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Why Beavers are Worth a Dam!

Beavers are a keystone species, playing a critical role in biodiversity and providing direct benefits to surrounding ecosystems as well as fish, wildlife and people. Dams created by beavers create wetlands that help decrease the effects of damaging floods, recharge drinking water aquifers, protect watersheds from droughts, decrease erosion, stabilize stream banks, remove toxic pollutants from surface and ground water and many threatened and endangered species rely on the wetland habitat created by beavers. They also produce food for fish and other animals, increase habitat and cold water pools that benefit salmon, repair damaged stream channels and watersheds, preserve open space, and maintain stable stream flows.

Over the last century, beaver populations in North America have declined from over 60 million to as few as 6 million, just 10 percent of their historic size. However, there are no current population assessments of beavers in California, and their population numbers and distribution are not monitored in the state. Beavers have struggled due to the one-two punch of population decimation and habitat loss. Historically, beaver populations declined due to aggressive hunting of their soft silky fur and castor glands, which were used for trade and to be converted into medicine and perfume, and because beavers’ tree harvesting and waterway flooding affect urban and agricultural land uses, but now the primary threat to beavers is habitat destruction and degradation. Human development has resulted in serious impairments to watersheds that beavers depend on.

Consequently, incised stream channels, altered streamflow regimes, and degraded riparian vegetation limit the potential for beaver re-establishment. For these reasons, preventing further habitat degradation and restoring degraded habitats are key to protecting and restoring beaver populations.

Ecosystem Engineers

Beavers are unique because they can create or modify their habitat by building dams and lodges, therefore, reestablishing beavers may help to restore degraded systems. Relocating beavers is effective to restore extirpated populations, expand current ranges, and bolster low population numbers. The beaver itself is one of the major sources for wetland development in the United States, and since 3 out of 10 endangered animals in the United States rely on wetlands, beaver restoration should be a priority.

California has lost more wetlands than any other state. Agricultural and urban uses have altered our rivers by diking, levying, channeling, and canalizing waterways that were once extensively braided river systems. For example, in the Sacramento / San Joaquin Rivers only 7% of historic floodplain area and 9% of stream length remains. It’s time to rebuild those wetlands with a little help from our furry friends.

Beavers are a cost effective and sustainable wetland habitat restoration tool overflowing with water conservation benefits of surface water storage and groundwater recharge. The ecosystem services that beavers provide cannot be replicated by humans and the benefits they provide are irreplaceable.

Beavers Need Help

While the North Coast Region has a beaver deficit, every year hundreds of beavers are killed in California’s Central Valley by Wildlife Services, a federal agency tasked with (lethal) “removal” of “problem” or “nuisance” animals because landowners view them as a pest. The Department of Fish and Wildlife also issues depredation permits for landowners to trap and kill nuisance beavers on their property.

Instead of trapping and killing beavers that are unwanted in other regions, it is imperative that a relocation program is created, so that beavers can be relocated to North Coast rivers and other places to help restore streams and wetlands. Beaver reintroduction is a sustainable cost-effective strategy, but we need to work with stakeholders to navigate the political, regulatory and biological frameworks to safely restore their populations.


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