Balea lake sedaDNA
The high alpine and subnival zones of the Carpathians offer rich pastures, yet archaeological evidence for early livestock use is lacking, suggesting a late onset of alpine grazing. Using sedimentary ancient DNA (sedaDNA) from Lake Bâlea (2039 m a.s.l.), we demonstrate that alpine grazing began as early as in the Early Bronze Age at ~4900–4800 cal BP triggered by the westward migration of Yamnaya herders. These incursions likely displaced local Copper Age communities upslope, initiating sheep and pig transhumance. We reveal repeated pulses of alpine grazing coinciding with later steppe-derived and north-eastern migrations (e.g., Noua, early Slavs, Hungarians), indicating that pastoral retreat into highlands was a strategic response to external pressure. Intensifying grazing brought lowland and nival species, including the endemic Carex curvula to the alpine zone in the Late Bronze Age (~3450 cal BP). These episodes altered alpine vegetation, leading to long-term plant diversity increases and the replacement of dwarf shrub heaths with forb-rich grasslands. Our data challenge the notion of delayed alpine herding in the Carpathians and highlight the role of climatic shifts and cultural displacement in shaping high-altitude pastoral landscapes.