Abstract Detail

Biogeography

Madriñán, Santiago [1], Cortés, Andrés J. [2], Richardson, James E. [3].

Rapid speciation in the high Andes.

“No zone of alpine vegetation in the temperate or cold parts of the globe can well be compared with that of the Páramos in the tropical Andes.” “Nowhere, perhaps, can be found collected together, in so small a space, productions so beautiful, and so remarkable in regard to the geography of plants.” Alexander von Humboldt Aspects of Nature & Personal narrative Understanding the processes that cause speciation is a key aim of evolutionary biology. Lineages or biomes that exhibit recent and rapid diversification are ideal model systems for determining these processes. Species rich biomes reported to be of relatively recent origin, i.e., since the beginning of the Miocene, include Mediterranean ecosystems such as the California Floristic Province, oceanic islands such as the Hawaiian archipelago and the Neotropical high elevation ecosystem of the Páramos. Páramos constitute grasslands above the forest tree-line (at elevations of c. 2800–4700 m) with high species endemism. Organisms that occupy this ecosystem are a likely product of unique adaptations to an extreme environment that evolved during the last three to five million years when the Andes reached an altitude that was capable of sustaining this type of vegetation. Akin to the Galapagos Islands, made famous by Darwin's study on the evolution of finches, and seen as the quintessential laboratory for the study of evolutionary processes, we show that the Neotropical Páramos, a continental island system, offer a host of examples of comparable biological diversifications. Darwin’s finches diversified into 15 extant spp. during the last 2.3 Ma at a rate of SRln=0.876, but we report on nine plant groups from the Páramo ecosystem with higher diversification rates. We compared diversification rates of lineages in fast evolving biomes using 73 dated molecular phylogenies. We demonstrate that average diversification rates of Páramo plant lineages are faster than those of other reportedly fast evolving hotspots and that the faster evolving lineages are more likely to be found in Páramos than the other hotspots. Páramos therefore represent the ideal model system for studying diversification processes. Most of the speciation events that we observed in the Páramos occurred during the Pleistocene possibly due to the effects of species range contraction and expansion that may have resulted from the well-documented climatic changes during that period. Understanding these effects will assist with efforts to determine how future climatic changes will impact plant populations.

Broader Impacts:

Related Links:
Laboratorio de Botánica y Sistemática

1 - Universidad de los Andes, Laboratorio de Botánica y Sistemática, Apartado Aéreo 4976, Bogotá, DC, 00001, Colombia
2 - Uppsala University, Evolutionary Biology Centre, Box 256, Uppsala, 751 05, Sweden
3 - Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, United Kingdom

Keywords:
biogeography
molecular dating
diversification rate
rapid radiation
paramo
Colombia
Neotropics.

Presentation Type: Oral Paper:Papers for Topics
Session: 50
Location: Magnolia/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 4:15 PM
Number: 50011
Abstract ID:710
Candidate for Awards:None