Morphological variability of cushion plant Lyallia kerguelensis (Caryophyllales) in relation to environmental conditions and geography in the Kerguelen Islands: implications for cushion necrosis and climate change

• Published in: Polar Biology
• Main Authors: Marchand, Lorène Julia, Tarayre, Michèle, Dorey, Thomas, Rantier, Yann, Hennion, Françoise
• Other Authors: Université de Rennes 1 (UR1), Ecosystèmes, biodiversité, évolution Rennes (ECOBIO), Université de Rennes 1 (UR1)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes 1 (UR1)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes 1 (UR1)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Universität Zürich Zürich = University of Zurich (UZH), Centre National de la Recherche Scientifique, IRP grant “AntarctPlantAdapt”, Project 1116, Institut Polaire Français Paul Emile Victor
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Cushion plant; Kerguelen Islands; Morphological variability; Necrosis; Photointerpretation; Sub-Antarctic; [SDE]Environmental Sciences; [SDV]Life Sciences [q-bio]; Antarctic; Kerguelen; Antarc*; Polar Biology
• Online Access: https://hal.science/hal-03036374; https://hal.science/hal-03036374/document; https://hal.science/hal-03036374/file/Marchand%20et%20al-2020-Morphological%20variability%20of%20cushion%20plant%20Lyallia%20kerguelensis%20%28Caryophyllales%29-corrected_manuscript_V2.pdf; https://doi.org/10.1007/s00300-020-02768-2

International audience In recent decades, climate change has been faster in various parts of the world. Within species, to counter rapid climatechanges shift of geographical area, individuals’ plastic responses or populations’ genetic adaptation might occur. The sub-Antarctic islands are subject to one of the most rapid climate changes on earth, with already visible impacts on nativevegetation. Such might be the case of Lyallia kerguelensis a cushion plant strictly endemic to the Kerguelen Islands. In L.kerguelensis, necrotic parts were observed in cushions these last decades and possibly related to water stress. We analysedmorphological variability of L. kerguelensis, including necrosis extent, across 19 populations spanning a wide range ofenvironments across the Kerguelen Islands. Inter-population variations in the cushion surface area, shape and compactnesswere well explained by topography, degree of wind exposure, slope aspect, proportions of coarse sand and bare soil, andgeographical distance between populations. All these variables are related to wind intensity and water availability. Moreover,in cushions with less than 10% necrosis in surface area, necrosis extent was positively correlated to soil sodium. Sodiumavailability might reduce the plant’s capacity for osmotic adjustment in face of other abiotic stresses, such as water stress. Weconclude that cushion morphology may have the capacity to adjust to environmental variation, including aspects of climatechange, but that cushion necrosis may be accelerated in the driest and most saline environments.