Catalina Island: Island ecology and restoration

Catalina Island is dear to my heart because of several childhood vacations there.  It was thrilling to return after 60 years and find it unchanged from my memories.  Avalon, the small town of about 3,500 people, is still a quaint collection of little wooden shacks, painted bright colors.  But as an adult, my recent visit to Catalina was broader and encompassed the entire island, which was unknown to me as a child.  That broader perspective on Catalina is my focus today. (1)

Avalon Harbor, Catalina Island. Creative Commons

Catalina is one of the Channel Islands off the coast of Southern California.  It rose from the ocean about 5 million years ago as the result of geologic processes lifting the ocean floor as tectonic plates collided.  Like other oceanic islands (as opposed to those that broke off from continents), it was composed of barren rock for thousands of years.  It took thousands of years to build soil needed to support plants.  Then it took thousands of years to establish plants from the seeds blown in the wind from the mainland, brought by birds in their stomachs or adhered to their feathers and feet, or brought by waves carrying plants in storms.  When plants gained a foothold, the island was able to support insects brought by wind and waves.

The process of populating Catalina with plants and animals accelerated with the arrival of American Indians about 10,000 years ago.  Foxes were probably brought to Catalina by the Indians and oaks probably arrived as acorns brought by the Indians.  Archaeological remains of Indian settlements indicate that there were as many as 2,500 Indians living on Catalina, using only the food and materials available on the island or the surrounding ocean.

Most of the plant and animal life on Catalina came from the mainland of California, only 22 miles away from the island.  When plants and animals evolve in isolation from their ancestors, their gene pools gradually drift apart and are eventually distinct species.  That’s why there are about 60 plant and animal species on Catalina that are endemic, meaning that they exist only on Catalina.  This process of diverging evolution from mainland ancestors to unique island species is typical of all island ecosystems.

Europeans arrive on Catalina

Catalina was visited by Spanish explorers for the first time in 1542 and again in 1602.  Although their visit was brief, it was fatal because they brought diseases to which Europeans were immune and the Indians were not.  Most of the Indians on the island were killed by those diseases, a scenario that played out all over the New World in the 16th and 17th centuries.

Europeans tried to establish communities on the island in the 19th century, but their economic ventures were not successful.  They brought sheep, cattle and goats.  But there wasn’t sufficient forage for their herds and supplementing their diets by growing hay wasn’t economically viable.  They tried mining, but found little of value.  They introduced animals for hunting, such as mule deer and pigs.

Towards the end of the 19th century, Europeans made their first attempt to turn the island into a tourist destination.  The first effort ended when the entire town of Avalon burned in a fire in 1915.  That fire set the stage for the final chapter in the development of the island.  William Wrigley Jr. was able to purchase the entire island in 1919 in the “fire sale” that resulted in a bargain price.

The Wrigley Era on Catalina

William Wrigley Jr. made his fortune manufacturing and selling chewing gum.  He had the means to indulge his passion for the island, which he envisioned as a recreational paradise.  He built a magnificent Art Deco casino in Avalon that opened in 1929 and turned the town of Avalon into a famous destination that attracted celebrities as well as one million visitors each year, arriving on the huge steamers Wrigley built to bring them to Catalina.

Bison on Catalina Island. Creative Commons

Many movies were made on Catalina and movie stars were frequent visitors to the island.  One of the movies brought bison to the island to feature in their western themed story.  The bison herd grew and eventually became another challenge to the survival of vegetation on the island.

The conservancy era on Catalina

When William Wrigley died, his heirs changed the direction of the island’s development.  The island could have continued to grow into a tourist destination, but in 1972 Wrigley’s heirs decided that nearly 90% of the island would be turned into a nature reserve.  The Catalina Island Conservancy was born.  Access and development on conservancy land is restricted.

Catalina Island Conservancy land.

The conservancy has made big investments in restoring the island’s ecosystems and protecting endemic plant and animal species.  Sheep and cattle were removed, which wasn’t difficult because those enterprises had largely failed.  Feral pigs and goats were much harder to round up and were killed by hired sharp shooters.  The extermination of the pigs and goats was as controversial on Catalina as it has been on other Channel Islands.  A decade later, “with the quality of the island habitat rebounding and increased ecotourism revenue being realized by island businesses, the bitterness surrounding the pig and goat eradication is subsiding.  Conservation, contrary to popular belief, is not one long group hug.  This stuff can be hard.”  (1) Indeed, “restorations” in the San Francisco Bay Area have caused one pitched battle after another for over 20 years.  They might have been less heated battles if all opinions had been treated with equal respect, as they seem to have been on Catalina Island.

The population of mule deer is being controlled with hunting licenses.  Most of the herd of 600 bison was given to an Indian reservation in South Dakota.  The remaining herd of 150 is being controlled by a contraception program.  Maintaining the small bison herd is considered a concession to their popularity with residents and tourists on the island.

Island fox. Catalina Island fox is a sub-species of the Island fox on other Channel Islands. USFWS

The Catalina Island Fox, an endemic species, was nearly wiped out by distemper virus introduced by a castaway raccoon.  Fortunately, conservancy staff figured out why the population dwindled to only 100 foxes in time to save the foxes from extinction.  A captive breeding and vaccination program returned the fox population to over 1,500 animals in 2011.  A captive breeding program for the island’s bald eagles has also restored their population.

Invasive species

Like most restorations, the Catalina Island Conservancy is concerned about invasive species.  However, their approach to controlling non-native plants is less extreme than many similar projects.  They consider a species of broom (Genista linifolia) their highest priority for eradication.  Although they have tried and will continue trying to control it they acknowledge that it may not be possible.

Genista linifolia is native to the Canary Islands.  It was introduced to Catalina over 100 years ago when it was used to landscape the Saint Catherine Hotel when it was originally built in 1900.  The conservancy launched the Avalon Grasses Initiative in 2016 to prevent similar introductions of grasses that have a high potential to spread on the wind—such as pampas and fountain grass–from gardens in Avalon to conservancy wildlands.  Conservancy staff quietly patrol the gardens in Avalon, looking for these exotic grasses.  When they find them they approach the property owner with their proposal to remove them and replace them with native plants.  The 20 property owners who have agreed to this proposal express satisfaction with the substitution.  This strategy seems to treat the property owners with respect. (2)

Over 200 species of non-native plants live on the island, but the conservancy considers only 35 of the species a problem.  They describe their approach to non-native plants:

“The Catalina Island Conservancy has developed a thoughtful and comprehensive set of strategies for dealing with invasive plants.  First, they realized that not all introduced plants are invasive and some are less likely to outcompete native species.  Those considered invasive were ranked according to the magnitude of the problems they present, including how widespread they are, how fast they can spread and how damaging to the local native species they are.  On the basis of this information, each highly ranked invasive species is being treated with the purpose of reducing its impact on the native communities, reducing its spread or eliminating the threat.” (1)

They acknowledge that “topical chemical treatments” are one of the methods they use to control plants they consider invasive, but details of their pesticide use are not available to me.  The conservancy is a private entity that is not subject to public record laws.

My eucalyptus litmus test

Catalina Ironwood is one of few species of native trees on the Island. It is an endemic species, like most of the native trees on the island.

There are few species of native trees on Catalina Island and their population on the island is also very small.  Therefore, most trees on the island were introduced.  Eucalyptus (mostly Red River gum and blue gum) were introduced to the island in the 1920s by the Wrigley family for a variety of reasons:  aesthetic, shade, wind break, erosion control of road cuts, etc.  Eucalypts are still there and they are the predominant tree species on the island.  Eucalyptus is found throughout the island, including the town of Avalon and several places on conservancy land, where they were planted.


The bark of Catalina ironwood is shredded, similar to the peeling bark of Blue Gum eucalyptus

The conservancy does not plan to eradicate eucalyptus on the island:  “The eucalyptus trees…are non-native, but are not highly invasive. Because of their non-invasive growth pattern and their place in the cultural heritage of the Island, they are not targeted for replacement, except when they die of natural causes.” (3)

The myth that eucalypts are highly flammable that is used as an excuse to eradicate them in Northern California is not heard on Catalina Island.  An enormous wildfire torched about 10% of the island in 2007.  The fire started on conservancy land and spread to the outskirts of Avalon where it was finally extinguished after destroying several homes.  The town was evacuated and its residents stood on the beach front watching the fire approach their homes.  The eucalyptus trees that surround Avalon did not burn.  In the conservancy description of the fire, no mention is made of eucalyptus.  Although the fire was started by unsafe use of mechanized equipment, the conservancy describes fire as a natural and beneficial feature of the chaparral ecosystem of the island.

A street in Avalon is named “Eucalyptus Street.” In the background are some of the eucalypts that surround the town of Avalon.

A restoration that makes sense

I have been studying native plant restorations for over 20 years.  I have finally found on Catalina a restoration that makes some sense to me.  The restoration on Catalina Island has been more constructive than it is destructive.  It has killed less and preserved more.  It preserves eucalyptus because they aren’t doing any harm.  It does not fabricate a cover story to justify killing eucalypts just because they aren’t native. 

The conservancy also acknowledges that difficult choices must be made and that differing opinions must be respected.  Recreational interests and aesthetic preferences are not always consistent with the goals of conservation.  The conservancy preserves bison because people like to see them, despite the fact that they are not native to the island. Competing interests must be balanced if the restoration is to be supported by residents of the island:  “We have realized that people are an intrinsic part of the nature of the island—an influential and fundamental component of the conservation effort.”  (1)

Most of this article comes from this book (1) which was written by the leadership of the Catalina Island Conservancy:

  1. Frank Hein & Carlos de la Rosa, Wild Catalina Island: Natural Secrets and Ecological Triumphs, Natural History Press, 2013
  2. “Protecting Catalina’s Wildlands from Invasive Plants,” Catalina Island Conservancy Times, Fall 2017
  3. Catalina Island Conservancy website:

7 thoughts on “Catalina Island: Island ecology and restoration”

    1. Will, I’ve given a lot of thought to why this particular restoration is unique. I would like to say that it is an indication of progress in the heavy-handed approach that is often more destructive than necessary and does not reflect the opinions of the majority of the public. Unfortunately, that is not the conclusion I have reached.

      In fact, I think the explanation for the approach of this restoration is that it is one of the oldest projects in California. It began in 1972, long before most projects began in the late 1990s and they didn’t reach a fever pitch until the 2000s. The “bad rap” about eucalyptus did not yet exist. Because it was breaking new ground it is was in a position to make its own rules. Because it was a project on an island that had been previously entirely devoted to recreational interests, it was more likely to take those interests into consideration as it devised its strategies. The new owner of the island had no desire to destroy what his father had created.

      In other words, I don’t think the restoration on Catalina Island can be considered “progress” in our quest to preserve existing landscapes. Rather it seems to be more proof that restorations can and should be less destructive if we can roll back the religious fervor of nativism. And the only way we can achieve that is with our continued advocacy.

  1. This is a beautifully written and interesting article. I think you should try to have it published, perhaps first in the Catalina newspaper, or in a Catalina Conservancy publication. I see that there are several listed on the Catalina website.

    1. Thanks for the compliment, Lynn. It was a pleasure to write because of my fond memories of Catalina and the fact that they are preserving their eucalyptus trees.

      I had to correspond with the conservancy while writing the article because I couldn’t find the species of the eucalyptus. So, I sent them a link to the published article. They seemed to like it and they asked for permission to post it to their social media outlets. If so, that would be rewarding.

      As you may have noticed in the comments, our friends at Scripps Ranch in San Diego noticed the article. Of course we know it isn’t necessary to eradicate eucalyptus and now we have confirmation of our opinion by a major restoration effort. I hope it will help us to defend our eucalyptus everywhere in California.

  2. Thank you for this wonderful and fascinating article! It’s all the more special because of your memories and experience with Catalina Island.

    The history is so important to know, for those trying to protect plants and animals, and for those believing the nativist propaganda.

    You’re right that this must be shared with everyone spreading myths about eucalyptus being flammable and calling for their killing. What a perfect microcosm of proof that they aren’t a fire risk at all.

    I realize that most people who talk about “eucalyptus” aren’t even aware of how many kinds are in the Bay Area, with some of the species being unrecognizable as eucalyptus, such as the popular street tree, Ironbark.

    A couple of days ago, a friend showed me Sugarloaf Ridge State Park in Sonoma County, to see the wonderful wildflowers, but it’s also interesting in that there is a beautiful Redwood and Douglas Fir forest that survived the fire though we can see the scorching on their trunks. (The oaks on the hills had a harder time in the fire.)

    This region becomes extremely hot in summer and I would have never thought Redwoods could survive there, but they are in a canyon and I believe their close relationship with the Douglas Fir, as well as the Madrones, Maples, Bays and other trees help protect them from drying out. So again, more reason to not “thin” or try to separate or isolate trees. Clearly their growing so densely helped them survive the fire, and they helped the other plants also, including glorious Western Azaleas (now blooming.)

  3. Finally, a post on the mt blogsite that I can agree with! But I would say that the Catalina experience is more typical than unique. Most conservation/restoration initiatives are informed by invasion biology and target chiefly the most aggressive, ecosystem-destroying invaders, including for economic reasons. Naturalization of many species is simply accepted. Every situation should be evaluated on its own merit, and fanatical approaches for or against non-natives should be avoided. As noted, on an island originally bare of vegetation, every plant and animal was an invader at one time. It is usually those introduced by humans which cause the damage!

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