Zoological Indication of Climate Change in the Central Kazakh Steppe Compared to the Middle of the 20th Century Using the Example of Carabid and Tenebrionid Beetles

Studies of communities of ground beetles (Carabidae) and black beetles (Tenebrionidae) were conducted in central Kazakhstan along 70° E in typical, dry, and desert steppe subzones in 1976–1978 and 2018. Parallel to that, soil-cover studies were conducted and the climate indicators of the studied areas were compared. Despite a considerable change in climate over 50 years, which has been expressed in a rise in temperatures with a simultaneous increase in precipitation, the basic features of soils have not undergone essential changes, but they keep or get strong potentials for solonetz and solonchak elementary soil processes, which are capable of drastically changing the structure of the soil cover. The generality of local fauna of carabids in 1976–1978 was 48–62% and, at the beginning of 21st century, it decreased to 16% in dry steppe and to 7% in desert steppe. In tenebrionids, which are more adapted to aridity, the faunal similarity decreased from 70–75 to 37% in the typical steppe and increased to 87% in the dry steppe. There are more “southern” subarid species in the communities and fewer relatively “northern” boreal and polyzonal species, which disappear completely in dry and desert steppes. The Tencar index that expresses the ratio of the number of individuals and species of arid tenebrionids and more humic carabids is used as an integral zoo indicator of changes in aridity of the environment. In the typical steppe, the index values are low and change little in the long-term dynamics and along the catena. However, in the dry steppe, Tencar index values increased 5 times in 2018 when compared to the middle of the 20th century and in desert steppe they grew by two orders of magnitude. The trigger for changes in the composition and structure of local communities of carabids and tenebrionids is not a change in atmospheric humidity, but a rise in average annual temperatures, which exceeded the global trend values and activated the salinization of soils, creating the conditions for the desertification of the territory and biota.