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. : 179-180.


DYNAMICS OF AGE AND SEX STRUCTURE IN THE KOKPAK GREY MARMOT POPULATION


S.B. Pole*, V.S. Arakelyantz**, N.L. Klassovski*, V.I. Sapozhnikov **

*Kazakh Antiplague Research Institute, Almaty
**Taldykorgan Antiplague station, Taldykorgan, Kazakhstan


The objective estimation of the marmot population structure as far as their age and a concerned depends directly on the reliability of method in defining their age, the number of marmots examined, the period and the area of trapping which has been mentioned by many authors (Bibikov, 1967, 1989; Pole, 1974, 1981 et al.).

This report includes the results of analysis on age and sex structure of season suveys in materials obtained over a long period of time (1968-1995) in partial and total trapping of marmots in the course of epizootic survey in the Kokpak mesofocus of plague. 10496 marmots have been examined during the given period of time. The materials was classified according to three altitude zones (the steppe, the forest-meadow-steppe and alpine belts).

The comparison of data on total and partial trapping (table 1) are indicative of the fact that the number of sexually immature animals in partial trapping is 20 per cent higher than that in total trapping. The proportion of male and female animals practically remained unchanged (54.2:43.8 and 53.7:44.3% in total and partial trapping respective).

The analysis of the proportion of age- and sex-groups during the simultaneous survey in the three altitude zones (table 2) shows that the percentage of young animals in the alpine zone is significantly greater whereas the part of yearlings in less than in the forest-meadow-steppe zone. This is indicative of the fact, though indirectly, that the death-rate of young animals in the alpine zones is higher and, as a result, the effectiveness of compensation mechanism in populations at the expense of the greater number of reproductive females. In 1971-1973 the proportion of males and females in surveys carried out in the steppe zone was appsoximately 1:1, while such proportion in the forest-meadow-steppe belt and the alpine zone - 1.2:1.

The analysis of the surveys carried out during a number of years in the steppe and forest-meadow-steppe zones (table 3) confirms the conclusion that the total trapping mainly affects the proportion of age-groups and generally has a rather small effect an the proportion of males and females in the samples.

Thus the percentage of immature animals in the samples carried out in all altitude belts in partial trapping is practicaliy twice as large as tbe number of adult marmots, whereas in total trapping the result is quite the opposite one. And the proportion of males and femafes changes quite insignificantly.

The results obtained open a great possibility of their application as a correction factors in the comparison of the results obtained through using different methods and in various landscapes.


Table 1.
Grey Marmot population struciure in the forest-meadow-steppe zone
in partial and total trapping (Kokpak, 1969)

Trapping methodNumber of trapped animalsAdults (%)Immature
MalesFemalesMalesFemales
Total20134.828.819.417.0
Partial56223.120.530.625.8

Table 2.
Age and sex structure in Grey Marmot population in different Altitude Zones (Kokpak, 1971-1973, partial trapping)

GroupsAltitude Zones
Steppe (n=634)Forest-Meadows-
Steppes (n=1625)		Alpine (n=1531)
Adult (%) males14.8±1.5217.2±1.214.7±1.56
Reproductive females (%)9.0±2.311.1±1.314.0±0.7
Barren females (%)5.8±0.64.8±0.98.0±0.4
Yearling males (%)8.6±1.45.3±1.25.1±0.6
Yearling females5.7±1.09.0±1.95.7±0.2
Young males (%)27.4±2.223.2±1.724.2±1.2
Young females (%)28.8±3.329.4±3.333.5±1.7


Table 3.
Dynamics of age and sex structure in Grey Marmot population in the steppe and in forest-meadow-steppe zones (Kokpak, 1968-1983, partial trapping).

GroupsAltitude Zones
Steppe (n=2,728)Forest-Meadow-Steppe
Mature males (%)16.1±1.2819.5±0.97
Reproductive females (%)11.1±1.1311.9±0.65
Barren females (%)5.8±0.735.1±0.67
Yearling males (%)8.5±1.217.2±0.99
Yearling females (%)7.9±1.248.4±1.1
Young males (%)25.3±2.4422.2±1.75
Young females (%)25.0±1.9524.5±1.58


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