Tracing the origin of Oriental beech stands across Western Europe and reporting hybridization with European beech – implications for assisted gene flow

Abstract

Human-aided translocation of individuals within the species' range, assisted gene flow (AGF), has been suggested as a climate change mitigation strategy, especially for foundational species, such as forest trees. The benefits and risks of AGF largely depend on the genetic divergence between host and donor populations, their rate and direction of hybridization, and the climate distance that the transfer involves. In this study, we explored the use of Oriental beech (Fagus sylvatica subsp. orientalis), growing from Iran to the Balkans, for AGF in populations of European beech (F. sylvatica subsp. sylvatica), which grow throughout Europe and are increasingly affected by climate warming. Using 16 microsatellite loci and samples from 13 and 6 natural populations of Oriental and European beech, respectively, we identified 5 distinct genetic clusters in Oriental beech with a divergence (FST) of 0.15 to 0.25 from European beech. Using this knowledge, we tracked the origin of 11 Oriental beech stands in Western Europe, some established in the early 1900s. In two stands of Greater Caucasus origin, we additionally genotyped offspring and found evidence for extensive hybridization, with 41.3% and 17.8% of the offspring having a hybrid status. Further, climate data revealed a higher degree of seasonality across the Oriental beech growing sites than across the planting sites in Western Europe, with some sites additionally having a warmer and drier climate. Accordingly, in one of these stands, we found evidence that bud burst of Oriental beech occurs four days earlier than in European beech. These results suggest that AGF of Oriental beech could increase the genetic diversity of European beech stands and may even help the introgression of variants that are more adapted to future climatic conditions. Our study showcases an evaluation of the benefits and risks of AGF and calls for similar studies on other native tree species.

Differentiation and admixture ofFagus sylvaticaL. andFagus orientalisLipsky in a northern German forest — learning from pioneer forest work

“…Fagus orientalis has been recommended as species with high future potential in Germany but there is an urgent need for prior research initiatives confirming the suitability of F. orientalis provenances and a careful assessment of the risks. Hybridization between F. orientalis and F. sylvatica has previously been reported in the natural range where both species co-occur (Müller et al, 2019;Papageorgiou et al, 2008) and also in locations where F. orientalis was planted in Central Europe (Kurz et al, 2022).…”

“…Flowering phenology in both species is metandric with female flowers of one tree being receptive before pollen release on the same tree and controlled pollination experiments between both species previously reported good success rates (Nielsen and Schaffalitzky de Muckadell, 1954). Kurz et al (2022) observed that spring phenology (assessed on buds and leaves) was slightly earlier in F. orientalis compared to F. sylvatica in two sites in Switzerland suggesting that this might also be the case for the flowering phenology. A similar finding in spring phenology was observed in a growth chamber experiment, comparing populations of the two species from their natural range in Greece (Varsamis et al, 2019).…”

“…This most likely reflects that the gene pool Cl3 was least well represented in our samples but also that the F. orientalis trees from Memsen do not originate from the direct vicinity of Lagodekhi. Kurz et al (2022) also identified the Greater Caucasus region as the main source of planting material for F. orientalis in Central Europe. Genetic differentiation between the two species in Memsen was high, which was also reflected by the leaf morphological traits enabling species determination.…”

Usability of some woody plants in monitoring and reducing the Mn, Zn, Ba, and Sr concentrations in the air

“…Besides that, the most useful plants to be used in monitoring and reducing heavy metal pollution should be determined regionally because plants' capacity to fulfill the functions and benefits expected from them depends on their healthy growth and development [54][55][56][57][58][59]. Plant development, as with all other phenotypic characteristics, is shaped by the mutual interaction between genetic structure [60][61][62] and environmental conditions [63][64][65][66][67][68][69][70]. For this reason, the optimum development conditions of each plant are related to different edaphic and climatic conditions [71][72][73][74].…”

Change of Calcium Concentrations in Forest Soils by Plant Species and Soil Depth

“…The nutrient element content of the soil is one of the most important factors influencing the root development of plants [32][33][34]. As with all other organisms, the phenotypical characteristics and development of plants are shaped under the effects of plants' genetic structures [35][36][37] and environmental factors [38][39][40][41].…”