Overview

• Grapevine samples show roughly 3.7‰ higher Δ13C than olives, reflecting differing water-use traits and targeted management.
• Intensive irrigation of vineyards appears from the Middle Bronze Age, with grape cultivation sustained in zones otherwise too dry for vines.
• Isotope signals align with major dry pulses around 4.2 and 3.2 thousand years ago, indicating spikes in crop stress and likely irrigation.
• By the Iron Age, cultivation concentrated in wetter areas above about 500 mm reconstructed precipitation, yet grapes persisted beyond natural niches.
• The authors conclude farmers balanced plant survival, irrigation effort, and product demand, giving wine production precedence over olive oil.