1067-4136/03/3403- $25.00 © 2003
Russian Journal of Ecology, Vol. 34, No. 3, 2003, pp. 202–209. Translated from Ekologiya, No. 3, 2003, pp. 225–234.
Original Russian Text Copyright © 2003 by Evdokimov.
Regular (cyclic) ﬂuctuations of population size are
characteristic of relatively few mammalian species (the
lynx populations in Canada provide a classic example
of cyclic ﬂuctuations). When there is only a tendency
toward cyclicity, such ﬂuctuations are referred to as
, 1989). Population cycles
and quasi-cycles have also been observed in small
mammals, such as lemmings and voles living at high
northern latitudes. Attempts to divide the population
cycles of these species into phases were unsuccessful,
and no lucid explanation for regular ﬂuctuations of
their abundance was obtained in the course of active
, 1973; Krebs and Myers, 1974).
The northern mole voles live underground, in a rel-
atively stable environment, establishing long-term fam-
ily colonies with permanent home ranges. Hence, this
species is a convenient experimental model for analyz-
ing the dynamics of population size and structure.
Observations of marked mole voles of the Kurtamysh
population (1985–1994) were used in my previous
study, in which the analysis of population structure was
based on identiﬁcation of three phases of population
dynamics and animal generations born at each phase
Between 1985 and 1994, the dynamics of the Kur-
tamysh population had a cyclic pattern: the years of
high animal abundance (1986, 1989, and 1992) alter-
nated with the years of low abundance (1985, 1988,
1991, and 1994); in the intermediate years (1987, 1990,
and 1993), the number of animals decreased slightly. In
1990, however, there was an increase in animal abun-
dance, rather than a decrease, and population decline in
1991 was indistinct (Fig. 1).
In the following three years (1995–1997), the above
periodicity of population dynamics (with the phases of
high, low, and decreasing abundance) was absent: ani-
mal abundance in this period increased gradually,
remaining generally low (Fig. 1). Such a pattern of pop-
ulation dynamics indicated that the corresponding pro-
cesses should be analyzed using a different approach.
Indeed, the study of a speciﬁc (subterranean) form of
rodents, such as the northern mole vole, required a spe-
The purpose of this work was to analyze the dynam-
ics of population size and structure in the northern mole
vole and to estimate the period of ﬂuctuations in the
abundance of these rodents.
MATERIAL AND METHODS
The study was performed by the mark–recapture
method in the Kurtamyshskii region of Kurgan oblast
(1985–1997), in the forest–steppe zone (aspen–birch
groves, grainﬁelds, and grassland), in an area of
approximately 8 ha. The animals were captured by fam-
ilies (Evdokimov and Pozmogova, 1998) using Golov’s
live traps (Golov, 1954). Trapping and marking (by ﬁn-
ger clipping) were carried out twice a year, in April–
May and August–September. On the whole, 24 families
were studied, 675 animals were marked, and each indi-
vidual was trapped 2 to 13 times.
To facilitate statistical analysis of the quantitative
composition of mole vole families, they were divided
into four groups: (1) two to three members (young fam-
ilies consisting of a female and one or two males),
(2) four to nine members (parents and their progeny of
Fluctuations of Population Size and Structure
in the Northern Mole Vole: Preliminary Analysis
N. G. Evdokimov
Institute of Plant and Animal Ecology, Ural Division, Russian Academy of Sciences, ul. Vos’mogo Marta 202,
Yekaterinburg, 620144 Russia
Received August 16, 2000
—Long-term stationary studies on the ecology of the northern mole vole (
formed by the mark–recapture method from 1985 to 1997, have provided original data on population dynamics
and structure. The analysis shows that, to reveal cyclic ﬂuctuations of population size in this species, the period
of three years should be taken as a unit of time for estimating the duration of one phase. The 12-year population
has four distinct phases: an increase, a peak, a decline, and a minimum. At each phase, the
population is characterized by certain features of family structure, age composition, birth and death rates, and
the composition of migrants.
: northern mole vole, dynamics of population size and structure, phases of population cycle, age
structure, birth rate, mortality, life span, migrants (emigrants, immigrants, intermigrants, and transmigrants).