Martinez Cabrera, Hugo , Schlichting, Carl , Jones, Cynthia S. .
Environmental niche evolution and diversification in Pelargonium .
The Radiation of the South African genus Pelargonium is one of the largest in a region that is well known for the presence of highly diverse clades. Sharp climatic gradients in South Africa and in particular in the Cape Floristic Region (CFR) provide a diversity of niches over short distances that potentially promoted ecological diversification in local clades. Niche conservatism, on the other hand, may limit ecological diversification because it restricts the range of environments species may inhabit. Here we integrate phylogenetic information and environmental niche models (ENM) to determine the role of niche conservatism during Pelargonium diversification. We calculated ENMs of more than a third of the species in the genus (113) using maximum entropy and assessed niche overlap among species within major clades and sections. Patterns of environmental niche evolution varied among clades, but niches were conserved in few cases. Niches among species within sections were rarely identical, and in only 20% of cases were they more similar than expected by chance. Phylogenetic patterns of niche similarity indicate that niche similarity and phylogenetic distance were independent in most clades, with the exception of section Pelargonium, which showed a pattern of divergent evolution. Overall, more diverse clades had lower levels of environmental niche conservatism and functional integration than less diverse clades, suggesting that radiation in Pelargonium may have been facilitated by the combined forces of habitat heterogeneity and, in the more successful clades, higher potential to adapt to novel environments.
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1 - University of Connecticut, Ecology and Evolutionary Biology, 75 North Eagleville Rd, U-3043, Storrs, Connecticut, 062693043, USA
2 - University of Connecticut, Ecology & Evolutionary Biology, 75 North Eagleville Road, U-3043, Storrs, Connecticut, 062693043, USA
3 - University of Connecticut, Ecology & Evolutionary Biology, 75 North Eagleville Rd, U-3043, Storrs, CT, 062693043, USA
Environmental niche evolution
Presentation Type: Oral Paper:Papers for Sections
Location: 552A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 4:15 PM