Yes, cattle can graze without leaving streams in toilet-like conditions. We all know this. And when researchers at UC Davis confirmed that grazing and clean water could be compatible, many of you emailed us the link to the article about the study.
From June-November 2011, a team of UC Davis researchers headed by Dr. Leslie Roche, of UC Davis’ Rangeland Watershed Laboratory collected 743 water quality samples from 155 sites. They investigated key cattle grazing areas, recreational areas, and places where neither humans nor cattle typically tread. The results showed little difference between areas grazed by cattle and those used by people. The majority of the samples (83% of all sites) were below the Environmental Protection Agencies benchmarks for protecting human health.
Roche’s article on their work concludes by saying “These results suggest cattle grazing, recreation, and clean water can be compatible goals across these national forest lands.” This is great news for folks who are facing legislation potentially excluding livestock from streams and other waterways. Except what happens in Vegas stays in Vegas, and what happens in the US Forest Service Lands in California might not translate to every other site under consideration.
The Roche study conclusions countered findings of other researchers on other sites. For example, Robert Derlet and his colleagues did a study in California’s Sierra Nevada in 2006 and found that 53% and 60% of study sites exceeded the EPA’s benchmarks for human health. Another study in the Sierra Nevada from 2009 -2011 done by Lindsey Myers and her colleagues found an increase in algae coverage and E. Coli in sites below areas grazed by cattle.
What Does This Mean To Graziers?
We just got great news from one set of researchers. But Myers concludes her article with “widespread pollution of surface waters is occurring due to livestock grazing on National Forest lands in the Sierra Nevada.” Both studies were published in peer-reviewed journals which gives us confidence in the methods involved. So why are the results so different?
Each article and each set of results is only able to report on the particular area they studied: the 5 National Forests covered by Roche’s study, and the California Sierra Nevada covered by the Detler and Myers studies. The conditions under which each study was conducted can play a part in the results. Streambanks, topography, soil type, grazing management, rainfall frequency and intensity, vegetation, are all factors in the giant equation of the environmental research.
Nothing is as simple as “yes” or “no” in this story, it turns out. Researchers tell us that in some cases grazing and water quality are compatible; others say, no, they are not. Does that mean livestock need 100% exclusion from surface water?
We can all figure out that too much poop in the water is a problem, and manage to avoid making our streams and waterways into livestock toilets. If we try to use any single piece of research though, in developing laws and regulations that could affect us, we will miss the near-infinite variations between study sites and where each of us live and farm.