Phylogenetic insights into Andean plant diversification

Federico Luebert,Maximilian Weigend

doi:10.3389/fevo.2014.00027

Abstract

Andean orogeny is considered as one of the most important events for the developmentof current plant diversity in South America. We compare available phylogenetic studies anddivergence time estimates for plant lineages that may have diversified in response to Andeanorogeny. The influence of the Andes on plant diversification is separated into four major groups:The Andes as source of new high-elevation habitats, as a vicariant barrier, as a North-Southcorridor and as generator of new environmental conditions outside the Andes. Biogeographicalrelationships between the Andes and other regions are also considered. Divergence timeestimates indicate that high-elevation lineages originated and diversified during or after the majorphases of Andean uplift (Mid-Miocene to Pliocene), although there are some exceptions. Asexpected, Andean mid-elevation lineages tend to be older than high-elevation groups. Mostclades with disjunct distribution on both sides of the Andes diverged during Andean uplift.Inner-Andean clades also tend to have divergence time during or after Andean uplift. This isinterpreted as evidence of vicariance. Dispersal along the Andes has been shown to occur ineither direction, mostly dated after the Andean uplift. Divergence time estimates of plant groupsoutside the Andes encompass a wider range of ages, indicating that the Andes may not benecessarily the cause of these diversifications. The Andes are biogeographically related to allneighbouring areas, especially Central America, with floristic interchanges in both directionssince Early Miocene times. Direct biogeographical relationships between the Andes and otherdisjunct regions have also been shown in phylogenetic studies, especially with the easternBrazilian highlands and North America. The history of the Andean flora is complex and plantdiversification has been driven by a variety of processes, including environmental change,adaptation, and biotic interactions

Highlights

Gentry (1982) suggested that Andean uplift is responsible for nearly half of the Neotropical plant species diversity (Figure 1)
Due to its geographical setting in the South American continent, the Andes have been proposed to act as a corridor, promoting North-South exchange of biotic elements, as a barrier, generating both East-West and internal vicariance, and as promoter of speciation, with new high elevation environments becoming available during their formation (Simpson, 1975, 1983; Luebert et al, 2009, 2011b; Antonelli and Sanmartín, 2011b; Hoorn et al, 2013)
The purpose of this review is to offer a synopsis of Andean plant diversifications as known today based on phylogenetic studies

Summary

INTRODUCTION

The uplift of the Andes is considered as one of the most important events in the biogeographical history of the Neotropical biota (Hoorn et al, 2010) and the tropical Andes are one of the most diverse areas on earth in terms of vascular plant species (Barthlott et al, 2005). Gentry (1982) suggested that Andean uplift is responsible for nearly half of the Neotropical plant species diversity (Figure 1). No comparable paleobotanical evidence is available for the onset of aridity in the Peruvian and Atacama deserts, but phylogenetic studies in Atacama endemic taxa tend to indicate a rather recent (MiocenePliocene) origin of diversification of these lineages in response to aridity (e.g., Luebert and Wen, 2008; Dillon et al, 2009; Heibl and Renner, 2012), falling into the range of estimates for onset of present-day hyperaridity of the Atacama Desert (Alpers and Brimhall, 1988; Hartley, 2003; Hartley and Rice, 2005; Arancibia et al, 2006; Reich et al, 2009) These climatic changes exerted feedbacks on Andean uplift. There is no intention www.frontiersin.org to exhaustively revise all the literature or to cover all Andean plant groups

EFFECTS OF THE ANDES ON PLANT DIVERSIFICATION

THE ANDES AS PROMOTERS OF DIVERSIFICATION OUTSIDE THE ANDES

DISCUSSION