Nativism turns a blind eye to climate change

“Reflexive demonization of alien species ignores the beautiful but complex truth that nature fights to find a way—and for a planet navigating the pressures of climate change and overpopulation, that just might be our saving grace.” – Marianne Willburn, Garden Rant

Margaret Renkl writes an opinion column for the New York Times that I usually enjoy because she frequently writes about nature, often based on observations of wildlife in her own garden.  She lives in her childhood home in Nashville, Tennessee.  Much of her garden was planted with non-native plants and trees decades ago by her deceased mother.  Yet, in a recent column, Ms. Renkl blames non-native plants for a variety of crimes against nature. 

  • She suggests that non-native trees are blooming earlier than native trees, which she says has “skewed our experience of spring.”  She is apparently unaware that spring does indeed arrive earlier than it has in the past because of climate change.  Warmer weather arrives earlier, triggering the blooms of spring, not vice versa.  Both native and non-native plants are blooming earlier than they did in the past. 
  • She suggests that gardens planted with non-native plants are “blooming wastelands where the flowers feed nobody at all,” yet her columns are usually filled with the wildlife that lives in her own garden, with introduced plant species.
  • Although she does not use pesticides in her own garden, she believes that her neighbors’ non-native gardens require them to use pesticides that kill wildlife.  She says, “The typical suburban yard is actually worse than a wasteland. It’s a death trap.” She does not seem to know that most herbicide is used to kill non-native plants, not native plants nor does she seem to realize the contradiction in her indictment of gardening with non-native plants.  If there are more insects living in native gardens than non-native gardens, why would more pesticide be needed in non-native gardens?  If people could learn to love the clover, dandelions, and English daisies in their lawns as much as I do, they would use less “weed killers” on their lawns.

Ms. Renkl’s misperceptions about non-native plants seem to be based on a mistaken belief in their origins.  She says, “Ambulatory and omnivorous, human beings are a migratory species. That’s not true for the vast majority of plants.”  In fact, plants are just as mobile as animals, including humans.  Plants are carried by birds, animals, wind, ocean currents, etc.  They come and go as the climate changes, as it has many times in the past 500 million years that plants have existed on Earth.  Plants now considered non-native existed here in the distant past, in a different climate.  Here are a few examples of such dispersals; most occurred before humans even existed:

The ability to migrate is essential to the survival of plant and animal species.  As the climate changes, this survival strategy is quickly becoming even more important.  When we demand that plants be restricted to their historical “native” ranges, we doom them to extinction because when the climate changes, the vegetation must change.

Where did Ms. Renkl learn these myths?

Ms. Renkl’s cites Doug Tallamy’s Nature’s Best Hope as one of the sources of her mistaken beliefs.  Tallamy considers the existence of non-native plants the root of all evil in nature.  He calls them “ecological tumors.” He blames non-native plants for declining populations of both native plants and insects, and by extension to declining populations of birds that eat insects. 

In Nature’s Best Hope, Tallamy says, “…we must not use climate change as an excuse to do nothing.  Most species of plants and animals are far more resilient to climate variability than we give them credit for.  Besides, increasing the number and biomass of the plantings in our yards and public spaces is one of our most accessible and convenient tools to fight climate change.”  The problem with Tallamy’s dogma is that it inspires the public and land managers to eradicate established landscapes that are not native based on Tallamy’s claims that non-natives are “crowding out” native species and depriving wildlife of food. All native plant “restorations” begin by eradicating non-native plants, usually with herbicides that retard new growth.  In other words, the native plant ideology is causing the loss of vegetation and therefore the loss of stored carbon and the reduced capacity for carbon sequestration in the future.  The native plant ideology is not increasing biodiversity, nor is it “fighting climate change.”  It is more destructive than constructive. 

I’m not looking for “an excuse to do nothing.”  On the contrary, I believe every effort must be made to stop or at least slow down the inexorable advance of climate change.  The most basic effort we can make is to stop destroying functional vegetation, especially trees.  Then, there is a lengthy list of what we should be doing to reduce greenhouse gas emissions, which is another, equally important topic. 

Native plant advocates consider climate change irrelevant because they believe the existence of non-native plants is the sole culprit of all problems in the environment.  They see every environmental issue through the narrow lens of their dogma.  This comment on an article about the value of non-native plants by Marlene Condon published in [Chesapeake] Bay Journal is an example of such a misinterpretation of an environmental issue:

“English ivy is an evergreen, non-native, invasive groundcover that has demolished undisturbed natural areas…In salmon country that’s the difference between clean, cold streams and warmer streams filled with sediment.”

Eradicating ivy on stream banks is likely to produce more sediment because it will take some time for replacement vegetation to cover the ground, especially if herbicides are used to eradicate the ivy. Water is warmer in streams because of climate change and because there is less water due to water diversion and droughts. There are many other reasons for declining populations of salmon, particularly dams that prevent salmon from reaching their spawning grounds upstream.

Treat the cause, not the symptom

The native plant ideology ignores the underlying causes of changing ecosystems. Most changes are caused by the activities of humans, such as agriculture, development, water diversion, and pesticides.  Climate change is the underlying cause of some changes in nature and it will steadily become a more important factor.  Eradicating non-native plants will not reverse any of those changes nor will it prevent changes in the climate.    


  1. Alan de Queiroz, “The resurrection of oceanic dispersal in historical biogeography,” Trends in Ecology and Evolution, 20 No. 2, February 2005

Photo credit for featured photo: Garden Rant, Marianne Willburn

Science meets the “restoration” industry

I was encouraged to hear a presentation by an academic scientist at the recent Beyond Pesticides Forum that was another indication of the paradigm shift in invasive species management toward a less destructive approach.  Dr. Bernd Blossey is a Professor at Cornell University, where he directs the Ecology and Management of Invasive Plants Program in the Department of Natural Resources.  His many years of studying invasive plants, such as purple loosestrife, garlic mustard, water chestnut, Japanese knotweed, and phragmites have convinced him that there are often “multiple stressors” that contribute to such invasions.  Some factors such as the presence of earthworms and deer can be more important factors in the Northeast than the non-native plants themselves. 

Based on his research experience, Dr. Blossey delivered wise advice to land managers at the Beyond Pesticide Forum.  The featured photo at the top of this article was his introductory slide. 

Before a restoration project begins, these questions should be asked and answered:

Source: Dr. Blossey’s presentation to Beyond Pesticides Forum on June 8, 2021

If the project seems worthwhile after such analysis is done, this is Dr. Blossey’s advice about monitoring the project and measuring its success:

Source: Dr. Blossey’s presentation to Beyond Pesticides Forum on June 8, 2021

Practicing what he preaches

Dr. Blossey used these principles in his study of garlic mustard in the forests of the northeast. (1) Over a period of more than 10 years, Dr. Blossey and his collaborators measured the abundance of garlic mustard in 16 plots from New Jersey to Illinois where no attempt had been made to control or eradicate it.  They found that growth rates initially increased, but decreased over time and eventually the population started to decline.  Dr. Blossey explained their findings in a recent webinar that is available HERE:

Garlic mustard was first recorded in North America in 1868 on Long Island, New York.  It spread west from there and is now found from southern Canada to Georgia and from New York and Quebec to Oregon, British Columbia and Alaska.  Because land managers believed that garlic mustard suppresses populations of native plants, they have been trying to eradicate garlic mustard in northern forests for decades, with little long term success.  Dr. Blossey addressed that concern in his webinar. 

Source: Dr. Blossey’s webinar about garlic mustard

Earthworms are the prerequisite for garlic mustard invasion.  Earthworms in northern forests are also considered alien invaders because they were killed, along with forests, by advancing glaciers during the Ice Age.  When forests returned after the Ice Age over 10,000 years ago, they evolved without earthworms that were reintroduced by European settlers less than 500 years ago. 

When deer are excluded from areas by fencing plots with garlic mustard populations, abundance of native vegetation does not decline.  Deer have a strong preference for native vegetation.  Absent deer, garlic mustard does not seem to suppress the growth of native plants in northern forests.

In other words, garlic mustard is not guilty as charged.  Dr. Blossey explains the disadvantages of attempting to eradicate it.  The decline of garlic mustard abundance over time is attributed to negative soil feedback that builds over time as the soil microbial community responds to the new plant. Removing garlic mustard episodically prolongs the process of building that negative soil feedback.  When groups of well-meaning young people are sent into the forest to pull garlic mustard, they trample the very native plants they are trying to save. 

Are there lessons for land managers in the Bay Area?

Because garlic mustard doesn’t exist in California and our native earthworms are considered beneficial to soil health, you might wonder if this study is relevant here.  California was not glaciated during the Ice Age.  Our earthworms survived the Ice Age and they evolved with our forests. 

So, what can we learn from this study?  The pattern of initial growth and eventual decline of populations of introduced plants is not unique to garlic mustard“A phenomenon that has received increased attention is whether introduced species go through boom and bust cycles, ultimately becoming non-threatening members of local communities.” (1)  One recently published study was based on nearly 5,000 vegetation inventories collected in 49 National Parks in the eastern United States.  It reported that non-native plants appeared to decline after 100-200 years: 

Residence time appears a core part of invasion that interacts with other mechanisms, such as climate matching, propagule pressure and empty niche. Initially, time appears to benefit non-native species as they establish in a novel range. They likely face low enemy loads, and any successful dispersal increases their populations and invaded range. As they spread, initial barriers, such as distance or suboptimal habitat, were overcome, as was resistance from native relatives. However, their biggest challenge appeared to be time, as they all declined after ~1 to 2 centuries, suggesting that pathogens and herbivores caught up with them.” (2)

The message for land managers everywhere is that patience is needed to judge the impact of introduced species.  Most will fit into ecosystems eventually and attempts to speed up that process often do more harm than good.  We can’t judge changes in nature by the short-term perspective of human lifetimes because the evolution of nature is a continual process that began long before humans existed and is likely to persist long after we are gone. 

Applying Dr. Blossey’s “Core Knowledge” to local projects

What if Dr. Blossey’s “Core Knowledge” had been applied to projects in the San Francisco Bay Area?  Here are examples of local eradication projects that might have benefitted:

  • San Francisco has been trying to eradicate oxalis in its parks for over 20 years by spraying a selective herbicide (Garlon).  There seems to be more oxalis now than there was 20 years ago.  Oxalis is visible only about 2 months of the year.  When it dies back in the spring it leaves behind the native plants with which it co-exists.  If a control plot had been set aside before they started eradicating oxalis perhaps we would know the answer to these important questions:  Does oxalis suppress the growth of native plants?  Does attempting to eradicate oxalis produce more or less oxalis?
  • California, Oregon, and Washington have been trying to eradicate non-native spartina marsh grass along the entire West Coast for over 20 years.  Here in the Bay Area, non-native species of spartina have been 99% eradicated, but a hybrid of the native and the non-native remains and is poisoned with imazapyr annually.  According to a recent presentation by the Invasive Spartina Project, the hybrid is visually indistinguishable from the native and it occupies the same elevation of the marsh.  Over 500 genetic tests are needed every year to distinguish the hybrid from the native in order to poison the hybrid.  Dr. Blossey’s approach might ask these important questions:  What harm is hybrid spartina doing?  Do more or fewer animals live in hybrid spartina?  What effect has 20 years of spraying imazapyr had on the soil and the microbes that live in it?  Is the eradication project doing more harm than good? 
oxalis bloom, February 2021

We don’t know the answers to these important questions because projects were initiated and implemented without the analysis and monitoring metrics needed to answer the questions.  The projects continue without being accountable for the damage they are doing.  Public money is funding these projects without requiring the projects to be accountable for the consequences. 

California has made a commitment to spend billions of dollars on “nature based solutions” and achieving “biodiversity goals.”  This is an opportunity to start new projects off on the right foot by:

  • Requiring the analysis needed to determine the impacts and causes of perceived problems in the environment.
  • Requiring control plots so that the effects of the project can be compared with the option of not doing the project.
  • Requiring that projects be monitored, using established metrics so that the success of the project can be measured.

  1. Bernd Blossey, et. al., “Residence time determines invasiveness and performance of garlic mustard (Alliaria petiolota) in North America, Ecology Letters, February 2021.  
  2. Robert Warren, et. al., “Multiple mechanisms in woodland plant species invasion,”  Plant Ecology, April 2019.

The National Park Service has an epiphany

“We were probably always wrong to think about protected places as static.” – NPS Scientist

During the Trump administration federal agencies were forced to be silent about climate change.  Behind closed doors, many federal agencies were quietly preparing for the day when they would be able to begin the process of adapting to climate change. 

Shortly after the 2020 presidential election, the National Park Service published a natural resources report that announced a radical departure from traditional conservation strategy that was based on an assumption that nature is static and evolution a historical event.  “Resist-Accept-Direct—A framework for the 21st century resource manager” acknowledged that the rapidly changing climate requires a new approach based on the knowledge that nature is dynamic and evolution is a current and continuous event.  Many other federal agencies participated in the preparation of the report, which implies that other federal agencies may adopt the new conservation strategy. (1)

In April 2021, the National Park Service published policy guidance for park managers based on the principles of “Resist-Accept-Direct.” The New York Times interviewed the lead author of the policy guidance, who described the new conservation strategy of the National Park Service:   “The concept of things going back to some historical fixed condition is really just no longer tenable.” 

Acadia National Park, Maine

An ecologist and the science coordinator of Acadia National Park in Maine told NY Times what this new strategy meant to him and his colleagues.  He said that as recently as 2007 protected areas like the national parks were still being thought about as static places that could be preserved forever with the right techniques. “We weren’t being trained on how to manage for change,” he said. “We were being trained on how to keep things like they were in the past.”  That means nearly everyone in his line of work was caught unprepared for the current reality. “You have a whole profession of people having to shift how we think.  We were probably always wrong to think about protected places as static.”

Evolution of National Park Service Policy:  From preservation to restoration

The federal law that established the National Park Service in 1916, defined its mission:

“…which purpose is to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations.”

H.R. 15522, An Act to establish a National Park Service, engrossed August 5, 1916 (1)

Preservation was the original mission of the National Park Service.  In 1963, the mission of the National Park Service was radically changed by the Leopold Report, written by A. Starker Leopold, the son of Aldo Leopold.  The Leopold Report recommended a goal for national parks of maintaining historical conditions as closely as possible to those “of primitive America.”  When the Leopold Report was adopted as official policy by the National Park Service in 1967, it committed NPS to restoring park lands to pre-settlement conditions:

“Passive protection is not enough. Active management of the natural environment, plus a sensitive application of discipline in park planning, use, and development, are requirements for today’ Simultaneously, that edition of NPS policies also described the primary management task as a seemingly simple undertaking: ‘[safeguard] forests, wildlife, and natural features against direct removal, impairment, or destruction,’ and ‘[apply] ecological management techniques to neutralize the unnatural influences of man, thus permitting the natural environment to be maintained essentially by natural agents’” (1)

In 1967, the land management goals of the National Park Service became more ambitious.  The goal of “preservation” was replaced by the goal of “restoring” historic landscapes and ecosystems.  The pre-settlement landscape of 500 years ago on the East Coast and 250 years ago on the West Coast was established as the baseline landscape that NPS was committed to re-creating.  The baseline landscape was presumed to be “pristine” although it had been actively gardened by indigenous people for thousands of years.

The new land management strategy of the National Park Service

The National Park Service calls its new land management strategy the RAD framework, an acronym that summarizes three alternative strategies:  

  1. “Resist the trajectory of change, by working to maintain or restore ecosystem processes, function, structure, or composition based upon historical or acceptable current conditions.
  2. “Accept the trajectory of change, by allowing ecosystem processes, function, structure, or composition to change, without intervening to alter their trajectory.
  3. “Direct the trajectory of change, by actively shaping ecosystem processes, function, structure, or composition towards desired new conditions.” (1)

Every land management decision will choose among these alternatives based on an analysis that will begin with a climate assessment. Instead of looking to the past for guidance, the planning process will assess current conditions and project future climate conditions.  Based on that assessment, the purpose of land management plans will be adaptation to current and anticipated conditions.  Every plan will be designed for a specific place, based on specific current and anticipated conditions.  There is no one-size-fits-all plan, only a framework for devising individual plans tailored for specific parks or ecosystems within parks. 

The new strategy also makes a commitment to monitor the project as plans are implemented and modify the strategy as the environment continues to change and the ecosystem responds to land management.  This is called “adaptive management” and it is essential in a rapidly changing environment. The project doesn’t end, because nature never stops changing.  It’s a process for which there is no end-stage.

It’s a challenging strategy, but one that has the potential to be less destructive than the “restoration” paradigm that always began by destroying plants and animals perceived as intruders without historical precedents.  Precisely what it will mean remains to be seen.  There will probably be pockets of resistance from those who remain committed to the “restoration” paradigm and those who are economically dependent on existing projects.  All the more reason to continue to watch what is being done and participate in whatever public process is available

An example of an NPS project that should be abandoned.

There are undoubtedly hundreds, perhaps thousands of NPS projects that are based on the ambitious restoration goals of the 1963 Leopold Report.  Perhaps some were successful.  My personal knowledge of NPS projects is limited to those in the San Francisco Bay Area, my home.

Point Reyes National Seashore

An attempt to eradicate European beach grass in the Point Reyes National Seashore (PRNS) is an example of an NPS “restoration” project that should be abandoned if the new RAD framework is implemented.  The PRNS project was described by NPS staff at the 2018 conference of the California Invasive Plant Council, a source and a setting that should be considered credible by the most ardent supporters of ecological “restorations.”

About 60% of sand dunes in the Point Reyes National Seashore were covered in European beach grass when the eradication effort began in 2000.  The goal of the project was to restore native dune plants and increase the population of endangered snowy plovers that nest on bare sand.  The project began by manually pulling beach grass from 30 acres of dunes at Abbott’s Lagoon.  The grass grew back within one year, presumably because the roots of the beach grass are about 10 feet long.  Manually pulling the grass from the surface does not destroy the roots. 

A new method was devised that was more successful with respect to eradicating the beach grass.  The grass and its roots were plowed up by bulldozers and buried deep in the sand.  The cost of that method was prohibitively expensive at $25,000 to $30,000 per acre and the barren sand caused other problems.  The barren dunes were mobile in the wind.  Sand blew into adjacent ranches and residential areas, causing neighbors of the park to object to the project.  The sand also encroached into areas where there were native plants, burying them.  The bare sand was eventually colonized by “secondary invaders.”  Different non-native plants replaced the beach grass because they were more competitive than the desired native plants. 

In 2011, the National Park Service adopted a third strategy for converting beach grass to native dune plants.  They sprayed the beach grass with a mixture of glyphosate and imazapyr.  At $2,500 to $3,000 per acre, this eradication method was significantly cheaper than the mechanical method.  However, it resulted in different problems that prevented the establishment of native dune plants.  The poisoned thatch of dead beach grass was a physical barrier to successful seed germination and establishment of a new landscape.  Where secondary invaders were capable of penetrating the dead thatch, the resulting vegetation does not resemble native dunes. 

Presentation at California Invasive Plant Council conference regarding attempt to eradicate European beach grass at Point Reyes National Seashore, November 2018

The concluding slides of the presentation of NPS staff about this project were stunning.  The slides said it is a “Restoration fallacy that killing an invader will result in native vegetation.”  My 20-plus years of watching these futile efforts confirm this reality.  However, I never expected to hear that said by someone actually engaged in this effort.  The presenter mused that such projects are like Sisyphus trying to roll a boulder up hill.

Presentation at California Invasive Plant Council conference regarding attempt to eradicate European beach grass at Point Reyes National Seashore. November 2018

Looking forward, not back

The realization—or perhaps acknowledgement—that the NPS strategy of re-creating historical landscapes is unrealistic was a long time coming.  Over the 50 years that the “restoration” strategy was attempted much unnecessary damage was done.  Useful, functional landscapes were destroyed.  Healthy trees were destroyed solely because they were planted by Europeans.  Animals were killed because they were perceived to be competitors of “native” animals.  Herbicides poisoned the soil, preventing regeneration or germination of new vegetation.  Established landscapes that had not needed irrigation were replaced with native plants that required irrigation.  Stabilizing vegetation was destroyed, resulting in erosion and drifting sand. 

The National Park Service has awakened to the failure of their “restoration” strategy because of the combination of failed projects that were based on mistaken assumptions and the impacts of climate change. NPS led public land managers into the dead end of attempting to re-create historical landscapes. Now NPS will lead public land managers out of that dead end into the reality of a changed environment with a rapidly changing future. Better late than never.


  1. Schuurman, G. W., C. Hawkins Hoffman, D. N. Cole, D. J. Lawrence, J. M. Morton, D. R. Magness, A. E. Cravens, S. Covington, R. O’Malley, and N. A. Fisichelli. 2020. Resist-accept-direct (RAD)—a framework for the 21st-century natural resource manager. Natural Resource Report NPS/NRSS/CCRP/NRR—2020/ 2213. National Park Service, Fort Collins, Colorado. https://doi.org/10.36967/nrr-2283597
  2. Planning for a Changing Climate: Climate-Smart Planning and Management in the National Park Service, NPS, April 2021.  https://toolkit.climate.gov/reports/planning-changing-climate-climate-smart-planning-and-management-national-park-service

Featured Photo from RAD Natural Resource Report.  Photo caption:

“Multiple federal agencies, including the National Park Service (Bandelier National Monument), tribes, and others steward the East Jemez Mountains ecosystem of New Mexico, an ecologically transforming landscape where massive forest die-off is projected to occur more frequently in the future. Piñon pines, normally evergreen, have reddish-brown foliage in October 2002 (left). By May 2004 (right), the dead piñon pines lost all their needles, exposing gray trunks and branches. The photos were taken from the same vantage point near Los Alamos, N.M. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire. Credit: C. Allen, USGS” (1)

Improvements in pesticide use by supplier of water in the East Bay

Four years ago, a small group of activists brought their concerns about the use of pesticides to the attention of the Board of East Bay Municipal Utilities Department (EBMUD), the supplier of our water in the East Bay. 

In particular, we showed EBMUD officials photos of inappropriate applications of herbicide, specifically RoundUp (glyphosate).  The photos showed that District employees were spraying RoundUp in residential neighborhoods without posting pesticide application notices.  They weren’t wearing protective gear.  They were spraying RoundUp on bare ground, which is not how RoundUp should be applied because it is not a pre-emergent that is effective on seeds or roots.  It must be sprayed on green vegetation during the growing season.  In one case, the District employee was spraying RoundUp from an ordinary garden hose, which means far more herbicide was being applied than necessary, even if anything were growing there.  In other words, the manner in which RoundUp was being applied suggested that District employees didn’t understand what they were doing.

EBMUD officials were responsive to our report.  They hired a Pesticide Control Advisor as a consultant to evaluate their program who identified several significant deficiencies in the District’s IPM program.  The District responded by making many improvements in their use of pesticides, such as:

  • There is now a comprehensive, annual training program for all employees who apply pesticides.
  • There are now more accurate and complete records of EBMUD’s pesticide use.
  • The PCA consultant was retained on a contractual basis to monitor some pesticide applications for compliance with product labels and District policies.
  • An annual report of the District’s pesticide use, including quantities and products, is presented to the Board at an annual meeting and posted to the District’s website. (1)
  • The District’s IPM Program guidelines were updated and posted to the website in April 2021. (2)
  • The revised guidelines are more comprehensive and detailed.  Requirements for posting notices of pesticide applications are clearer. (2)

Some of these improvements have probably contributed to the decrease in pesticide use in the past five years from over 600 gallons per year to over 400 gallons per year.  Most pesticide used by EBMUD is herbicide and most herbicide used by EBMUD is glyphosate products. 

EBMUD is still using a lot of herbicide, but their practices are safer for their employees and the public.  Their pesticide applications are more visible to the public and the public now has access to information about their pesticide applications. 

EBMUD uses pesticides primarily to maintain their facilities.  Little pesticide is used on EBMUD’s watershed property.  EBMUD does not use herbicide to prevent eucalyptus and bay laurel resprouts when those tree species are destroyed.  Most trees destroyed by EBMUD are intended to reduce fire hazards and many of the tree removals are requested by Cal Fire.   

Lessons Learned

It pays for the public to pay attention to what is happening on our public lands and to speak up if you see something that doesn’t make sense to you.  There are usually mechanisms for figuring out what is happening, asking questions, and making your concerns known. 

Changing public policy isn’t easy, but it can be done.  It’s often frustratingly slow and it takes persistence. Personally, I have found it more effective to be consistently polite and as patient as needed to get your message through. In the case of EBMUD’s pesticide use practices, there is more they can do to reduce their use of pesticides, so the public should continue to pay attention because the quality of our water is extremely important to our health.


  1. Annual IPM Report is available HERE. Scroll down to to “Integrated Pest Management” and lick on “Annual IPM Report.”
  2. IPM Guidelines are available HERE.  Scroll down to “Integrated Pest Management” and click on “IPM Guidelines 2021.”

The Grand Delusion: Controlling Nature

“This is a book about people trying to solve problems created by people trying to solve problems.”

Elizabeth Kolbert’s earlier book, The Sixth Extinction was ground-breaking, not because it described the consequences of climate change in the 21st Century, but because it put modern climate change into the context of similar events in the past 500 million years of life on Earth.  Although the current episode of climate change is man-made, five previous mass extinctions were natural events.  What past extinction events have in common with the sixth extinction is the inevitable consequence of such changes in climate:  when the climate changes, all life on Earth changes with it.  Plants and animals will adapt, change, or they will go extinct as they have for 500 million years. (1)

Kolbert’s new book, Under a White Sky, turns the page on this cataclysmic event in the Earth’s history to focus on the efforts being made to control nature to address environmental problems, including climate change.  To say that Kolbert is skeptical of those efforts is to understate her critical evaluation of them. 

Controlling Nature

In 1990, I was introduced to the human delusion that we can control nature by John McPhee’s The Control of Nature.  His book had a profound influence on my thinking about nature.  It was the basis for my belief that attempts to turn back the botanical clock to 500 years ago to a pre-settlement landscape, mistakenly believed to be pristine, are futile, misguided, and often damaging.  Kolbert’s latest book is written from the same perspective as McPhee’s seminal work and she gives him credit for his pioneering work.

Map of Mississippi River Delta

McPhee’s book predicted the catastrophic flooding of New Orleans by hurricane Katrina in 2005.  Human engineering of the Mississippi River for over 100 years set the stage for that disaster.  New Orleans sits at the Gulf end of the Mississippi River.  Historically, the river flowed from Minnesota to the Gulf, accumulating sediment along its way and depositing it as it entered the Gulf, fanning out into streams and swamps that created the Mississippi Delta.  The labyrinth of land and marsh created by the sediment deposited by the river created a barrier that protected New Orleans from storms. 

However, the uncontrolled and episodic flow of the river caused periodic flooding that was not convenient for the human inhabitants of New Orleans and the Delta community.  So, the flow of the river was controlled by levees and pumps were used to return water from the land to the river.  Sediment from the river could no longer replenish the land because it was confined to the constrained river, which put the human engineers onto a never-ending treadmill of building higher levees and bigger pumps.  It was inevitable that the river would eventually overwhelm the defenses built by the engineers and so it did during Katrina in 2005.

Kolbert updates this untenable situation in the Mississippi Delta in her new book.  The underlying cause, as told by McPhee is recapped by Kolbert.  Then new manmade environmental issues are added to the catastrophic circumstances that will inevitably doom the human inhabitants.  Rising sea levels caused by climate change are one factor.  The incursion of salt water into fresh water swamps killed vegetation that acts as a buffer during storms. Oil and gas exploration and extraction in the Delta has caused the land to drop further. 

Many Delta communities and some neighborhoods in New Orleans have been abandoned because they are essentially underwater.  Since Katrina, no serious effort has been made to change the approach to the issues.  Bigger, more powerful pumps have been built and levees have been made higher and stronger.  No one is seriously considering the need to relocate New Orleans or surrounding communities to higher ground.  The delusion that humans can outsmart the river continues. 

A comedy of errors

Kolbert introduces the many projects that are trying to solve problems that were created by bad decisions made earlier by other humans with a quote from Albert Einstein: “We cannot solve our problems with the same thinking we used when we created them.”  These wise words from a wise man are clearly not being heeded by the masterminds of the projects Kolbert describes in her book:

Dead carp
  • High on the list of projects in which society is heavily investing is the attempt to prevent carp from entering the Great Lakes from the Mississippi River.  After many different approaches were tried and failed, the current strategy is an electrified fence separating the Chicago River (connecting to the Mississippi River) from Lake Michigan that kills untold thousands of fish every day.  This deadly project is the end stage of previous bad decisions.  A link between Lake Michigan and the Mississippi River was created by a massive engineering project that reversed the flow of the Chicago River in 1887.  Later, carp was introduced to the Mississippi River from China as biological control to address pollution issues.  One species of carp was introduced to control aquatic weeds and another carp species was introduced to consume nutrients in sewage ponds.  Kolbert says such biological controls became popular after Silent Spring was published because Rachel Carson considered pesticides a curse and biological control a panacea. (Which is not to say that pesticides aren’t a curse.) In other words, we traded one problem for another.
  • Island eradications of introduced mammals such as rats and mice are also popular projects (with some people).  Genetic engineering is being aggressively pursued as a possible substitute for the rodenticides that are being used for these projects.  These projects have the potential to drive an entire species into extinction or alter their physiology such that they could become killers or prevent them from being killers.  Kolbert buys a genetic engineering kit for $209 from a young entrepreneur in Oakland that enables her to make E.coli cells resistant to an antibiotic.  E.coli is a deadly bacteria that can be fatal if untreated by antibiotics.  In other words, anyone with $209 can turn bacteria into killers with no special training or equipment.  What could possibly go wrong, Kolbert asks rhetorically.

The promise and threat of geoengineering

Kolbert visits several different geoengineering projects that are trying to prevent the consequences of climate change without reducing greenhouse gas emissions, the underlying cause of climate change.  One such project is turning CO₂ into stone.  Apparently it CAN be done, but to do it on a scale that would actually prevent climate change would be to devote much of the surface of the Earth to that purpose. 

Kolbert visits a project that believes injecting aerosols into the atmosphere to block the sun is the best bet to stop climate change.  The proposal strikes Kolbert as both preposterous and dangerous.  The researcher detects her skepticism and retorts, “People think of all the bad examples of environmental modification.  They forget all the ones that are more or less working.  There’s a weed, tamarisk, originally from Egypt.  It’s spread all around the desert Southwest and has been destructive.  After a bunch of trials, they imported some bug that eats the tamarisk, and apparently it’s kind of working.” 

Tamarisk defoliation along Colorado River, near Needles, California

In fact, the introduced tamarisk beetle is working too well.  It has spread far beyond the regions where it was introduced and produced wastelands of dead trees in Arizona and Southern California.  Since one of the rarest desert birds depends upon tamarisk there isn’t much to celebrate about this over-achiever beetle.

Compounding the problem

Instead of addressing the source of environmental issues, we compound them by creating new problems with our theoretical “fixes.”  The native plant movement, in their zeal to save native plants, sprays herbicides that kill as many native plants as non-native plants and poison the soil while doing so, stunting all new growth, both native and non-native. 

I share Kolbert’s skepticism about the projects she describes for the same reasons she gives.  Every “fix” has the potential to create new problems that could be more disastrous than the problems they are meant to resolve.  And the resources used to develop new techniques such as massive geoengineering projects could be used instead to address the underlying cause of the problem, which is the greenhouse gas emissions causing climate change.  We don’t want to give up our fossil-fuel driven economy, so instead we conjure up even more damaging ways to ameliorate the inconveniences of climate change.  It’s a fantasy that prolongs and exacerbates the consequences of climate change.

Finally, let’s give Kolbert the last word:  “This has been a book about people trying to solve problems created by people trying to solve problems…Geoengineering may be ‘entirely crazy and quite disconcerting,’ but if it could slow the melting of the Greenland ice sheet, or take some of ‘the pain and suffering away,’ or help prevent no-longer-fully-natural ecosystems from collapsing, doesn’t it have to be considered?…But to imagine that ‘dimming the fucking sun’ could be less dangerous than not dimming it, you have to imagine not only that the technology will work according to plan but it will be deployed according to plan.  And that’s a lot of imagining…But let’s just say the record here isn’t strong.”  (2)

Thank you, Elizabeth Kolbert, for calling out the grand delusions of humans who mistakenly believe it is possible to control nature to avoid inconveniencing human society. 


  1. Elizabeth Kolbert, The Sixth Extinction, Henry Holt and Co., 2014
  2. Elizabeth Kolbert, Under a White Sky, Crown New York, 2021

What does this mean: “Nature-based solutions to achieve California’s climate change and biodiversity goals”?

In October 2020, Governor Newsom signed Executive Order N-82-20 “enlisting California’s vast network of natural and working lands – forests, rangelands, farms, wetlands, coast, deserts and urban greenspaces – in the fight against climate change. A core pillar of Governor Newsom’s climate agenda, these novel approaches will help clean the air and water for communities throughout the state and support California’s unique biodiversity.”

The California Natural Resources Agency has invited the public to tell them what you think that means.  They are holding a series of virtual on-line workshops (register here) and they are inviting the public to complete a survey (available here) by the deadline of May 14, 2021.  Recordings of workshops that have already taken place are available HERE.   Email address for feedback and questions is californianature@resources.ca.gov.

Click on picture to see San Francisco Bay Area regional workshop

I attended one of the workshops and I’ve read the material available on their website.  This is what little I can tell you about the project.  There seem to be three elements to this initiative:

  • The Natural and Working Lands Climate Smart Strategy will “expand climate smart land management across California to achieving carbon neutrality and reduce climate risks to communities and ecosystems and build climate resilience across California.”
  • The 30X30 initiative establishes a state goal of conserving at least 30 percent of California’s land and coastal waters by 2030, while “safeguarding our State’s economic sustainability and food security, protecting and restoring biodiversity.” Conservation measures will focus on a “broad range of landscapes, including natural areas and working lands, in partnership with land managers and natural resource user groups while building climate resilience and reducing risk from extreme climate events.”  Projects will also “expand equitable outdoor access and recreation for all Californians.”  Approximately 22% of land in California is presently protected, but only 16% of our coastal waters. 
  • “The California Biodiversity Collaborative will bring together groups and leaders from across our state to take bold action to maintain California’s extraordinary natural richness. This Collaborative was a directive set forth in Governor Newsom’s 30×30 Executive Order and is the next generation of the State’s Biodiversity Initiative.”

I have no idea what these vague commitments mean when they are translated into specific land acquisitions and funded projects, but I know that non-governmental organizations see this as an opportunity to obtain funding for what they want. 

Only 10% of the audience for the San Francisco Bay Region workshop was the general public. Over 50% of the 280 people at the workshop (by far the largest constituency at the workshop) I attended were employees of non-governmental organizations.  The California Invasive Plant Council (Cal-IPC) asked their members to attend the workshops and participate in them:  “This is a critical opportunity to make sure the need for invasive plant management is heard, loud and clear. We encourage you to attend to learn more about 30×30 and share your ideas.”  These are Cal-IPC’s suggestions for participants:  “Several points to consider making: (1) the definition of “protected” — and the metrics used to measure 30×30 success — need to include adequate funding for ongoing stewardship; (2) funding for the Weed Management Area (WMA) program is critical for county collaborations staying on top of high priority invasive plants across jurisdictional boundaries; (3) wildfire fuels reduction should follow best practices, including control of invasive plants, so that habitat is enhanced, not damaged.” California Native Plant Society is also asking its membership to participate in the 30 X 30 public outreach effort in support of CNPS objectives.

If you have your own priorities for how your tax dollars are used, you may want to participate in this public process as well because the projects will have an impact on land management practices throughout the State of California.  Please consider attending a workshop and completing the long, complex, and vague on-line survey by May 14, 2021.  I have no idea if the California Natural Resources Agency will take the public’s input into consideration, but I know this:  If you don’t participate, you will take whatever you get. 

What I WANT it to mean

This initiative is going to be a major public investment and non-governmental non-profit organizations see it as an opportunity to fund their projects.  The disparate goals of this initiative are often in conflict.  If climate change solutions and related wildfire hazard reduction goals conflict with biodiversity goals, addressing climate change hazards must be the top priority because all life is threatened by the consequences of climate change.  The public must understand that when the climate changes, the vegetation changes.  The ranges of native plants and animals have changed and will continue to change in response to climate change.  Native vegetation is not inherently less flammable than non-native vegetation.

On August 18, 2020, the CZU Lightning Complex Fire swept through Big Basin Redwoods State Park, burning over 97% of the land, forested in native redwood trees. (AP Photo/NicCoury published by CA State Parks)

The native plant movement is a form of climate change denial.  We cannot replicate the landscape of 250 years ago, as native plant advocates wish, because it is not adapted to the current and anticipated climate.  Biodiversity is appropriately defined as all species of plants and animals, regardless of their origins.  Forests are major carbon sinks, whether they are native or considered non-native by people with a short-term perspective of nature and evolution.

Over 160 million native conifers have died in California in the past 8 years. They were killed by high temperatures, drought, and native bark beetles. All of these factors are consequences of climate change.

The survey for this project is not user friendly.  Within its constraints, here is a sample of the specific points I was able to make:  “Do not fund projects that use pesticides, including herbicides.  Do not replace established vegetation that does not require irrigation with vegetation that will require irrigation to become established.  Do not fund projects that will require recreational access restrictions. Stop eradicating non-native spartina marsh grass with herbicides because it protects wetlands year around from storm surges.  Where afforestation is possible, plant only trees that are adapted to the current and anticipated climate. Fund projects that protect residential communities from coastal flooding and salt-water incursion into ground water. Fuels management projects must assume that native and non-native vegetation is equally flammable because flammability is unrelated to the origin of plants.  If climate solutions conflict with biodiversity goals, climate solutions should be the top priority because all life is threatened by climate change.  If fuels management goals conflict with biodiversity goals, fire safety should be the top priority.”

Michael Soulé: The consequences of crisis conservation

Recently published Beloved Beasts is a collection of brief biographies of major figures in conservation, starting with Carl Linnaeus, the creator of the system of classifying plant and animal species in the 18th Century that is still used today.  I was most interested in the chapter about Michael Soulé because I knew the least about him.  I heard Soulé speak at the California Native Plant Society conference in 2015.  He was very angry about the criticism of invasion biology that had recently emerged and was getting louder.  He wasn’t having it!

Daniel Simberloff is an ally of Michael Soulé’s. This is Simberloff’s rogues gallery of critics of invasion biology shown at the most recent conference of the California Invasive Plant Council in October 2020. The chorus of critics is bigger than it was in 2015 when Soulé spoke to the California Native Plant Society.

Beloved Beasts explained that Soulé was one of the first academic scientists to engage in political activism in support of his beliefs about conservation and he was an active participant in the major turning points in conservation science and practice.  His approach was unique at the time because data and analysis took a back seat to what he called “crisis conservation.”  Most academic scientists are reluctant to take their knowledge into the realm of public policy.  As a student of Paul Ehrlich, the author of Population Bomb, Soulé was a member of the doom and gloom crowd.  He and his colleagues believed that human population was devouring the planet.  They said we can’t wait for careful analysis, we must act.

Crisis Conservation

Crisis conservation requires a top-down strategy.  The “experts” want the authority to dictate conservation strategies so they can be implemented quickly without the interference of the public who is considered the source of environmental problems, not the solution.  I encountered this attitude over 20 years ago when I objected to plans to transform the public parks of San Francisco into native plant gardens in which the public was not welcome.  In a heated debate over the 700-page plan for this transformation, the leading light of the native plant movement in San Francisco admitted that he had not read the plan and did not intend to read it.  He said, “We know what needs to be done and we just want to be left alone to do it.” He was as angry about the public’s interference as Michael Soulé was about other academic scientists questioning his opinion that non-native plants and animals must be eradicated.

The author of Beloved Beasts explains the disadvantages of the top down approach to conservation in a chapter about conservation projects in Namibia.  The goal of these projects is to preserve wildlife, including critically endangered animals such as rhinos.  Initially, protected areas were created that excluded indigenous people and rangers were hired to patrol and enforce prohibitions against hunting.  It quickly became apparent that the people who lived there could not be prevented from hunting, particularly during extreme droughts in which starvation was the only alternative to hunting.  A handful of rangers were no match for a much larger population of residents who were more familiar with the land and the animals living there. 

Over time, project leaders realized that a new strategy was needed that would include the participation and accommodation of the people.  The residents were given the authority to organize themselves into community conservation groups that set hunting quotas and enforced them themselves.  Cooperative relationships with hunting tourism organizations provided revenue to the residents to compensate them for the loss of some of the food they had hunted in the past.  These conservations groups were possible because indigenous people usually care as much about wild animals as foreign visitors do. 

The tragedy of the commons

The narrative of the tragedy of the commons was central to the beliefs of Soulé and his allies and it supported their authoritarian approach to conservation projects.  The tragedy of the commons assumes that a shared resource will be depleted by its users absent legal regulation and enforcement.  As popularized by Garrett Hardin in 1968, “Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons.  Freedom in a commons brings ruin to all.”  That viewpoint justifies authoritarian control over the people who share a resource, who are presumed to be irresponsible users of the resource.

Community conservation projects in Namibia are not consistent with the dire predictions of the tragedy of the commons because the indigenous people cared as much about the wild animals as the foreign visitors of the animals.  Many examples have existed and still do exist where members of a community with regulated access to a common resource co-operate to exploit those resources prudently without collapse. Elinor Ostrom was awarded the 2009 Nobel Prize in Economic Science for demonstrating this concept in her book Governing the Commons, which included examples of how local communities were able to do this without top-down regulations or privatization.

Elinor Ostrom had a unique understanding of the complexity of human society and she was deeply suspicious of conservation strategies portrayed as a magic bullet.  According to Beloved Beasts, “She knew how corrosive panaceas could be; all her data could not dislodge Hardin’s metaphor from the public imagination, and the tragedy of the commons remains a powerful panacea for optimism.”  Beloved Beasts endorses Ostrom’s viewpoint:  “The great challenge of conservation is to sustain complexity, in its many forms, and by doing so protect the possibility of a future for all life on earth.  And for that, there are no panaceas.”

At the core of the native plant movement is the mistaken belief that the existence of non-native plants is the sole obstacle to the survival of native plants.  This is an oversimplification of complex ecosystems that are undergoing rapid change and are evolving and adapting to those changes.  Eradicating non-native plants and animals is not a panacea.  In fact, in many cases futile attempts at eradication are doing far more harm than good. 

Unintended Consequences

The unintended consequences of many conservation projects are the cost of the top-down strategies used to design the projects.  The “experts” frequently do not realize the limits of their knowledge. The “crisis” mentality prevents the careful analysis needed to prevent disastrous outcomes.

green crab

A failed effort to eradicate green crabs in a lagoon in Marin County is a case in point.  After years of killing adult green crabs, the total crab population exploded to 30 times its original size.  The failure of the project was studied by scientists who were not responsible for the original project.  They knew that adult crabs eat their young.  When the adults were killed, the unchecked population of young crabs exploded.  Genetic studies also determined that the green crabs in the lagoon are related and connected to green crab populations in adjacent bodies of water.  The green crab population in the Bay Area is a regional, not a local issue.  Taking a longer view of the issue also revealed fluctuations in the population over the long-term, suggesting that a crisis response is inappropriate over time.  Such fluctuations in abundance are common in nature.  The second team of scientists recommended a new, much less aggressive management approach that aims to keep the population below 40% capacity.

The professor and ecologist who revised the strategy explained what he learned from the experience:  “A failure in science often leads to unexpected directions. We slapped our foreheads at the time, but with thought and understanding, it’s told us a lot about what we shouldn’t be doing and provided a way forward for us. The world should get less focused on total eradication and work toward functional eradication.”

Sacrificing common animals in service of rare animals

Crisis conservation is committed to preserving species rather than individual animals.  Those who subscribe to that agenda are willing to sacrifice individual lives. For example, native barred owls are being shot because they are perceived to be competitors of rare spotted owls.  We are sacrificing common animals to save rare animals. 

Farallon Islands, NOAA. Click on the picture to see a brief video about the Farallons eradication project and the email address of the California Coastal Commission to comment on the project.

A proposed project on the Farallon Islands is an example of a project that will sacrifice hundreds of individual birds and marine mammals based on the belief that one species of rare sea bird will benefit.  The project will aerial drop 1.5 tons of rodenticide on the Farallon Islands with the intention of killing mice.  The mice don’t eat birds or chicks, but they are the preferred prey of a small population of burrowing owls who eat chicks of the rare sea bird.  The project claims that the burrowing owls won’t visit the Farallons if the mice are eradicated.  The project admits that there will be “collateral” damage from the rodenticide that is likely to be eaten by hundreds of non-target birds and marine mammals.  This loss seems worthwhile to the promoters of this project.  It seems entirely unjustified to me and many others. 

The message of Beloved Beasts

Beloved Beasts makes a strong case for a conservation strategy that considers the needs of humans and values the lives of individual animals.  Such a strategy requires greater appreciation of the complexity of nature and animal societies, including human society.  It is suspicious of simple solutions that often have unintended consequences.  For all these reasons Beloved Beasts is entirely consistent with the mission of Conservation Sense and Nonsense.  I recommend it to you with enthusiasm. 

Looking for Godot: Finding achievable restoration goals

There are chemical and non-chemical approaches to native plant restoration. Neither succeeds.  Non-chemical methods are labor-intensive, which makes them prohibitively expensive.  Chemicals are cheaper and they kill non-native plants, but they don’t restore native plants because they kill them and damage the soil. Either strategy must be repeated continuously to be maintained. This article is the 25-year story of reaching the conclusion that neither chemical nor non-chemical approaches are capable of restoring native plants on a landscape scale.  Where do we go from here?

In 2014, the California Invasive Plant Council (Cal-IPC) conducted a survey of land managers to learn what methods they were using to control plants they considered “invasive.”  The Cal-IPC survey reported that herbicides are used by 94% of land managers and 62% use them frequently.  Glyphosate was the most frequently used herbicide by far. In 2014, no other eradication method was used more frequently than herbicides.

Frequency of herbicide use by land managers in California to kill “invasive” plants. Source California Invasive Plant Council, 2014

We have learned a great deal about the dangers of herbicides since 2014. 

  • The World Health Organization has categorized the most frequently used herbicide—glyphosate—as a probable carcinogen.
  • The manufacturer of glyphosate, Monsanto-Bayer, was successfully sued by terminally ill users of glyphosate.  These product liability lawsuits resulted in multi-million dollar awards for damages. The awards were reduced on appeal but ultimately upheld.  Monsanto has agreed to pay more than $10 billion to settle close to 100,000 product liability claims. 
  • The US Environmental Protection Agency has finally published its Biological Evaluation (BE) of the impact of glyphosate products (all registered formulations of glyphosate products were studied) on endangered animals (mammals, birds, amphibians, reptiles, fish, invertebrates) and plants. The BE reports that 1,676 endangered species are “likely adversely affected” by glyphosate products. That is93% of the total of 1,795 endangered species evaluated by the study. Both agricultural and non-agricultural uses of glyphosate products were evaluated by the BE. Although only endangered plants and animals were evaluated by the BE, we should assume that all other plants and animals are likewise harmed by glyphosate because the botanical and physiological functions of plants and animals are the same, whether or not they are endangered. 

How have land managers responded to the dangers of herbicides?

San Francisco’s Recreation and Park Department has increased the use of herbicides in public parks every year since 2016.  In 2020, herbicide use increased significantly from 243 applications in 2019 to 295 applications in 2020.  SF RPD has been spraying herbicides on non-native plants for over 20 years.  They have been using hazardous herbicides on some 50 target plant species year after year. The longer they use them, the more resistance to the herbicides the plant develops.

Herbicides used by Natural Resource Division of San Francisco Recreation and Parks Department. Source San Francisco Forest Alliance based on public records of pesticide use

Chris Geiger, director of the integrated pest management program at the San Francisco Department of the Environment, told San Francisco Public Press that although the city has reduced its use of glyphosate outside parks, it won’t ban glyphosate because it hasn’t found a more efficient or safer alternative for controlling some weeds. He said, “In habitat management, there are certain plants you cannot remove from a natural area by hand.”

San Francisco’s IPM program recently published  “Pest Prevention by Design Guide” that illustrates the bind they are in with respect to promoting native plants while trying to reduce pesticide use.  On the one hand, the Guide promotes the use of native plants in landscape design plans by making the usual claim that “Native species are generally best suited to supporting local insect populations and ecosystems.”  On the other hand, the Guide recommends the use of “pest resistant” species that are not eaten by insects and grazing animals and are capable of outcompeting weeds.  Can’t have it both ways, folks!!  

East Bay Regional Park District has made a commitment to phase out the use of glyphosate in developed areas such as parking lots, playgrounds and picnic areas.  However, EBRPD remains committed to using glyphosate and other herbicides to eradicate non-native plants on undeveloped park land. In 2020, no glyphosate was used in developed areas, but about 23 gallons of glyphosate were used to eradicate non-native plants on undeveloped park land. Twenty-one gallons of triclopyr were also used to eradicate non-native shrubs and to prevent non-native trees from resprouting after they were cut down. They continued the 15-year effort to eradicate spartina marsh grass with imazapyr. A few other selective herbicides were used on other eradication projects. (2)

In the San Francisco Bay Area, most land managers are still committed to using herbicides, particularly in so-called “natural areas,” regardless of the damage herbicides do to human health, wildlife, and native plants.  In fact, the City of Oakland is planning to begin using herbicides on 2,000 acres of public parks and open spaces for the first time to implement its vegetation management plan.  The vegetation management plan is both a fuels reduction program and a “resource protection” program, which is a euphemism for native plant “restoration.”

Given what we now know about the dangers of herbicides, why are public land managers still committed to using herbicides?  The City of Oakland explains in the EIR for its vegetation management plan why it is proposing the use of herbicides where they were prohibited in the past:

“It is estimated that if the City were to rely on hand removal and mechanical treatments in place of herbicide, it would cost the City up to 40 times more to treat these areas than under the VMP. The cost for herbicide treatments, not including any associated physical treatments, is approximately $250-$500 per acre. This reflects a range of potential vegetation conditions, vegetation types, and densities. The cost for hand removal and mechanical treatments is estimated at approximately $1,000-$4,000 per acre, using the same range of site-specific conditions.” (page 5-9)

In other words, herbicides are the preferred method of killing non-native plants because it is the cheapest method.  However, there is another reason why herbicides are preferred to non-chemical methods.  There isn’t a non-chemical method that is more effective than using herbicides.

Looking for an alternative to herbicides

As we should expect, new information about glyphosate has increased the public’s awareness of the dangers of pesticides.  California Invasive Plant Council has responded to the public’s growing awareness and concern about the herbicides to which they are exposed in our public parks and open spaces.  They recently published a comprehensive 300-page brochure entitled “Best Management Practices for Non-Chemical Weed Control.”  (1) Many highly qualified land managers participated in the preparation of this credible publication.  The Cal-IPC brochure is credible because it frankly admits that no method of eradication is without problems.  Irrigation and intensive planting are required for good results, but without continuing regular maintenance the results are only temporary.  Few land managers have the resources needed for success.

If you wonder why herbicides are the preferred method of eradicating non-native plants, reading Cal-IPC’s brochure about non-chemical methods will tell you why.  There is no non-chemical method that achieves better results than using herbicide. 

Herbicides are not a magic bullet

Herbicides are the most frequently used method of killing non-native plants, but using herbicides does NOT result in a native landscape.  “Lessons learned from invasive plant control experiments:  a systematic review and meta-analysis,” analyzed 355 studies published from 1960 to 2009 to determine which control efforts were most effective at eradicating the target plants and which method was most successful in restoring native plants. The analysis found that “More than 55% of the studies applied herbicide for invasive plant control.” Herbicides were most effective at reducing invasive plant cover, “but this was not accompanied by a substantial increase in native species,” because, “Impacts to native species can be greatest when programs involve herbicide application.”  It’s not possible to kill non-native plants without simultaneously killing native plants and damaging the soil.

Reaching a dead—and deadly—end

Public land managers in the San Francisco Bay Area have been trying to restore native landscapes for over 25 years.  Every project begins by eradicating non-native plants, usually with herbicides.  Our public parks have been poisoned repeatedly, but native landscapes have not replaced the plants that were killed.  Meanwhile, we have learned that herbicides are dangerous to our health and animals who live in our parks. 

Oyster Bay is a park in San Leandro that was built on a former garbage dump on landfill in the San Francisco Bay.  The garbage was capped with barren soil and many acres were planted with native bunch grass, as shown in these photos.  This “restoration” method is called competitive planting. The bunch grasses did not survive and the ground was quickly colonized by weeds that were then sprayed with herbicides. 

The only viable alternative to using herbicides to “restore” native plants is to change the goals for native plant restorations such that herbicides won’t be required: 

  • An exclusively native landscape cannot be achieved where native plants have never existed, such as the many parks along the bay waterfront that were built on landfill.  It is an unrealistic goal.
  • Given that no effective method of achieving this unrealistic goal has been found after 25 years and the most popular method is poisoning our environment, it is time to stop trying.
  • Smaller, achievable goals must be set.  Landscape scale projects should be abandoned and replaced with small scale projects where native plants already exist. 
  • Smaller areas can be managed without using herbicides because they will be affordable to manage with labor-intensive methods that are more expensive.
  • If smaller projects are more successful, they will be less controversial.  The projects are unpopular partly because they aren’t successful. 

The native plant movement in the San Francisco Bay Area has bitten off more than it can chew.  Native plant advocates need to back out of their dead end and regroup with plans that are less destructive and more realistic.  As the Economist magazine said in 2015, “you can garden in a garden, but you can’t garden nature.”


(1) California Invasive Plant Council is offering free video training for non-chemical methods of killing “invasive” plants on May 4, 2021, 1-5 pm.  Sign up HERE. 

(2) 2020 IPM Report, East Bay Regional Park District available HERE.   

Computer models predict the future? Garbage in, garbage out

Computer modeling is an increasingly popular tool used in ecological studies.  The rapidly changing climate is putting pressure on scientists to predict the trajectory of the change and the impacts those changes will have on the environment.  However, a computer model is only as predictive as the assumptions used to build it.  In other words, “garbage in, garbage out.”

That sets the stage for a study published in 2018 that predicted that “grassland may be a more reliable carbon sink than forests in California.”(1) The study was quickly adopted by native plant advocates as a weapon in their battle to destroy non-native trees in favor of grassland they prefer. (2) They prefer grassland because it was the pre-settlement coastal landscape.  They don’t acknowledge that burning by Native Americans and grazing by native ungulates were the primary reasons why grassland did not succeed to shrubs and forests prior to settlement. Pre-settlement grassland was as much a human creation as any modern landscape.

Source: US EPA, 2018

Most carbon storage is below ground, in roots and soil.  That is true of both grassland and forests. If the forest burns, the carbon it has stored in soil remains, just as the below ground carbon sink of grassland remains. 

The study (1) that claims grassland may be a more reliable carbon sink than forests reaches its erroneous conclusion by comparing below ground carbon storage in grassland with above ground carbon storage in forests. It’s a classic case of inappropriately comparing apples with oranges to the disadvantage of forests.  It seemed such an unlikely comparison that I asked the study’s authors to confirm they had compared below ground carbon storage in grassland with above ground carbon storage in forests.  They confirmed that they did, indeed, make that inappropriate comparison.

The study also bolsters its mistaken conclusions by erroneously claiming that forests are more likely to burn than grasses:

“The fire resistance for grasses is 0.5 while that of trees range from 0.1−0.3, making grasses more resistant to wildfires than trees, which is roughly consistent with field-observations since in the event of a wildfire, when compared to trees, a smaller fraction of the biomass of grass is damaged.” (1)

However, the study cited as the source of this statement (3) says exactly the opposite:

“The fraction of individuals killed depends upon the prescribed PFT fire resistance, which represents the PFT survivorship during a fire (see Table 1). In the fire model, grasses and litter are fully consumed.” (3)

Table 1 PFT parameter values for fire resistance
PFTFire Resistance (%)
Woody
Tropical broad-leaved evergreen12.0
Tropical broad-leaved raingreen50.0
Temperate needle-leaved evergreen12.0
Temperate broad-leaved evergreen50.0
Temperate broad-leaved summergreen12.0
Boreal needle-leaved evergreen12.0
Boreal summergreen12.0
Grasses
C3 grass100.0
C4 grass100.0

Table 1 is consistent with this statement in the abstract of the cited study:  “Estimated litter moisture is the main driver of day‐to‐day fire probability.”  (3) Forests retain more moisture in the soil and leaf litter because of the shade provided by the tree canopy.  I wrote to the study author again, asking “where is the source of your statement that grasses are more fire resistant than trees?”  He did not reply.

If a study doesn’t seem to make sense, or it contradicts other sources of information, it is worthwhile to look under the hood.  What is driving the model?  Is it fueled by hot air?  Is it serving an activist agenda? Are cited studies accurately quoted? 

Some truth emerges from the model’s black box

Despite the erroneous assumptions of the computer model used by this study, there is some truth in the conclusions it reaches.  Vegetation type conversions are occurring now and they will continue as the climate continues to change because when the climate changes, the vegetation changes. We are presently witnessing the transition of native conifers at high altitudes to lower altitude hardwood trees. Although these changes will occur gradually and there will be many intermediary transitions, the fact is that grassland is more likely to survive than forests in a warmer, drier climate in the long run. 

The Guardian has published a comprehensive report about the loss of forests all over the world.  In the Rocky Mountains, one-third of places where trees burned 20 years ago are now occupied by shrubs and flowers.  About 15% of forests in the Rocky Mountains are not expected to grow back if killed by fire because the climate is no longer suitable for them.  About half of existing forests in Alberta, Canada are expected to vanish by 2100.  The “megadrought” in south-western US is expected to convert 30% of forests to shrubland or another type of ecosystem.

In the short run, the loss of forests can be mitigated by reforestation with tree species that are better adapted to a warmer, drier climate.  The study (1) acknowledges the potential for mitigation to preserve forest ecosystems:  Factors such as species traits, biodiversity, rapid evolution, and human management intervention could alter our model-based findings from the projections provided here. Consequently, our results indicate the potential direction of change as opposed to predictions that consider the full ensemble of ecological, physiological and management factors that can alter pathways and responses of ecosystems to climate change.”

From the standpoint of carbon storage, it is not good news that grassland is likely to inherit hot, dry lands previously occupied by forests.  Forests and wetlands store more carbon than grasslands, as the above chart in a USDA publication about carbon storage shows.  Sustaining below ground carbon sinks will depend on carbon sequestration by above-ground plants and trees.  Because above-ground carbon sequestration is primarily dependent upon the biomass, forests will always do a better job than grassland in the long run.  In the short-run, grassland will grow back more quickly than forests, but it will never achieve comparable biomass. 

Forests are presently absorbing about one-quarter of all human carbon emissions annually. Forests make a significant contribution to reducing carbon emissions, but planting trees is not a panacea as long we continue to burn fossil fuels to generate energy. The loss of carbon-sequestering capabilities of forests will exacerbate climate change in the long-run.  It’s one of many dreaded feedback loops that are reaching tipping points:  the impacts of climate change are destroying the mechanisms that mitigate climate change. 

The study (1) acknowledges that by the end of the 21st Century, under current climate conditions (warming limited to 0.3⁰ – 1.7⁰ Centigrade) forests will have removed 5 times more net carbon (carbon storage minus carbon loss) per hectare from the atmosphere than grassland in California.  See Table 1 in the study (1).  Thus, the study agrees that forests store more carbon than grassland.

From the standpoint of wildlife, it is not good news that grassland is likely to replace forests in a warmer climate. The insects, birds, and animals that live in the forest will lose their habitat. Forests are home to over 80% of terrestrial species.  We will lose our shade in a warming climate and our windbreak. 

Not an argument for destroying forests

This study (1) is unfortunately being used by the native plant movement to advocate for the preemptive destruction of healthy urban forests that are not more likely than native forests to burn in wildfires.  Virtually all wildfires in California occur in native vegetation. There is no advantage to destroying healthy forests that are expected to live for another 100-200 years.  We don’t amputate our limbs to avoid breaking them.  Nor should we destroy our forests before they die.

(1)“Grasslands may be more reliable carbon sinks than forests in California,” Pawlok Dass, Benjamin Z Houlton, Yingping Wang and David Warlind, 10 July 2018, Environmental Research Letters, Volume 13, Number 7 

(2) “Importance of Grasslands for Carbon Storage,” Yerba Buena Chapter of California Native Plant Council, Quarterly Newsletter, March 2021, page 6. 

(3) “The role of fire disturbance for global vegetation dynamics: coupling fire into a dynamic global vegetation model,” Thonicke K, Venevsky S, Sitch S and Cramer W 2001,  Glob. Ecol. Biogeogr.10 661–77

The founding error of American environmentalism

The Sierra Club, like many American institutions, is trying to come to grips with systemic racism.  The Club was founded in 1892 under the leadership of John Muir who “…made derogatory comments about Black and Indigenous peoples that drew deeply on harmful racist stereotypes, though his views evolved later in his life,” according to Sierra Club executive director Michael Brune in his letter of July 2020 to Club members (available HERE).

John Muir is the founder of the Sierra Club.

Author and activist, Rebecca Solnit, follows up on the roots of racism in the American environmental movement in the most recent edition of Sierra Magazine, the national magazine for Club members.  Her telling of events reveals the founding error of the native plant movement that was based on the mistaken assumption that European settlers were entering a pristine landscape that had been unaltered by humans.  The goal of the native plant movement has therefore been to replicate the pre-settlement landscape, presumed to be the ideal landscape.

Early settlers were well aware that they were entering occupied land.  After all, the settlers had to dispossess Native Americans to occupy the land.  But that reality was quickly forgotten, enabling “the lovers of the beauty of the American landscape who reimagined the whole continent before 1492 as an empty place where, as the Wilderness Act of 1964 puts it, ‘the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.’” (1)

John Muir’s lack of respect for Indigenous culture prevented him from understanding that he was looking at the results of Indigenous land management when he admired Yosemite Valley:  “The word garden occurs over and over in the young John Muir’s rapturous account of his summer in the Sierra Nevada in 1869. ‘More beautiful, better kept gardens cannot be imagined,’ he declared. When he saw Yosemite Valley from the north rim, he noted, ‘the level bottom seemed to be dressed like a garden.’ He assumed he knew who was the gardener in the valley and the heights, the meadows and the groves: ‘So trim and tasteful are these silvery, spiry groves one would fancy they must have been placed in position by some master landscape gardener. . . . But Nature is the only gardener able to do work so fine.’” (1)

In fact, Yosemite Valley looked like a garden to John Muir, because it was a garden, the garden tended by Native Americans for thousands of years:

“Native Americans as hunters, gatherers, agriculturalists and horticulturalists, users of fire as a land-management technique, and makers of routes across the continent played a profound role in creating the magnificent North American landscape that Europeans invaded. Their use of fire helped maintain plants and spaces that benefited these first human inhabitants—including increasing animal populations, causing plants to put forth new growth in the form of straight shoots suitable for arrow making and basket making, and keeping forests open and underbrush down. In Yosemite Valley, burning encouraged oak trees and grasslands to flourish; conifers have since overtaken many meadows and deciduous groves. The recent fires across the West are most of all a result of climate change—but more than a century of fire suppression by a society that could only imagine fire as destructive contributed meaningfully.” (1)

Native Americans setting grass fire, painting by Frederic Remington, 1908

Solnit correctly describes the consequences of this founding error on the development of environmentalism:  “Had he been able to recognize and convey that the places he admired so enthusiastically looked like gardens because they were gardens, the plants in them encouraged, the forests managed by the areas’ Native people, the history of the American environmental movement might have been different.”  (1)

Solnit believes there are three significant losses to American society and the environmental movement because of the initial lack of respect for Native Americans and their cultural practices.  The first was the greatest loss to Native Americans because disrespect for them as people and a functioning society made it easier to justify dispossessing and marginalizing them.  The second was the loss to American society that would have benefitted from understanding and emulating their accomplishments.  And the third loss was the founding error of American conservation policy that is based on the mistaken assumption that the pre-settlement landscape is the ideal landscape because it was unchanged by humans.

Several recent scientific studies have found that lands occupied by indigenous people in Australia, Brazil, and Canada have much more biodiversity than lands that have been designated as “protected areas” by governments.  Typically, indigenous people have been forced out of the protected areas, based on the assumption of traditional conservation that humans harm the environment.  As the Coordinator of Indigenous Organizations of the Amazon River Basin explains in a recent article in New York Times, “If you’re going to save only the insects and the animals and not the Indigenous people, there’s a big contradiction [because] we’re one ecosystem.”

A new conservation ethic

Our conservation goals require a major revision to right this wrong.  New goals must acknowledge that humans have altered every place on the planet for thousands of years.  New goals will acknowledge that nature is dynamic, that changes in nature are usually impossible to reverse, and that they have both positive and negative impacts. New goals will be adapted to the current environment, such as higher temperatures and drought.  New land management strategies can be informed by those used by Native Americans, but replicating the landscapes of 500 years ago will remain out of reach because underlying conditions have been fundamentally altered by evolution and the activities of modern society.

A new conservation ethic can honor the traditions of Native Americans as well as the sovereignty of nature.  We must stop damaging nature in the futile effort to replicate a landscape that was as much a human creation as the landscape of the Anthropocene era. 


(1) “Unfinished Business:  John Muir in Native America,” Rebecca Solnit, Sierra Magazine, March/April 2021