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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

Abstract : 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.
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https://hal.archives-ouvertes.fr/hal-03036374
Contributor : Françoise Hennion <>
Submitted on : Wednesday, December 9, 2020 - 2:44:18 PM
Last modification on : Thursday, April 15, 2021 - 2:49:57 PM
Long-term archiving on: : Wednesday, March 10, 2021 - 7:19:05 PM

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Lorène Julia Marchand, Michèle Tarayre, Thomas Dorey, Yann Rantier, Françoise Hennion. 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. Polar Biology, Springer Verlag, 2021, 44 (1), pp.17-30. ⟨10.1007/s00300-020-02768-2⟩. ⟨hal-03036374⟩

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