title: The building of a biodiversity hotspot across a land-bridge in the Mediterranean.
abstract: Many of the macroevolutionary processes that have shaped present-day phylogenetic patterns were caused by geological events such as plate tectonics and temporary land-bridges. The study of spatial patterns of phylogenetic diversity can provide insights into these past events. Here we focus on a western Mediterranean biodiversity hotspot located in the southern Iberian Peninsula and northwest Africa, two regions that are separated by the Strait of Gibraltar. We explore the spatial structure of the phylogenetic relationships within and across large-scale plant assemblages. Significant turnover in terminal lineages tends to occur between landmasses, whereas turnover in deep lineages tends to occur within landmasses. Plant assemblages in the western ecoregions of this hotspot tend to be phylogenetically overdispersed but are phylogenetically clustered on its eastern margins. We discuss our results in the light of potential scenarios of niche evolution (or conservatism) and lineage diversification. The significant turnover between landmasses suggests a common scenario of allopatric speciation that could have been facilitated by the intermittent joining of the two continents. This may have constituted an important stimulus for diversification and the emergence of this western Mediterranean biodiversity hotspot.
authors.affiliation: Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Apartado 1095, Sevilla 41080, Spain rafmolven@gmail.com.
authors.forename: Rafael
authors.initials: R
authors.lastname: Molina-Venegas
authors.affiliation: Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Apartado 1095, Sevilla 41080, Spain.
authors.forename: Abelardo
authors.initials: A
authors.lastname: Aparicio
authors.affiliation: Laboratoire d'Écologie Alpine, CNRS - Université Grenoble Alpes, Grenoble, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lavergne
authors.affiliation: Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Apartado 1095, Sevilla 41080, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Arroyo
mesh_terms: D044822:Biodiversity; D005075:Biological Evolution; D049810:Genetic Speciation; D009018:Morocco; D010802:Phylogeny; D010944:Plants / Q000235:genetics*; D013030:Spain
keywords: Mediterranean hotspots; angiosperm flora; land-bridges; phylogenetic alpha diversity; phylogenetic beta diversity; speciation