DOI
https://doi.org/10.25772/KHTP-9H32
Defense Date
2025
Document Type
Thesis
Degree Name
Master of Science
Department
Biology
First Advisor
Andrew Eckert
Second Advisor
Chris Gough
Third Advisor
Julie Zinnert
Fourth Advisor
Qiqi Lu
Abstract
Abstract
Local adaptation is known to occur in multiple tree species, with climate as a main force for it occurring, indicating adaptation and changes occurring in spatially and temporally changing climates. With increased climate change, the question now is what future persistence may appear as, and by what magnitude trait mismatch may occur. This is observed in southwestern white pine (Pinus strobiformis) for drought-response traits: resistance (RT), recovery (RC), and resilience (RS). Using previously collected data, the genetic and phenotypic diversity were analyzed. Using that information, the trait values for individuals where only genetic data was known was determined using genome-wide association studies, as well as determining the effect size necessary. Finally, the different levels of mismatch were calculated for three future climate year sets by finding the difference between current and predicted phenotype values. It was found that there was strong isolation-by-distance present genetically, with low inbreeding within populations. There was no strong IBD for phenotypes, as well as overall weak correlation between phenotype difference and genetic difference between populations, indicating no confounding variables to explain the phenotype patterns seen. The effect size necessary to accurately predict phenotype value was 364 SNPs, with very strong accuracy. Climate was found to be a strong predictor for the phenotypes, particularly variables associated with drought conditions. Overall, to maintain current conditions in future environments, there needs to be a decrease in RT, with an increase in both RC and RS. These lead towards an overall increase in post-drought growth, and a decrease in during-drought growth. With shifts in growth patterns, a new strategy may need to develop, with focus on post-drought growth and minimal during-drought growth. Additional research to better understand persistence would be to determine sites where future conditions are likely to cause less trait mismatch and maladaptation.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
8-7-2025