The evolving goals of ecological “restorations”

We are publishing a “progress report” from a member of our tree team who attended a Weed Management Workshop on June 3, 2017.  This report suggests that the goal of local ecological “restorations” may be more realistic than they were in the past and potentially less destructive. 


I attended a Weed Management Workshop this morning that was co-sponsored by East Bay Regional Park District and the California Invasive Plant Council.  It was attended by about 70 people, representing many of the “stewardship” organizations engaged in native plant “restorations.”  The main speakers were Doug Johnson, Executive Director of the California Invasive Plant Council and Pam Beitz, a member of the Integrated Pest Management staff of the East Bay Regional Park District.

The primary purpose of the workshop was to recruit new volunteers for the many “restoration” projects in the East Bay.  Similar workshops will be offered in Mill Valley (June 17), San Jose (June 24), and Portola Valley (July 15).  Since volunteers do not use pesticides or heavy equipment, those methods of eradicating “invasive” plants were not discussed. [Information about remaining workshops available HERE.]

Although the usual accusations about the negative impact of “invasive” plants were discussed, the speakers made several acknowledgements about limitations on their objectives that represent significant progress in the 25-year debate about invasion biology.

In the spirit of encouragement, I will tell you about a few of them.

Doug Johnson set the tone at the beginning of the workshop when he said, “Non-native plants aren’t evil.  It’s important not to get ideological about this.”  The audience did not react negatively to his appeal to base judgments about non-native plants on their ecological function and impacts on ecosystems.

Pomo gathering seeds, 1924. Smithsonian photo archieve

Pam Beitz acknowledged that the historical landscapes, which “restorations” attempt to recreate were, in fact, manmade.  She provided several observations from Kat Anderson’s Tending the Wild to illustrate that point.  Native Americans intensively gardened the landscape to foster the plants they needed for food, shelter, and tools.  The implication of that history of our landscape is that ecological “restoration” must make a permanent commitment to managing the landscape. [HERE is an article on Million Trees about “Tending the Wild.”]

Beitz said the goal of these weed management projects is to eliminate “invasive” plants from a small enough area that it can be managed for the long term.  She said it is no longer considered feasible to eradicate “invasive” plants.

In answer to the question, “Why manage the wildlands?” Beitz said, “Because we are driven to alter our environment.”  She also said that human disturbance maximizes biodiversity, citing a study by Joe Connell that found the greatest diversity where there are intermediate levels of disturbance.  This is a radical departure from the earlier view that the most effective conservation eliminates all human activities.

There were also many representatives of local “restoration” projects who described their projects and recruited more volunteers.  Some of their presentations indicated the shifting emphasis of native plant “restorations.”

  • Margot Cunningham of Friends of Albany Hill said that 50% of the 300 plants on Albany Hill are natives, despite the fact that it is heavily forested in eucalyptus, and that many of those native plants are growing under the eucalypts.  She said there are 100 species of butterflies and moths and that monarchs roost in the eucalyptus trees.  There are 80 species of birds.  Her organization is trying to eliminate plants they consider invasive, such as ivy. [HERE is an article on the Million Trees blog about Albany Hill, which corroborates the view of Friends of Albany Hill.]  

    Native toyon under eucalyptus on Albany Hill
  • Wendy Tokuda is one of the most prominent native plant advocates in the East Bay.  She described several of the projects she has been working on for about 10 years, such as trying to eliminate broom along 3 miles of a trail in EBRPD.  She emphasized the importance of focusing one’s effort on a small enough area that the goal can be both attained and sustained. [HERE is an article on the Million Trees blog about the 10-year attempt to eradicate broom on a trail in the East Bay Regional Park District.]  
Broom on EBRPD trail after 10 years of effort, April 2017
  • Friends of Five Creeks said, “In a city, stewardship is forever.”

I have been following the native plant movement for over 20 years.  I believe this workshop articulated some significant departures from their original agenda:

  • There is a new understanding that the historical landscape was created by humans.
  • Any attempt to recreate the historic landscape will require a permanent commitment to manage the landscape.
  • Because of the scale of such an undertaking, it is not realistic to transform all open space to pre-settlement conditions.  Projects must be scaled to match available resources.

Anonymous member of the tree team

The observation that humans are “driven to alter our environment” struck a chord.  We are in the camp that prefers not to interfere with the workings of nature any more than necessary because we believe that human knowledge is inadequate to presume to make better management decisions than natural processes.  There are pros and cons to every change in nature.  Some plant and animal species will benefit and some will be harmed.  It’s like flipping a coin.  I prefer to put the coin in the hands of nature, rather than the hands of humans.  However, we understand and are sympathetic to the human desire to “help” nature. 

Robin and chicks. Courtesy SF Forest Alliance

A recent article in the New York Times provided a good example of how the good intentions of humans often lead to intrusions into the natural world.  The author explained how she became the self-appointed guardian of birds nesting in her garden.  Her small dog was a predator of fledgling birds.  She felt obligated to identify all the nests in her garden so that she could keep her dog indoors when the birds left the nest. 

When her dog died, she discovered that she could not give up that role.  If one bird was competing with another for a nesting spot, she found herself choosing sides, although she knew she had no business choosing winners and losers in the natural world:   “It is wrongheaded to interfere in nature when something is neither unnatural nor likely to upset the natural order.  I can’t help myself…It’s humiliating, all the ways I’ve interfered.”

We know that volunteers in “restoration” projects mean well.  Since they don’t use pesticides or have access to the heavy equipment needed to destroy trees, we don’t argue with them directly.  Our advocacy for the preservation of our urban forest is aimed at the managers of our public lands because we are as much the owners of those lands as anyone else and our tax dollars are used to fund their projects.

Million Trees

10 thoughts on “The evolving goals of ecological “restorations””

  1. I was there, too. Characteristically, you didn’t identify or introduce yourself.You mischaracterized the conference. There were no policy statements. The statements you quoted were just the views of the speakers. It is absurd to claim that past human management of ecosystems should guide our current actions. It says nothing about what is best for the wildlife. What humans want is irrelevant. We don’t live there. The wildlife own their habitat, and their views are more important than ours.

    1. Making a distinction between “policy statements” and the “views of the speakers” is a legalistic quibble. In the case of the California Invasive Plant Council, they are THE official organization that classifies non-native plants as “invasive.” Their evaluations are based on many factors, including an assessment of the impact of plants on wildlife.

      In the case of East Bay Regional Park District they authorize and supervise volunteers to work on projects on their 120,000+ acres of parkland. If they don’t authorize the project, the volunteers are prohibited from destroying plants in their parks.

      There is no evidence that non-native plants are doing any harm to wildlife. In fact, there is plenty of evidence to the contrary. Friends of Albany Hill reported 100 species of moths and butterflies and 80 species of birds on Albany Hill, which is heavily forested in eucalyptus. Albany Hill is one of many eucalyptus forests in the Bay Area in which monarch butterflies roost in the winter.

      Here are several other studies that found no empirical evidence that more animals are found in native gardens or forests:
      And here are studies that reported no benefit to wildlife after non-native plants were eradicated:

      Mr. Vandeman seems to have missed the implications of the fact that pre-settlement landscapes were created by humans who gardened the landscape to provide food, shelter, and tools. Here are the implications of this historical fact:
      • Native ranges reflect the choices made by Native Americans. They do not necessarily reflect the forces of nature. The modern obsession with “where plants belong” is based on a fantasy of why plants were found where they were when Europeans arrived in California.
      • The land management practices of Native Americans are no longer being practiced, which means that the plants they preferred are no longer receiving the care that ensured their survival in the past. Humans no longer set fire to the landscape every year. Therefore, the landscape has changed and will continue to change to correspond to changed practices:
      o Grassland is succeeding to shrubs.
      o Shrubs are succeeding to forest.
      o Plant species that require fire to germinate their seeds are dying out. For example, several species of Manzanita are now endangered because they cannot be propagated in the absence of fire.
      o Plant species that require full sun for their survival are dying out because they are now shaded by shrubs and trees.

      1. I find this blog one of the most interesting regarding nature and conservation. I am thankful for the wisdom of those who share the concerns that I share for how we as a society deal with nature.

    2. I agree with Million Trees, of course, because I care about our environment.

      It seems hypocritical for a nativist to mention caring about wild animals since the killing of non-native plants ignores what the wild animals themselves choose and why they choose as they do.

      One of the many benefits of Eucalyptus is that they are much safer for large birds to nest and fledge in, which is why if you want to see eagles, large owls, hawks, etc. look for Eucalyptus.

      With all the human-made disasters that are increasing, we need as much bio-diversity as possible.

      I can’t help but love the photo of the flowering broom. I can almost smell their deliciousness.

  2. The argument against invasive species is the reduction in biodiversity. How is that so hard to understand?

    1. A simple argument and like many simple arguments it isn’t true. There are no empirical studies that find reduced biodiversity as a result of the introduction of non-native plants.

    1. The article you cite was published 17 years ago. Its author is one of the academic hold outs still clinging to the assumptions of invasion biology despite 20 years of studies that find no empirical evidence to corroborate those assumptions.

      Here is the abstract from one of the most recent publications debunking those assumptions: “The commonplace, quantitative assertion that ‘invasions’ of exotic (introduced) organisms constitute the ‘second greatest threat’ of species extinction debuted in Edward O. Wilson’s 1992 book, The Diversity of Life. Based only on three interrelated publications summarising concerns about the conservation status of North American freshwater fishes, Wilson laconically extended the claim to planetary significance. This inspired the most-cited article ever published in the American journal BioScience, subsequently underpinning thousands of peer-reviewed publications, government reports, academic and popular books, commentaries, and news stories. While carefully recounting the origin, promotion, and deployment of the ‘second greatest threat’, I argue that its uncritical acceptance exemplifies confirmation bias in scientific advocacy: an overextended claim reflexively embraced by conservation practitioners and lay environmentalists because it apparently corroborated one particular, widely shared dismay about modern society’s regrettable effects on nature.” (Matt Chew, “Ecologists, environmentalists, experts, and the invasion of the ‘second greatest threat,” International Review of Environmental History, 2015)

      There are many other similar publications that analyze specific claims made by Simberloff and Wilson. For example, Mark Davis’s Invasion Biology informs us that there is not a single extinction of a plant in the continental US that is attributed to an introduced plant. He also explains that the “second-greatest-threat” theory is only true in Hawaii and is not true in Canada.

      Here are a few studies that dismantle the claim about the cost of introduced species:

      Scientists abandoned creationism in favor of evolutionary explanations for plant and animal species about 150 years ago. There are still a few hold outs who refuse to abandon their belief in creationism. Likewise, there are still many hold outs who believe in invasion biology. Naturally, there are still many because the empirical evidence that overturns their assumptions is more recent than the evidence of evolution.

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