Skip to Main content Skip to Navigation
Theses

Comprendre l'adaptation locale et la plasticité phénotypique des caractères liés à la valeur adaptative dans l'aire de répartition du hêtre européen : implications en contexte de changement climatique

Abstract : Climate change is modifying the distribution ranges of species worldwide. To better understand and more realistically predict future species ranges, it is critical to account for local adaptation and phenotypic plasticity in populations’ responses to climate. This is challenging, however, because local adaptation and phenotypic plasticity are trait dependent and because traits co-vary along climatic gradients across the range, with differential consequences for fitness. One way to address this challenge is to build models with empirical data from large-scale common-garden experiments such as those that have been established in past decades for some forest tree species. This thesis used individual measurements of several fitness-related phenotypic traits (vertical and radial tree growth, spring and autumn leaf phenology and recruit mortality) of European beech (Fagus sylvatica L.) recorded in the frame of BeechCOSTe52, the largest network of tree phenotypic traits measured in common gardens throughout Europe (>150,000 trees) for modeling the species’ likely response to recent climate change. Specifically, I pursued the following objectives: (i) to quantify range-wide variation and co-variation of local adaptation and phenotypic plasticity for four major phenotypic traits related to fitness (vertical growth, radial growth, survival, and leaf flushing phenology), and to project its species range under current and future climate based on this information (chapter 1); (ii) to quantify variation among populations in spring and autumn leaf phenology and the resulting growing season length, and to predict their patterns at the range-wide scale under current and future climate (chapter 2); and (iii) to quantify phenotypic plasticity at different development stages for vertical growth, radial growth, survival, and spring and autumn leaf flushing phenology, and to determine the extent to which inter-annual climate variation during the 20th century is related to variation in phenotypic plasticity across the species range (chapter 3). After setting up the required databases, I performed different types of linear mixed-effect models that related trait variation and co-variation to local adaptation (i.e., trait variation related to the climate of the planted populations’ origin) and phenotypic plasticity (i.e., trait variation related to the climate of plantation site). Finally, I calculated a phenotypic plasticity index for populations based on their reaction norms (i.e., the shape or specific form of the phenotypic response to the environment of an individual or genotype). My results revealed that: (i) the contribution of plasticity to intra-specific trait variation is always higher than that of local adaptation, suggesting that beech is less sensitive to (moderate) climate change than previously reported; (ii) different traits and underlying climatic drivers constrain beech populations in different parts of the species range; (iii) considering trait co-variation improves predictions based on single traits; (iv) growing season length will increase under climate change in northern beech provenances but shrink in populations from the core and the southern range; (v) northern beech populations show high phenotypic plasticity for the investigated traits; and (vi) phenotypic plasticity tends to increase with age in growth-related traits. My results underline that population responses to climate across large geographical gradients are trait-dependent, suggesting that a complete set of fitness-related traits is required to fully understand species sensitivity to climate change.
Complete list of metadatas

Cited literature [354 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02872202
Contributor : Abes Star :  Contact
Submitted on : Wednesday, June 17, 2020 - 4:19:08 PM
Last modification on : Thursday, September 3, 2020 - 4:36:03 AM

File

GARATE_ESCAMILLA_HEMERO_2019.p...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02872202, version 1

Collections

Citation

Homero Alejandro Garate Escamilla. Comprendre l'adaptation locale et la plasticité phénotypique des caractères liés à la valeur adaptative dans l'aire de répartition du hêtre européen : implications en contexte de changement climatique. Climatology. Université de Bordeaux, 2019. English. ⟨NNT : 2019BORD0403⟩. ⟨tel-02872202⟩

Share

Metrics

Record views

80

Files downloads

34