Life's vicious cycle: Species eradication in the Channel Islands
California's Channel Islands are fertile ground for a novelist's imagination.
Saturday, March 5, 2011 - 19:58
The Channel Islands, a group of eight islands off the Southern coast of California, have a fascinating history, and are home to some of the richest ecosystems on Earth. So it seems natural that California writer T.C. Boyle would want to build a novel, "When the Killing's Done," around these ecological wonders.
The islands were given National Park status in 1980, and five of them are part of a National Marine Sanctuary. Several non-profit organizations and government agencies monitor conditions on and around the islands, and scientists have been able to learn a great deal about what keeps these complex habitats in balance.
In recent decades, biologists and wildlife specialists have undertaken numerous "ecological interventions" in island habitats, with the intent to protect and support native flora and fauna. A method of intervention chosen repeatedly over the years has been eradication. The term "eradication" makes the process sound rather tidy, but the fact is, it's a mass killing, targeted toward a specific species, and invariably accompanied by some collateral damage.
A brief list of animals previously eradicated in the Channel Islands:
Santa Cruz Island, the largest of the Channel Islands, became overwhelmed by its wild sheep in the 1980s, and scientific studies showed increased bare ground and higher soil erosion rates, decreased herbaceous vegetation, reduction and modification of shrub communities and a decrease in abundance and diversity of birds on the island. Not a good ecological report card. It was determined that the sheep must go, and they did.
Sheep eradication, however, had the unintended effect of unleashing wild fennel, which spread across Santa Cruz Island in the wake of sheep removal. As Jason and Roy Van Driesche write in Conservation Magazine, "... recovery is more often a drawn-out series of mistakes and course corrections than it is a straightforward shift from invaded to native."
Black rat eradication performed in 2001-2002 was intended to prevent the collapse of a native and threatened seabird species, Xantus's Murrelet, on Anacapa Island. A National Park Service (NPS) research summary describes rats as "omnivorous scavengers with voracious appetites," and explains that "rats can severely impact seabird breeding habitats by eliminating burrows." In 1999, government officials came to the grim conclusion that without removal of the rats, it would be impossible to protect and restore seabird populations across Anacapa.
The Fund for Animals and the Channel Islands Animal Protection Association filed a lawsuit to prevent the action, but the suit was dismissed. Anacapa Island has been officially rat-free since mid-2003, and the Xantus population is resurgent.
The NPS states that pigs have "major direct impacts to native plant communities, rare plant species and archaeological sites" on Santa Cruz Island. In addition, other species on the island, both animal and plant, are in decline because of the wild swine. Expert consensus resulted in pig eradication, conducted between 2005 and 2007.
It's possible the pig removal was necessitated by previous sheep eradications. In an article in Science Magazine, wildlife ecologist Bruce Coblentz of Oregon State University speculates that, "Removing sheep might have helped pigs overmultiply by giving them more forage and cover."
Eradication operations have not been limited to these three species. Rabbits, feral cats, burros, horses and cattle have also been targets when when their elimination was deemed necessary in order to stabilize island environments. The questions is, will it ever end?
What this has to do with T.C. Boyle
Reading the New York Times review of "When the Killing's Done" prompted me to learn more about the Channel Islands. In her review, Barbara Kingsolver poses the question, "Who could love a rat?" In Boyle's book the rat lover, a fictional man modeled on a real-life Santa Barbara man, is fervently opposed to the black rat eradication on Anacapa Island. Kingsolver observes, "The fascinating terrain of this novel is the question of how and why people decide to care as they do."
I discovered many things about the Channel Islands when I was researching their history, and was sad to learn of these eradications. I found myself sympathizing with the "threatening" non-native species ... and thinking that I'm probably one of those people who could love a rat.
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