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.
Should characteristics of a regional flora reflect the relative abundance of a soil type over the region’s evolutionary history?
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
Central European Scenario
Ewald (in press) cites:
Dominance of calcium-rich environs around the time of the last glaciations
Recent environmental bottleneck
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
Southeastern USA Scenario
Does the Southern Blue Ridge exhibit a negative relationship between pH and species richness as implied by the findings of Pärtel and Ewald?
No.
Southeastern USA Scenario
How is the flora of the Southern Blue Ridge distributed across the pH gradient?
Species pool for a pH range calculated as the total number of species occurring in a set of 10,000 species occurrences
Genus pool for a pH range calculated as the total number of species occurring in a set of 10,000 species occurrences
Family pool for a pH range calculated as the total number of species occurring in a set of 10,000 species occurrences
Southeastern USA Scenario
How specialized is the flora of the Southern Blue Ridge across the pH gradient?
Cumulative species occurrences and cumulative species median positions encountered when moving across the pH gradient
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