Geographic Variation in Liver Metal Concentrations of Greater Sage-Grouse

Abstract

Abstract Populations of greater sage-grouse (Centrocercus urophasianus) have declined throughout the species' range. We evaluated metal concentrations in livers sampled from greater sage-grouse collected from hunters in Eureka County, Nevada, during autumn of 2008 and 2010. We make local comparisons of metal concentrations between two populations of greater sage-grouse in Eureka County, as well as regional comparisons with previously reported values for greater sage-grouse collected in Wyoming and Montana. With one exception, tissue concentrations of lead, arsenic, and mercury were below method detection limits. Mean concentrations of iron, molybdenum, and zinc differed between the two Nevada populations, and magnesium, cadmium, molybdenum, and selenium differed between greater sage-grouse in eastern Nevada, and values reported for Wyoming and Montana. In contrast, we found no evidence for local variation in magnesium, copper, cadmium, or selenium, or for regional variation in iron, zinc, or copper. Of particular interest were low selenium concentrations in our study system relative to Wyoming and Montana. Some individuals in our study returned liver selenium values considered consistent with selenium deficiency in domestic poultry. This research adds to the small body of literature on background contaminant levels in greater sage-grouse, and provides evidence for geographic variation in metal concentrations at local and regional scales.