Format: ORAL

Ana Afonso1; Sílvia Castro1; João Loureiro1; Juan Arroyo2; Albano Figueiredo3; Sara Lopes1; Mariana Castro1

1 Centre for Functional Ecology, Associate Laboratory TERRA, Department of Life Sciences, University of Coimbra, Coimbra, Portugal 2 Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Sevilla, Spain 3 Centre of Studies in Geography and Spatial Planning (CEGOT), Department of Geography and Tourism, University of Coimbra, Portugal

The prevalence of polyploidy in the evolutionary history of angiosperms within the Mediterranean region appears intricately linked to the regions dynamic paleogeography and climatic oscillations. Polyploids often possess distinctive traits, enabling them to circumvent exclusion by the minority cytotype. These traits may enable polyploid individuals to thrive in habitats divergent from their progenitors, thereby expanding into new places and promoting spatial segregation. This study delves into the role of environmental variables to explain current distribution patterns of the five main cytotypes of Linum suffruticosum s.l. (diploids, tetraploids, hexaploids, octoploids and decaploids) across its distribution range. Employing maximum entropy modelling alongside niche equivalency and similarity tests, we discerned the realised environmental niche of each cytotype. Discrepancies in environmental conditions among L. suffruticosum s.l. cytotypes were evident, with polyploids demonstrating an affinity for habitats characterised by elevated drought and soil pH levels, lower temperature ranges, and diminished soil water and cation exchange capacities. Diploids exhibited the broadest environmental niche, while polyploids occupied a subset of diploid niche. Although some polyploids exhibited ecologically equivalent niches, they did not coexist naturally. Furthermore, the ecological niche of this polyploid complex diverged between continents, with North African habitats featuring distinctions in soil texture, higher pH, lower cation exchange capacity, precipitation, and soil water capacity, as well as higher temperatures compared to habitats in southwest Europe. While these ecological conditions played a pivotal role in cytotype distribution, the mosaic pattern remained incompletely explained by environmental variables alone. Other factors, such as reproductive isolation and competitive interactions among cytotypes, likely contributed to the extant diversity and distribution patterns. This study yields pertinent insights into the niche requirements of each cytotype, laying the groundwork for subsequent competition and reciprocal transplant experiments.