Integrating fossil data, vegetation modelling and genetic analyses of modern tree populations to reconstruct the history of Larix in Europe
Final Report Abstract
This project focuses on the consequences of past climate and anthropogenic changes on populations of the European larch (Larix decidua Mill.) by integrating palaeoecological and genetic data. Such retrospective approaches provide a useful context for evaluating possible impacts of ongoing changes. A limitation of current studies dealing with forest trees is that they often deal exclusively with postglacial recolonization. Effects of more rapid changes on forests, including those caused by recent plantations or by abrupt climatic events of the last glacial, have been largely neglected. In this study high resolution genetic data and precise vegetation records correlated with high-resolution climate records of the last interglacial/glacial cycle (130,000 years) were used to precisely document longterm and short-term events that impacted the history of European larch. For the genetic analysis, highly informative nuclear markers (microsatellites) and mitochondrial markers (sequence data) were designed and applied on a range-wide sample of 45 modern L. decidua populations. The mitochondrial and nuclear data were analysed independently and in combination to establish a baseline for studies focussing on recent translocations. Results revealed that larch has been planted extensively, generating admixture between native and non-native populations from multiple sources across the range. Translocation events and admixture rates were distributed unevenly across the range, with a particularly high frequency in Poland, Slovakia and the Czech Republic where larch has a more scattered distribution compared to the Alps. Some of the most valuable populations appear to be seriously endangered by translocations. The palaeoecological results showed that larch persisted close to its modern distribution throughout the last interglacial/glacial cycle but that its range was highly dynamic and in equilibrium with both long-term and short-tem climate events, in line with the pioneer character of the species. The extent of species distribution was maximal during the first early Weichselian interstadial when larch built boreal forests in the north-central European lowlands (87,000 – 109,000 years ago). Six to seven Last Glacial refuges were detected using fossils and genetic data. The precision and the richness of details provided by the two approaches can be considered as a new step in reconstructing a species history on the global range scale and provides at the same time a baseline and tools for different research issues (e.g. adaptation, selection, larch canker).
Publications
- (2012) Two highly informative dinucleotide SSR multiplexes for the conifer Larix decidua (European larch). Molecular Ecology Resources 12, 717-725
Wagner S, Gerber S, Petit RJ
- (2013) History of the European larch (Larix decidua Mill.) Binational PhD thesis, University of Bonn, Germany, University of Bordeaux 1, France, 165 p.
Wagner S
- (2013) Le chancre du mélèze dans le Massif Central en fonction de l'origine génétique des peuplements. Rapport Interne DSF/DGAL/MAAF 13 p.
Piou D, Wagner S, Fabreguettes O, Robin C
- (2015) Within-Range Translocations and Their Consequences in European Larch. PLoS ONE 10(5): e0127516
Wagner S, Gerber S, Liepelt S, Petit RJ
(See online at https://doi.org/10.1371/journal.pone.0127516) - History of Larix decidua Mill. (European larch) since 130 ka. Quaternary Science Reviews
Volume 124, 15 September 2015, Pages 224-247
Wagner, S., Litt, T., Sanchez-Goni, M.-F., Petit, R.J.
(See online at https://doi.org/10.1016/j.quascirev.2015.07.002)
