Lithological Features as a Factor of Economic Development and Distribution of the Population in the Udmurt Republic

The natural characteristics of a region historically affected the character of its economic development and distribution of population. The most important factor of the landscape differentiation in the Udmurt Republic is the alternation of Quaternary deposit types, which greatly complicates the zonal sequence of soil types. Depending on soil fertility, two background nature management types were formed within each natural landscape: agricultural and forestry. The aim of our work was to confirm the relationships between Quaternary deposit types (as soil substrates) and settlement indicators (as indicators of nature management type). The relationships were studied within the Udmurt Republic landscape zoning scheme by professor V.I. Sturman. Calculation of pair correlation coefficients was the key method for estimating the relationships. The study has shown lower density of population and settlements, low density of the road network, and higher average population of rural settlements in landscapes with higher fraction of aeolian, boggy, and alluvial deposits. An opposite trend in all the above indicators occurs for landscapes with a higher level of eluvial, eluvial-deluvial, and deluvial-solifluction deposits. It has been proven that the strength of correlations between Quaternary sediment types and settlements indicators varies in different parts of the republic against the background of zonal climate changes and azonal relief change. The distribution of geographically incompatible aeolian and eluvial-deluvial deposits, which occupy the largest areas, has the greatest impact on the population distribution. The strength of most correlations has been found to decrease against the general trend of rural-to-urban migration in the period from 1970 to 2020. That was due to the “low base effect,” which leveled territorial contrasts in the population distribution within the landscapes of the Udmurt Republic.