Nutritional and Physical Attributes of Seeds of Some Common Sagebrush-steppe Plants: Some Implications for Ecological Theory and Management

Abstract

A study was conducted to identify seed attributes which might influence granivore preferences. Physical and chemical characteristics were estimated for seeds of 7 common sagebrush-steppe species (Artemisia tridentata, Bromus tectorum, Oryzopsis hymenoides, Pascopyrum smithii, Purshia tridentata, Stipa comata and Stipa viridula) and 1 sacrifice food species (Panicum miliaceum). Seed weights and caloric contents were determined, as well as % composition contributed by 5 organic, 3 inorganic and 5 synthetically defined fractions (including crude protein, solvent extract, structural and soluble carbohydrates and lignin). Results indicate that % soluble carbohydrate may be a good predictor of granivore seed preference. The generality of this or any other predictor is unknown, since sufficiently detailed seed attribute data are unavailable for most species. For management scenarios involving seeds subject to predation, such data would help effectively translate ecological understanding of granivory into more efficient management practices.