Beaver trapping would be prohibited along impaired waterways on public lands in Oregon under a bill that’s headed for a vote in the House.

Supporters of House Bill 3932, including environmental and animal advocates, argue it’s imprudent to allow the rodents to be killed in areas where expensive riparian habitat improvements are meant to attract them.

“It’s counterproductive, unproductive and quite frankly wasteful to simultaneously allow those beavers to be trapped for recreational purposes,” said Rep. Pam Marsh, D-Ashland.

The proposal is meant to encourage “nature’s engineers” to inhabit streams and rivers with degraded water quality, as their dams are known to filter out pollutants by slowing water movement, which causes sediments to settle.

“It’s very clear that when the beavers were present, the water quality improves much more,” said Katie Holzer, senior environmental scientist with the City of Gresham, which has streams that have been recolonized by the species.

Research conducted by the city indicates beavers have doubled the removal of heavy metals and nutrients in a constructed wetland that helps clean stormwater, she said.

Only about 4% of the beavers harvested in Oregon are trapped on public lands, and HB 3932 would only apply to a subset of those areas with impaired water quality, said Marsh, a chief sponsor of the proposal.

“This bill still supports most of the recreational trapping in the state,” she said.

By relying on wildlife to improve water quality, the proposal would help strengthen connections between state agencies such as the Department of Environmental Quality and Department of Fish and Wildlife, which typically take a more narrow view of specific problems, said Sristi Kamal, deputy director of the Western Environmental Law Center.

“We know beavers can help with impaired waterways. It’s a matter of keeping them there and making sure they’re not trapped out before they give us the benefits they need to give,” Kamal said.

These arguments have apparently proven persuasive to the House Climate Committee, which recently approved the bill 7-4, sending it to a House floor vote that’s scheduled for April 21.

The Oregon Farm Bureau is neutral on the proposal, citing an exception to the bill’s trapping prohibition that applies to beavers that cause injury to neighboring property.

“This should provide a pathway for public land managers to take action to protect public infrastructure and private farmlands and structures from beaver damage and flooding when that land or infrastructure is adjacent to public land,” the group said in written testimony.

Several organizations representing hunters and trappers are opposed to HB 3932, arguing that beaver trapping is already sufficiently regulated by state wildlife officials.

“I strongly suggest we leave the management and policy-making to the hired individuals and biologists who are hired to do this kind of work,” said Andrew DeHart, board member of the Oregon Trappers Association.

Like most rodents, beavers are “prolific” in their reproductive habitats, which has resulted in a plentiful population in Oregon, he said.

“Left unmanaged, they can do devastating things to their environment, including eat themselves out of house and home,” DeHart said.

While the species can legitimately enhance water quality, those benefits are regularly negated when strong stream flows blow apart beaver dams and release collected sediments into waterways, said Jeremy Watson, vice president of the Oregon Trappers Association.

Trappers don’t want to kill all the beavers, just participate in a regulated harvest, and shouldn’t be blamed for their absence in certain areas, he said.

If the species doesn’t occupy a waterway, that’s likely because the habitat is unsuitable, Watson said.

It’d make more sense to focus on improving those conditions than on banning trapping in impaired waterways on public land, he said.

“Beavers are in every single place the habitat is there. It’s not the trapper, it’s the habitat,” Watson said.