Multi-provenance assisted seed dispersal slows range contractions under climate change.

Rapid climate warming threatens the persistence of temperate European forests, raising urgent questions about whether traditional reliance on local seed sources remains viable. Using Quercus petraea in France as a model system, we combined provenance-specific species distribution models with a dynamic range-shift model (simRShift) to evaluate climate-informed assisted dispersal under SSP5-8.5 from 2020-2100. We tested six regional provenances and five planting efforts within the operational seed zones framework used in French forestry. Across all scenarios of planting efforts, Q. petraea experienced substantial loss of climatically suitable habitat. However, assisted dispersal markedly slowed this decline. Mixed-provenance plantings consistently outperformed local-only strategies, retaining ~2.5× more habitat by 2100. Local provenances maintained clear advantages only in climatically stable mountain regions, whereas warmer lowlands increasingly favored Atlantic, continental, and Pyrenean origins. Seed flows reorganized along aridity, continentality, and elevation gradients, producing multi-directional and altitudinally structured provenance mosaics rather than simple northward shifts. Planting effort showed strong diminishing returns, with moderate interventions (5%) capturing most of the attainable benefits. Our results demonstrate that climate-explicit seed sourcing can substantially enhance persistence of temperate oaks under rapid climate change. Integrating assisted dispersal into an existing seed zoning framework, offers an operational pathway toward climate-adapted reforestation across Europe.