Areas of endemism and recent speciation in the Southern Cone of South America, using Senecio (Asteraceae) as a proxy

Abstract

Abstract We set out to identify areas of endemism (AEs) among vascular plants in the Southern Cone of South America, using the genus Senecio (Asteraceae) as proxy. The use of a proxy allows a large-scale study to be carried out in a relatively short time and is suitable for pinpointing areas of interest for further investigation. Senecio is the most obvious choice for a proxy in the Southern Cone, because it is the most diverse genus in the region. We analysed the distribution of 200 endemic species using an optimality criterion (VNDM program). In general, endemism of Senecio in the Southern Cone forms 16 AEs that coincide with previously defined AEs and/or with distribution patterns also supported in phylogeographical studies. As such, Senecio appears to be a suitable proxy in endemicity studies, bearing in mind that these species are of young ages and therefore identify neoendemic AEs. Senecio distribution patterns in the Southern Cone corroborate that high Andean environments are prime sites for endemism, which peaks in the Cuyan High Andean AE, an AE that was not identified in previous endemism studies. Nevertheless, towards the south, the ecotone between the Patagonian Steppe and the Southern Andean forest becomes equally important for speciation.