Stop 3: Prisoner's Harbor Tour

Part of the historic eucalyptus grove in Prisoner's Harbor is visible near the pier.

Tim Hauf, timhaufphotography.com

Return of the Natives
The over 100-year-old blue gum eucalyptus grove in the Prisoner's Harbor area was one of many groves that were planted throughout the island during the ranching era for use as windbreaks, fuel, and wharf piles. Many other nonnative plants that reached the islands during the ranching period, however, are not as benign.

What was once an island covered with coastal sage-scrub, chaparral, oak scrub, oak woodland, and native grasslands (both annuals and perennial) has given way to nonnative, European grazing grasses and an assortment of weeds, including oats, bromes, fox-tails, thistles, mustard, and fennel. Today, nearly 25 percent of the plant species found on eastern Santa Cruz Island are introduced, providing approximately 75 percent of the ground cover.

Native plants that developed in isolation often are vulnerable to competition from introduced or alien species. Many of these alien plants have evolved with grazing pressure, whereas the native island plants have not co-existed with grazers or browsers on the islands since the pygmy mammoths, nearly 12,000 years ago. With sheep, cattle, horses, and pigs grazing and browsing on the native vegetation and disturbing the soil, the alien plants spread rapidly, competing with the natives for limited soil and moisture. The nonnatives eventually overwhelm the natives, which often have longer germination and growth cycles.

The restoration of the island's native vegetation is the goal of the National Park Service. Special focus is being placed on the plants that are endemic to the islands, those occurring only on the Channel Islands and nowhere else in the world. Eight of these occur only on Santa Cruz Island. Nine of these endemic plants are listed as endangered species. To ensure the survival of these unique species and encourage the recovery of the island's native vegetation, the National Park Service, along with The Nature Conservancy, is working towards the removal of nonnative species. Over 9,000 sheep were removed from the eastern 6,200 acres of Santa Cruz Island between 1997 and 1999 (Sheep were eliminated by The Nature Conservancy from the rest of the island by the late 1980s.) Pigs were removed from the island by 2007 and weed control is currently underway.

In 2011, work began here at Prisoner's Harbor to restore the largest coastal wetland on the Channel Islands. Island ranchers reduced this wetland habitat by more than 50 percent when they filled it with gravel, rerouted and channelized the creek, and planted eucalyptus and other nonnative trees and plants. Restoring the westland included excavating thousands of cubic yards of fill and reshaping the landscape to allow the wetland to flood naturally. In addition, nonnative trees and plants were removed and replaced with native vegetation. Learn more about this wetland restoration project on page 55 and by visiting the signs around the wetland area.

One needs only to look at the recovery of vegetation, reduction of erosion, and the condition of archeological sites on San Miguel Island since the removal of sheep in the 1950s to envision what may eventually occur on all of Santa Cruz Island. Described as a "barren lump of sand" in the 1930s, San Miguel Island has undergone a remarkable recovery and now is densely vegetated with a diverse assemblage of native plants. In fifty years, we hope to write about the remarkable recovery and return of the native plants of Santa Cruz Island.

Wetland Restoration
Coastal wetlands in California are increasingly rare-over 90 percent have been eliminated. Prior to alterations in the late 1800s, the Prisoner's Harbor wetland was the largest wetland on the Channel Islands and provided a variety of habitats (open water, marsh, riparian, and woodland) for native plants and wildlife.

Ranchers reduced this wetland habitat by more than 50 percent when they filled it with gravel, rerouted and channelized the creek, and planted eucalyptus and other nonnative trees and plants.
The process of reviving the wetland's natural function and ecology on nearly 50 acres of land began in 2011. Thousands of cubic yards of fill were excavated and the landscape was reshaped to allow the wetland to flood naturally. In addition, nonnative trees and plants were removed and replaced with native vegetation.

The return of the wetland not only increases the diversity and abundance of plants and animals, it also helps protect archeological resources and historic structures from erosion and flooding and provides visitors the opportunity to experience, enjoy, and learn about a natural wetland ecosystem.

More Restoration Information
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 60 of these endemic species. Some, like the island 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 nonnative plants and animals has caused their extinction along with eight other rare and unique island species. Once found only on the Channel Islands, they have been lost forever.

To save 10 other island species, including the island fox, from the brink of extinction as well as to protect more than 2,000 significant archeological sites, the National Park Service and The Nature Conservancy embarked upon a multi-year program to restore Santa Cruz Island. This restoration program is part of the National Park Service 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. As owner of over 70 percent of Santa Cruz Island, it is the mission of The Nature Conservancy to preserve the plants and animals that represent the diversity of life on Earth by protecting the land and waters they need to survive.

The National Park Service, The Nature Conservancy, and natural and cultural resource experts identified nonnative feral pigs as the most significant disturbance to the island's sensitive resources. Pigs cause major direct impacts to native plant communities, rare plant species, and archeological sites.

Pig rooting caused massive destruction of native species and resulted in bare ground that was easily eroded and colonized by invasive weeds, especially fennel. This activity was 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 also damaged a large number of archeological sites on the island that are associated with the Chumash native people who occupied the island from at least 9,000 years ago until the early 1800s. The feral pigs rooted three feet deep at a number of sites, disturbing these sacred sites and destroying their archeological value.

Moreover, feral pigs played a pivotal role in the catastrophic decline of island foxes. Piglets provided a year-round food source for golden eagles, allowing these formerly rare or occasional visitors to expand their range and establish a resident population on the island that then preyed on island foxes. Golden eagle predation placed the fox on the brink of extinction on Santa Cruz, Santa Rosa, and San Miguel Islands.

The consensus among numerous experts was that the eradication of feral pigs was the most important action that could be taken to protect and restore Santa Cruz Island. The National Park Service had success restoring other islands in the park through the removal of nonnative animals. The eradication of European rabbits from Santa Barbara Island and sheep and burros from San Miguel Island resulted in tremendous natural recovery. Feral pigs were also eradicated from Santa Rosa Island in a similar program. Pig eradication began on Santa Cruz Island in 2005 and was completed in 2007.

Other management actions to initiate recovery of the island ecosystem were implemented. Golden eagles were live captured and relocated to northeast California. A captive breeding program for island foxes was established to restore a wild island fox population. The last captive bred island fox was released in 2008. The island fox was delisted as an endangered species in 2016 and has been recognized as one of the quickest and most succesful recoveries of an endangered species. Monitoring of the island fox population continues.

Also, native bald eagles were reestablished on the island. This predator disappeared in the 1950s due to DDT poisoning, hunting, collecting, and intentional poisoning. Bald eagles eat fish, seabirds, and animal carcasses, not live foxes and are very territorial.
In 2006 this program paid off. For the first time in more than 50 years, two bald eagle chicks were hatched unaided from two separate nests on Santa Cruz Island. Today the island is home to over 30 resident bald eagles.

This multi-year program to remove golden eagles, reestablish bald eagles, save island foxes, and eradicate pigs has helped restore the balance to the naturally functioning ecosystem on Santa Cruz Island. Once restored, the island will offer one of the last opportunities to experience the nationally significant natural and cultural heritage of coastal southern California.

Duration:

19 minutes, 32 seconds

Close to the mainland yet worlds apart, Santa Cruz Island is home to plants and animals that are found nowhere else on Earth. The introduction of of non-native, exotic plants and animals have caused the loss of some of these rare species and pushed many others, including the island fox, to the brink of extinction. In order to save these island species, as well as protect sacred Chumash Native American cultural sites, the National Park Service and The Nature Conservancy embarked upon a multi-year program to help restore balance to Santa Cruz Island’s naturally functioning ecosystems. This high-definition video documents the various aspects of this complex restoration program, including the removal of golden eagles, reintroduction of bald eagles, captive breeding island foxes, removal of sheep, and eradication of pigs. The Santa Cruz Island restoration program is part of the National Park Service 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.