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Vers une taxonomie intégrative pour la circonscription des espèces du genre Cecropia Loefl

Abstract : RÉSUMÉ DE LA THÈSE EN ANGLAISThe Neotropical genus Cecropia Loefl. includes pioneer trees that colonize open gaps and disturbed environments. They constitutes a model for study in a wide variety of disciplinary fields. In spite of the volume and diversity of research carried out on this genus, it is paradoxical that the core ability to identify species remains problematic and impedes progress. The monograph by Berg & Franco-Rosselli (2005) describe 61 species and 2 subspecies. The proposed circumscription is essentially based on morphological characters. The objective of this thesis is to organize a framework through a series of software and analytical tools to i) extract the “substantial marrow” of the monograph by a numerical approach and ii) to review the circumscription of species by an integrative taxonomy approach coupling numerical taxonomy and niche models on a continental scale.Our results show that the monograph is coherent, with taxa that are morphologically well delineated, but with a massive synonymy that is not argued. Our analysis allows us to identify the most discriminating characters to be used in a numerical taxonomy and allowed us to build a multi-entry identification key for the genus. The modelling of the climatic niche shows a strong overlap between the species and no climatic identity really specific to one of them. We also identify several species with highly invasive potential.This work calls for the integration of molecular biology approaches that seem indispensable to help circumscribe species and better understand the evolutionary dynamics of what appears to be a species complex, where frequent hybridization generates a morphological continuum.
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Submitted on : Tuesday, May 4, 2021 - 2:41:10 AM
Last modification on : Tuesday, May 4, 2021 - 3:35:41 AM


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  • HAL Id : tel-03216380, version 1



Xuan Bach Nguyen Le. Vers une taxonomie intégrative pour la circonscription des espèces du genre Cecropia Loefl. Sylviculture, foresterie. Université de Guyane, 2020. Français. ⟨NNT : 2020YANE0010⟩. ⟨tel-03216380⟩



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