title: Desiccation and Mortality Dynamics in Seedlings of Different European Beech (Fagus sylvatica L.) Populations under Extreme Drought Conditions.
abstract: European beech (Fagus sylvatica L., hereafter beech), one of the major native tree species in Europe, is known to be drought sensitive. Thus, the identification of critical thresholds of drought impact intensity and duration are of high interest for assessing the adaptive potential of European beech to climate change in its native range. In a common garden experiment with one-year-old seedlings originating from central and marginal origins in six European countries (Denmark, Germany, France, Romania, Bosnia-Herzegovina, and Spain), we applied extreme drought stress and observed desiccation and mortality processes among the different populations and related them to plant water status (predawn water potential, ΨPD) and soil hydraulic traits. For the lethal drought assessment, we used a critical threshold of soil water availability that is reached when 50% mortality in seedling populations occurs (LD50SWA). We found significant population differences in LD50SWA (10.5-17.8%), and mortality dynamics that suggest a genetic difference in drought resistance between populations. The LD50SWA values correlate significantly with the mean growing season precipitation at population origins, but not with the geographic margins of beech range. Thus, beech range marginality may be more due to climatic conditions than to geographic range. The outcome of this study suggests the genetic variation has a major influence on the varying adaptive potential of the investigated populations.
authors.affiliation: Thünen Institute of Forest Ecosystems Eberswalde, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bolte
authors.affiliation: Thünen Institute of Forest Ecosystems Eberswalde, Germany.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Czajkowski
authors.affiliation: Instituto per la Protezione Sostenibile delle Piante (IPSP), Consiglio Nazionale delle Ricerche Sesto Fiorentino, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Cocozza
authors.affiliation: Dipartimento di Bioscienze e Territorio, Università del MolisePesche, Italy; EFI Project Centre on Mountain Forests (MOUNTFOR), Edmund Mach FoundationSan Michele all'Adige, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Tognetti
authors.affiliation: BIOGECO, INRA, Université de Bordeaux Cestas, France.
authors.forename: Marina
authors.initials: M
authors.lastname: de Miguel
authors.affiliation: Institute of Forest Ecology, Slovak Academy of Science Zvolen, Slovakia.
authors.forename: Eva
authors.initials: E
authors.lastname: Pšidová
authors.affiliation: Institute of Forest Ecology, Slovak Academy of Science Zvolen, Slovakia.
authors.forename: Ĺubica
authors.initials: Ĺ
authors.lastname: Ditmarová
authors.affiliation: Marin Dracea National Forest Research-Development Institute Bucharest, Romania.
authors.forename: Lucian
authors.initials: L
authors.lastname: Dinca
authors.affiliation: BIOGECO, INRA, Université de Bordeaux Cestas, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Delzon
authors.affiliation: PIAF, INRA, Université Clermont Auvergne Clermont-Ferrand, France.
authors.forename: Hervè
authors.initials: H
authors.lastname: Cochard
authors.affiliation: Department of Geosciences and Natural Resource Management, University of Copenhagen Frederiksberg C, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Ræbild
authors.affiliation: Grupo de Clima, Agua, Cambio Global y Sistemas Naturales, Departamento de Geografía y Ordenación del Territorio, Facultad de Filosofía y Letras, Instituto de Investigación en Ciencias Ambientales, Universidad de Zaragoza Zaragoza, Spain.
authors.forename: Martin
authors.initials: M
authors.lastname: de Luis
authors.affiliation: Faculty of Forestry, University of Banja Luka Banja Luka, Bosnia and Herzegovina.
authors.forename: Branislav
authors.initials: B
authors.lastname: Cvjetkovic
authors.affiliation: Swiss Federal Institute for Forest, Snow and Landscape Research WSL Birmensdorf, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Heiri
authors.affiliation: Thünen Institute of Forest Ecosystems Eberswalde, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Müller
keywords: Fagus sylvatica; LD50SWA; desiccation; drought; genetic variation; mortality; pre-dawn water potential; soil water availability