This study using a modified Robel pole was conducted in the central Black Hills, South Dakota. The objectives were to test the relationship between visual obstruction readings and standing herbage, develop guidelines for monitoring, and estimate sample size. The relationship between visual obstruction and standing herbage was linear with 2 segments in a piecewise model. Regression coefficients were highly significant (P ≤ 0.001). Standard error of the estimate for a single mean was 373 kg · ha−1. Herbage ranged from 89 to 3821 kg · ha−1 with a mean of 1416 kg · ha−1. The average number of visually obstructed bands was 6.4 and ranged from 0.21 to 20.4. Cluster analyses grouped the visual obstruction readings into 3 management categories: short, medium, and tall. A minimum of 3 transects (20 stations per transect) is recommended for monitoring areas ≤259 ha (1 section) to be within 20% of the mean at 80% confidence. The protocol developed to monitor standing herbage is accurate, precise, and easy to apply. This tool provides pertinent information for managers to develop guidelines based on the bands and/or standing herbage for monitoring livestock and wildlife use.
Uresk, Daniel W. and Benzon, Ted A.
"Monitoring with a modified Robel pole on meadows in the central Black Hills of South Dakota,"
Western North American Naturalist: Vol. 67
, Article 6.
Available at: https://scholarsarchive.byu.edu/wnan/vol67/iss1/6