Opredelenie absoliutnoï plotnosti naseleniïa i tchislennosti sourkov (Estimation de la densité absolue et du nombre des populations de marmottes (Marmota). Estimation of absolute population density and numbers of the marmots (Marmota)].

Résumé

Proposition d'une méthode de calcul à partir du nombre de marmottes dans une famille, de la densité de familles et de leur répartition.The author proposes to calculate absolute population density and numbers of the marmots by the number of animals in a family, by the density of the families distribution, and by the habitats areas. The first index characterizes temporal fluctuations of the population density and numbers, while the second and third indices characterize spatial fluctuations. The number of specimens in a family is determined every year by observations with binoculars (12x). The density of the families distribution is estimated only once during the period of studies in accordance with the family groups of holes on plots .The main criterion of their distinguishing is the distance between constant holes. Estimation of the family densities is recommended to be carried out separately for the different types of plant associations. The areas of habitats are estimated once during the period of studies with the help of large-scale geobotanical and land-utilization maps taking into account the data obtained during visual examination of the territory. The method proposed makes it possible to investigate considerabIe areas rapidly and accurately, makes it easier to carry out censuses in the consequent years, gives an additional biologically important information, and above all, provides a reliable basis for extrapolation. The method was tested in plain and in mountains. The techniques of censuses is described in details; indices obtained are presented.