• A Taxonomic Field Herbarium

      Williams, Tod B.; Francis, Richard E. (Society for Range Management, 1989-08-01)
    • An Automated Range-Animal Data Acquisition System

      Adams, D. C.; Currie, P. O.; Knapp, B. W.; Mauney, T.; Richardson, D. (Society for Range Management, 1987-05-01)
      An automated range-animal data acquisition system (ARADS) has been developed to collect individual animal data without human intervention. Records include date, time, identification, live-weight, water consumption, and weather variables. The system is presently being used to monitor free-ranging yearling steers and mature cows. ARADS is composed of 7 portable scale units, a weather station, and a central computer all linked together through a radio communication network. The system is expandable to include additional data stations and parameters, and the number of animals identified is not limited by the system. Scale units and the weather station operate in extreme temperatures (40 to -40 degrees C), precipitation and wind.
    • Comparative rumen and fecal diet microhistological determinations of European mouflon

      Chapuis, J. L.; Boussés, P.; Pisanu, B.; Réale, D. (Society for Range Management, 2001-05-01)
      The population of European mouflon (Ovis musimon Pallas) established on an island of the sub-Antarctic Kerguelen archipelago is characterized by a demographic cycle. Every 2-5 years, there is a massive winter mortality due to food shortage. A good knowledge of food resources utilization appeared essential to understand the population growth dynamics. We investigated the validity of the microhistological analysis of feces by a comparative analysis of 30 paired rumen and fecal samples collected in winter. Sixteen and 17 food items were identified respectively in rumen and fecal samples. Most fragments could be accurately determined because plant diversity was low. Both methods gave similar results Though quantitative differences appeared between methods for some items, the same 4 major food constituents were identified in relatively close proportions in both rumen and fecal samples. There is a risk of slight overestimation of annual meadow-grass (Poa annua L.) and mosses in feces, and of Azorella selago Hook. f. in the rumen.
    • Microhistological analysis of sheep gastro-intestinal content to confirm poisonous plant ingestion

      Yagueddu, C.; Cid, M. S.; Lopez, T. (Society for Range Management, 1998-11-01)
      The epidermal remains of 4 poisonous plant species that produce acute intoxication in ruminants were quantified by microhistological analysis in the gastro-intestinal content of sheep experimentally poisoned. These species were 'romerillo' or 'mio mio' (Baccharis coridifolia DC); 'duraznillo negro' (Cestrum parqui L'Hérit.); 'poison hemlock' (Conium maculatum L.), and 'sunchillo' (Wedelia glauca (Ort.) Hoff.). All of these species produce important economic losses of livestock in the Flooding Pampa, Buenos Aires, Argentina. The plants used for intoxication were at the vegetative stage of growth. Results indicate that the microhistological technique can be used to confirm the diagnosis of ruminant intoxication by duraznillo negro, romerillo, and sunchillo, but not by poison hemlock because digestion degrades its fragments beyond recognition. It would be convenient to sample the final sections of the digestive tract to confirm romerillo and sunchillo ingestion, because their fragments tend to concentrate there. The uniformity of duraznillo negro fragment distribution would allow identification of this species from any section of the digestive tract. However, the considerable variability in fragment distribution found among animals poisoned with the same plant species makes it necessary to sample more than 1 digestive region if only 1 animal is available for necropsy.
    • Riparian Area Definition—A Viewpoint

      Anderson, E. William (Society for Range Management, 1987-04-01)
    • Use of UV absorption for identifying subspecies of Artemisia tridentata

      Spomer, G. G.; Henderson, D. M. (Society for Range Management, 1988-09-01)
      Use of UV absorption spectra for identifying subspecies of Artemisia tridentata Nutt. was investigated by analyzing the relative optical densities of alcohol extracts from herbarium and fresh plant material at 240 nm, 250 nm, and 265 nm. In all but 1 comparison, mean relative optical densities were significantly different (p=0.95) between subspecies, but intraplant and intrasubspecies variation and overlap was found to be too large to permit use of UV absorbance alone for identifying individual specimens. These results held whether dry or fresh leaves were extracted, or whether methanol or ethanol was used as the extracting solvent.