Biome conservatism prevailed in repeated long-distance colonization of Madagascar's mountains by Helichrysum (Compositae, Gnaphalieae)
Blanco-Gavaldà, Carme (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)
Roquet, Cristina (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)
Puig-Surroca, Genís (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)
Andrés-Sánchez, Santiago (Universidad de Salamanca. Departamento de Botánica y Fisiología)
Razafimandimbison, Sylvain G. (Swedish Museum of Natural History)
Letsara, Rokiman (Herbarium of the Parc Botanique et Zoologique of Tsimbazaza)
Bergh, Nicola G. (South African National Biodiversity Institute)
Cron, Glynis V. (University of the Witwatersrand. School of Animal, Plant and Environmental Sciences)
Moreyra, Lucía D. (Institut Botànic de Barcelona)
Calleja, Juan Antonio (Universidad Autónoma de Madrid)
Castillo, Oscar (Institut Botànic de Barcelona)
Bayer, Randall J. (University of Memphis)
Leliaert, Frederik (Meise Botanic Garden)
Susanna, Alfonso (Institut Botànic de Barcelona)
Galbany-Casals, Mercè (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)

Date:	2025
Abstract:	Colonization and diversification processes are responsible for the distinctiveness of island biotas, with Madagascar standing out as a biodiversity hotspot exceptionally rich in species and endemism. Regardless of its significance, the evolutionary history and diversification drivers of Madagascar's flora remain understudied. Here we focus on Helichrysum (Compositae, Gnaphalieae) to investigate the evolutionary and biogeographic origins of the Malagasy flora. We inferred a highly resolved phylogeny based on target-enrichment data from 327 species (including 51 % of Malagasy endemics) and conducted ancestral range estimation analyses. Our results revealed at least six trans-oceanic dispersal events from different African regions to Madagascar during the Pliocene. In this process, biome conservatism prevailed, as evidenced by similarities between Malagasy lineages and their African relatives. The southern African grasslands, known to be the center of diversification and the main source of African Helichrysum lineages, played a key role in the colonization of Madagascar as the ancestral source area of at least three clades. The Tropical Afromontane region was revealed as the source of at least two montane Malagasy lineages that substantially radiated in-situ. Finally, a dispersal event from southwestern Africa led to a lineage represented by a single species adapted to the island's southwestern arid conditions. The main radiations of Helichrysum in Madagascar's mountains occurred within the last 2 My, coinciding with a transition towards cooler and drier conditions and the expansion of open habitats, likely driven by a combination of geographic and ecological speciation. Overall, our findings highlight the affinities between the montane floras of continental Africa and Madagascar.
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Afromontane flora ; Asteraceae ; Biogeography ; Dispersal ; Helichrysum ; Madagascar ; Target-enrichment
Published in:	Molecular phylogenetics and evolution, Vol. 204 (March 2025) , art. 108283, ISSN 1095-9513

DOI: 10.1016/j.ympev.2024.108283

16 p, 13.9 MB

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