Research
My research interests seek to understand how plants are locally adapted to their environments, how populations of the same species differ in local adaptation, and how this affects rapid evolution and responses to extreme environmental perturbations. I am particularly interested in stress responses to drought, heat, salt, and eutrophication. I use an ecophysiological approach to understanding adaptation to global climate change and have interests in long-term eco-evo studies and resurrection approaches to study evolution. Additionally, I am interested in how plasticity (including transgenerational plasticity) affects evolutionary responses, how it itself evolves, and how this relates to niche breadth evolution and local adaptation.
What are the tolerance thresholds for different plant species?
Studying local adaptation and niche breadth is integral for our understanding of why some species reside where they do and why they aren't found in other places. Distribution is a product of both abiotic and biotic factors, but the limitations of physiological processes is a genetic component that affects tolerance thresholds. During my undergraduate and master of science degrees, I studied heat tolerance of reproductive structures in crop and wild desert species. The small pink flowers of Trianthema portulacastrum ----> |
How will species/populations adapt to changing environments? The ability for populations to respond to changing climates is based on their baseline tolerance thresholds, the genetic variation within the population, mutation rate, and the presence of plasticity. All of these are affected by climatic histories, such as spatial and temporal variability. With my collaborator, Daniel Anstett, and my PhD advisor, Amy Angert, we are investigating rapid evolution across the range of Mimulus cardinalis (scarlet monkeyflower) following a severe drought. We find that phenological and growth traits evolve in just a few generations. The tubular flower of the scarlet monkeyflower (photo by D. Anstett) ----> |
Can anatomy keep up with rapid environmental change and how does this affect persistence?
I'm interested in how the architecture of plants facilitates physiological processes and behaviour. Specifically I examine whether changes in the make up of the mesophyll (proportion spongey vs palisade), epidermal alterations (stomatal and trichome density and size), and leaf overall thickness will affect photosynthetic processes and water loss. By examining the interaction between morphology and physiology, we can better understand water use strategies and stress responses. My current work on Mimulus cardinalis highlights the importance of examining adaptive responses at a finer scale (to be placed on bioRxiv shortly). Leaf cross section of M. cardinalis -----> |
What is the effect of plasticity on the rate of adaptation and how does/can plasticity/transgenerational plasticity evolve? The last chapter of my thesis examines how transgenerational plasticity (both accumulative/provisioning and epigenetics) affects responses to dry environments and whether populations with different historical climates are more likely to express transgenerational plasticity. Transgenerational plasticity may buffer species/populations, providing time to evolve and a faster response time when exposed to stress (i.e. priming). However, it may also hinder the adaptive response through phenotypic lags where current phenotypes reflect adaptation to the environments of their grandparents or early generations rather than responding to current environmental pressures. Full siblings grown in different treatments (wet or dry) with parents that were exposed to different treatments (wet or dry). From left to right (parent-current treatment): wet-wet, wet-dry, dry-wet, dry-dry ----> |
Connect
Email: haley [dot] branch [at sign] yale [dot] edu
Twitter: @haleyabranch |