Format: ORAL

Pedro Jimnez Mejas1 Mara Sanz Arnal1 Pablo Garca Moro1 Ana Morales Alonso2 Carmen Acedo3 Carmen Bentez Bentez4 Asuncin Cano5 Sabina Donado6 Kerry Ford7 Ral Lois3 Modesto Luceo1 Jos Ignacio Mrquez Corro8 Muthama Muasya9 Paulo Muoz-Schler10 Nora Oleas11 Tamara Villaverde2 Karen Wilson12 Daniel Spalink13 Santiago Martn-Bravo1

1 Universidad Pablo de Olavide 2 Universidad Rey Juan Carlos 3 Universidad de León 4 Universidad de Sevilla 5 Universidad Nacional Mayor de San Marcos 6 Instituto de Botánica Darwinion, CONICET 7 Manaaki Whenua – Landcare Research 8 Royal Botanic Gardens, Kew 9 University of Cape Town 10 Universidad de Concepción 11 Universidad Tecnológica Indoamérica 12 Royal Botanic Gardens, Sydney 13 Texas A&M University

Carex (2000 spp) diversity is not equally distributed across the continents. This cold-adapted genus was originated in E Asia during the Eocene, from where it expanded and diversified across the Northern Hemisphere. The colonization of the Southern Hemisphere (SH) happened from the Miocene onwards. Remarkably, the resulting diversity levels in each of the landmasses are very different. South America (SA) and New Zealand (NZ) harbor the largest diversity compared to Africa and Australia. Here we perform a continental-level comparison of Carex evolutionary history in the SH. Results indicate that all the areas were recurrently colonized by different lineages. N to S migrations happened repeatedly from the Miocene to the Pleistocene, suggesting that no single bioclimatic event or colonization route were the triggers of the dispersal events. The number of groups in these areas increased towards the late Miocene, pointing that the Neogene global cooling facilitated colonization. Most lineages appear to be ecologically pre-adapted to SH cold/temperate climates, since little differences in the bioclimatic niche is observed compared their sister groups. Africa, NZ and SA displayed a few large in-situ radiations, which entailed to some extent niche diversification. Most diversity in NZ was explained by extensive radiation of two clades, which seemingly have had a competitive exclusion effect preventing the establishment or diversification of other lineages. SA diversity is equally due to in-situ diversification and also to a number of poorly diversified groups. The higher connectivity of SA with the Northern Hemisphere, and the larger available area for Carex to diversify, explains these differences. In turn, the relatively low diversity in Australia and Africa appears to be due to the limited ecologically available area in these landmasses. Essentially the differences respond to the huge Carex diversity and its diverse natural history, involving different taxonomic groups, geoclimatic events and colonization routes.