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., 104-105 (Russian), 157-159 (English).


A CHANGE IN THE BIRTH-RATE IN THE DEM OF MARMOTA BOBAC AS A RESPONSE TO REMOVAL OF DIFFERENT INTENSIVITY


N.Yu. Kholodnaya, V.V. Uzhik

Kharkov State University, Kharkov, Ukraine


The problem of rational use of population Marmota bobac invisages the development of effective ways of controlling the state and behaviour of this multilevel complex biosystem. Evidently, for solving such problems it is necessary, first of all, to carry out investigations connected with the analysis of integral and fairly universal parameters characterising the life activity of the given object. Here, alongside with investigations of the monitoring type it is also necessary to carry out active experiments whose purpose is obtaining information on peculiarities of functioning the biosystem under study under conditions of the action of pertubating factors of different nature and intensity with reflecting the obtained information in coordinates " time-action intensity-effect" both for each factor separately and for cases of their combined action. At the initial stage of investigations it is expedient to limit the scope of the experiment by conditions of a short experiment (with times of realisation of the analyzed effects which are significantly shorter than the characteristic time of functioning the object). Up to now, biology and adjacent sciences have accumulated a sufficient amount of information on pecularities of responses of biosystems to external action of different nature. It has been noted that one of the common features of the response development is a step-by-step change of functional states by the biosystem under the action of the load characterised by the presence of definite critical levels connected with reconstructions in some cases leading to a change in the response strategy.

We have obtained data on the influence of a single removal with intensity 4; 12; 17; 22; 33; 58 % on the change in the number in the population of. Marmota bobac. A visual complete counting of the number of animals on 7 regions was made in the summer of 1995 before removal and then in the summer of 1996.

Under the conditions of ravine system typical of the places of inhabitance of Marmota bobac on the territory of Velikoburluk district of Kharkov region in the Ukraine the population is a conglomerate of dems which are a group of individuals (families) of member of the given population which densely inhabit a territory bounded by natural boarders and whose exchange of genetic information with other groups is minimised.

On the basis of comparison of data on the correlation between the number of adult animals and current-year-born animals in 1995-1996 we have analysed a variation of birth-rate as an integral quantity characterising a functional state of the biosystem.

The birth-rate was characterised by three ccomplementary parameters whose application is necessiated by peculariaties of the object under investigation. Parameters of variation of internal characteristics of the object were calculated.


1. A change in the avarage number of current-year-born animals per an adult individual -P-was defined by formula (1) for each dem
P = mc1/mb1 - mc2/mb2 (1)
were mc1-the number of current-year-born animals according to 1995 data
mb1 the numbers of adult individuals according 1995 data
mc2-the number of current-year-born animals according to 1996 data
mb2 the numbers of adult individuals according 1996 data

2. A change in the number of reproduced families -N- was defined by formula (2) for each dem
N = [ n2 - n1 / nc] 100% (2)
were n1 - the number of reproduced families according to 1995 data
n2 - the number of reproduced families according to 1996 data
nc - the total number of families wich does not change during yhe experimental

3. A change in the avarage number of current-year-born animals in a reproduced family -R- was defined by the formula (3) for each dem
R = mc2/n2 - mc1/n1 (3)
were mc1-the number of current-year-born animals according to 1995 data
n1 - the number of reproduced families according to 1995 data
mc2-the number of current-year-born animals according to 1996 data
n2 - the number of reproduced families according to 1996 data


Fig.1
Dependence of a change in the avarage number of current-year-born animals per one adult individual in a dem on removal of different intensivity.

Fig2.
Dependens of a change in the number of reprodused families in a dem on removal of different intensivity

Fig.3
Dependence of a change in the avarage number of current-year-born animals in reproduced families in a dem on removal of different intensivity.

Fig.4
Dependence of the variation coefficient of the number of current-year-born animals in reproduced families in a dem on removal with different untensivity

Variation coefficient of number of current-year-born animals in a reprodused families -S- was calculated in the usual way.

On the curve showing a change in the avarage number of current-years-born animals per one adult animal built in the coordinates "intensivity of action-effect" there is a part of a fairly monotone change of the given function which is characterised by low values of variability, a region of "transient" state ( corresponding to 22% removal) which is characterised by a higher value of S, a region of a stress quazistationary state corresponding to 33% removal and characterised by a lower variability in which a sharp pice of birth is realised both at the expence of an increase in the number of reproduced families and increase in the number of current-year-born animals in reproduced families. A load in the form 58% removal leads the biosystem into a terminal state characterised by a irreversable degradational processes, low values of S can be explained by a general depression of reproductional processes.



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