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United States Department of Agriculture

Agricultural Research Service

Research Project: PROACTIVE MANAGEMENT FOR SUSTAINABLE RANGELAND PRODUCTION

Location: Livestock and Range Research Laboratory (LARRL)

Title: Estimating influence of stocking regimes on livestock grazing distributions

Authors
item Rinella, Matthew
item Vavra, Martin -
item Naylor, Bridgett -
item Boyd, Jennifer -

Submitted to: Ecological Modelling
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 23, 2010
Publication Date: October 27, 2010
Citation: Rinella, M.J., Vavra, M., Naylor, B.J., Boyd, J.M. 2010. Estimating influence of stocking regimes on livestock grazing distributions. Ecological Modelling. 222:619-625.

Interpretive Summary: Livestock often concentrate grazing at small hotspots in the larger landscape, and dispersing livestock away from these intensively grazed areas is one of the central challenges in range management. We evaluated a technique based on shifting the stocking date to prevent overgrazing of small areas containing grasslands and meadows within a largely forested mountain rangeland. In a large pasture (i.e. 2373 ha), cattle stocking was alternated between early in one year and late in the next, for 18 years. Early stocking occurred when vegetation was actively rowing, and late stocking occurred during senescence. Each year, animal position data were recorded from a sample of cattle wearing radio or GPS collars. Based on the average of these data over all years, cattle grazed the study units between six and 10 times more heavily than expected under evenly distributed grazing, regardless of wheather uniform grazing is defined in terms of the amount of biomass consumed or the ratio of consumption to production So anagement that disperses cattle away from the study units is clearly desirable. Grazing under late stocking was less than one third as intense as grazing under early stocking in some study units. Averaged over all study units, grazing in most late stocking years was less than half as intense as grazing in the average early stocking years. Thus, late stocking appears to be a very effective means for reducing disproportionately intense grazing of small grasslands and meadows in mountain rangelands.

Technical Abstract: Ungulates often concentrate grazing at small hotspots in the larger landscape, and dispersing livestock away from these intensively grazed areas is one of the central challenges in range management. We evaluated a technique based on shifting the stocking date to prevent overgrazing of small areas containing grasslands and meadows withing a largely forested mountain rangeland. In a large pasture (i.e. 2373 ha), cattle stocking was alternated between early in one year and late in the next for 18 years. Early stocking occurred when vegetation was actively growing, and late stocking occurred during senescence. Each year, animal position data were recorded from a sample of cattle wearing radio or GPS collars. Based on the average of these data over all years, cattle grazed the study units between six and 10 times more heavily than expected under evenly distributed grazing, regardless of whether uniform grazing is defined in terms of the amount of biomass consumed or the ratio of consumption to production. so management that disperses cattle away from the study units is clearly desirable. Based on most likely parameter estimates from our causal modeling, grazing under late stocking was less than one third as intense as grazing under early stocking in some study units. Average over all study units, grazing in most late stocking years was less than half as intense as grazing in the average early stocking years. Thus, late stocking appears to be a very effective means for reducing disproportionately intense grazing of small grasslands and meadows in mountain rangelands.

Last Modified: 4/17/2014