Major
Biology
Research Abstract
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 ecosystems. The California Floristic Province provides a unique landscape with a dramatic precipitation gradient. Within that gradient, serpentine soil ‘islands’ dot the landscape. Serpentine soil is characterized by harsh abiotic factors that make it difficult for plants to grow. Plants that can tolerate serpentine soils can be found growing on and off of serpentine soils in sympatry, and are a model system for studying local adaptation via stress-tolerant traits. Plants that grow in stressful environments often have adaptive traits to help them tolerate or avoid such stressors, and these adaptations often trade off with competitive ability. One such trait is accelerated phenology, or the timing of flowering, a response to low soil moisture. Phenology has important implications for gene flow and reproductive isolation between populations. Here, I leverage heterogeneous landscapes to study how precipitation mediates local adaptation and reproductive isolation in plants that occur in specialized habitats. I predict that the amounts of drought stress and competition stress within serpentine and non-serpentine habitats are more divergent in regions with higher precipitation. I hypothesize that this larger difference in environmental stress will result in more divergence of certain traits, i.e. those associated with the drought-competition tradeoff, in wetter regions. I predict that nearby populations of a plant growing on serpentine and non-serpentine soils will have more divergence in phenology and higher genetic differentiation in wetter regions. These results would suggest that climate is a driver of divergence via local adaptation to specialized edaphic habitats. This information is important to our understanding of how soil specialist plants have evolved in the past, and how different plant communities may be affected by changes in climate in the future.
Faculty Mentor/Advisor
John Paul
PowerPoint presentation
Climate as a driver of divergence in soil-specialist plants
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 ecosystems. The California Floristic Province provides a unique landscape with a dramatic precipitation gradient. Within that gradient, serpentine soil ‘islands’ dot the landscape. Serpentine soil is characterized by harsh abiotic factors that make it difficult for plants to grow. Plants that can tolerate serpentine soils can be found growing on and off of serpentine soils in sympatry, and are a model system for studying local adaptation via stress-tolerant traits. Plants that grow in stressful environments often have adaptive traits to help them tolerate or avoid such stressors, and these adaptations often trade off with competitive ability. One such trait is accelerated phenology, or the timing of flowering, a response to low soil moisture. Phenology has important implications for gene flow and reproductive isolation between populations. Here, I leverage heterogeneous landscapes to study how precipitation mediates local adaptation and reproductive isolation in plants that occur in specialized habitats. I predict that the amounts of drought stress and competition stress within serpentine and non-serpentine habitats are more divergent in regions with higher precipitation. I hypothesize that this larger difference in environmental stress will result in more divergence of certain traits, i.e. those associated with the drought-competition tradeoff, in wetter regions. I predict that nearby populations of a plant growing on serpentine and non-serpentine soils will have more divergence in phenology and higher genetic differentiation in wetter regions. These results would suggest that climate is a driver of divergence via local adaptation to specialized edaphic habitats. This information is important to our understanding of how soil specialist plants have evolved in the past, and how different plant communities may be affected by changes in climate in the future.
