Ecological modeling of Yamal tundra ecosystems: Traditional nature use as a factor of instability

This paper represents the results of a comprehen� sive study on the consistent patterns of the functioning (dynamics) of the shrub and northern tundra ecosys� tems of the Yamal Peninsula that have been subjected to longterm anthropogenic impact connected with the traditional reindeer breeding and are now sub� jected to some new influences connected with the development of the oil and gas industry. The study is based on the integration of data accumulated during several decades of investigation of Yamal ecosystems in which we have participated. The main approach to solving this task was the use of system analysis, which implies the development of modeling (computer) models describing interactions between the key components of the northern and shrub tundra ecosystems of the Yamal Peninsula and verification and analysis of these models. Shwartz (1) considered that such a model can be developed only on the basis of actual data on the structure and dynam� ics of basic components ("blocks"), composing the "core" of tundra biocenoses and including plants, small mammals, reindeer (mainly domestic), preda� tory mammals (mainly Arctic foxes), and birds of pray. The abovementioned components are functionally related with one another; as a rule, these relations are complex (nonlinear), which complicates the predic� tion of the ecosystem dynamics (2). Tundra ecosys� tems of the Yamal Peninsula are considered to be a constellation of two overlapping subsystems, natural (biogeocenosis) and anthropogenic (anthropogeo� cenosis), which surrounds humans and "works" for them (3). A simplified diagram of such a system is shown in Fig. 1. In this paper, we describe only the results of our analysis of the influence of deer breeding (the main type of the traditional nature use in terrestrial Yamal ecosystems) on the vegetation; we did not take into account hunting, because it is less important for both economics of the aboriginal population and vegetation