TY - JOUR
T1 - Insights on the evolution of plant succulence from a remarkable radiation in Madagascar (Euphorbia)
AU - Evans, Margaret
AU - Aubriot, Xavier
AU - Hearn, David
AU - Lanciaux, Maxime
AU - Lavergne, Sebastien
AU - Cruaud, Corinne
AU - Lowry, Porter P.
AU - Haevermans, Thomas
PY - 2014/9
Y1 - 2014/9
N2 - Patterns of adaptation in response to environmental variation are central to our understanding of biodiversity, but predictions of how and when broad-scale environmental conditions such as climate affect organismal form and function remain incomplete. Succulent plants have evolved in response to arid conditions repeatedly, with various plant organs such as leaves, stems, and roots physically modified to increase water storage. Here, we investigate the role played by climate conditions in shaping the evolution of succulent forms in a plant clade endemic to Madagascar and the surrounding islands, part of the hyper-diverse genus Euphorbia (Euphorbiaceae).We used multivariate ordination of 19 climate variables to identify links between particular climate variables and threemajor forms of succulence - succulent leaves, cactiformstem succulence, and tubers. We then tested the relationship between climatic conditions and succulence, using comparative methods that account for shared evolutionary history. We confirm that plant water storage is associated with the two components of aridity, temperature, and precipitation. Cactiform stem succulence, however, is not prevalent in the driest environments, countering the widely held view of cactiforms as desert icons. Instead, leaf succulence and tubers are significantly associated with the lowest levels of precipitation. Our findings provide a clear link between broad-scale climatic conditions and adaptation in land plants, and newinsights into the climatic conditions favoring different forms of succulence. This evidence for adaptation to climate raises concern over the evolutionary future of succulent plants as they, along with other organisms, face anthropogenic climate change.
AB - Patterns of adaptation in response to environmental variation are central to our understanding of biodiversity, but predictions of how and when broad-scale environmental conditions such as climate affect organismal form and function remain incomplete. Succulent plants have evolved in response to arid conditions repeatedly, with various plant organs such as leaves, stems, and roots physically modified to increase water storage. Here, we investigate the role played by climate conditions in shaping the evolution of succulent forms in a plant clade endemic to Madagascar and the surrounding islands, part of the hyper-diverse genus Euphorbia (Euphorbiaceae).We used multivariate ordination of 19 climate variables to identify links between particular climate variables and threemajor forms of succulence - succulent leaves, cactiformstem succulence, and tubers. We then tested the relationship between climatic conditions and succulence, using comparative methods that account for shared evolutionary history. We confirm that plant water storage is associated with the two components of aridity, temperature, and precipitation. Cactiform stem succulence, however, is not prevalent in the driest environments, countering the widely held view of cactiforms as desert icons. Instead, leaf succulence and tubers are significantly associated with the lowest levels of precipitation. Our findings provide a clear link between broad-scale climatic conditions and adaptation in land plants, and newinsights into the climatic conditions favoring different forms of succulence. This evidence for adaptation to climate raises concern over the evolutionary future of succulent plants as they, along with other organisms, face anthropogenic climate change.
KW - Adaptation
KW - Climate
KW - Comparative analysis
KW - Euphorbia
KW - Ordination
KW - Phylogeny
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U2 - 10.1093/sysbio/syu035
DO - 10.1093/sysbio/syu035
M3 - Article
C2 - 24852061
AN - SCOPUS:84906278908
SN - 1063-5157
VL - 63
SP - 698
EP - 711
JO - Systematic biology
JF - Systematic biology
IS - 5
ER -