Abstract Detail

Biogeography

Federman, Sarah B. [1], Dornburg, Alex [2], Downie, Alexander [3], Daly, Douglas [4], Richard, Alison [5], Donoghue, Michael [6].

The biogeographic origin of a radiation of trees in Madagascar: Implications for the assembly of a tropical forest biome.

Madagascar’s rain forests are characterized by extreme and uneven patterns of species richness and endemicity, the biogeographic and evolutionary origins of which are poorly understood. Here we use a time-calibrated phylogeny of a dominant group of trees in Madagascar’s eastern rain forests, Canarium, and related Burseraceae (Canarieae), to test biogeographic hypotheses regarding the origin and radiation of the flora of this unique biome. Our findings strongly support the monophyly of Malagasy Canarium, suggesting that this clade represents a previously undocumented in situ radiation. Contrary to expectations of dispersal from Africa during the Oligocene, concurrent with the formation of Madagascar’s rain forest biome, our analyses support a late Miocene origin for Malagasy Canarium, probably by long distance dispersal from Southeast Asia. Our study illustrates the importance of considering long distance dispersal as a viable explanation for clades with pantropical distributions diversifying subsequent to the Oligocene, and highlights the formation of the Indo-Australian Archipelago and associated fast-moving equatorial surface currents as a possible source for generating global patterns in tropical biodiversity. Additionally, we postulate that the relatively recent establishment and radiation of Canarium in Madagascar may have been facilitated by the highly stochastic climates associated with these forest ecosystems.

1 - Yale University, Ecology & Evolutionary Biology, 21 Sachem St., ESC 358C, New Haven, CT, 06511, USA
2 - Yale University, Ecology & Evolutionary Biology, 21 Sachem St., 358A, New Haven, CT, 06511, United States
3 - Yale University, Ecology & Evolutionary Biology, 21 Sachem St., ESC, 358C, New Haven, CT, 06511, United States
4 - New York Botanical Garden, ISB, 2900 Southern Blvd., Bronx, NY, 10458-5126, USA
5 - Yale University, Anthropology, 10 Sachem St., Apt 2, New Haven, CT, 06511, United States
6 - Yale University, Department Of Ecology And Evolutionary Biology, 21 Sachem Street, PO Box 208105, New Haven, CT, 06511, USA

Keywords:
biogeography
Canarium
long-distance dispersal
Madagascar
Phylogeny
radiation.

Presentation Type: Oral Paper:Papers for Topics
Session: 59
Location: Salon 3/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 11:00 AM
Number: 59011
Abstract ID:817
Candidate for Awards:George R. Cooley Award