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Close to the mainland yet worlds apart, Santa Cruz Island is home to plants and animals that are found nowhere else on Earth. Like the Galapagos Islands of South America, the Channel Islands exist in isolation, allowing evolution to proceed independently, fostering the development of 145 endemic or unique species. Santa Cruz Island is host to 70 of these endemic species. Some, like the island scrub jay and the Santa Cruz Island silver lotus, are found only on Santa Cruz Island.
Unfortunately, this isolation has also made these species vulnerable to extinction. The melodic song of the Santa Barbara Island song sparrow and the crimson flower of the Santa Cruz Island monkey flower are no longer heard or seen within the park. The destruction of these species’ habitats by non-native, exotic plants and animals have caused their extinction along with eight other rare and unique island species. Once found only on the Channel Islands, they have been lost forever.
In order to save 10 other island species, including the island fox, from the brink of extinction as well as protect 3,000 internationally significant archeological sites, the National Park Service (NPS) and The Nature Conservancy (TNC) have embarked upon a multi-year program to restore Santa Cruz Island. This restoration program is part of the NPS mission, as mandated by Congress, to preserve unimpaired the natural and cultural resources and values of the national park system for the enjoyment, education, and inspiration of this and future generations.
The Problem
The NPS, TNC, and natural and cultural resource experts have identified non-native feral pigs and non-native fennel (an invasive weed) as the most significant disturbances to the island’s sensitive resources. Both pigs and fennel cause major impacts to native plant communities, rare plant species, and archeological sites.
Pig rooting causes massive destruction of native species, resulting in bare ground that is easily eroded and colonized by invasive weeds, especially fennel. This activity has been a factor in the decline of nine island plant species listed as threatened or endangered by the U.S. Fish and Wildlife Service.
Pig rooting has also damaged a large number of archeological sites on the island that are associated with the Chumash Native Amercian people who occupied the island from at least 9,000 years ago until the early 1800s. Rooting to a depth of three feet has been noted in a number of sites, completely disturbing and desecrating these sacred sites and destroying their archeological value.
In addition, feral pigs have played a pivotal role in the catastrophic decline of island foxes. Piglets provide a year-round food source for golden eagles, allowing these former rare or occasional visitors to expand their range and establish resident populations on the island and prey on island foxes. Golden eagle predation has placed the fox on the brink of extinction on Santa Cruz, Santa Rosa, and San Miguel Islands.
The Solution
Scientists agree that the eradication of feral pigs is the most important action that can be taken to protect and restore Santa Cruz Island. The National Park Service has had tremendous success restoring other islands in the park through the removal of non-native animals. The eradication of European rabbits from Santa Barbara Island and sheep and burros from San Miguel Island has resulted in tremendous natural recovery. Feral pigs have also been eradicated from Santa Rosa Island in a similar program.
Wildlife experts advise that pigs can be eradicated from Santa Cruz Island if we act aggressively and persistently. Island vegetation is responding rapidly to the removal of feral sheep, completed on western Santa Cruz Island by the The Nature Conservancy in 1980s and on the eastern portion of the island by the National Park Service in 1999. However, significant resources may be lost if the pigs are not removed from the island as soon as possible. Therefore, pig eradication along with control of dense stands of fennel began in 2004.
Other management actions to initiate recovery of the island ecosystem have already begun. Golden eagles are being captured and relocated to northeast California. A captive breeding program for island foxes has been established as insurance against losses due to golden eagles. Also, native bald eagles are being reintroduced. This predator disappeared in the 1950s due to DDT poisoning. Bald eagles eat fish, seabirds, and animal carcasses, not live foxes, and are very territorial. It is hoped that once they mature, they will establish territories and drive off any newly arriving golden eagles. In 2006, for the first time in more than 50 years, two bald eagle chicks were hatched unaided from two separate nests on Santa Cruz Island.
This multi-year program to remove golden eagles, reintroduce bald eagles, breed island foxes, eradicate pigs, and control fennel will help restore the balance to Santa Cruz Island’s naturally functioning ecosystem. Once restored, the island will offer one of the last opportunities to experience the nationally significant natural and cultural heritage of coastal southern California.
For more information please visit the Santa Cruz Island Primary Restoration Plan.
