The Altai Mountains are well-known for their unique archaeological records, with rich, chronologically sequenced Palaeolithic, Neolithic and the Bronze Age (late fourth-early first millennium BC) sites and, in particular, the Iron Age Scytho-Siberian and early historical monuments represented by burial sites, ritual structures, and rock-art. The Altai prehistoric archaeological localities are distributed across a broad range of topographic and ecological settings, encompassing altitudinal zones from 800 m asl in the lower reaches of glacial river valleys up to 2500/3000 m asl on the high mountain plateaus. The partial spatial overlap of these (often multi-component) geoarchaeological loci over time suggests that similar adaptive strategies were employed by countless generations of hunter and later nomadic communities-their actions constrained by the locally specific forms of (palaeo-)relief and the associated ecosystems. The dynamics of the initial occupation of the boreal and alpine Altai landscapes and subsequent processes of (re-)colonisation during the Final Pleistocene-Holocene transition are directly linked to transformations in the regional hydrological systems after the LGM. The principal settings for early pastoral settlements were the xerothermic grasslands that formed on the flat glacio-lacustrine terraces which rise above the modern fluvial floodplains-the remains of ice-dammed wastage lake basins drained at the end of the Pleistocene (15,000-13,000 year BP). Marked climatic changes, evidenced by regional variations in temperature and humidity across the territory, are well attested in the geological, biotic and archaeological records. The initial Sub-Boreal aridification correlated with the beginnings of the Altai Bronze Age traditions continued until the early Iron Age-causing an expansion of parkland-steppe in the main valleys and a forest retreat in the foothills. Mountain steppes constituted the most essential food-procurement habitat for the Holocene prehistoric and historical settlements of Southern Altai. The current degradation of insular alpine permafrost poses an imminent threat to preservation of the region's most precious archaeological monuments-the frozen burial mounds of the Pazyryk culture (sixth-third century BC) belonging to the UNESCO World cultural heritage.