Ecological Balance Benefits Rare Fox At Channel Islands National Park
A story about pigs, foxes, and golden eagles might sound like it was pulled from Aesop's Fables, but at Channel Islands National Park it's one of how ecological balance has rescued one species from possibly vanishing forever.
For were it not for the pigs, which roamed wild on the islands of the national park off the coast of California, the foxes might not have also turned into the eagles' prey.
But today, after a recovery program focused on removing the feral pigs, and the golden eagles, from the six islands, the Island Fox is considered to be on the doorstep of population recovery.
According to the National Park Service, "during a five-year period in the 1990s the island fox populations on the northern Channel Islands declined by over 90 percent due to predation by golden eagles."
Yet today, less than a decade after four of the six island fox subspecies were listed as federally endangered, biologists believe they are on the cusp of meeting the criteria for delisting.
"The decline of the island fox population was so severe it caused biologists to shift from tracking fox populations to worrying about the fate of individual foxes," said Channel Islands National Park Superintendent Russell Galipeau. "We are thrilled with this rapid recovery, which is one of the quickest recoveries of an endangered species in the history of the Endangered Species Act."
At the lowest point, in 1999, there were only 15 foxes each on San Miguel and Santa Rosa Islands-a catastrophic drop in fox numbers from 450 and 1,500 respectively, notes the Park Service. In 2000 there were less than 70 foxes on the largest Channel Island, Santa Cruz, it adds.
Today, though, there are about 1,300 foxes on Santa Cruz Island, 500 on San Miguel Island, and 600 on Santa Rosa Island, with each population having a 90 percent annual survival rate, the park notes.
Saving the Island fox from the brink of extinction was only one facet of a decade-long restoration effort to return balance to the ecosystem on Santa Cruz Island. Between 2000 and 2006, the park said in a release, "44 golden eagles were carefully live-captured and relocated successfully to the eastern Sierra Nevada. Today, they are infrequent visitors due to the absence of feral pigs."
"From 2005 to 2006 over 5,000 nonnative feral pigs were eradicated on Santa Cruz Island. Feral pigs had attracted golden eagles as a new predator to the island, rooted up vegetation including nine endangered native plants, caused massive erosion, spread invasive weeds, and destroyed ancient Chumash archaeological sites," the release continued.
While the golden eagles were removed, bald eagles, which don't prey on the diminutive fox, were returned to the islands.
A five-year program to reestablish bald eagles, which included the release of 60 eaglets from 2002 to 2006, has yielded over 40 resident birds on the northern Channel Islands, the park reports. This year's breeding season there are at least six known active bald eagle nests on the northern Channel Islands.
Recovery of vegetation, resulting from removal of sheep and pigs, also contributed to improving habitat and supporting the recovery of the island fox.
"This recovery is a terrific example of what can happen when people roll up their sleeves to restore an ecosystem," said Dr. Scott Morrison, lead scientist for The Nature Conservancy in California, which collaborated with the Park Service on the fox recovery program. "So many scientists, managers, and partners had a hand in this and are celebrating with us today."
The Nature Conservancy and the National Park Service are continuing their partnership to preserve resources on Santa Cruz Island. In 2011 they began a project to restore what was once the largest coastal wetland on the Channel Islands at Prisoners Harbor on Santa Cruz Island. The project, which extends over nearly 60 acres of land, restores approximately four acres near the shore and nearly one mile of stream habitat in the valley improves habitat for native plants and wildlife such as the Santa Cruz Island fox, island scrub-jay, and migratory waterfowl.
You can watch a restoration film "Restoring Balance-Santa Cruz Island, at this site.