Climate-Adaptive Reproductive Material Sourcing of Quercus cerris in Central Europe

Botond B. Lados, László Nagy, Csilla É. Molnár, Attila Benke, Zoltán A. Köbölkuti, and Klára Cseke

Published May 2026 in International Oaks No. 37: 215–224

Abstract

The increasing frequency of drought periods poses serious challenges for mixed oak forests in Central Europe. In this context, assisted gene flow is a promising approach to increase local diversity and support the adaptive potential of local populations. In Central Europe it is currently thought that this would involve assisted gene flow from the southeast to the northwest, based on the assumption that southeastern populations have evolved under warmer and drier conditions. In our study, we investigated the genetic diversity of 32 Quercus cerris (Turkey oak) populations in Central and Southeast Europe to evaluate the opportunities for, and potential effects of, assisted gene flow. Population genetic analyses were performed using thousands of genome-wide SNP markers, generated by ddRAD-seq genotyping of 321 individuals. The results showed a gradient of increasing genetic diversity from southeast and southwest to northwest, with a diversity hotspot identified in the northwestern part of the study region. According to the results, the central part of the Carpathian Basin, an area projected to undergo critical climatic changes, and therefore a primary target for assisted gene flow, shows higher diversity than the potential source region (Balkan Peninsula). Moreover, the observed diversity gradient runs counter to the commonly proposed southeast-to-northwest transfer strategy. These findings highlight the importance of evaluating species-specific genetic patterns rather than applying generalized management approaches.

Keywords

Turkey oak, assisted migration, population genetics, genetic diversity, population structure, Balkan Peninsula, Carpathian Basin, ddRAD-seq

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