Nutrient runoff is a growing problem in many parts of the United States but researchers from the University of Rhode Island say beavers could be an ally in reducing nitrogen runoff that can lead to low-oxygen “dead zones,” says the American Society of Agronomy.
The ponds that form behind beaver dams slow the flow of water and trap organic material that becomes host to bacteria that transforms nitrate runoff into nitrogen gas. As much as 45 percent of the nitrogen can be removed, depending on the pond and the amount of nitrogen present, say the scientists. One of the researchers, Arthur Gold, said his team decided to study the beaver ponds after noticing that the presence of the ponds “would confound” the expected results of nitrogen movement.
“Beaver ponds represent a relatively new and substantial sink for watershed N (nitrogen) if current beaver populations persist,” the scientists said in a summary. Julia Lazar, part of the research team, said the results may change the way people look at beavers and discourage development along the small streams where beavers build their dams. “So, it may be important to keep these areas from being developed so they can have effects on nitrogen levels downstream,” she said.