Research finds need for standardized evaluations to assess livestock impact
The use of streambank alteration to evaluate livestock management in riparian areas is subject to four variables that may affect its accuracy, according to a new study.
The study results are presented in an article in the November 2008 issue of Rangeland Ecology & Management, “Evaluating Livestock Grazing Use With Streambank Alteration Protocols: Challenges and Solutions,” written by Jeremiah D. Heitke, Richard C. Henderson, Brett B. Roper, and Eric K. Archer.
“Although measurements of streambank alteration are relatively repeatable by different observers, results were affected by several factors not directly related to grazing intensity,” according to the article. These factors are training, professional background, location and intensity of measurements, and protocol used. The study evaluated streambank alteration in 10 fallgrazing areas on land managed by the U.S. Forest Service in 2003 and 2004 in western Montana. The two evaluated protocols in 2004 were greenline (GL) and greenline precise (GLP), which measure disturbance along a line centered on the greenline and perpendicular to the stream channel.
After the observers received training, the researchers found that the consistency of site evaluations improved. “Given the higher means and variability associated with untrained observers, assessing streambank alteration with untrained observers could seriously undermine the credibility of land management based on those assessments,” according to the article.
The researchers recommend using independent, trained technicians to provide the training. They also found that the chosen protocol could affect the observers’ results. While GL took an average of 30 minutes, GLP required about 60 minutes but generally was more accurate.
“Specialists need to understand how the choice of protocol, level of training, and professional background affect these estimates,” the researchers write. They also caution that because no protocol is error-free, managers should be careful when making a decision based on a single assessment.