Save the bunnies, eliminate the swamp rat. How flooding has impacted San Joaquin wildlife.
STANISLAUS COUNTY — Northern California's record-breaking wet season is wiping out some wildlife and allowing others to thrive. The San Joaquin River National Wildlife Refuge (NWR) is home to the endangered riparian brush rabbits and is also where nutria, known as the swamp rat, are emerging.
The refuge is currently closed to the public because of all the flooding. The rising waters are putting riparian brush rabbits at risk, already wiping out about 80% of its population.
CBS13 joined California Representative Josh Harder and U.S. Fish and Wildlife experts on Wednesday to learn more about the keystone species.
"They are not only an important species to prey on for many predators, but they also tunnel in the vegetation and modify the habitat to make it more suitable for other wildlife like other small mammals," said Eric Hopson, the refuge manager at the San Joaquin River NWR.
Hundreds of years ago, the rivers would spread out and the rabbits could spread out as the flooding came. Now, we have levees that confine the rivers.
"When the rabbits want to leave the levee and want to go back out, their only cover is all this flood debris and not the vegetation itself," said Hopson.
As the flooding comes and water rises quickly, rabbits have very few spots to hop to.
One solution is "bunny mounds," a refuge for stranded rabbits on the floodplain, but these bunny mounds cannot support high densities of rabbits for extended duration floods, more than a month. Mounds with high densities of rabbits were trapped and the bunnies relocated to prevent starvation.
"We have been able to rescue 306 through this pretty heroic effort," said Harder.
Fish and Wildlife is going out in kayaks to rescue the rabbits. Not only are the rabbits up against rising waters, but they are facing a respiratory disease known as the Rabbit Hemorrhagic Disease Virus.
This disease has been killing rabbits before this year's floods. Fish and Wildlife said recent years had estimates of 2,000 to 2,800 rabbits. Because of the disease, a December 2022 estimate of the brush rabbits was just over 1,800.
Since January, Fish and Wildlife has saved 306 rabbits from the imminent danger of drowning in the flood. Hopson said they do not currently know how many additional rabbits survived this year's flooding.
Before they release the rabbits into safe locations around the refuge, they vaccinate them for the respiratory disease.
While the floodwaters have not been good for the bunnies, the swamp rats are thriving in these conditions.
"They destroy water infrastructure, they burrow under our canals, they eat trees, they create huge amounts of damage," said Harder.
Fish and Wildlife is starting to use specially trained dogs that can find nutria scat in the water by their scent, to help capture the orange-toothed aquatic rodent.
With extreme heat on the way, Fish and Wildlife is expecting the water to rise soon once again from the snow melt and water releases from reservoirs.
