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., 63-64 (Russian), 167-168 (English).


STRUCTURAL ELEMENTS OF MARMOT POPULATION


V.I. Mashkin

Prof. Zhitkov' VNIIOZ, Kirov, Russia


In everyday practice the "settlement" is interpreted rather freely and as a synonym is used for the terms a family and a colony. It is known that a spatial population structure of marmots is formed from the groups of various size and complexity and is a multilevel system of families, colonies and settlements.

A family (a group of 2-18 individuals of different sex and age) is the basis of every spatial marmot group. It is a simple, independent, structural and functional part of a population that shares the territory, resources and covers, has endogenous reproduction, regulates its numbers and has family information permitting animals to distinguish the individuals of their family. It is possible to define quite precisely the family linear borders in the territory by means of visual observations on marmots or on the results of their activity. The family site area may be from 0.6 to 15 ha.

Colonies are groups of families (from 3 to 100 families and more) which occupy comparatively isolated territories and are connected by visual and sound communication. Through dispersion pubescent individuals are connected with other existing or forming colonies. The colony size is not a statistical concept but a functional one and it is defined by landscape hetero geneity and the character of ethological contacts. The colony borders may coincide with the contours of the grounds - natural and territorial complexes corresponding to a certain form of a mesorelief.

When marmot families are diffusely dispersed over vast territories and the character of interfamily relations is nowhere broken, then under those circumstances we deal with settlements - larger territorial structures, but not with colonies. A settlement is a population of functionally related families or colonies occupying a certain landscape type - a system of interdependent and interactive grounds forming a diverse, specific, natural and territorial complex with its own individual peculiarities (Tseselchuk, 1963).

When estimating the borders of a settlement it is necessary to take into account natural or artificial barriers: rivers, mountains (ranges), river watersheds, ploughed areas etc. that lead to isolation of certain territorial groups. To reveal the groups of a higher rank it is necessary to estimate the level of their spatial and genetic isolation (Yablokov, 1967).

A population spatial structure is expressed in natural distribution of family groups with respect to certain landscapes and to each other, and reflects a certain type of their topograhic location in a space. The types of settlements are defined according to these features. The type of a settlement is a one-moment charactiristic of a spatial structure. There are 4 types of marmot settlements: steppe, gully, mosaic (Bibikov, 1967) and net (Rumiantsev, 1991).

The formation of families, colonies and settlements takes place during the process of intrapopulation moving. The following movement categories are differentiated: feed; when changing the holes of different types; under the influence of human activities; marking; removing of pubescent individuals; moving of individuals of various age and sex to some other families (regrouping); when number changes take place and during acclimatization.


Retour au sommaire / Back to Abstracts contents