Riparian Brush Rabbit News

Refuge for One of California's Most Endangered Mammals

This summer, remarkable images were captured on trail cameras at River Partners’ Dos Rios Ranch Preserve in the San Joaquin Valley. Riparian brush rabbits — one of California’s most endangered mammals — have discovered the habitat River Partners built for them, and are making their homes in the restored river landscape.

As testament to the success of our years-long habitat restoration efforts at Dos Rios, this is great news, and a message of hope for endangered species. Over 60% of the cameras we deployed across the site captured images of riparian brush rabbits, indicating that this isn’t just a few individuals but a robust population of animals living entirely within 600 acres of restored riparian forest River Partners has reintroduced at the Preserve.

This habitat did not exist until we planted it in 2014, and it represents almost a doubling of the available habitat for the rabbit within its historic range.  There is no doubt that this is a scale of habitat that is suitable for longevity. The rabbits have ample room to thrive.

These riparian brush rabbits were filmed by a trail camera at Dos Rios ranch.

The rabbits are moving and expanding into new habitats and founding new communities without human intervention. Their autonomy indicates they’re not reliant on us for their survival, so long as the habitat they depend on exists.” — Haley Mirtz, River Partners biologist

Once common along California’s rivers, habitat loss has made the riparian brush rabbit much more vulnerable to survival challenges like predators and major flood events. The great flood of 1997 had such a catastrophic impact on the population that biologists feared the species had gone extinct, but a few animals were found hanging on in remnant habitat near the San Joaquin River. The near-disaster gave biologists a clear picture of the way forward: Help the remaining rabbits establish new populations in restored habitat to increase species resiliency to flooding events.

Today, River Partners is leading the way for the recovery of California’s most endangered mammal. At Dos Rios, a 2,100-acre restoration site at the confluence of the Tuolumne and San Joaquin Rivers, we’ve created vegetated levees and “bunny mounds” that provide refuge for the animals during flood events. The reappearance of rabbits on the site demonstrates that the new habitat is high-quality and capable of supporting a large number of animals.

“This is a result of the effort of so many in a private-public collaboration to protect this species,” says Erin Hagen, Director of Science at River Partners. “Years of work were invested to acquire and restore this land, and it’s amazing to be able to document the intended outcome: riparian brush rabbits established at Dos Rios Ranch.”

 

Header photo: Riparian brush rabbit at the San Joaquin River National Wildlife Refuge. Photo courtesy USFWS Pacific Southwest Region. (CC BY 2.0)

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