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United States Department of Agriculture

Agricultural Research Service

Title: Grazing Intensity, Forbs, and Plant Species Richness on Sand Sagebrush-Grassland

Authors
item Gillen, Robert
item Sims, Phillip

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 26, 2004
Publication Date: February 5, 2005
Citation: Gillen, R.L., Sims, P.L. 2005. Grazing intensity, forbs, and plant species richness on sand sagebrush-grassland [abstract]. Society for Range Management, 58th Annual Meeting and Trade Show, February 5-11, 2005, Fort Worth, Texas. CDROM.

Technical Abstract: Knowledge of the relationship between stocking rate or grazing intensity and plant community composition is fundamental to the sustainable management of rangelands. Our objective was to determine the impact of stocking rate on forb populations and plant diversity of a sand sagebrush (Artemisia filifolia Torr.)-grassland. Stocking rates averaging 43, 57, and 85 animal-unit-days ha-1 (AUD ha-1) for year-round grazing were applied from 1941 to 1961. Basal cover of grasses and forbs were measured along line transects 7 times during the study period at 2 to 7 year intervals. The forb component was dominated by annuals which contributed about 78% of the total forb cover and 8 of the 10 most abundant species. As a group, annual forbs were not affected by stocking rate. Plains sandparsley (Ammoselinum popei Torr. and Gray) was the only annual forb more abundant under the highest stocking rate and this occurred in only 2 years. Perennial forbs were more abundant at 43 and 57 AUD ha-1 compared to 85 AUD ha-1 in 4 of the last 5 sample years. The richness of annual forbs was not affected by stocking rate but the richness of perennial forbs was reduced at the highest stocking rate. Species richness of grasses was slightly higher at 57 AUD ha-1 in 2 years. Forb populations were more responsive to weather than to stocking rate. Heavy grazing did not increase the abundance or richness of forbs.

Last Modified: 9/2/2014
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