Preserving Channel Islands

Natural areas, such as Channel Islands National Park, play an important role in indicating when critical changes are happening on the earth, our life support system. Parks can play the role of "the canary in the mine." Just as the miner's canary alerted mine workers to poison gases in a shaft, natural areas can alert us to biological, chemical, and environmental changes that will affect our quality of life and the survival of species.

The Channel Islands played a role in two events in 1969 that galvanized our nation to take seriously the growing warning signs of our deteriorating environment. In January 1969, an environmental disaster occurred in the Santa Barbara Channel. An offshore oil platform suffered a blowout. 200,000 gallons of crude oil escaped into the ocean over a period of eleven days. The oil created an 800-square- mile slick that impacted all of the northern Channel Islands and nearby mainland beaches. Thousands of seabirds and marine mammals died.

At the same time, scientists were becoming aware of a serious decline in the breeding success of California brown pelicans. Adult brown pelicans appeared to still be numerous, providing a deceptive façade that things were all right. However, when the scientists looked more closely, they realized with horror that the pelicans were unable to nest successfully because the eggshells were too thin to withstand incubation and thus were crushed in the  nest. For several years, the pelicans suffered nearly total reproductive failure. In 1970, only one chick was successfully raised on Anacapa Island, an island that had historically been the largest breeding colony for California brown pelicans on the west coast of the U.S.

The cause of the failed pelican breeding was DDT, an organochlorine pesticide. In the late 1960s and early 1970s the mean eggshell thickness was found to be approximately 50% thinner than normal. High levels of DDT residues were correlated with the eggshell thinning--the higher the DDT levels the thinner the eggshells. Later analysis of museum eggshells collected before 1943 and the notes of biologists showed that the eggshells of California brown pelicans were substantially thinner by 1962. Also, a long-term decline of brown pelicans had started along the California coast as early as the mid-1950s. DDT similarly affected bald eagles and peregrine falcons. However, because there was no standardized biological monitoring of pelicans (or any other wildlife), the problem wasn't identified until the populations had nearly collapsed.

Pollutants have hit other species hard on the Channel Islands. Bald eagles were once an important component of the island ecosystem. It is estimated that at least twenty nesting pairs of bald eagles occurred on the park islands in the early 1900s. Hunting, egg collection, and DDT all took their toll and resulted in the total elimination of bald eagles by the 1950s. 

Fortunately, the American public and government reacted strongly to the loss of wildlife and the growing pollution of the environment. Many consider the publicity surrounding the Santa Barbara oil spill and the fate of the California brown pelican a major impetus to the environmental movement. Just one year later, in the spring of 1970, Earth Day was born.

Fire Regime

There is relatively less fire on the Channel Islands than on the mainland because ignition sources are much less common there and the foggy maritime climate generally limits fire spread. Although similar plant communities on the mainland experience regular fire, fire on the islands would have been much less frequent during the evolutionary history of island plant communities until evidence of human occupation on Channel Islands that extends back some 13,000 years. Several island taxa have relaxed fire-adapted traits such as serotiny and seed germination characteristics.

Sediment cores from Santa Cruz and Santa Rosa Island were used to evaluate historic fire occurrence on the islands. Cores from an upland site on Santa Rosa (Soledad Pond) showed that fire occurred throughout the 12,000 years of the sediment record with large scale, major fire events occurring with a minimum frequency of between 1 event/1000 years and 4.5 events/1000 years. A second coastal site on Santa Rosa Island (Abalone Rocks) yielded estimates of large-scale fire events ranging from 5.5 to more than 9 events/1000years. Records from both Santa Cruz and Santa Rosa show that fire frequencies increased over the last 5000 years and reached their peaks during the historic period, approximately the last 200 years. Although it seems logical that the increase in fire activity could be attributed to Native American burning, the data could not distinguish between climatic or anthropogenic causes. Whatever the source of the fires represented in the charcoal record was, the historic fire return intervals on the Channel Islands are significantly longer than estimates of modern fire return intervals in mainland shrubland communities.

Wildlife Studies

California's Channel Islands are often called "the Galapagos Islands of North America" due to their unique and diverse array of plants and animals, 145 of which are found nowhere else on earth. It is highly unusual to have such an assemblage of "one of a kind" species located in such a small area, a product of evolution in isolation on the islands. Unfortunately this isolation has also made some of these species vulnerable.

One of these is the diminutive island fox. Feral pigs have played a pivotal role in the catastrophic decline of island foxes. Formerly rare or occasional visitors, golden eagles have taken up residence on the islands, sustained by the year-round supply of piglets. Golden eagles predation has placed the island fox on the brink of extinction. Feral pigs also destroy native vegetation, cause widespread erosion, threaten rare plants, and disturb archeological sites.

Restoring Anacapa Island

Anacapa Island provides critically important habitat for seabirds, pinnipeds, and endemic plants and animals. The island's steep, lava rock cliffs have numerous caves and crevices that are particularly important for the increasingly rare seabird species, Xantus's murrelet and ashy storm-petrel. The largest breeding colony of the California brown pelican in the United States is Anacapa Island and a unique subspecies of deer mouse occurs only here as well.

The Anacapa ecosystem, however, has been degraded by the presence of non-native black rats (Rattus rattus). Rats have been introduced to over 80% of the world's islands, accounting for an estimated 40-60% of all bird and reptile extinctions in the world. On Anacapa, rats were introduced prior to 1940, most likely as stowaways on ships to the island. They have had large impacts on nesting seabirds, preying heavily on eggs and chicks of seabirds as their food source. Approximately 40% of Xantus's Murrelet nests on Anacapa have shown evidence of egg predation. Rats also prey directly on the native island deer mouse.

In the mid-1990s, the park teamed with the Island Conservation and Ecology Group (ICEG) to determine if and how rats could be eradicated from Anacapa Island. ICEG, active internationally in the restoration of island ecosystems through the eradication of non-native species, was aware of several successful eradications of rats from islands, particularly in New Zealand. Rats have been eradicated on over 100 islands worldwide by applying rodenticide bait; trapping alone has never succeeded.

Anacapa Island presented special challenges. The island has extensive steep cliffs, making placement of bait into the territory of every rat difficult. The endemic deer mice would feed on any bait that was attractive to rats. The endangered California brown pelican, extremely sensitive to disturbance, breed and nest on a large portion of the island during eight months of the year.

Following extensive consultation with experts, the park and ICEG determined that rats could be eradicated through the distribution of bait pellets with brodifacoum, the anticoagulant used in the majority of successful rat eradications. This product contains half the amount of rodenticide that is found in products that homeowners commonly purchase in the local grocery store and it would not accumulate in the environment since it breaks down into harmless carbon dioxide in water.

Fortuitously, the American Trader Trustee Council (ATTC), consisting of California Department of Fish & Game, National Oceanic and Atmospheric Administration, and the U.S. Fish & Wildlife Service, had court settlement monies resulting from an oil spill in southern California. The purpose, in part, of the settlement monies was to restore seabird populations injured by the oil spill. The trustees supported eradication of the black rat from Anacapa Island because it is one of the most significant islands for breeding seabirds in southern California.

The bait application (from a hopper suspended under a helicopter) was scheduled during the fall, the end of the dry season, when rats were very hungry and both visitation and bird populations were low. Protection of the native deer mice had two components: a) holding a small population of mice in captivity, and b) maintaining deer mice in the wild by treating East Anacapa one year prior to treating Middle and West Anacapa.

Phase I, application of bait to East Anacapa Island, was completed in December 2001 and Phase II, treatment of Middle and West Anacapa, was completed in fall 2002. Extensive ecological monitoring pre- and post-rat eradication was conducted to determine the environmental impacts of the project. This monitoring has found substantial recovery of rare seabirds and other native wildlife on Anacapa Island following the eradication of rats. Mouse populations have returned to normal and they are breeding abundantly in the wild, while juvenile side-blotched lizards and slender salamanders are thriving in the absence of rats.

Scientists have recorded a dramatic and positive response by Xantus's murrelets, a rare seabird that nests on the island. Thomas Hamer, of Hamer Environmental, reports, "We have detected increases in the number of birds visiting nesting colonies ranging from 58% to more than two times higher when compared to the number of detections that we recorded per night in any of the previous years." Nest surveys by researchers from Humboldt State University have found 14 murrelet nests, including the first documented on Cat Rock since 1927.

Channel Islands National Park Superintendent Russell Galipeau, comments, "This project was critical to protecting and restoring the rare and unique wildlife on Anacapa. The National Park Service is dedicated to ensuring a diverse, naturally functioning island ecosystem."

Numerous environmental groups endorsed the project including the American Bird Conservancy, Pacific Seabird Group, California Audubon Society, Endangered Species Recovery Council, Audubon Living Oceans, and Jean-Michel Cousteau's Ocean Futures. American Bird Conservancy President, George H. Fenwick, stated, "The Anacapa Island project is precisely the type of well-designed, extensively researched, and responsibly implemented program that the American Bird Conservancy supports and encourages. The long-term benefits of rat eradication on Anacapa Island are enormous for the conservation of one of North America's most distinctive ecosystems."

Restoring Santa Cruz Island

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 American 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.

Assessment of Coastal Water Resources Watershed Conditions

This report is a cooperative effort between the Marine Science Institute, University of California Santa Barbara, and the National Park Service, and provides a summary of the current status of aquatic resources (freshwater and marine) at Channel Islands National Park. The purpose of this report was to examine existing information pertaining to water quality, the condition of aquatic habitats and their biota, sources of point and non-point pollution in the region, avenues of transport of pollutants to Park waters, and threats to aquatic resources stemming from consumptive and non-consumptive uses of Park habitat. In addition, the report identifies current information gaps and makes recommendations for addressing them.

Note: This document requires Adobe Reader (http://www.adobe.com/products/acrobat/readstep2.html) to view and is separated for easier downloads on slow connections.

Cover Page and Executive Summary (PDF, 240 Kb) 

Park Description (PDF, 1.5 Mb) (http://www.nps.gov/chis/parkmgmt/upload/Title%20and%20Exec%20Sum%20FINAL...)

Assessment of Water Quality (PDF, 2 Mb) (http://www.nps.gov/chis/parkmgmt/upload/II.%20Assessent%20of%20Water%20Q...)

Other Concerns (PDF, 845 Kb)  (http://www.nps.gov/chis/parkmgmt/upload/III.%20Other%20concerns%20FINAL_...)

References and Appendices (PDF, 727 Kb) (http://www.nps.gov/chis/parkmgmt/upload/References%20and%20Apendicies%20...)

Full-sized Document (PDF, 5Mb) (http://www.nps.gov/chis/parkmgmt/upload/FINAL_CHIS_REPORT.pdf)