Evolution and Diversification in the Sapindales
Fine, Paul , Mesones, Italo , Daly, Douglas C. .
Habitat specialization and speciation in Protium (Burseraceae) in the Amazon Basin.
The disparity in tree species richness between tropical and temperate forests is enormous. Any explanation for this pattern must include a reason why speciation rates are higher and/or why extinction rates are lower in the tropics. One such way that speciation rates might be higher in tropical forests is if habitat specialization is more prevalent there, causing high turnover in species composition between habitats, and allowing more species diversity to be harbored within a region. Previous research in the Western Amazon on the family Burseraceae has shown that a majority of species found in lowland terra firme rainforest are found only in one of three possible soil types. Here, we present data on three different species complexes in the genus Protium that include taxa in white-sand, brown sand, clay and flooded forests. We have found significant morphological differences between taxa that are consistent with habitat type and preliminary phenological observations over the last three years indicate differences in flowering times between the putative species that occur in neighboring habitats. Molecular DNA sequence data show differences, but in the range of 1%-3% sequence divergence for ITS, lower than ITS sequence divergence between most other Protium sister taxa that have been sampled to date. Our preliminary conclusion is that these species are extremely young, and are likely to have formed by reproductive isolation related to habitat differences.
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1 - University of California, Berkeley, Department of Integrative Biology, 3060 Valley Life Sciences Bldg #3140, Berkeley, CA, 94720, USA
2 - Universidad Nacional de la Amazonia Peruana, Department of Forestry, Iquitos, Peru
3 - New York Botanical Garden, Institute of Systematic Botany, 200 St. & Kazimiroff Blvd., Bronx, NY, 10458-5126, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Boulevard B/Hilton
Date: Tuesday, July 10th, 2007
Time: 10:30 AM