Chyornye Zemli of Kalmykia: Is the Desert Returning Back?

Natural pastures in arid regions are most prone to degradation which often occurs as a result of human activity. For example, overgrazing and a change in land use in the south of Chyornye Zemli in Kalmykia region in the middle of the last century have led to the emergence of the first and the only anthropogenic desert in Europe in the 1980s. However, in the 1990s, vegetation began to recover due to significant economic changes in the USSR and Russia and the reduction of grazing pressure in Kalmykian pastures. By mid–late 2000s, a desert had turned into a secondary anthropogenic tall-grass steppe with the dominance of feather grass and wheatgrass, minor presence of psammophytes, and a small fraction of weed pasture species. Since that time, the pasture communities have changed dramatically once again. Dry years combined with high grazing pressure favored the expansion of non-stabilized sands. Vegetation height and especially cover that were increasing during the steppe formation have decreased sharply. With some delay, the rodent community has reacted to the changes in the plant communities. The process of desertification that began five years ago as a result of pasture degradation gave an advantage to typical representatives of the desert fauna such as the midday gerbil. A rather rapid population growth and recolonization of the previously abandoned territories in the 2021–2022 may be a warning signal of upcoming abrupt transition of the population of the midday gerbil from low- to high-abundance state. If this expectation is true, there is a high probability of reemergence of natural plague foci in Kalmykia.

midday gerbil, pasture degradation, desertification, population dynamics, plant communities