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Abstract Detail


Folk, Ryan [1], Soltis, Pamela [2], Soltis, Douglas [2], Guralnick, Robert [3].

Drivers of inverse biodiversity gradients in Saxifragales.

Although biodiversity drivers remain challenging to identify across clades, even less is known about biodiversity gradients in primarily temperate clades, although these groups are likely to have experienced starkly different historical pressures and diversification timings compared to their frequently studied tropically diverse relatives. Synthesizing a robust phylogeny and deeply sampled environmental and functional trait data in the flowering plant clade Saxifragales (2400 species), which is most diverse in arctic-alpine and arid regions, we tested for potential historical and contemporary drivers of temperate species and trait biodiversity. We designed a set of custom methods to generate gridded community metrics of phylogenetic and trait diversity. We used model comparison techniques to identify potential drivers of diversity, comprising (1) contemporary diversification and trait evolutionary rates (“tip rates”), and (2) gridded environmental datasets measuring historical climatic stability, topographic complexity, and a wide set of contemporary soil and climatic variables. As expected in a group with its greatest diversity in montane regions, higher species and trait diversity is strongly associated with increasing topographic complexity. While weaker, a significant negative association between species/trait diversity and historical temperature change was also detected, suggesting both topography and climate were associated with the inverse biodiversity gradient. However, contemporary species and trait diversity in Saxifragales is largely uncoupled from macroevolutionary rates. While the highest rates of diversification and trait evolution are indeed in montane and mostly temperate areas, most temperate communities are not experiencing rapid diversification and evolutionary rate alone cannot explain diversity gradients in Saxifragales.

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1 - University Of Florida, Florida Museum Of Natural History, Po Box 117800, Gainesville, FL, 32611, United States
2 - Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, Florida, 32611, USA
3 - University of Florida, 1659 Museum Road, Gainesville, FL, 32611, United States

latitudinal diversity gradient
functional traits
Species Richness

Presentation Type: Oral Paper
Session: MACRO1, Macroevolution I
Location: Tucson B/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 10:30 AM
Number: MACRO1009
Abstract ID:726
Candidate for Awards:None

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