1. Species richness and species pool size variation across pH gradients in Southern Blue Ridge Forests Joel M. Gramling, Robert K. Peet, Jason D. Fridley, and Thomas R. Wentworth.

2. Should characteristics of a regional flora reflect the relative abundance of a soil type over the region’s evolutionary history?

3. High pH specialists in the flora of Central Europe Richness and edaphic characteristics vary according to the evolutionary centers of a regional flora (Pärtel 2002) Central European Scenario

4. Ewald (in press) cites: Dominance of calcium-rich environs around the time of the last glaciations Recent environmental bottleneck

5. How might these hypotheses be applied to the Southeastern USA? Southern Blue Ridge Mountains have always had primarily acidic soils. The flora of the Southern Blue Ridge would be expected to be acidophilic. Southeastern USA Scenario

6. Does the Southern Blue Ridge exhibit a negative relationship between pH and species richness as implied by the findings of Pärtel and Ewald? No.

7. Average number of species in 100-plot segments along a pH gradient

8. Southeastern USA Scenario How is the flora of the Southern Blue Ridge distributed across the pH gradient?

9. Species pool for a pH range calculated as the total number of species occurring in a set of 10,000 species occurrences

10. Genus pool for a pH range calculated as the total number of species occurring in a set of 10,000 species occurrences

11. Family pool for a pH range calculated as the total number of species occurring in a set of 10,000 species occurrences

12. Southeastern USA Scenario How specialized is the flora of the Southern Blue Ridge across the pH gradient?

13. Species accumulation along the pH gradient based upon the total pH range of observed occurrences

16. Cumulative species occurrences and cumulative species median positions encountered when moving across the pH gradient

17. Conclusions Southern Blue Ridge diversity at the species, genus and family level is positively correlated to soil pH Observed species pool is biased toward basic soils Lack of high pH specialists in Southern Blue Ridge flora

18. Acknowledgements