Sea Otters are Saving California Marshlands
The return of these furry predators has put the brakes on the damage to the landscape
California’s collapsing marshlands are being saved in the nick of time as a familiar face has returned to their midst. Sea otter populations once stretched from California to Alaska, even stretching into Russia and Japan, but the fur trade in the 19th century decimated their numbers. At one point, only around 2,000 individuals remained, and were mostly in Alaska. Thankfully, hunting bans and habitat restoration have allowed sea otters to flourish once again further south. A combination of fewer threats and the Monterey Bay Aquarium’s programme for raising and releasing sea otter orphans has helped them thrive, and they are beginning to recover their former range.
But how does this help the marshlands? Historically, sea otters have played a vital role as key predators on the landscape, and one of their favourite foods is the striped shore crab. This crab is known for digging burrows in the marsh banks and eating away at the roots of the marsh grass pickleweed, which holds the dirt in place. Left unchecked, they have been weakening the banks to such an extent that they collapse upon impact of big waves and storms. This has created erosion that far exceeds natural levels, but the return of the otters has slowed this down considerably.
This isn’t the first time the return of a top predator has helped balance an ecosystem, or indeed the first time sea otters themselves have done so. In a separate study, it has been shown that sea otters help kelp forests regrow by controlling sea urchins, who would devastate the landscape otherwise. Similarly, the story of the reintroduction of wolves to Yellowstone National Park is a famous example of a rewilding success story, but sadly one that is now under threat. It is hoped that efforts from environmental activists will help the wolves survive.
Comments