Water and bevers

Researchers Become “Beaver Believers” After Measuring the Impacts of Rewilding

Ecologists and ranchers alike know that rivers and streams with healthy beaver populations support more biodiversity, are more drought resilient, and keep water available on the land for more days of the year. But witnessing the impact of nature’s engineers on a single stream is easier than measuring it across a region, or choosing which of a hundred streams is an ideal site to reintroduce beavers.

Now a NASA-supported effort in Idaho adds remote sensing data to the suite of tools used to predict which streams can support beavers and to monitor how water and vegetation change once they return.

While working on water monitoring for ranchers, scientists Jodi Brandt and Nick Kolarik heard about “beaver fever.” Ranchers had gone from seeing beavers as a nuisance to recruiting them onto their land. Brandt is now an associate professor of human-environment systems at Boise State University, and Nick Kolarik is her Ph.D. student. Brandt leads a team using NASA’s Earth observation data to help quantify how beavers can have an outsized and positive impact on local ecosystems. She works with Wally Macfarlane and Joe Wheaton, both at Utah State University, who developed the Beaver Restoration Assessment Tool (BRAT).

The team is focusing on Idaho and nearby regions because, while wet ecosystems comprise only 5% of the landscape, those areas are critical for more than 90% of species living in the area during the dry season. Brandt’s team collaborates with dozens of local fish and wildlife organizations, watershed managers, land trusts, conservation and restoration NGOs, and individual ranchers.

Adding water and vegetation data from NASA missions to their process addresses two major challenges: how to quantify change over time and how to consistently monitor large areas.

Earth Observations Streamline Results

Sending people out into the field to take measurements is time-intensive, which can be expensive for smaller research teams working in remote sites. It is also limiting because humans can only visit one location at a time, and not necessarily in all seasons.

NASA’s fleet of Earth-observing missions collect data across large areas of the world and pass over the same areas regularly and across seasons. Researchers can observe an area in real time and also look back to previous weeks, months, or even years. In the case of Brandt’s team, the scientists are turning data from Earth science missions like Landsat and Sentinel into information that more people can understand and use.

Cory Mosby of Idaho Fish and Game is excited about how satellite data can expand his crew's ability to the monitor miles of waterways across his state. What they’re looking to establish, he says, is more vegetation. Or, as he puts it, “more green groceries” to support wildlife and livestock.

When spring snow melts in Idaho, if there's no interruption, the water flows straight over the land, down the rivers, and into the ocean. When beaver build dams across streams, they naturally disperse and hold water on the land longer, which supports more plants and creates habitats like ponds and meadows. Mosby said that restored ecosystems provide better places to live for aquatic species—like salmon and trout—and land creatures—like sage grouse and mule deer. The dams also create more fresh drinking water and better grazing land for cattle, and they make the landscape more resilient to fire and drought.

According to Mosby, remote sensing data helps them monitor more areas and quantify those positive changes. “We’re going to see a wider green vein later into the year and we will see more water later in the season."