| Assessing traits provides insights into species' ecological roles, yet cryptic traits like age
and genome size remain understudied. This research focused on two objectives: evaluating non-
destructive methods for estimating age and examining genome size's relationship with resource
availability in Artemisia tridentata (big sagebrush), a dominant sagebrush steppe species. First,
we assessed non-destructive techniques for estimating age using morphological traits in one big
sagebrush subspecies, finding basal stem circumference most correlated with age. We extended
the analysis to assess this trait's accuracy across two subspecies. While basal stem circumference
remained a strong predictor, accuracy varied by subspecies and site, suggesting environmental
factors impact reliability. Second, we examined genome size's relationship with resource
availability in big sagebrush seedlings using a controlled greenhouse experiment. We tested how
genome size influences seedling performance under varying nitrogen, phosphorus, and water
availability. Individuals with larger genome sizes had a competitive advantage under high
resource availability, particularly when nitrogen and water were abundant. Significant resource
co-limitation effects were also observed, with water enhancing nitrogen and phosphorus impacts
on biomass and water content. These results highlight a complex interplay between genome size
and resources, with water playing a key role. This work underscores genome size and age
determination's importance for restoring and conserving declining ecosystems like sagebrush
steppe.
Keywords: genome size, co-limitation, age estimation, sagebrush, Artemisia |