LB 24-211 - Predicting genetic complexity of a foundational shrub species with spectral signatures

Big sagebrush (Artemisia tridentata) is a keystone species across the western U.S. that has adapted to a wide range of environments resulting in complex communities with multiple subspecies. The three dominant subspecies of big sagebrush (A. tridentata) are mountain big sagebrush (A. tridentata ssp. vaseyana), basin big sagebrush (A. tridentata ssp. tridentata), and Wyoming big sagebrush (A. tridentata ssp. wyomingensis) each occupying select niches determined by local variations in climate, soil type and depth, and elevation. Genetic complexity or polyploidy in big sagebrush reflects the number of genome duplicates in a given individual. Big sagebrush subspecies present as diploid or tetraploid, except for Wyoming big sagebrush which is tetraploid only. Polyploidy may increase the adaptive potential for an individual to survive stressful conditions and occupy novel ecological niches; however, polyploid individuals are often indistinguishable from their diploid progenitors without using molecular detection techniques. The complexity of the relationship between big sagebrush and local environmental conditions complicates our ability to understand how a changing environment will influence the distribution of sagebrush subspecies and restoration efforts. To predict big sagebrush ploidy levels we sampled spectral response of big sagebrush at five sites along an elevational gradient in southern Idaho to identify local variation in the distribution of ploidy levels. We confirmed ploidy level for individual plants using flow cytometry and paired this information with both near infrared spectroscopy (NIRS) spectroscopy and hyperspectral UAS imagery. We collected spectral response in both June and September to capture peak leaf greenness, and seed production. Preliminary support vector machine models of ploidy level samples paired with NIRS and hyperspectral imagery of big sagebrush results in 73% and 85% classification accuracy. Mapping A. tridentata will provide a spatial and temporal context to characterize the links between genomic diversity and survivability in a changing environment and will further scientific methodologies for land managers and researchers.