Ecophysiology: restoring climate-resilient meadows by harnessing local plant evolutionary potential
David Ackerly, Professor
Integrative Biology
Closed. This professor is continuing with Fall 2023 apprentices on this project; no new apprentices needed for Spring 2024.
Habitat restoration will only provide long-term benefits if restored vegetation is resilient to climate change. Sourcing plant material from distant climate zones may achieve climate resilience but carries other risks. Restorationists need a framework for sourcing climate-resilient plant material locally.
Our research addresses this problem for Lemmon’s willow (Salix lemmonii) in Sierra Nevada meadows, where S. lemmonii helps regulate water resources, provides critical wildlife habitat, and is used culturally by indigenous communities. A recent, severe drought revealed S. lemmonii populations may be highly vulnerable to the hotter, drier conditions predicted to occur over the next century of climate change. However, S. lemmonii may be harboring local-scale genetic variation that restorationists could harness to mitigate this risk. Using roughly 230 cloned S. lemmonii cuttings collected from from 38 meadows across Tahoe National Forest, we are conducting a common garden experiment to quantify heritable variation in drought resistance among S. lemmonii populations, and to identify the environmental factors shaping this variation.
We hypothesize that meadows with lower moisture availability in the growing season (as represented by April 1 snowpack) will harbor more drought-adapted genotypes due to local adaptation, and that heritable phenotypic variation in drought resistance traits will also be shaped by patterns of wind dispersal among meadows. Ecophysiological work to date has demonstrated that plants sourced from drier meadows have lower turgor loss points—a measure of physiological resistance to wilting in dry conditions—consistent with our local adaptation hypothesis.
The next step is to conduct a dry-down experiment, during which “treatment” plants will receive limited watering, and “control” plants will continue receiving daily watering. We will compare growth, survival, and ecophysiological responses between treatments to quantify drought resistance. (Later GIS and statistical work will test hypotheses regarding the influence of wind patterns on heritable adaptive phenotypic variation.)
Qualifications: Tasks: The student’s role will be to assist with ecophysiological and demographic measurements during greenhouse dry-down experiment. We will use porometers to quantify stomatal conductance, a measure of water loss from each plant’s leaves. We will use Scholander pressure chambers to measure water potential, a measure of each plant’s water deficit. We will use dissecting microscopes to measure stomatal density. We will also measure growth, survival, and leaf loss during the experimental drought. Additionally, the student may assist with plant care such as repotting and/or installing an irrigation system.
Students should be prepared to commit at least 5 hours per week. It is not necessary to commit to more than 5 hours per week, but opportunities for more hours can easily be arranged.
Learning outcomes: Kyle Rosenblad, the PhD student running the experiment, will provide hands-on instruction and mentorship. The student will thereby gain technical expertise in using the methods and equipment described in “Tasks”. Through informal discussions with Kyle, the student will also learn about the ecological and evolutionary concepts underpinning this project and the justifications behind the methods used to test our hypotheses. The student will be welcomed as a member of our lab community, which includes other undergraduates, graduate students, and postdocs. If interested, the student will be invited to attend lab meetings and social events with lab members, although there is absolutely no expectation or requirement in this regard. This will provide opportunities to build the student’s network of peers and mentors. If the student is interested in continuing the mentoring relationship after the conclusion of their involvement with the project, the student can expect Kyle to keep in touch.
No qualification required. Kyle is happy to train you!
Hours: to be negotiated
Related website: https://kylerosenblad.org/
Related website: https://kylerosenblad.org/