NicoleToyon Road

Climate as a Driver of Divergence in Soil-specialist Plants

Guest Speaker: Nicole Ibañez, Masters candidate, University of San Francisco

The global climate is changing rapidly, and stochastic events like droughts are becoming increasingly frequent and severe. It is important to understand how communities are affected by climate, especially in rare, fragmented habitats. Serpentine soil occurs as fragmented ‘islands’ across California, and provides unique habitats, characterized by harsh abiotic conditions that are stressful for plants. Plants that are found on and off serpentine soils in sympatry are a model system for studying local adaptation via stress-tolerant traits. These plants have adaptations to tolerate abiotic stress, which often trade off with competitive ability. One such trait is accelerated phenology, or the timing of flowering, a response to low soil moisture. Phenology can affect gene flow and reproductive isolation between populations. Previous studies have found correlations between precipitation gradients and biogeography of serpentine specialists. Here, I leverage heterogeneous landscapes to study how climate mediates local adaptation and reproductive isolation in plants within specialized habitats. I discuss how certain environmental stressors are more divergent between serpentine and non-serpentine habitats in regions with higher precipitation. As a result, I predict more divergence of traits associated with the drought-competition tradeoff in wetter regions. I predict that nearby serpentine and non-serpentine populations will have more phenological divergence and higher genetic differentiation in wetter regions. These results would suggest that climate is a driver of divergence via local adaptation to specialized habitats. This is important to understanding how soil specialists evolved, and how climate change will affect different plant communities in the future.

Program Outline:Wiry snapdragon (Antirrhinum vexillocalyculatum) blooming in Marin County.SnapdragonI. Introduction
a. What is serpentine?
b. Linking serpentine endemism and precipitation
c. Questions and hypothesis
II. Methods
a. Study species – Antirrhinum vexillocalyculatum
b. Site selection
c. Fieldwork
d. Greenhouse study
e. Molecular study
III. Results
a. Key takeaways
IV. Discussion
a. Importance of results
b. Future Directions
V. Acknowledgements
VI. Questions

Nicole Ibañez is a nature enthusiast, born and raised in the Central Valley of California. She completed her Bachelor’s of Science in Field and Wildlife Biology at Cal Poly San Luis Obispo in 2016. Here, she grew her passion for conservation ecology, and developed a strong interest in California native plants. After college, she moved to Sacramento and began a career in environmental consulting, furthering her knowledge of California native plants and wildlife, and providing guidance on natural resource and special-status species avoidance and mitigation. Closely studying the ecology of rare plants sparked an interest in species that grow in specialized habitats, such as serpentine. In 2019, she moved to San Francisco to begin a Master’s degree program in Biology at the University of San Francisco. She is co-advised by Dr. John R. Paul and Dr. Sevan Suni, whose labs study botanical evolution, and plant-pollinator relationships, respectively. With the help of her advisors, Nicole has conducted a novel research project on the effects of climate on local adaptation to serpentine soils.