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Harvard Forest Research Project 2024

• Title: Microevolution of Q. rubra over the past 100 Years
• Principal investigator: Meghan Blumstein (blumstein@fas.harvard.edu)
• Institution: Harvard Forest
• Primary contact: Meghan Blumstein (blumstein@fas.harvard.edu)
• Team members:
• Abstract:

  The degree to which species are resilient in the face of climate change depends on both their ability to respond to environment via plasticity and their genetic background. However, most climate change studies to date have lacked integration between the study of physiological and developmental mechanisms of response to changing climates with eco-evolutionary processes. Here, we propose to collect genomic information from northern red oak (Quercus rubra), a foundational canopy species of eastern temperate forests, located in the SI-GEO plot.
  
  We propose to collect and sequence oak genomes via low-coverage, whole-genome sequencing from understory cohorts growing throughout the SI-GEO plot (seedling, sapling, and mid-canopy), which we will add to our existing database of red oak canopy trees from this plot. Our goal is to examine allele recruitment and extinction in real time across cohorts (seedling, sapling, canopy trees) to document rapid adaptation (or the lack thereof) in eastern forests. Specifically, we intend to explore the following hypotheses:
  1. The transition from seedling to sapling is where the strongest selective sieve acts, leading to a decrease in genetic variation between the two cohorts.
  2. Genetic variation in mid-story trees will be different from the suite of genetic variation identified in canopy trees, indicating adaption to current versus past climate respectively.
  
  We expect to identify the genes and alleles used for adaptation to global change in red oak (i.e. those that differ between seedling, sapling, and canopy stages). Our work will be the first study of its kind to examine evolution in real-time in forest trees. Recent work in our group has demonstrated an abundance of genetic diversity in canopy trees in this region in red oak, indicating that a larger sampling effort would reveal a high degree of genetic variation and, possibly, a temporal signature of changing allele frequencies.
  
  In the long term, this will improve our ability to predict and to mitigate maladaptive biological responses to rapidly changing environments. In order to survive climate change, plants can either alter their traits plastically, or rapidly adapt via the changing of allele frequencies in a population. This project directly addresses whether adaptation is occurring and if so, at what rate alleles are altering across cohorts. In addition, phenotypic records are also being generated on these same individuals as researchers measure plant traits, such as phenological timing and growth. Altogether, this data will be useful in the short-term for examining rapid adaption in forests, and in the long-term will form the basis of modeling studies asking the critical question of “over what time-scales can forests adapt” and GWAS studies examining how trait variation aligns with adaptive variation in the genome.