ARS | Publication request: Grazing Intensity Does Not Affect Plant Diversity in Shortgrass Steppe

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 25, 2009
Publication Date: February 22, 2010
Citation: Derner, J.D., Hickman, K.R. 2010. Grazing Intensity Does Not Affect Plant Diversity in Shortgrass Steppe. Society for Range Management Meeting Abstracts P C-92.

Technical Abstract: Responses of livestock gain and forage production to grazing intensity in shortgrass steppe are well-established, but effects on basal cover and plant diversity are less so. A long-term grazing intensity study was initiated on shortgrass steppe at the Central Plains Experimental Range (USDA-Agricultural Research Service) in 1939. Treatments were imposed to remove 0% (ungrazed), 20% (light), 40% (moderate) and 60% (heavy) of the current year’s grass growth. We sampled 60, 0.1 m2 (0.2 x 0.5 m) quadrats systematically spaced in each 130 ha pasture each year from 2004 to 2008. Basal cover of species was visually estimated in late July using modified Daubenmire cover categories of: 1=0-5%, 2=6-15%, 3=16-25%, 4=26-40%, 5=41=60% and 6= >60%. Midpoint values of cover classes were used in analyses. Total basal cover and species richness exhibited treatment X year interactions. Total basal cover did not differ among any of the grazing intensities (P=0.37). Species richness did differ with grazing intensity (P=0.0518), with ungrazed different from the remaining grazing intensities. The absence of a grazing treatment difference among the light, moderate and heavy grazing intensities for species richness indicates that grazing in the shortgrass steppe does not affect species diversity.