Author
 |
Seefeldt, Steven |
|
Submitted to: Society for Range Management Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 9/15/2006 Publication Date: 2/10/2007 Citation: Seefeldt, S.S. 2007. Manipulation of sheep grazing can be used to predictably alter vegetation in the sagebrush steppe. Society for Range Management Meeting Proceedings(CD). Interpretive Summary: There are many opinions about the impact of grazing animals on vegetation in the Western rangelands of North America. People understand that grazing will alter vegetation, but the argument concerns whether or not this change improves or deteriorates the pasture. People often forget that the vegetation community will change even if grazing is removed. Historic and recent studies at the U.S. Sheep Experiment Station north of Dubois, ID have measured the amount and type of vegetation changes and concluded that these changes are predictable based on the timing, duration, and intensity of sheep grazing. For example, in the sagebrush steppe, medium to heavy grazing in the spring will reduce broad-leaved plants, but will increase grasses, whereas light to medium grazing in the late fall will reduce sagebrush cover and increase broad-leaved plants. Short duration and high intensity grazing at the time when weed species are most vulnerable can be used to reduce the seed set of undesirable species. The absence of grazing in the moister areas of the sagebrush steppe will result in dense sagebrush. If a land manager knew what vegetation mix was most desirable for a wildlife species, then carefully managed sheep grazing could be made an important component in driving the vegetation community towards that vegetation goal. Technical Abstract: There is considerable debate about the impact of grazing animals on vegetation in the Western rangelands of North America. It is a given that any animal grazing will alter vegetation. Furthermore, the vegetation community will change even if grazing is removed. Historic and recent studies at the U.S. Sheep Experiment Station north of Dubois, ID have shown that these changes are predictable based on the timing, duration, and intensity of sheep grazing. For example, in the sagebrush steppe, medium to heavy grazing in the spring will reduce forbs, but increase grasses, whereas light to medium grazing in the late fall will reduce sagebrush canopy and increase forbs. Short duration and high intensity grazing at the appropriate time can be used to reduce the seed set of undesirable species. The absence of grazing will result in dense sagebrush. If a land manager was to give a description of a desired vegetation community for a wildlife species, carefully managed sheep grazing could be made an important component in driving the vegetation community towards that vegetation goal. |
