Seed production estimation for mountain big sagebrush (Artemisia tridentata ssp. vaseyana)

ABSTRACT Seed production is an essential component of postdisturbance recovery for mountain big sagebrush (Artemisia tridentata Nutt, ssp vaseyana [Rydb] Beetle; MBS). We tested a method for rapid estimation of MBS seed production using measurements of inflorescence morphology. We measured total stem length, stem length from first branchlet to stem tip, stem diameter, fresh weight, and number of stem branchlets for 750 inflorescences collected from five central and southern Utah sites. Florets per inflorescence were counted to provide an estimate of seed production potential. We used regression analysis to assess associations between morphological traits and potential seed production and evaluated the efficiency and scalability of each measure for field application. Site means for morphological measures varied ∼2 to 11-fold while mean number of florets per inflorescence varied ∼ 8-fold. Inflorescence weight was the best predictor of seed production potential (P < 0.0001, r2 = 0.897), although correlations...