Andean Mountain Building Did not Preclude Dispersal of Lowland Epiphytic Orchids in the Neotropics

Abstract

The Andean uplift is one of the major orographic events in the New World and has impacted considerably the diversification of numerous Neotropical lineages. Despite its importance for biogeography, the specific role of mountain ranges as a dispersal barrier between South and Central American lowland plant lineages is still poorly understood. The swan orchids (Cycnoches) comprise ca 34 epiphytic species distributed in lowland and pre-montane forests of Central and South America. Here, we study the historical biogeography of Cycnoches to better understand the impact of the Andean uplift on the diversification of Neotropical lowland plant lineages. Using novel molecular sequences (five nuclear and plastid regions) and twelve biogeographic models, we infer that the most recent common ancestor of Cycnoches originated in Amazonia ca 5 Mya. The first colonization of Central America occurred from a direct migration event from Amazonia, and multiple bidirectional trans-Andean migrations between Amazonia and Central America took place subsequently. Notably, these rare biological exchanges occurred well after major mountain building periods. The Andes have limited plant migration, yet it has seldom allowed episodic gene exchange of lowland epiphyte lineages such as orchids with great potential for effortless dispersal because of the very light, anemochorous seeds.

Community structure of vascular epiphytes: a neutral perspective

“…stochasticity). Secondly, we expect dispersal limitation to vary across metacommunities due to variation in topography, where we expect the flat Amazonian forests to be less dispersal limited than the mountainous regions in Central America or the Andes (Pérez‐Escobar et al ). Furthermore, because species relying on wind dispersal (e.g.…”

Parallel diversifications ofCremastospermaandMosannona(Annonaceae), tropical rainforest trees tracking Neogene upheaval of the South American continent

“…However, a notable contrast is presented by results in tropical orchids, for which there is evidence of more recent trans-Andean dispersal, suggesting that the barrier is less effective for plants with more easily dispersed diaspores (Pérez-Escobar et al, 2017a, 2017b.…”

Multiple Geographical Origins of Environmental Sex Determination enhanced the diversification of Darwin’s Favourite Orchids

“…Species names, geographical origins, voucher specimens, and GenBank accession numbers of sequences included in phylogenetic analyses are provided in Table S1. We built our alignment based on the molecular datasets of Whitten et al 33 , Salazar et al 51 , Neubig et al 62 , Bone et al 63 , and Pérez-Escobar et al 34,64 , and further generated 57 nuclear ribosomal and 25 plastid sequences for poorly sampled lineages such as Catasetum, Dressleria and Grobya (Tab. S1).…”