• DroughtView: Satellite-based Drought Monitoring and Assessment

      Weiss, Jeremy; Crimmins, Michael (College of Agriculture, University of Arizona (Tucson, AZ), 2017-05)
      Remotely sensed data are valuable for monitoring, assessing, and managing impacts to arid and semi-arid lands caused by drought or other changes in the natural environment. With this in mind, we collaborated with scientists and technologists to redevelop DroughtView, a web-based decision-support tool that combines satellite-derived measures of surface greenness with additional geospatial data so that users can visualize and evaluate vegetation dynamics across space and over time. To date, users of DroughtView have been local drought impact groups, ranchers, federal and state land management staff, environmental scientists, and plant geographers. Potential new applications may include helping to track wildland fire danger. Here, we present the functionality of DroughtView, including new capabilities to report drought impacts and share map information, as well as the data behind it.
    • How Do Domestic Herbivores Select Nutritious Diets on Rangelands?

      Howery, Larry D.; Provenza, Fred. D.; Ruyle, George B.; Univ Arizona, Coll Agr & Life Sci (College of Agriculture, University of Arizona (Tucson, AZ), 2016-12)
      Animal learning has been shown to play a major role in the development of diet selection by domestic herbivores. Dr. Frederick Provenza and his associates at Utah State University have conducted a series of studies over the past 30 years to learn how physiological and behavioral mechanisms govern diet selection. In this paper, we synthesize several key diet selection concepts presented in 4 articles (i.e., Provenza et al. 1992; Provenza 1995, 1996, 1997). Reviewed 12/2014; originally published 05/1998.
    • Principles of Obtaining and Interpreting Utilization Data on Rangelands

      Ruyle, George B.; Smith, Lamar; Maynard, Jim; Barker, Steve; Stewart, Dave; Meyer, Walt; Couloudon, Bill; Williams, Stephen; Univ Arizona, Coll Agr & Life Sci (College of Agriculture, University of Arizona (Tucson, AZ), 2016-10)
      A primary expression of stocking levels on rangeland vegetation is utilization defined as the proportion or degree of current years forage production that is consumed or destroyed by animals (including insects). Utilization may refer either to a single plant species, a group of species, or the vegetation as a whole. Utilization is an important factor in influencing changes in the soil, water, animal, and vegetation resources. The impact of a specific intensity of use on a plant species is highly variable depending on past and present use, period of use, duration of use, inter-specific competition, weather, availability of soil moisture for regrowth, and how these factors interact. Utilization data can be used as a guideline for moving livestock within an allotment with due consideration to season, weather conditions and the availability of forage and water in pastures scheduled for use during the same grazing season. In combination with actual use and climatic data, utilization measurements on key areas and utilization pattern mapping are useful for estimating proper stocking levels under current management. Utilization studies are helpful in identifying key and problem areas, and in identifying range improvements needed to improve livestock distribution. Reviewed 10/2016. Originally published 5/2007.
    • Principles of Obtaining and Interpreting Utilization Data on Rangelands

      Ruyle, George B.; Smith, Lamar; Maynard, Jim; Barker, Steve; Stewart, Dave; Meyer, Walt; Couloudon, Bill; Williams, Stephen; Natural Resources & the Environment, School of (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2007-05)
      A primary expression of stocking levels on rangeland vegetation is utilization defined as the proportion or degree of current years forage production that is consumed or destroyed by animals (including insects). Utilization may refer either to a single plant species, a group of species, or the vegetation as a whole. Utilization is an important factor in influencing changes in the soil, water, animal, and vegetation resources. The impact of a specific intensity of use on a plant species is highly variable depending on past and present use, period of use, duration of use, inter-specific competition, weather, availability of soil moisture for regrowth, and how these factors interact. Utilization data can be used as a guideline for moving livestock within an allotment with due consideration to season, weather conditions and the availability of forage and water in pastures scheduled for use during the same grazing season. In combination with actual use and climatic data, utilization measurements on key areas and utilization pattern mapping are useful for estimating proper stocking levels under current management. Utilization studies are helpful in identifying key and problem areas, and in identifying range improvements needed to improve livestock distribution.