Nutritional Analysis of Sagebrush by Near-Infrared Reflectance Spectroscopy

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Sagebrush (Artemisia spp.) habitat in the Intermountain West is one of the most endangered ecosystems in North America due, in part, to fire, climate change, and anthropogenic disturbances. However, restoration efforts rarely consider the dietary quality of sagebrush that is conserved or restored despite growing evidence that it is an influential parameter explaining habitat use by many important wild and domestic herbivores. The objective of this study was to evaluate the capacity of near-infrared reflectance spectroscopy (NIRS) to measure and monitor the dietary quality of sagebrush. Leaf samples were collected from two sagebrush species over two seasons and three sites in Idaho, USA. We developed calibration equations for crude protein (CP), dry matter digestibility (DMD), 1,8-cineole (cineole), and total polyphenolics. The coefficient of determination (r2) and ratio of performance to deviation (RPD) were 0.93 and 3.5 for CP, 0.83 and 1.8 for DMD, 0.64 and 1.5 for cineole, and 0.64 and 1.6 for total polyphenolics. These results indicate that NIRS may offer a rapid, noninvasive, diagnostic tool for assessing dietary quality of sagebrush, but future research should explore the potential for development of improved prediction equations and in situ analysis of sagebrush dietary quality with field spectroscopy.