Abstract <p>Culturable bacterial communities associated with the main soil types of the temperate climate zone of central Russia were studied to assess physiological differences between bacteria inhabiting temperate soils and bacteria in arid soils and permafrost sediments. The potential metabolic activity of the communities and the proportion of psychrotolerant strains within them were assessed. The resistance spectra of pure bacterial cultures to temperature, pH, and NaCl content were estimated. A comparative analysis was conducted into the resistance of strains isolated from temperate soils and various soils and sediments in which bacteria are experiencing available moisture deficiency. The presence of stress-tolerant bacteria was shown to be characteristic of culturable microbial communities of both temperate and arid soils: bacteria associated with temperate soils exhibit higher resistance to various ambient temperatures, while bacterial communities from arid ecotopes exhibit greater resistance to environmental pH, especially in highly contrasting (acidic and alkaline) ranges. The prevalence of bacteria extremotolerant to various environmental factors is higher in communities of arid ecotopes. Majority of culturable soil bacteria were found to maintain metabolic activity across a wide range of key environmental factors (temperature, pH, and presence of sodium chloride). These data indicate the presence of physiological mechanisms supporting adaptation, stress tolerance, and the functioning of bacterial communities in arid ecotopes that differ from those in temperate soils.</p>