Great Plains Natural Science Society


Date of this Version


Document Type



The Prairie Naturalist· 41 (3/4): December 2009, pp121-125


We used a modified Robel pole to measure vegetation for a study conducted in the northern Black Hills, South Dakota. Objectives were to determine the relationship between visual obstruction readings and clipped standing herbage, and develop guidelines for monitoring standing herbage. The relationship between visual obstruction readings and standing herbage was linear and regression coefficients were significant (P≤ 0.001). Herbage ranged from 140 to 3313 kg· ha-1 with a mean of 1386 kg· ha-1 (SE = 320 kg· ha-1) for 123 transects. Visual obstruction readings (VOR) ranged from 0.6 to 30.4 (number of 1.27 cm bands obscured) with a mean of 10.9. Cluster analyses grouped the visual obstruction readings and standing herbage into 3 VOR categories; short, intermediate, and tall. Our results indicate a minimum of 4 transects (20 stations/transect) is needed to be within 20% of the mean at 80% confidence for monitoring areas≤ 259 ha (1 section). The protocol we developed provides pertinent information for managers to develop guidelines and monitor standing herbage for livestock and wildlife use in meadows of the northern Black Hills.