Browsing Journal of Range Management, Volume 35, Number 2 (March 1982) by Subjects
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Concentration of Monoterpenoids in the Rumen Ingesta of Wild Mule DeerForage from a sagebrush-dominated winter range and rumen ingesta from mule deer wintering on this range were analyzed for monoterpenoids. The average monoterpenoid level of the rumen ingesta was 0.3%, compared with an average of 1.64% expected from the proportion of monoterpenoid-containing plants in the diet. This 80% reduction between the monoterpenoid level from the rumen compared to the level expected from the ingested forage was highly significant (p<.01). The exact method in which the monoterpenoids are lost from the ingesta was not determined, but evidence from other studies suggests that monoterpenoids may be lost from ingested forage as early as the mastication process. The amount of monoterpenoids found in the rumen ingesta at the time of sampling does not appear to be high enough to interfere with microbial activity. This loss of monoterpenoids may explain the conflict between in vitro evidence that big sagebrush monoterpenoids inhibit rumen microorganisms and digestive trials which show that big sagebrush is a highly digestible winter forage.
Factors Influencing Development of Cryptogamic Soil Crusts in Utah DesertsThe relation of some physical and chemical soil characteristics to cryptogamic crust development was determined from sites in semidesert regions of southern Utah. The effects of grazing on cryptogamic crust development also was examined. Electrical conductivity, percentage silt, and soil phosphorus were found to be correlated with well-developed cryptogamic crusts. Both total cryptogamic cover and the number of cryptogamic species decreased under grazing pressure. The management of rangelands, especially in arid regions, would be strengthened by understanding the role of cryptogamic crusts and considering them in range management decisions.