Holarctic Marmots as a factor of Biodiversity.
Rumiantsev V.Yu;, Nikol'skii A.A. & Brandler O.V. eds.,
3d Conference on Marmots (Cheboksary, Russia, 25-30 August 1997),
Moscow ABF 1997, 216p., 31 (Russian), 149 (English).
PLANT COVER OF MARMOTS (MARMOTA SIBIRICA PALL.) BURROWS
ON EASTERN KHANGAI (MONGOLIA)
N.P. Guricheva, P.P. Dmitriev
Botanical Institute, Russian Academy of Sciences, St.Peterburg,
Department of Biology Moscow State University,
We regard plant cover of marmots burrows as complex microphytocenohora (MPCH) consisted of serial nanogroups (Hg), that are imperfect successionally labile plant communities. MPCH of marmots burrows have such characteristics. (1). Hg have a lot of species, less than on the background: at the initial stages of succession only 2-4, at the last stages - 15-20 species (on the background - 40-50 species). (2).The species status changes on burrows vegetation. The dominant plants of background become assectators on the burrow, and assectators become dominants. The following species may be dominant in Hg: Artemisia changaica, Dracocephalum moldavica, Potentilla
bifurca, Galium verum, Scizonepeta multifida, Adenophora stenanthina, and other, and from explerents - Dontostemon integrifolius, Artemisia palustris, and annual plants from family Chenopodiaceae. (3). The effect of intensive plant growth on burrows
is known by literature. Most of plants become higher and stronger. The vegetation is poor or absent only near burrows entrances. (4). The vegetal season become longer on marmot MPCH. (5). There is no accurate aspect change on marmot MPCH. The phenological phases prolong and superpose one on another.
The dynamic status of separate Hg is reflected on composition and plant abundance (numbers, frequency, productivity). Those indexes depend on the state of burrows, the character of animal using or abandonment, and burrow age. Hg of initial successional stages characterized by little species diversity and predomination of annual plants such as Salsola australis, Axyris hybrida, Chenopodium album, Lappula echinata and other. On the advanced stages of microsuccession mobile rootstock and root sucker perennial plants (Artemisia changaica, Carex duriuscula, C. korshinskyi,
Leymus chinensis and other), and nitrophilous plants (Urtica canabina) appear.
The concrete successional line of Hg shows the successional advancement of marmot MCPH, and summary successional lines of all MCPH show the state of the marmots population.
The stable marmots settlements attendant symmetrical successional lines or a tendence to asymmetry because of diversity increase (initial stages of line). The absence of animals in settlements increase the advanced stages of successional lines.
Last effect was noted for marmots settlements on dry (with Stipa, Caragana) steppes. Summary successional lines of marmots settlement on droughty bunch grass steppes have greatest number of steps (85), they are symmetric participation of initial and advanced steps, or asymmetric to initial stages. Last fact indicates the permanent function of settlement.
Summary successional lines on meadow steppe have many advanced steps (xeromesophyte group). It is a result of very old marmot population and stable location of their