Dynamics of the ethnic contrast coefficient in the Republics of the Ural-Volga region from 1926 to 2021

One of the tasks of ethnodemography and ethnocultural geography is the search for quantitative indicators that make it possible to assess interethnic interaction in specific territories. The indicator, calculated at the level of individual regions on the basis of “interethnic distances” measured by E. L. Soroko, and taking into account the ethnic structure of the population of the territories, is proposed to be called the ethnic contrast coefficient (or Soroko coefficient). The purpose of the study is to identify the features of the dynamics of the ethnic contrast coefficient at the level of the republics of the Ural-Volga region from 1926 to 2021. In addition, the calculation of ethnic contrast coefficients at the regional level made it possible to come close to solving the problems posed during the modernization of the concept of ethno-contact zones, carried out within the framework of the geospatial approach. These include two classifications: 1) according to the severity of ethno-contact zones; 2) according to the degree of complementarity of ethnic groups forming ethno-contact zones. The ethnic contrast coefficient of the Ural-Volga region republics was not constant, and its dynamics were associated with changes in the ethnic composition of the population of the republics. In accordance with the value of the Soroko coefficient, regional ethnic contact zones (within the borders of the republics) are divided into relatively contrasting (Bashkortostan) and relatively complementary (other republics). The value of the ethnic mosaic index multiplied by the ethnic contrast coefficient was adopted as a quantitative criterion in the classification of ethno-contact zones by degree of severity. Regional ethno-contact zones are divided into three classes according to the degree of severity: mildly expressed (Udmurtia and Chuvashia); pronounced (Mordovia and Tatarstan); the most pronounced (Bashkortostan).