Data from: Adaptation and divergence in edaphic specialists and generalists: serpentine soil endemics in the California flora occur in barer serpentine habitats with lower soil calcium levels than serpentine tolerators
Sianta, Shelley A., University of California, Santa Cruz
Kay, Kathleen M., University of California, Santa Cruz
Published May 14, 2019 on Dryad.
Cite this dataset
Sianta, Shelley A.; Kay, Kathleen M. (2019). Data from: Adaptation and divergence in edaphic specialists and generalists: serpentine soil endemics in the California flora occur in barer serpentine habitats with lower soil calcium levels than serpentine tolerators [Dataset]. Dryad. https://doi.org/10.5061/dryad.t12ch7h
• Premise of the study: Adaptation to harsh edaphic substrates has repeatedly led to the evolution of edaphic specialists and generalists. Yet, it is unclear what factors promote specialization versus generalization. Here, we search for habitat use patterns associated with serpentine endemics (specialists) and serpentine tolerators (generalists) to indirectly test the hypothesis that trade-offs associated with serpentine adaptation promote specialization. We predict that 1) endemics have adapted to chemically harsher and more bare serpentine habitats than tolerators, and 2) edaphic endemics show more habitat divergence from their sister species than tolerators do among on- and off-serpentine populations. • Methods: We selected 8 serpentine endemic and 9 serpentine tolerator species representing independent adaptation to serpentine. We characterized soil chemistry and microhabitat bareness from one serpentine taxon of each species and from a paired nonserpentine sister taxon, resulting in 8 endemic and 9 tolerator sister taxa pairs. • Key results: We find endemic serpentine taxa occur in serpentine habitats averaging twice as much bare ground as tolerator serpentine taxa and 25% less soil calcium, a limiting macronutrient in serpentine soils. We do not find strong evidence that habitat divergence between sister taxa of endemic pairs is greater than between sister taxa of tolerator pairs.• Conclusions: These results suggest serpentine endemism is associated with adaptation to chemically harsher and more bare serpentine habitats. It may be that this adaptation trades off with competitive ability, which would support the longstanding, but rarely tested, competitive trade-off hypothesis.
Description of data files and R script
dataset containing the soil chemistry and texture results for each taxon
dataset containing the percent cover of bare ground data for each taxon.
consensus tree generated in MrBayes of the taxa used in this study.
Habitat and Phylogenetic analyses
R script that contains all the analyses done in this publication. Refer to the README file for details on organization and structure.