 plots revealed significant differences only for Poa arctica and Polygonum laxmannii (Ta- ble 4). Species more often found only around main burrows and outside latrines of marmots were these vascular plants: Alope- curus alpinus, Delfinium chamissonis, Myosotis suaveolens, Poa

    arctica, Polygonum laxmannii, Potentilla gelida, Rhodiola ro-

    TABLE 3

    Comparisons of species richness, Shannon-Weaver diversity (H) and equitability (J) among three plot categories of each home range

    HR1 HR2 HR3

    P1 P2 P3 KW P1 P2 P3 KW P1 P2 P3 KW

    N 10 16 54 12 14 54 12 4 64

    MRV 6.5b 9 10

  • FIGURE 1. Home range 1. Factorial plans F] and F2(COA) obtained from species abundance data. Plot coordin- dates (a) are expressed as closed cirles (heavily impacted plots regrouped by ellipse 1); open cirles (medium and lightly impacted plots regrouped by el- lipse 2 and 3). Floristic coor- dinates (b) regrouped in rela- tion to plot categories. Eigen- values diagram (c) shows the data structure. Species associ- ated with PI plots; dech-Delfi- nium chamissonis; mysu-Myo- sotis suaveolens; poar-Poa arc- tica; plla-Polygonum laxman- nii; ptge-Potentilla gelida; rhro-Rhodiola rosea; tach-Ta- raxacum chamissonis.

    sea, and Taraxacum chamissonis. Most of the species associated with P1 plots were common to the three home ranges.

    PERCENT COVER AND AVERAGE PLANT HEIGHT

    Median cover percent and median average height of Poa arctica associated with P1 plots were significantly higher than in P2 and P3 plots (Table 5). We conclude that Poa arctica biomass increased in the core area of black-capped marmots. This results in light green patches of vegetation that conspicu- ously distinguishes these locations from the general tundra dur- ing summer.

    Discussion

    Concepts of coexisting species in ecological communities are based on partitioning and utilization of common resources, wherea...

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