Holarctic Marmots as a factor of Biodiversity.
Rumiantsev V.Yu;, Nikol'skii A.A. & Brandler O.V. eds.,
Abstracts, 3d Conference on Marmots (Cheboksary, Russia, 25-30 August 1997),
Moscow ABF 1997, 216p. : 184.


TO THE PROBLEM OF THE BOBAC MARMOT AREA STRUCTURE


V.Yu. Rumiantsev

Dept. of Geography, Moscow State University, Moscow, Russia


Two interpretations of the species "bobac" (Marmota bobac Muller, 1776) content are known. The "broad" one includes all described forms of steppe, grey and Mongolian marmots as equal rank subspecies. Today only D.I. Bibikov (1967, 1989 and others) seems to keep that opinion. By the "narrow" interpretation, which is generally accepted now, the species includes only those marmots, who inhabit zonal plain steppes. And within the latter interpretation Russian name "bobac" corresponds to the synonym "steppe marmot".

Thus, the species includes at least two modern subspecies: European (western) - M. b. bobac Mull. (1776) and Kazakhstanian (eastern) - M. b. schaganensis Bash. (1930). V.A.Fokanov (1966) described the third "Volga region" subspecies - M. b. kozlovi Fokanov (1966), but actually later it was ignored, although the first two subspecies are recognized nearly by everybody. Usually their distribution is described as following : "... European part of the area..., Kazakhstan part of the area..." (Gromov et al., 1965, p.341) or is not discussed at all. At the same time European subspecies is under protection and Kazakhstanian subspecies is commercially hunted, however the border between their areas is not known. And if we accept the third subspecies, then what is its status and what populations does it comprise ?...

Look over the history of the very first description of those species makes the problem more confusing. The place where M. b. bobac was first described is unknown - probably it is the Right Bank part of the Ukraine (fig.). M. b. kozlovi description originates from the area between the rr. Volga and Tereshka (Saratov Region). Apparently, if we accept that subspecies, we should include in it all natural populations of the Right Bank Volga region (fig.). M. b.schaganensis, now known as "Kazakhstanian", was described by B.S.Bazhanov (1930) in the south-western (!) part of modern Orenburg (!) region - environs of the village Miroshkin at the r. Chagan (fig.). At the same time V.A.Fokanov (1966) considered that it also comprised populations from Tatarstan area over the r.Volga (fig.). Thus, modern western populations of M. b. bobac are remote from the site where the subspecies was first described. The populations from the area over the r.Volga, currently considering as the subspecies parts, actually represent M. b. schaganensis, because they were first described as the latter subspecies. Populations from the Volga region were described as M. b. kozlovi and formally that was not reviewed. Finally, marmots from the Urals area, defined by everyone as M. b. schaganensis, were never analysed by taxonomists.

Regardless of the number of subspecies accepted, the problem is where this or that population should be places. We lack enough data to consider the problem on the base of the analysis of geographical variability of marmot typical features, although data have been extensively collected during last years. So, it is reasonable to base on evidences which seem obvious from the biogeographic position. Subdividing into structural units the area as long (altitude) and narrow (longitude) as the bobac species area results is growth of importance of physical and biotopical barriers preventing animal migration, dispersion (historical scale) and interpopulation contacts. For the bobac, a hibernating and low mobile animal, valleys of the big rivers crossing the area from the north to the south may be the main physical barrier. Regarding the modern area we mean the valleys of the rr. Don, Volga, Ural. In historical past the same role probably was played by the r. Dnepr and Kumo-Manych depression (fig.). Beyond the Urals mountains Turgay hollow represents a great and old biotopical barrier (Rumiantsev, 1991).

Thus, we can suggest a preliminary draft scheme of subdividing the European part of the bobac area (fig.) without discussing so far the status of the structural units we define. It may be helpful in avoiding mistakes while working on artificial dispersing of marmots (see Bibikov, Dimitriev et al., present edition). Later the scheme will be updated and developed in details the base of the data on the bobac natural variability and the role of barriers, both physical and biotopical. Interesting, that even now the scheme is in good conformance with conclusions made by A.A.Nikolsky (1997, present edition) regarding variability of the species vocalization.

Fig. The scheme of subdivisions of the European part of the bobac area.
1 - supposed natural border of the area; 2 - main sites where bobacs survive during peak of number depression; 3 - present natural populations; 4 - bobac presence in historical times is debatable; 5 - areas where the subspecies were first described: 1 - M. b. bobac (hypothetically), 2 - M. b. kozlovi, 3 - M. b. schaganensis; 6 - supposed borders of the species area subdivisions; 7 - supposed definitions of the subdivisions (draft): 1) West-Ukranian (no present m natural marmot settlements); 2) Dnepr-Don (or Donetsk-Don); 3) Northern Caucasian (debatable); 4) Central Russian-Volga Region; 5) Over Volga Region (or Volga Region-Urals); 6) Urals-Turgay (in Asian part of the area - up to Turgay hollow).


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