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Restoration or Destruction?

June 24, 2010

A recent trip to the Channel Islands off the coast of California inspires us to consider the pros and cons of restorations.  Islands are particularly attractive targets for restorations. They often contain endemic species that do not exist anywhere else because they have adapted to unique conditions in isolation.  And the relative isolation of islands implies that once non-native species of plants and animals are eradicated, re-introduction of those species can be prevented.

Santa Cruz Island, Wikimedia Commons

Some of the Channel Islands were inhabited by Native Americans as long as 13,000 years ago.  Ranching by Europeans began on some of the islands in the 1850s. Europeans brought sheep, cattle, pigs, mule deer, and elk to some of the islands.  Five of the eight Channel Islands were designated as a National Park about 30 years ago. 

Restoration began in earnest in the 1990s when ranching operations were ceased and tens of thousands of sheep and cattle were either removed from the islands or destroyed.  Black rats were eradicated from some islands after native mice were herded into protective enclosures so the rats could be poisoned.  Rabbits were eradicated from another island.  We don’t know how that was achieved. 

The next big effort was the eradication of about 6,000 feral pigs. When this was accomplished by sharp shooters, the first unintended consequence of this ambitious restoration was revealed.  It seems that the feral pigs had been the chief diet of a population of Golden Eagles, considered non-native to the Channel Islands.  When the pigs were removed from their menu, they turned to the rare, endemic Channel Island Fox. 

Channel Island Fox, Wikimedia Commons

The population of Channel Island Foxes plummeted.  Those that remained were captured so they could breed in protected conditions while the Golden Eagles were captured and removed to a remote location.  The Channel Island Fox is making a come-back, but the Golden Eagles are apparently gone for good. 

The eagle considered native to the Channel Island, the Bald Eagle, has been reintroduced.  It apparently lives in peace with the Channel Island Fox because it eats fish. 

Mule deer and elk are next up on the eradication agenda for fauna.  Non-native plants are also doomed.  Ice-plant and fennel are the top priorities for eradication by 2011.  Herbicides and prescribed burns are used for this purpose.   

Prescribed burn, Santa Cruz Island, NPS photo

We were surprised to see notice of herbicide application for Garlon 4 Ultra during our visit to this fragile place.  Someone dressed from head to toe in protective clothing was spraying this chemical on a steep hillside.  We have reported the toxic effects of Garlon in our post about herbicides.

This is a complex ecosystem in which simplistic solutions—such as killing all the non-natives—can result in a big mistake.  For example, do we know if there are native Anise Swallowtail Butterflies on the islands that are now dependent upon non-native fennel for their survival?  Do we know how the application of Garlon will impact the survival of the rare, endemic Island Jay?  The US Forest Service found in its risk assessment done for the EPA that the application of Garlon had a significant negative impact on the reproductive success of birds.  Are those who decided to spray Garlon aware of this study?

Herbicide application notice, Santa Cruz Island

We went to the Channel Islands with open minds.  We thought the strongest arguments could be made for restorations on islands.  However, when we learned of the thousands of animals who were sacrificed to this effort and the dangerous and toxic methods used to accomplish the restorations, we were not convinced.  We nearly lost the Channel Island Fox because of the unforeseen consequences of killing feral pigs.  Man would like to believe that he is capable of managing nature.  But can he do so without causing more harm than good?

7 Comments leave one →
  1. HarryEye permalink
    June 24, 2010 10:10 pm

    I object to these actions being called “restorations” as they are no such thing.
    They are the actions of fanatics who will do anything for their hobby, no matter how poisonous to the land, animals and watershed, no matter how much suffering and death it causes. It’s some kind of mental illness and obsession.

  2. Naturalist.charlie permalink
    September 12, 2010 9:09 pm

    I am confused by this post. The stated goal of this website is to protect trees. The feral pigs were largely preventing any of the trees (oaks, pines, even the introduced eucalyptus for that matter) from reproducing on the island – and as their population grew, it was likely they would halt tree recruitment altogether. A few more things that were left out:

    The golden eagles came to California because the bald eagles that once lived there had died off due to DDT poisoning. Because the territorial bald eagles were gone, and because there were piglets and carrion to eat, golden eagles soon invaded the islands.( http://www.nps.gov/chis/naturescience/fox-decline.htm ) They probably ate foxes then, too. Once the pigs were removed, they ate more foxes. Then the golden eagles were relocated back to the mainland and the foxes rebounded. Far from an example of restoration gone bad, this is an example of restoration overcoming unintended consequences and still coming out successful.

    There are no efforts to ‘remove all non-native plants’ from the islands, because that is impossible. A few highly invasive species are being targeted. Not sure about the prescribed burns, except that your normal concern that they may escape and destroy homes is not applicable in this case. This is a good place to try it and see if it works.

    The garlon issue is a tricky one, but I’ve talked to the people doing this restoration and it’s not an easy issue. There’s a good chance that invasives could completely destroy the ecosystem of the Channel Islands if not removed, even with the pigs gone. This would result in the jay dying off too, as it relies on acorns, pine nuts, and maybe wild cherries. All of these species might be inhibited in germination by invasive plants. I don’t know much about the Anice Swallowtail and haven’t seen any on the islands but it is a common species and unlike the island endemic species it is not threatened with extinction. I wouldn’t want to see butterflies removed from an ecosystem but an ecosystem with only fennel and anice swallowtails and maybe a couple of bird species seems a poor replacement for the 600 plant species and 120 birds currently on the site.

    On the mainland, meanwhile, methyl bromide and all kinds of horrible chemicals are being dumped on farmland. If you’re worried about pesticides, that’s the place to go looking for ways to reduce their use. Not much gets used on the islands compared to out there!

    “However, when we learned of the thousands of animals who were sacrificed to this effort and the dangerous and toxic methods used to accomplish the restorations, we were not convinced. ” – I’ve been accused of being overdramatic but I think this takes the cake. How many animals were ‘sacrificed’ when the pigs were introduced in the first place? How many would be ‘sacrificed’ if the pigs were allowed to denude the island, then themselves suffered a population crash after they ate all the food.

    Certainly managing nature is fraught with unintended consequences. Dumping invasive organisms on an island then leaving town hardly seems like an acceptable alternative though!

  3. AaronJ permalink
    August 31, 2014 8:20 pm

    This is rather disconcerting. You should know something about conservation biology, ecology, chemistry, etc.. before posting intellectually dishonest content such is this. You provide NO hard evidence for your claim at all aside from speculative assumptions, hypothetical questioning, and a completely wrong interpretation of a classic success story of conservation biology(The Island Fox). There are so many things wrong with this article it would be too extensive to correct all its misconceptions, but addressing one in particular..
    Anise Swallowtail are not dependent on Fennel. Their caterpillars feed on any number of plants given that they are in the Carrot Family (Apiaceae), of which fennel just happens to be. You may find these butterflies in any number of environments absent of Fennel. In any case, it shouldn’t matter, it is a hypothetical, not evidence that can be taken seriously. Making an erroneous connection between the common name of a butterfly and its assumed host plant with an obvious neglect of research and using it to justify your false and obviously biased premise is dishonest and irresponsible, flat out. This is really horrible what you’ve done here, really. This is the type of slipshod writing that give environmentalist a bad name.

    • August 31, 2014 8:39 pm

      The source of the information regarding the Anise swallowtail butterfly is SD Graves and AM Shapiro, “Exotics as host plants of the California butterfly fauna,” Biological Conservation, 110 (2003) 413-433. Here is a verbatim quote from that study:

      “In at least two and possibly many cases, the use of exotic hosts has enabled butterfly species in California to extend their breeding seasons, resulting in more generations each year, in addition to extending their geographic ranges. Papilio zelicaon, the anise swallowtail, typically has one to two generations in the mountains and foothills of California where it feeds on native apiaceous hosts. However, along the coast, in the San Francisco Bay Area and the urbanized south coastal plains and in the Central Valley, P. zelicaon feeds on introduced sweet fennel, Foeniculum vulgare, and produces four to six or more generations each year…In any case, the use of exotics has greatly extended the range of P. zelicaon in lowland California.”

      Professor Shapiro is Distinguished Professor of Evolution and Ecology at UC Davis. He is also the author of Field Guide to Butterflies of the San Francisco Bay Area and Sacramento Valley Regions (University of California Press, 2007)

      You will find few statements on this blog that are not supported by specific empirical studies published by peer reviewed scientific journals. We know that we are critiquing deeply held beliefs; therefore, we must not stray far from established scientific facts and so we don’t.

    • Still Skeptical permalink
      September 1, 2014 9:05 am

      It is the nasty and uninformed arrogance of people like AaronJ that gives environmentalists a bad name. I find citations to published science throughout this blog. In contrast, AaronJ offers absolutely none.

  4. AaronJ permalink
    September 1, 2014 12:50 pm

    I do apologize for being antagonistic, but these are very valid points that I’m offering and should be taken constructively.

    This is the point: You must distinguish between “fun fact” observations of a field guide and scientifically supported data. The first sentence is “In at least two and possibly many cases “.. In at least two cases?! I guarantee that in any scientific journal ever has the abstract began with “In at least two cases”. Furthermore, your “study” never mentions the survival of this species being threatened nor does it speak a word at all about decline. It makes the assertion that population increases with fennel which seems logical. The most reasonable deduction to take away from this is; seemingly at worst, Anise Swallowtail may simply have reduced numbers, and this may very well be a GOOD thing for the “natural balance” of “complex ecosystems” to use your own words. Furthermore still, this is all irrelevant because should there be Anise Swallowtail on the Channel Islands there are over 20 native Apiastrum species on the islands that this hypothetical butterfly could easily transition to.

    Webmaster: Had you read Professor Shapiro’s paper–which you apparently still have not done though you wish to critique it–this is what you would know. First, the paper is not a “fun fact” field guide. It is a study published by a peer-reviewed scientific journal, representing your apparent discipline, conservation biology. The “cases” to which Professor Shapiro refers are different species of butterflies, not individual butterflies. You would also know that although there are native plant species that were used by the Anise Swallowtail historically, prior to the introduction of non-native fennel, they were not (and are not now) available year around nor as widely distributed as non-native fennel is now. Therefore, prior to the introduction of non-native fennel, the Anise Swallowtail was not multivoltine, nor was it as widely distributed as it is presently. Therefore, it is appropriate and correct to say that this species of butterflies is “dependent” upon non-native fennel to maintain its present population size and distribution.

    I can tell you that in the case of the Pygmy Blue Butterfly on Ancapa Island, a much rarer species, special precautions are being taken in regard to herbicide use. And Non-native spinach family members of which these butterflies are host-specifically dependent upon, are being gradually removed out of concern for the butterflies, but then again almost all cases of invasive species removal are gradual because they have to be. There is no other way to do it. “Restorations” as you call them are not hap-hazard operations run by sloppy, care free individuals. Any concerns you are speculating about here, have most likely also been pondered about, deeply, by the professionals in charge of these projects.

    Webmaster: Your speculation that our concerns “have most likely also been pondered about, deeply, by the professionals in charge of these projects,” is not particularly reassuring. Your reassurance is just as speculative as the questions we have raised. Our speculation is based on our local experience with similar, though less extreme, projects in the San Francisco Bay Area. We do not witness any evidence of “caution or gradual removal.” If the project on the Channel Islands is unique in that regard that would be good to know, though you have provided little evidence that is the case.

    I may have beliefs concerning this issue, but they are anything but dogmatic.

    Webmaster: Nor have we been “dogmatic.” We have asked questions, which remain unanswered to our satisfaction. For example, we would not agree that the demise of a population of butterflies would be a “GOOD thing.” Nor do we agree that a rare butterfly deserves more “special precautions” than any other living thing. And there you have it: ours is a radically different viewpoint from those who are making their living on these destructive projects, which we presume you do.

    Thank you for your visit and for your comment. If you have scientific studies to support your speculation, we will read them.

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