Multiple Pleistocene refugia and Holocene range expansion of an abundant southwestern American desert plant species (Melampodium leucanthum, Asteraceae)

Authors

  • CAROLIN A. REBERNIG,

    1. Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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  • GERALD M. SCHNEEWEISS,

    1. Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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    • Present Address: Systematic Botany and Mycology, Ludwig-Maximilians-University Munich, Menzingerstrasse 67, D-80638 Munich, Germany.

  • KATHARINA E. BARDY,

    1. Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
    2. Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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  • PETER SCHÖNSWETTER,

    1. Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
    2. Department of Systematics, Palynology and Geobotany, Institute of Botany, University of Innsbruck, Sternwartestrasse 15, A-6020 Innsbruck, Austria
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  • JOSE L. VILLASEÑOR,

    1. Instituto de Biología, Departamento de Botánica, Universidad Nacional Autónoma de México, Tercer Circuito s/n, Ciudad Universitaria, Delegación Coyoacán, MX-04510 México D. F., México
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  • RENATE OBERMAYER,

    1. Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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  • TOD F. STUESSY,

    1. Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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  • HANNA WEISS-SCHNEEWEISS

    1. Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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Errata

This article is corrected by:

  1. Errata: Erratum Volume 20, Issue 11, 2464, Article first published online: 9 May 2011

Gerald M. Schneeweiss, Fax: +43 1 4277 9541; E-mail: gerald.schneeweiss@univie.ac.at

Abstract

Pleistocene climatic fluctuations had major impacts on desert biota in southwestern North America. During cooler and wetter periods, drought-adapted species were isolated into refugia, in contrast to expansion of their ranges during the massive aridification in the Holocene. Here, we use Melampodium leucanthum (Asteraceae), a species of the North American desert and semi-desert regions, to investigate the impact of major aridification in southwestern North America on phylogeography and evolution in a widespread and abundant drought-adapted plant species. The evidence for three separate Pleistocene refugia at different time levels suggests that this species responded to the Quaternary climatic oscillations in a cyclic manner. In the Holocene, once differentiated lineages came into secondary contact and intermixed, but these range expansions did not follow the eastwardly progressing aridification, but instead occurred independently out of separate Pleistocene refugia. As found in other desert biota, the Continental Divide has acted as a major migration barrier for M. leucanthum since the Pleistocene. Despite being geographically restricted to the eastern part of the species’ distribution, autotetraploids in M. leucanthum originated multiple times and do not form a genetically cohesive group.

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