• Food Resource Partitioning by Sympatric Ungulates on Great Basin Rangeland

      Hanley, T. A.; Hanley, K. A. (Society for Range Management, 1982-03-01)
      The usefulness of a conceptual framework for understanding food selection by ungulates, based on four morphological parameters (body size, type of digestive system, rumino-reticular volume to body weight ratio, and mouth size), was tested by applying discriminant analysis to 194 monthly diet determinations based on microhistological fecal analysis for five sympatric species of ungulates in northeastern California and northwestern Nevada. In each season, the group means were located in the hypothesized order along the axis described by the first discriminant function: feral horse, domestic cow, domestic sheep, pronghorn, mule deer. Horse and cow diets consisted primarily of grasses. Pronghorn and mule deer diets consisted primarily of browse. Sheep diets were intermediate. Four browses (Artemisia spp., Cercocarpus ledifolius, Purshia tridentata, and Juniperus occidentalis) were selected as the most useful species for discriminating between animal species. The data and analyses support the hypothesized food selection framework.
    • Nutrient Testing of Soil sto Determine Fertilizer Needs on Central Sierra Nevada Deer-Cattle Ranges

      Evans, R. A.; Neal, D. L. (Society for Range Management, 1982-03-01)
      Soil samples representing six major forest soil series and two meadow unclassified types were collected from 17 locations on critical deer migration routes in the central Sierra Nevada, California. Nutrient tests were conducted in the greenhouse using soft chess (Bromus mollis) as an indicator species to determine deficiencies of nitrogen, phosphorus, and sulfur. These tests were carried out to assess fertilizer needs and the probability of field response to increased nutrient levels in the soil for improvement of forage quality and quantity on deer migration routes. All soils were nitrogen deficient; the meadow soils were less so than the forest soils. In 94% of the soils samples, the addition of phosphorus (70%) or phosphorus and sulfur (24%) with nitrogen increased plant yields dramatically (as much as 26 times) compared with adding nitrogen alone. Addition of sulfur with nitrogen produced a yield response equal to that produced by phosphorus or phosphorus plus sulfur with nitrogen in three soils. Nitrogen was the nutrient most limiting for plant growth; phosphorus was next important and was essential for best response in most soils. Sulfur produced variable responses, usually increasing plant yields only after nitrogen and phosphorus deficiencies were corrected. Productivity of forage and browse species growing on these soils is determined by nutrient status; characteristics delineated at the series level, such as depth, texture, and structure; and moisture-temperature relations in specific years.