Thousands of beavers once populated Southern Arizona’s rivers, with frontiersman James Ohio Pattie dubbing the San Pedro River as “Beaver River.” But the animals were hunted and trapped to extermination in the 1800s and early 1900s. However, in 1999 the Bureau of Land Management released 16 beavers into the San Pedro Riparian National Conservation Area. Since then, the population has ebbed and flowed, with 50 beavers now estimated along the San Pedro. This summer, BLM plans to introduce a new population of beavers to the Cienega Creek Natural Preserve southeast of Tucson with the hopes these keystone species will foster growth in the area.
Ahead of this introduction—and to celebrate International Beaver Day—the local environmental nonprofit Watershed Management Group is hosting a Beavers & Brews Binational Bash. This virtual party on April 7 will feature guest speakers from both sides of the border, including biologists, volunteers and community scientists discussing these introductions. This event is part of WMG’s Release the Beavers campaign, which advocates for beaver introduction and additional releases of beavers into the Santa Cruz and San Pedro international watersheds.
When BLM introduced those original 16 beavers into the San Pedro Riparian National Conservation Area, the population boomed to more than 100 after a decade. However, this was followed by a population crash, with hardly any beavers or dams seen in the area by 2019. There were beavers reported downstream and in Mexico, and in the last year, the population has risen again.
“Lessons from that can be drawn on for this Las Cienegas project,” WMG executive director Lisa Shipek said. “I think the San Pedro release was a success, the population did increase, and looking back we can see how much they disperse throughout the watershed from that original 16.”
Though the population was unstable, the release did lead to beavers spreading throughout the San Pedro watershed and even into the Santa Cruz watershed.
“Bringing back those keystone species that used to be abundant in both these watersheds and having them come in and do the work they do best helps flowing and spreading the water across the floodplain and creating more habitat,” Shipek said.
WMG’s Release the Beavers campaign comprises three goals: advocate for more beaver introduction; monitor the health of these new populations by coordinating an annual survey; and help restore local creeks — and ensure beavers can do the same.
“They’re released in a location that Arizona Game and Fish and BLM feel is appropriate from their habitat studies. And after they’re released, they see if the beavers stay in the area, if they build dams and lodges, or move off to other locations they feel are more suitable. Even if they do end up moving, that’s not necessarily not a success, as long as they can find suitable habitat,” Shipek said. “Essentially we want to help heal the watershed and make it a more suitable habitat for beavers in the future; basically making sure the riparian area is healthy and ensuring it is a place that can flow and infiltrate water into the aquifer.”
Their watershed restoration work includes hosting workshops for volunteers, repairing erosion damage and removing invasive species. The work is part of WMG’s 50-Year Vision to restore Tucson’s “heritage of flowing creeks and rivers.” Since they set this vision in 2013, their River Run Network has worked to conserve water, restore the aquifer and clean local rivers.
“It’s been incredible just to see the shift in thinking if nothing else. There’s so many things that have been happening, just to see the synergy in the area since we’ve put out this vision of restoring our heritage flows. There are so many other great organizations and agencies that are getting behind this vision, such as the Santa Cruz Watershed Collaborative,” Shipek said. “There is a real commitment behind this vision that is seeping into all levels of the community, from the grassroots to agencies.”
Watershed Management Group’s Beavers & Brews Binational Bash starts at 6 p.m. on Wednesday, April 7. The virtual gathering will feature stories from biologists, ecologists, and community scientists working directly with beavers in the San Pedro and Santa Cruz international watersheds. This includes speakers from the Arizona-Sonora Desert Museum, Cochise College and Profauna México.
For more information, visit watershedmg.org/event/beavers-brews-binational-bash