In the face of climate change, beavers are engineering a resistance
The study is largely a summary of existing research, pulling together and contextualizing established science about rivers and beavers. It makes the case that beavers were once pivotal in shaping and maintaining healthy riverscapes before their populations were crippled by years of trapping.
Chris Jordan, an Oregon-based ecologist with the Northwest Fisheries Science Center, is one of the study’s co-authors. He said the research stands in the face of “dire warnings” and the “doom” of harm beyond our control.
“In reality,” he said, “it’s not out of our control. Here is something that we can do. Here is something that we can think about as an adaptation and mitigation strategy – returning riverscapes to their natural state. And that’s going to give us climate change protection and resilience.”
That protection and resilience comes in a few forms. The first is a safeguard against flooding. Warming temperatures are increasing the frequency of heavy rain and rapidly melting snow. In the channel of a narrow stream or river, that surge of water is likely to quickly overtop the banks and flood. Beaver wetlands, with their wide swaths of soggy land, would help spread some of that water out and limit flooding downstream.
Just as they are helpful in the face of too much water, beaver complexes have proven useful in areas with not enough. High-mountain snow serves as a kind of natural reservoir for the region, slowly releasing water throughout the spring and early summer, assuring a steady supply to the places where humans divert and collect it. But as the West rapidly warms and dries, snowpack is getting smaller and melting earlier. Beavers, meanwhile, are essentially building miniature reservoirs in mountainous areas throughout the region.
Drought also means an increased risk of wildfires, and beavers have proven their mettle against the flames. Even in areas completely ravaged by wildfire, where tree trunks are scorched into blackened toothpicks and soil is left gray and ashen, beaver complexes survive unscathed. The wet earth and thriving greenery resist burning, leaving oases of green in the middle of the lifeless moonscapes left behind by wildfire.
Spreading water out across valley floors also has proven benefits for water temperature, water quality and even carbon sequestration. Water laden with sediment, nitrates or carbon slows down in beaver ponds, allowing particles in it to settle or get consumed by microbes, unlike in a fast-moving stream.
Rivers are fundamental landscape components that provide vital ecosystem services, including drinking water supplies, habitat, biodiversity, and attenuation of downstream fluxes of water, sediment, organic carbon, and nutrients. Extensive research has been devoted to quantifying and predicting river characteristics such as stream flow, sediment transport, and channel morphology and stability. However, scientists and society more broadly are often unaware of the long-standing effects of human activities on contemporary river ecosystems, particularly when those activities ceased long ago, and thus, the legacies of humans on rivers have been inadequately acknowledged and addressed
episode. An episode where honest to God Lassie invents the very first BDA – and now I’m thinking – goodness what else is out there that we don’t know about?
