**1. Introduction**

Actually observed climate changes, resulting from humans industrial, transport and agricultural activities triggering the green-house effect and changing precipitation volume and patterns, affect water availability [1,2] and occurrence of extreme weather-related events such as floods and heat waves [3–5]. Thus, the increased duration of dry periods between subsequent rainfall events causes threat of droughts in the areas affected by climate anomalies, usually expressed by decrease in precipitation during the warm period of the year [6]. Decreased precipitation and elevated temperatures are a serious threat to the water balance and biodiversity of natural ecosystems [7–9].

The most sensitive to increasing temperature and climate aridisation are those land areas where evolution took place under conditions of high water content, such as various types of wetlands, river valleys, streams and temporary streams. Wetlands cover approximately 6% of the of the Earth's land surface [10], and they are extremely vulnerable to the effects of climate change because they are very dependent on the water cycle. They are often found at the interface between terrestrial ecosystems, such as forests and grasslands, and water, such as rivers, lakes, estuaries, and oceans [11]. Wetlands and their biota are disappearing worldwide due to human activities, e.g., uncontrolled and unsustainable insufficient water resource management and increased water demand by growing urban populations [12–18]. In light of the above, global warming can be seen as a verdict against the conservation of biodiversity.

At the end of the 20th century and the beginning of the 21st century, the longest warming period in Eastern Europe took place over more than 120 years of systematic observations [19]. In Ukraine, from 1993 to 2010, the duration of the warm period increased by 4–10 d in Polesie and the forest-steppe and by 17–26 d in the steppe [20]. Under conditions of climate variations, with reduced rainfall at high temperatures, the distorted water balance of ecosystem will result in increased evapotranspiration quickly, leading to surface waters drying and a decrease in soil moisture in the range of plants root zones, subsequent reduction of water content in the unsaturated zone, and, finally, an increase in the water table level depth, thereby lowering the amount of retained water available for plants. The reduced water availability in the ecosystem in the form of surface and soil retention significantly endangers the environmental sustainability of the region by rearrangement of population distributions [21–23]. Special attention should be paid to support the natural forestation of ecosystems due to the significant ability of forests to intercept and retain precipitation water as well as limiting the ratio of soil, surface water and groundwater drying.

The increase in the duration of dry periods triggered by limited precipitation will obviously lead to a reduction in habitats for hygrophilous species, changing their populations' distribution and restructuring the ecosystem. It is not surprising that great attention is paid to studying the effect of temperature increases on individual biomes and their diversity on a global scale [24–28]. Thus, the influence of climate change on the reactions of animals from different taxonomic groups (birds, butterflies and amphibians, less often beetles) and the change in their geographic areal due to climatic changes are studied [29–33]. Terrestrial arthropods comprise most of the biodiversity in wetlands and include many rare and endangered wetland species [34–36]. It is quite possible that arthropods in the conditions of global warming will be practically deprived of refugia.

Among arthropods, ground beetles (Coleoptera: Carabidae) are considered to be useful environmental indicators that are important for understanding the patterns of changes in overall biodiversity [37]. Climatic variations have a significant impact on the level of soil moisture and, obviously, change the structure of their biological components. Ground beetles respond to changes in climatic conditions, but the speed and nature of the change in their assemblage are largely unknown.

The aim of our work is to establish the response of the assemblage of ground beetles to climate variations driven by aridization. We analyzed how climate variations affects the structure of the assemblage of ground beetles using the example of a local area.
