Tag: environment

Life on Earth has saved itself many times without help from humans. It must do so again.

“What exists now can only ever come from what came before.” –Thomas Halliday, Otherlands

The consequences of climate change were more severe this summer than ever before:

  • Many places around the globe experienced extreme and prolonged heat waves.
  • Extreme heat caused wildfires in many places around the world.
  • There were also many severe floods all over the world.
  • The collapse of a glacier and the bedrock under it killed thousands of people in Nepal and warned of similar cataclysmic events elsewhere in the future.
  • NOAA is predicting the strongest El Niño on record in 2026-2027.  It is expected to cause heavy rain in some places (such as California) and extreme droughts in other places around the world.

America is unwilling to do anything to reduce greenhouse gases causing climate change.  In fact, we are developing more sources of fossil fuels and preventing the development of renewable sources of energy that do not contribute to greenhouse gases causing climate change.

Today, I would like to put these radical changes in our planet into some perspective, by revisiting some of the many catastrophic changes on Earth in the 4.6 billion years of its existence.  In the 3.7 billion years that life has existed on Earth, 98% of all living species have become extinct. The species that survived those events were best adapted to the changed environment and many more evolved as conditions allowed. There are more species of plants and animals now than ever before, but many are threatened by climate change. 

Homo sapiens have lived on Earth for only about 300,000 years.  Clearly, humans have had little to do with the appearance of new species or the disappearance of extinct species over 3.7 million years until humans initiated the current round of climate change by burning fossil fuels to power our economy. 

We must look to nature to save itself.  Humans are not capable of doing so.  In fact, we are standing in the way.  Today, I am republishing an article that explains how nature has survived for billions of years without the “help” of humans and will do so again if we let it. 

Conservation Sense and Nonsense

Let Evolution Lead the Way to Adaptation and Survival of Life

Otherlands, A Journey Through Earth’s Extinct Worlds was written by a paleontologist using the latest scientific techniques available. (1)  Paleontology has advanced far beyond digging up fossils.  Computer and DNA analysis enables paleontologists to reconstruct models of whole animals from bone fragments as well as describe the lifestyle of extinct animals such as what they ate and what ate them. 

Geologic periods described by Otherlands. Source: Wikipedia

Thomas Halliday puts this knowledge of some of the 5 billion species that have gone extinct in the 4.6 billion years that Earth has existed into the context of geological and biological changes that caused their extinction.  He describes vivid scenes of specific places at specific times, starting 500 million years ago (mya), a geological period when we can recognize most of the phyla (major groups of animals sharing characteristics) that exist today. These snapshots of deep time illustrate that “Environments shape their inhabitants as much as their inhabitants shape them.” (1)

In this article, we will visit a few of these scenes that demonstrate the biological innovations resulting from evolution and the associated geological and atmospheric events.  And we will tell you about how modern conservation methods are often working at cross purposes against evolution and adaptation of life as it copes with catastrophic challenges. 

Biological Innovation

Primitive life is said to have existed on Earth 3.7 billion years ago (bya).  All life that presently exists on Earth is said to have evolved from the first life forms, although the common ancestor is yet to be identified.  No life on Earth is truly alien.

The diversification of life on Earth began to accelerate when cyanobacteria developed the ability to photosynthesize about 3 bya.  Photosynthesis converts sunlight to energy by consuming carbon dioxide, creating carbohydrates that feed plants and storing carbon in plants and the soil, while emitting oxygen into the atmosphere as a by-product.

This evolutionary innovation is responsible for the abundance and diversity of plants today. It is an important factor in the balance of carbon dioxide and oxygen in the atmosphere, which is one of the most important factors in the Earth’s climate.  More plants also mean more food for animals that evolve alongside plants, often forming relationships with one another. 

The first mass extinction, roughly 445 million years ago (mya), is the only mass extinction caused by a rapid change in the Earth’s climate from tropical to glacial, which is equivalent to saying the atmosphere changed from predominantly carbon dioxide to predominantly oxygen, the opposite of our currently changing atmosphere and climate. 

Carbon dioxide levels are said to have dropped from 7,000 parts per million (ppm) to 4,400 ppm during the Ordovician extinction event that killed about 85% of plant and animal species.  Currently our carbon dioxide level is about 420 ppm, just a fraction of what it was during the Ordovician period.  In the context of the history of Earth, the climate we are experiencing is mild, a reminder of the potential for a much more extreme climate in the near future.

This graph of global mean surface temperature on Earth in the past 485 million years tells us the Earth’s climate has been mild since humans evolved. The graph should help us understand the potential for the Earth’s climate to increase beyond the tolerance for human life.

Comparing contemporary sea levels with those in deep time is another way to appreciate the potential for devastating changes in the future.  20,000 years ago, at the height of the last ice age, sea levels were 120 meters lower than they are now.  Conversely, sea levels were highest during the mid-Silurian period, 430 mya, when sea levels were between 100-200 meters higher than they are now and atmospheric carbon dioxide concentrations were high. 

Although the causes of the drastic change in the atmosphere and therefore the climate during the Ordovician period are still debated, the advent of photosynthesis is considered a factor.  The development of fungi enabled plants to move from water to land by delivering moisture from soil to roots of plants, greatly increasing abundance and diversity of plants. About 80% of plants today receive much of their nutrients and moisture through mycorrhizal fungi. 

The photosynthesizing capabilities of plants is one of the ways greenhouse gas emissions, currently causing global warming, can be reduced.  Yet, we are using pesticides to kill plants that native plant advocates have arbitrarily decided “don’t belong.”  Pesticides also kill fungi in the soil that enable plants to survive during drought conditions created by global warming.  This is one of many examples of how management strategies used by humans are counteracting the accomplishments of evolution that occurred long before humans existed or began to think they were competent to “manage” nature.

Plant Evolution Timeline

To make a long, complicated story short, we’ll focus on the major plant groups we recognize today by starting with seedless land plants that reproduce by dispersing spores, such as mosses and ferns that evolved from algae about 460 mya. 

Gymnosperms, which we recognize today as conifers, cycads, and Gingkos, are seed-producing plants that evolved about 300 mya.  Early species of gymnosperms formed huge forests. The carbon they stored became the coal fields of today when they died during the Carboniferous period (360-300 mya).   Today, we draw our fossil fuels from these coal and oil basins.  They provide most of our energy, while releasing greenhouse gases causing climate change.

Continents were close together during the Cretaceous geologic period when angiosperms evolved. Source: Australian Museum

Angiosperms evolved from gymnosperms about 130 mya.  They are flowering plants whose seeds are often encased in fruit. They are by far the most diverse group of land plants.  The evolution of bees around the same time is an example of co-evolution: the flowers feed the bees and the bees pollinate the flowers, delivering pollen from the male anther to the female stigma.   This sexual method of reproduction creates greater genetic diversity than self-pollination.  Greater genetic diversity creates more opportunities for natural selection to operate on plant variations, which may result in species that are better adapted to existing conditions.   

A recent study (2) found that the decline in the population of bees has increased the frequency of self-pollination of some plant species that are capable of both methods of pollination.  This is an example of evolution at work today.  Plants are responding to the existential need to reproduce in the absence of bees by self-pollinating.   

What evolution has accomplished in the past can be undone.  In this case, our indiscriminate use of pesticides such as neonicotinoids has decimated bee populations. Some plants will adapt to the loss of bees by self-pollinating, but not without some loss of genetic diversity provided by sexual reproduction and consequently the long term fitness of plants to face challenges in the future. 

There’s another trade-off for both plants and bees. Producing nectar and attracting bees with colorful flowers is a big energy expense for plants.  Plants therefore save energy by reducing flower size and color, when they can rely solely on self-pollination for reproduction.  Obviously, self-pollination ultimately results in a loss of food for bees and may accelerate the decline in bee populations, a negative feed-back loop, if you will.

This example is a reminder that evolution is neither positive nor negative.  It is simultaneously both positive and negative.  It is what it is:  an inexorable force for change. 

Evolution of grasses

Grasses and grasslands are late comers to the Earth’s plant kingdom.  Grasses evolved from angiosperms about 70 mya, during the Age of Dinosaurs that abruptly ended 66 mya when an enormous asteroid collided with Earth.  Grasses are wind pollinated and their seeds are dispersed by the wind, which enables them to spread rapidly and widely. 

Grasslands became dominant ecosystems about 30 mya, replacing many forest ecosystems.  With the optimal combination of fuel, heat, and oxygen, wildfires were a factor in the transition from forests to grasslands in many places.  Once again, wildfires in conifer forests are presently playing a role in converting forests to grasslands, suitable to a warmer and drier climate.

The development of enhanced photosynthesis by C4 grasses gave them a competitive advantage in hot, dry places where photosynthesis is suppressed. C4 grasses are more drought tolerant and they store more carbon than their predecessors, C3 grasses. There are only about 60 groups of C4 grasses, including several important food crops, such as maize, sugarcane, and sorghum.  They are found in tropical and sub-tropical regions of Africa and South America and some deserts.  California’s native grasses as well as introduced grasses considered “invasive” are not C4 grasses, according to a list of C4 grasses available on Wikipedia. (3)

Because of their potential to improve drought tolerance and increase productivity and carbon storage, there is great scientific interest in converting C3 grasses to C4 grasses.  Despite decades of effort, agricultural science has not been able to duplicate what the natural forces of evolution have accomplished, reminding us that evolution is more powerful than we are.

The transition from forests to grasslands had a corresponding impact on the evolution of animals.  Some browsers of woody plants learned to be grazers, if they could, while others went hungry, and the diversity and abundance of grazers increased. 

Native plant advocates in California have selected grassland as their preferred ecosystem because it was the dominant ecosystem prior to the arrival of Europeans at the end of the 18th century. They have consistently failed to convert non-native grassland to native grassland in California.  Nor is it clear that there would be any benefit to the environment or to its inhabitants to return to the treeless landscapes of California that existed prior to settlement in the late 18th century.

Where populations of native grazers of grassland were reduced by the activities of humans, many grasslands in California naturally succeeded to shrubs and trees. “Restoration” projects attempt to prevent succession of grasslands. Some of these projects destroy native trees and shrubs (e.g. Douglas fir, coyote brush, juniper, etc.) mechanically and with pesticides to maintain ecosystems as grassland.  

Nativists also want to reintroduce the grazing animals of the pre-colonial period to replace domesticated animals humans introduced because nativists see them as competitors of native animals they consider superior. Where top predators have been killed, these herds of grazing animals outgrow available vegetation unless their numbers are controlled as domesticated animals are.

A recent meta-analysis of 221 studies of the impact of megafauna on plant abundance found, “no evidence that megafauna impacts were shaped by nativeness, “invasiveness,” “feralness,” coevolutionary history, or functional and phylogenetic novelty. Nor was there evidence that introduced megafauna facilitate introduced plants more than native megafauna. Instead, we found strong evidence that functional traits shaped megafauna impacts, with larger-bodied and bulk-feeding megafauna promoting plant diversity. Our work suggests that trait-based ecology provides better insight into interactions between megafauna and plants than do concepts of nativeness.”  (4)

The author of Otherlands agrees that the concept of nativeness is not a useful way to understand the environment or conduct conservation because:  “Where an animal or a plant from one part of the world appears in another, some might use the language of invasion, of a native ecosystem despoiled and rendered lesser by newcomers…In reality, species do move, and the notion of ‘native’ species is inevitably arbitrary, often tied to national identity…There is no such thing as a fixed ideal for an environment…To look into deep time is to see only an ever-changing list of inhabitants of one ecosystem or another…The concept of native that we so easily tie to a sense of place also applies to time…We must avoid putting our own ahistorical spin on what was, although certainly dangerous and unlikely, a journey guided entirely by chance.”  (1)

Migration

The history of evolution is also a history of migration.  The oscillation of the Earth’s climate between freezing cold and blistering heat created and destroyed land bridges that enabled or blocked migration as sea levels rose and fell.  When North America and South America were connected by Central America as a result of lower sea levels and geological events about 3 mya, the plants and animals of those continents were mixed by migration.  Likewise, aquatic life of the Pacific Ocean was separated from the Atlantic Ocean by the Central American land bridge until the Panama Canal was built in 1914.

Geological events also created or destroyed the same opportunities for migration.  The opening and closing of the Strait of Gibraltar is a case in point.  The Mediterranean Sea exists because the Strait of Gibraltar exists.  When the narrow Strait is open, the Atlantic Ocean flows into the Mediterranean Basin, creating the Mediterranean Sea, which is an obstacle for migration of plants and animals between Europe and Africa. 

About 6 mya the Strait of Gibraltar closed because the African tectonic plate moved north, colliding with the European tectonic plate.  The Mediterranean Sea slowly evaporated, concentrating ocean salt from the Atlantic Ocean, laying down a sea bed of salt in the Mediterranean Basin and ultimately creating a migration corridor between Africa and Europe. There is every reason to believe that the Strait could close again.  The Earth’s tectonic plates are in constant motion and there is no reason to believe they will stop moving.

The obsession with “where plants belong” seems to be based on ignorance of the history of dispersal and migration.  Much of China and North America have been in the same latitude since the evolution of angiosperms.  As a result, many of our plant species considered native in Eastern North America are also considered native in China.  These paired species in the same genus are called disjuncts.  There are many woody disjuncts in China and North America (magnolias, persimmons, hickory, catalpa, dogwood, sweetgum, tuliptree, tupelo, sassafras, Virginia creeper, etc) as well as many herbaceous disjuncts (ginseng, lopseed, mayapple, skunk cabbage, etc.). (5) They are different species because they have been separated long enough to change as a result of genetic drift, but are in the same plant lineage, therefore chemically similar and presumably used by the same insects.  The study of these disjuncts says, “Most scientists do not consider long-distance dispersal to have played much of a role.  The prevailing view is that most disjuncts are remnants of genera that were once widely distributed in the northern temperate zone during the Tertiary period [66 mya to 2.6 mya per Wikipedia].  These broad distributions in the northern hemisphere were made possible by recurring land bridges.” (5)

Lateral migration patterns of the past are changing in response to contemporary patterns of climate change.  The temperatures at different latitudes are becoming more similar because Polar Regions are warming at a much faster pace than temperate and tropical latitudes.  Plants and animals escaping extreme heat and associated changes in vegetation are moving to higher latitudes in the Northern Hemisphere and lower latitudes in the Southern Hemisphere.  The increasing similarity of the Earth’s climate is changing wind and ocean currents and contributing to the extreme weather events of our changing climate.  Although there are lessons in the events of deep time, we cannot assume that events in the past are entirely predictive of future events because of the complexity of natural processes and our limited understanding of them. 

Of all the nonsensical conservation strategies humans are presently using, perhaps one of the most damaging is the futile attempt to stop migration. It is one of few survival strategies of plants and animals needed in a rapidly changing climate and it cannot be stopped. 

The project that proposes to shoot barred owls in the Pacific Northwest is an example of a “conservation” project that does not deserve that honorific.  Barred owls have migrated from the East to the West Coasts of North America via the boreal forests of Canada.  This is another instance in which large contiguous stretches of land at the same latitude facilitate the migration of life because there is less variation in climate at the same latitude. 

Source: USFWS

Specialists vs. Generalists

Barred owls are more adaptable than their closely related relative in the same genus, spotted owls.  Barred owls have a more varied diet, they are willing to nest in less dense, second-growth forest, and they have greater reproductive success.  They are therefore perceived as competitors of endangered spotted owls. Instead of letting natural selection identify the winner of that competition, the US Fish & Wildlife Service intends to shoot 500,000 barred owls in the next 30 years based on their belief that spotted owls will benefit.  They do not expect to eradicate barred owls and they made a commitment to continue shooting barred owls in perpetuity.  While we continue to log old-growth forests in which spotted owls live, we will kill barred owls with no expectation that they can be eradicated.

This project is typical of American “conservation” projects that attempt to save a specialist species by killing a generalist species.  This strategy was enshrined in American law by the Endangered Species Act, which is now 50 years old.  Like many 50-year-old public policies, we now know that this conservation strategy is not working because it is inconsistent with evolutionary principles.  Change in nature is inexorable.  Legal mandates are not capable of stopping evolution.  If we had a functional political system, we could stop the greenhouse gas emissions causing climate change, but we don’t.  Therefore, we must rely on evolution to cope with the changes in the environment that we have caused.

The most recent mass extinction occurred 66 mya when an asteroid hit the Earth, ending the Age of Dinosaurs.  About 80% of all plant and animal species became extinct.  The species that survived were the most versatile and the most mobile.  Flying dinosaurs were the only dinosaurs that survived, as birds, perhaps because they were the most mobile.  “Of the specialized insects, 85% were lost and it was the generalists that survived.” (1) 

Mass extinctions have created many vacant ecological niches that are opportunities for experimentation, creating new species.  Some were better adapted than others.  Natural selection determined the winners of competition within ecological niches.  The end of the Age of Dinosaurs created the opportunity for the Age of Mammals, as well as bony fish, marsupials, and lizards. 

In other words, our outdated conservation strategy is wasting our limited resources to save specialized species that are probably doomed to extinction.  And we are doing so at the expense of generalist species that might survive if we would quit killing them.  Keep in mind that 99% of all life forms that have existed on Earth have gone extinct.  At a time when the climate is changing rapidly, the goal of saving every endangered species seems both unrealistic and wasteful of limited conservation resources.

Hybridization

Hybridization is one of the tools of evolution.  Closely related species, usually in the same genus and even family often mate and their offspring often survive to eventually give rise to new species.  Successful hybridization is a means of increasing biodiversity.  Hybridization is sometimes a means of improving adaptability and therefore survival.

Unfortunately, nativists see hybridization as a loss of biodiversity rather than an opportunity to improve adaptability and increase biodiversity.  Their “conservation” projects often attempt to prevent hybridization by killing hybrids.  For example, the plan to kill 500,000 barred owls includes all hybrids of barred and spotted owls.  Because barred owls are more versatile, hybridization with spotted owls could even the playing field with barred owls by expanding food sources and nesting habitats of spotted owls. 

The Spartina eradication project is another example of the pointless eradication of hybrids.  In the case of Spartina, the non-native species grows more densely and it doesn’t die back in winter.  Non-native Spartina provides better storm protection and better habitat for nesting birds.  The Invasive Spartina Project has been spraying hybrid Spartina with herbicides for over 20 years, without total success.  The hybrid looks so similar to native Spartina that 600 genetic tests are required every year to confirm their identification as hybrids before they are sprayed.  The Invasive Spartina Project is a waste of limited conservation resources and it serves no useful purpose.

Evolution vs. Conservation

Otherlands should be required reading for those who are engaged in the “restoration” industry.  Some of the methods and goals of conservation are at odds with the mechanisms of evolution that have ensured the survival of life on Earth for nearly 4 billion years. 

  • The use of pesticides by “restoration” projects is antithetical to the goal of conservation because they do more harm than good.
  • Migration is a means of species survival.  Natural migration of plants and animals cannot and should not be stopped.
  • Humans cannot duplicate the forces of evolution.  Natural selection is the most powerful, efficient, and effective method of determining the winners of competition.
  • Hybridization has the potential to improve adaptability of closely related plants and animals.  Hybridization cannot and should not be stopped.
  • Resources being wasted in the attempt to stop the natural forces of evolution should be redirected to reducing greenhouse gas emissions causing climate change.  Such efforts are appropriately called “conservation.”
  1. Thomas Halliday, Otherlands, A Journey Through Earth’s Extinct Worlds, Random House, 2023
  2. https://www.nytimes.com/2024/01/04/science/flower-sex-evolution-bees.html?searchResultPosition=1
  3. https://en.wikipedia.org/wiki/List_of_C4_plants
  4. Erik Lundgren et.al., “Functional traits—not nativeness-shape the effects of large mammalian herbivores on plant communities,” Science, February 2, 2024
  5. David Yih, “Land Bridge Travels of the Tertiary:  The Eastern Asian-Eastern North American Floristic Disjunction, Arnoldia, 2012

Originally published March 1, 2024

Revising the Eradication Goals of Invasion Biology

It is my pleasure to publish (with permission) Arthur M. Shapiro’s (Professor of Ecology & Evolution Emeritus, UC Davis) review of Ecological Explosions:  The History of Biological Invasion and Invasion Science, by Daniel Simberloff (Professor of Environmental Science, University of Tennessee).   

Professor Simberloff is a prolific and vociferous adherent to the hypotheses of invasion biology, as well as to the related commitment to eradicating non-native plants. I heard Simberloff speak at the conference of the National Park Service, “Science for Parks, Parks for Science,” at UC Berkeley in 2015. It was a time when critics of invasion biology were emerging and becoming more vocal and visible. Simberloff called out by name Emma Marris, Peter Kareiva and others for their criticism of invasion biology.

In 2020, I heard Simberloff speak at the annual forum of the California Invasive Plant Council.  His presentation was similar to his presentation in 2015 in that it was primarily focused on critics of invasion biology whom Simberloff calls “deniers.”  Simberloff categorized the criticisms of invasion biology then flipped them off, one by one.

Then, Simberloff’s presentation took an unexpected turn when he was asked this question by the moderator:  “Dan, you mention the “futility” argument, but what about the notion that the cost in environmental damage (e.g, pesticide use and nontarget impacts) is too high for some well-established invaders?”  Simberloff’s answer to this question was surprising and encouraging to critics of pesticide use to kill non-native species:

“Absolutely, it’s a huge problem, not only on non-target species, but also the fact that evolution of resistance leads to greater use of pesticides before they are useful and leads to greater impact on non-target species.  I didn’t talk about this, but yes, of course the cost both economically and ecologically might be too great even if management eradication is feasible.  But that’s not what denialism is about.  Denialism willfully denies that there are impacts or they confound arguments about values as if it is an argument about science.” Daniel Simberloff

Simberloff’s concern about the costs “both economically and ecologically” of eradicating non-native plants was as much a shock to the Executive Director of the California Invasive Plant Council–which actively champions the use of herbicides to eradicate non-native plants–as it was to me. 

Based on that experience, I had a premonition that Simberloff’s recent publication might be another surprise and so it is, as Professor Shapiro explains in his review.  Simberloff publishes this exhaustive tome at the age of 84.  Perhaps it is his last word.  It is a significant revision to the long crusade to eradicate every non-native plant. 

One hopes Simberloff’s book will influence the “restoration” industry to be more circumspect when choosing their eradication targets and their methods.  If so, it comes at a good time because every effort to reduce pesticide use in the US has been tried and failed. 

Last week, the US Supreme Court overturned product liability lawsuits brought by users of glyphosate with cancer, because the Environmental Protection Agency does not consider glyphosate carcinogenic, though it indisputably is. EPA’s determination now over-rides any state determination to the contrary. Earlier, President Trump also signed an Executive Order, promoting the use of glyphosate and Robert F. Kennedy, Jr., Secretary of Health and Human Services, endorsed the Executive Order. 

I am deeply grateful to Professor Shapiro for giving me this opportunity to publish his review of Professor Simberloff’s book about invasion biology.  I am also grateful to Professor Simberloff for taking a closer look at the consequences of eradicating non-native plants. 

Conservation Sense and Nonsense

REVIEW: ECOLOGICAL EXPLOSIONS: THE HISTORY OF BIOLOGICAL INVASIONS AND INVASION SCIENCE. Daniel Simberloff. University of Chicago Press. 2025. 729 pp.

I was fully prepared to detest this book—until I read it.

Dan Simberloff, as E.O. Wilson’s star graduate student at Harvard, was present at the creation of the theory of island biogeography, which used simple mathematical and graphical models to bring order to a vast heap of anecdotal information and in so doing radically transformed ecology—from natural history to analytical science (not everyone was thrilled). Simberloff’s subsequent career can be seen as the application of that approach to the implications of human-mediated changes in the geographic ranges of species generally. Now in his 80s, he has written this doorstop of a book as the envoi to his career. Why, I wondered, would anyone want to read it?

Simberloff and I are contemporaries. My undergrad adviser at Penn, Robert MacArthur, was Wilson’s collaborator on “The Theory of Island Biogeography,” and very much wanted me to do my Ph.D. with Wilson. MacArthur was under the illusion that I had mathematical talent, despite my best efforts to convince him otherwise. I knew it would be a bad fit, and to his frustration never even applied to Harvard. I went to Cornell for my degree, a place more in tune with a natural historian like me. I have often joked that had I gone to Harvard I would have become Dan Simberloff! Both Simberloff and I read Charles Elton’s “The Ecology of Invasions by Animals and Plants” (1958), the book that established invasion biology as a field and gave it its name. In Dan’s case reading that book shaped his entire career. It had many impacts on mine as well; I began observing and studying the adoption of naturalized host plants by native insects, mainly Lepidoptera, and it profoundly affected my teaching (community ecology, biogeography) for the next 50+ years. So it was natural that I, at least, would want to read it.

At the same time I had become disaffected with what I perceived as both the ideological and the faddish turn of invasion biology, and I was apprehensive about what I might find. I needn’t have been.

The first part of the book is a more-or-less chronological history of the development of invasion science, from the earliest observations of European weeds in New England by John Josselyn down to our own time. This is not a catalogue of case histories, but the ones selected are judiciously chosen to be representative of aspects of the field. Most were already familiar to me, but quite a few were not, even after more than five decades.

But the most important chapters for me were at the end. Chapter 18 (“Controversies Abound”) confronts head-on the conflation and entanglement of invasion biology on the one hand and xenophobia and racism on the other—exemplified by the term “native plant Nazis,” referring to those who advocate eradication of non-native species. The use of political and military metaphors (including the word “invasion” itself!) has contributed to such conflation and its undesirable resonances. The conflation has deep roots, which Simberloff explores—consider the New York socialite Madison Grant, a prominent lay conservationist, who authored the scurrilous racist tract “The Passing of the Great Race: or the racial basis of European history” (1916), by no means an isolated case. Simberloff has no patience for the blanket rejection of species solely on the basis of their “native” vs. “non-native” status. He recognizes that each case must be approached contextually and that there is no justification for eradication campaigns except in the most exigent circumstances (pathogens, parasites—the current alarm over the screwworm comes immediately to mind; invaders that pose grave risks to agriculture or to the survival of prized native species and ecosystems). Chapter 19, on the future of invasion science, elaborates on these themes in the context of a world that is changing at an ever-accelerating pace.

Do age and experience confer wisdom on us? Perhaps not inevitably. But this book convincingly demonstrates that they have done so for Dan Simberloff. If you are seriously interested in invasion biology, get and read this doorstop of an envoi: all 729 pages of it.

                                                                            ARTHUR M. SHAPIRO

University of California, Davis

The Illusive Definition of “Invasive” Plant

Kollibri Terre Sonnenblume and his writing partner, Nikki Hill, are co-authoring a book tentatively entitled “Don’t Blame the Messenger: A critique of the ‘invasive plant’ narrative.” Kollibri has published a draft chapter of their book on his Substack, “Speaking for the Trees, No Matter Where They’re From.”  The chapter is foundational to their book and serves as a teaser for the rest of the book.  More chapters of the book will be available to paid subscribers of Kollibri’s Substack, “Speaking for the Trees.”

Many thanks to Kollibri and Nikki for this important contribution to our understanding of invasion biology as an ideology based on many conundrums and contradictions.

Conservation Sense and Nonsense

St. Johnswort. Photo by Kollibri Terre Sonnenblume

What is an “invasive” plant?

What is an “invasive” plant? Colloquially, some gardeners call any plant that thrives and spreads with little or no care “invasive.” They cast the term on both “weeds” and on ornamental nursery plants that have the temerity to spread outside their apportioned area. Such gardeners are seeking to uphold a particular aesthetic and their impulse to design and direct can yield results ranging from elegant to cloying. If this were the only way that people used the word, “invasive,” it would be harmless, and there would be no need for this book. However, the label is applied far beyond this narrow context.

Going to the dictionary for the meaning of “invasive,” Merriam-Webster provides: “relating to, or characterized by military aggression.” The Cambridge Dictionary defines “invade” as: “to enter a country by force with large numbers of soldiers in order to take possession of it; to enter a place in large numbers, usually when unwanted and in order to take possession or do damage; to enter an area of activity in a forceful and noticeable way.” For “invasive” it says: “moving into all areas of something and difficult to stop.”

That’s clear enough. But what is the official definition of an “invasive species,” whether plant or otherwise?

The short answer is that there is none.

The longer answer is that there are many definitions crafted by various policy-makers, non-governmental organizations and advocacy groups. Here are a few:

  • US federal government: “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.”i
  • The United Nations Environmental Program: “introduced species that become established in a new environment, then proliferate and spread in ways that are destructive to human interests and natural systems.”ii
  • The International Union for Conservation of Nature (IUCN): “animals, plants or other organisms that are introduced by humans, either intentionally or accidentally, into places outside of their natural range, negatively impacting native biodiversity, ecosystem services or human economy and well-being.”iii
  • Convention on Biological Diversity: “species whose introduction and/or spread outside their natural past or present distribution threatens biological diversity.”iv

These definitions might seems straightforward at first glance, but a lot of ambiguity emerges as we unpack them.

The key words—“harm,” “destructive,” “negatively impacting,” “threatens”—beg the question of what constitutes “harm.” As we shall explore in this book, that’s not at all simple to answer in terms of ecological interactions. It’s even more difficult to identify what is “likely to cause” harm, as the feds put it. As invasion biologists have discovered, attempts to predict the results of species introductions based on the attributes of the species, for example, don’t have a very successful track record.

Also, if “harm” is being alleged then the possibility of benefit must also be admitted, a point completely ignored not just in these definitions but in most discussions or media coverage about “invasives.”

Economic concerns or “human interests” are named first by the US and UN, which might surprise people who think of the issue of “invasive” species as solely environmental. But commercial interests have had a strong hand in drafting the official policies that guide the “management” of “invasive” species. As we discuss in a later chapter, Monsanto and other nasty entities played a central role in the shaping US federal policy around “invasive species” because they profit from the sale of toxic pesticides used in their control. As for measuring the bottom line, one might assume that economic harm is readily quantifiable, but that’s also quite tricky, as we explain in the chapter “Lies, Damned Lies, and Statistics.”

“Alien” and “introduced” are synonyms for “non-native” (as are “exotic” and “non-indigenous”). The very concept of a “native plant” is a recent invention, though, and is another subject of contested deliberation, which we detail in “A Brief History of Invasion Biology.”

What is a fairly straightforward question in the Western Hemisphere—was it here before 1492?—is less clear in other regions. In the UK, some point to the Roman invasion of two millennia ago as the cut-off date (perhaps in part because that’s when bed bugs were introduced). In the case of Pacific islands like Hawai’i, some scientists designate species brought by Polynesians before the age of settler-colonialism as “non-native” but others limit it to European-introduced species. British colonization of the Australian continent commenced in 1788 (though the 1606 landing of a Dutch East India Company ship is the first documented European arrival) but some scholars label the dingo, introduced by Aboriginal people 4000 years ago, as non-native.

Conservation Sense and Nonsense

Political boundaries with no ecological significance can be a basis for defining nativeness, which also highlights the fact that nativeness is a scale-dependent factor. Tropical Milkweed (Asclepias curassavica) is native to North America from Mexico southwards but is called “invasive” in the United States (even though its pre-Columbian native range may have included southern Florida). Yet it’s also accurate to describe the species as “native to North America.” If a climate-induced, natural range shift of a species crosses the border of a country or a province will it be counted as non-native, but not otherwise?

Finally, how far does a species have to travel to be “out of range”? The endangered Monterey Cypress (Cupressus macrocarpa) is, according to journalist Andrew Cockburn, “a frequent target for the chain saws of the San Francisco Recreation and Parks Department—even though two small stands in Monterey, just fifty miles south, are cherished and protected as natives.”v Meanwhile, a 500 mile drive north of its relict range, a large specimen planted by European settlers near Brookings, Oregon, in the 1850’s is an officially designated “Heritage Tree,” which we personally hope grants it safety because we’ve seen it and it’s majestic.

“Introduced” is shorthand for “introduced by humans either intentionally or accidentally.” It doesn’t include the actions of animals, weather, or other more-than-human agents in transporting species. It also doesn’t usually include indigenous humans, not because their own actions in moving around species haven’t been significant or are considered qualitatively different than those of settler-colonialists, but simply because they are generally not considered at all. This narrative omission is meaningful because it narrows the realm of possibilities for both human activity and human nature, a point we will be returning to in depth in later chapters.

In some cases, the non-native requirement has been dropped entirely. The State of New York includes the native Cup Plant (Silphium perfoliatum), on their “Prohibited and Regulated Invasive Plants” list because they characterize its growth as “aggressive.”vi

This cursory sweep of these definitions demonstrates that we only need to scratch the surface of what is presented as a black and white issue to reveal a lot of gray area.

As we relate in detail later, similar accusations of “encroachment” by native flora are currently playing out with horrific results in the western US, where healthy woodlands of Pinyon-Juniper—declared a “native invasive” by somevii—are being razed to expand rangeland for cattle.viii

Further muddying the picture, the term “noxious weeds” is often used interchangeably with “invasive species” by organizations and individuals alike. The USDA has a list of “Introduced, Invasive, and Noxious Plants.”ix The designation of “noxious weeds” is typically decided by local government entities in support of conventional farming and ranching, so a particular plant—native or introduced—will be added because of its purportedly negative effect on domesticated crops or animals. Thus, St. Johnswort (Hypericum perforatum) is bad because it can cause phototoxicity in sheep, Chervil (Anthriscus sylvestris) because it might carry a rust fungus that can affect cultivated carrot seed crops, and Pigweed (Amaranthus palmeri) because it grows in cornfields. Note that in the first two cases the plant or animal species supposedly threatened are themselves not native, and are products of a system—industrial agriculture—that is severely detrimental to the environment wherever it is practiced. Though Corn (Zea mays) is native, the ultra-hybridized and genetically-modified varieties grown today are so far from what indigenous people tended in Three Sisters arrangements that one could question if it’s even the same plant anymore. All three of these “weeds” also happen to be edible or medicinal for humans, so it’s a matter of priorities rather than usefulness that they’re slapped with a negative label and their eradication actively pursued. The primary motivation of noxious weed management is economic, not ecological—despite recent glosses of “sustainability” or “conservation” applied by some of its adherents—and more often than not involves pesticides.

What about science? How does invasion biology itself define “invasive?”

Scientists are well-known for disagreeing about definitions, and “invasive” is no exception. One biologist summed up the discussion by stating that there is “no indication that the field [will] be able to achieve uniformity in language in the near future.”x

These are some of the concepts that have been used or proposed for “invasive”:

  • a species that successfully establishes itself in a new place
    • such a species that establishes and has impact
      • such a species whose impact is negative
  • a species that, regardless of impact, establishes and spreads rapidly
  • a species that does any of the above which is non-native and introduced by humans
  • a species that does any of the above which is non-native, regardless of how it was introduced
  • a species that does any of the above which is native

These can’t all be true at once, obviously. There are too many contradictions. The science also suffers for dearth of agreement. One researcher noted that the “lack of consensus regarding the definition of invasive alien species (IAS) and vagueness around the demonstration of their impacts limits knowledge and research in this field.”xi

Whether or not to use the word “invasive” at all is an ongoing debate in invasion biology. Historically, some scientists used the word “invade” and “colonize” to merely describe the movement of a species into a new area, or just the establishment of a species in a recently opened area, like after a fire, flood or landslide. But many scientists now recognize that, these days, the word has indisputably negative connotations which have implications not just within the field but for social discourse. Writes biologist Mark Davis, in his book, Invasion Biology:

I have never liked the term ‘invasion’ and think the field would have been much better off had it never been adopted, along with its accompanying military metaphors. Although the usage of military language may help to attract a group of highly motivated supporters, this same language may help foment a strongly confrontational approach, making it much more difficult to negotiate and resolve conflicts.xii

More on the discussions within the field of invasion biology about terminology follow later.

A “confrontational approach” has certainly been a feature of too many discussions about introduced plant species. We have both been saddened to watch as native plant forums online, once a place to good-naturedly share photos and get IDs, have become toxic places where the word “invasive” is wielded like a club. Hateful rhetoric is the hallmark of dogma, not reason or thoughtfulness, and unfortunately it has been metastasizing in too many circles. We wonder how different the attitudes would be if “invasive” had never been used and we’d only ever had something neutral like “introduced” or nostalgic like “pioneer.”

What’s not defined as “invasive” is just as important as what is

Excluded from virtually everyone’s definition are the hundreds of non-native domesticated plants important to agriculture. This is highly significant given that over one fifth of the land in the lower 48 states of the US is cropland. That’s nearly 400 million acres of what was originally habitat for many, many native plant species. The excuse of “We need to eat!” doesn’t fly here; only 20% of that cropland is devoted to growing food directly for people; the majority of the remainder is for ethanol production, export industries, and livestock feed.xiii

These stats should put the “invasive” dialogue into perspective. Picture the Midwest’s horizon-to-horizon corn and soy crops, California’s vast rice fields and almond orchards, or Oregon’s expanses of grass seed. These monocrops of non-native plants displaced prairies, forests and wetlands brimming with native flora and fauna. They are maintained with toxic pesticides and fertilizers, unsustainable water use, heavy machinery, fossil fuels, and oppressive labor practices. They dominate more than just their local geographical footprint, sucking in resources from distant places. According to the “invasive plant” narrative, the only “invasives” in these abused landscapes are the weeds coming up in the ditches or between the rows, a perspective we find perverse.

Other exemptions apply to the “invasive” label. As the US Department of the Interior’s Invasive Species Advisory Committee points out: “Kentucky bluegrass would be considered an invasive species in Rocky Mountain National Park in Colorado, but considered non-invasive a mere 60 miles away at a golf course in Denver.”xiv If anything is “invasive,” how is it not the golf course itself? In the arid Coachella Valley of southern California, over 140 irrigated golf courses represent the complete destruction of the desert habitats that they replaced, and are a significant draw on the region’s precious water.

The topic of golf courses leads us to another big omission: lawns, which in their emerald-green ideal are monocultures of non-native grass. If lawn grass were categorized as an irrigated crop in the US, it would be ranked number one in land area and water use.xv Yet it is the Dandelion that sprouts up in the front yard that’s “invasive.”

The “invasive plant” narrative is not ultimately about logic or facts. It’s about beliefs and prejudices, so a more relevant question than, “What is the definition of an ‘invasive’ plant?” might be, “What is meant by ‘invasive’?” What does the word signify? From what cultural foundations does it spring and what narrative edifice does it help perpetuate? There’s the narrative—that some plants are bad because they’re foreign—and then there’s the why of the narrative, which we delve into in Part 3, “Culture.”

“Bad plant”

In sum, the term “invasive plant” is thrown around so carelessly these days that, in common usage, it doesn’t really mean anything beyond some vague notion of “bad plant.”

But there are no “bad plants.” There are just particular plants that particular people in particular places at particular times have considered undesirable for particular reasons. That’s a lot of particulars. Too many to brand a whole species of plant with a pejorative label like “invasive” or “noxious” as if that’s its entire, intrinsic nature. Does it make sense to weed a garden? Of course. But that’s no reason to elevate our subjective calls—useful as they might be in a particular place and particular time—to the level of a universal constant, and to manufacture an army of villains in doing so. That just encourages our own misguided tendencies and puts off the day when we resume healthy connection and relating with life on this planet.

A very real invasion commenced in 1492, and with it came what some Anishnaabe tradition-bearers call “invasive land-ethics,”xvi a concept we explain in “Introduced Plants, Settler-Colonialism, Indigenous Perspectives and Decolonization.” These ethics drove the cutting of forests, draining of wetlands, mining of mountains, plowing of prairies, damming of rivers, and slaughter to near extinction of Buffalo, Prairie Dogs, Beavers, Bears, Cougars and Wolves. These misbegotten ethics are unequivocally real and are active threats to the planet’s environment. Without addressing them, the destruction will only worsen.

In the meantime, the “management” of “invasive plants” routinely has its own negative effects, which we detail in the next chapter.

Kollibri Terre Sonnenblume

Citations:

iExecutive Order 13112 – Section 1. Definitions, February 3, 1999. https://www.invasivespeciesinfo.gov/executive-order-13112-section-1-definitions

iiUnited Nations Environmental Programme. “Invasive Alien Species—A grwoing threat in regional seas” https://wedocs.unep.org/bitstream/handle/20.500.11822/13623/invasive_alien_brochure.pdf

iiiIUCN. “Invasive Alien Species” https://www.iucn.org/our-work/topic/invasive-alien-species

ivConvention on Biological Diversity. “What are Invasive Alien Species?” https://www.cbd.int/invasive/WhatareIAS.shtml

vCockburn, Andrew. “Weed Whackers: Monsanto, glyphosate, and the war on invasive species” Harpers (September 2015). https://harpers.org/archive/2015/09/weed-whackers/

viNew York State Department of Environmental Conservation. NYCRR part 575 Invasive Species Regulation. (September, 2014). https://www.dec.ny.gov/docs/lands_forests_pdf/isprohibitedplants2.pdf.

viiAnsley, R. “Managing Native Invasive Juniper Species Using Fire” Weed Technology 19 (Jul 2005):517-522 DO – 10.1614/WT-04-098R1.1 http://www.bioone.org/doi/abs/10.1614.

viiiFite, Katie. “The Terrible Destruction of Pinyon-Juniper Forests” Counterpunch (December 28, 2018). https://www.counterpunch.org/2018/12/28/the-terrible-destruction-of-pinyon-juniper-forests/.

ixUSDA https://plantsorig.sc.egov.usda.gov/java/noxious?rptType=Federal

xDavis, Mark. “Invasion Biology.” (New York: Oxford University Press, 2009), p. 3.

xiFachinello MC, Romero JHC, Chiba de Castro WA (2022) Defining invasive species and demonstrating impacts of biological invasions: a scientometric analysis of studies on invasive alien plants in Brazil over the past 20 years. In: Giannetto D, Piria M, Tarkan AS, Zięba G (Eds) Recent advancements in the risk screening of freshwater and terrestrial non-native species. NeoBiota 76: 13–24. https://doi.org/10.3897/neobiota.76.85881

xiiDavis, 2009.

xiiiMerrill, Dave and Leatherby, Lauren. “Here’s How America Uses Its Land” (Bloomberg, July 31, 2018). https://www.bloomberg.com/graphics/2018-us-land-use/.

xivUS Department of the Interior Invasive Species Advisory Committee. “Invasive Species Definition Clarification and Guidance” April 27, 2006, p. 3. https://www.doi.gov/sites/doi.gov/files/uploads/isac_definitions_white_paper_rev.pdf.

xvCristina, Milesi & Elvidge, Christopher & C, J. & D, B. & Nemani, Ramakrishna & E, S.. (2012). A strategy for Mapping and Modeling the Ecological Effects of US Lawns.

xviReo, Nicholas J., Ogden, Laura A. “Anishnaabe Aki: an indigenous perspective on the global threat of invasive species,” Sustainability Science (2018) 13: 1443-1452. https://doi.org/10.1007/s11625-018-0571-4.

Environmentalism in the Rear-View Mirror

One year ago, less than a month after Donald Trump was re-elected President, I announced on Conservation Sense and Nonsense my intention to “hunker down and watch the changes [in the federal government] play out.”  Although I predicted major changes in federal public policies, I did not foresee the scale and speed of changes in environmental policies that we have witnessed in the past year.  The uncomfortable reality is that some of what is being destroyed deserved to be destroyed, but at the expense of some valuable environmental protections. 

In describing the changes we have witnessed, I will focus primarily on environmental issues in the following main categories.  Please keep in mind that changes in environmental policies are but a small fraction of the changes that have occurred in all aspects of American life and global geopolitics, e.g., education, public health, arts and entertainment, architecture, science, economics, immigration, media sources, judicial system, disaster relief, social safety net, foreign aid, tariffs, etc. 

The Trump administration has left the international Paris Agreement, the legally binding treaty adopted in 2015 to limit global warming to below 2 degrees Celsius.  The US was not represented at the November 2025 meeting of the UN Conference of the Parties (COP30) to the agreement in Brazil, but the US actively campaigned against the new commitment on the agenda to limit pollution from cargo ships by using fines.  According to the New York Times, “…the United States launched a pressure campaign that officials around the world have called extraordinary, even by the standards of the Trump administration’s combativeness, according to nine diplomats on its receiving end.” US diplomats and officials were successful in threatening countries with loss of US port access and other onerous penalties if they voted for the proposal. The Trump administration hasn’t just dropped out of the Paris Agreement.  It is also actively engaged in preventing other countries from reducing greenhouse gas emissions that cause climate change. COP30 ended without any new commitments to reduce the sources of greenhouse gas emissions, or even explicit mention of fossil fuels as the primary greenhouse gas.   

America Accommodates

Many of these changes have been delayed by legal challenges, but until appeals reach the Supreme Court, the final verdict on most issues is not known at this time.  However, the Supreme Court has signaled their intentions with many emergency orders, also known as the shadow docket.  These decisions have upheld most of the federal government’s actions, without providing any legal reasoning for doing so.  These preliminary decisions foretell the ultimate victory of the actions of the Trump administration.

Other segments of American society are contributing to the control the President has over the implementation of his agenda. At his request, Congress has completely defunded National Public Radio and the Public Broadcasting Service.  They are scrambling to find other sources of revenue, while cutting programs and staff as well as closing stations. Associated Press was banned from White House press briefings when they refused to call the Gulf of Mexico the Gulf of America, as renamed by President Trump. Legal challenges have not restored AP’s access to White House press briefings.

Mainstream media has paid multi-million dollar settlements to resolve defamation lawsuits (ABC and CBS) brought by President Trump over perceived slights.  One major network (CBS) has changed ownership and is now owned by Trump supporters (Larry & David Ellison).  The Department of Defense (now calling itself the Department of War) has restricted access of the press to department staff and now requires department approval of press releases prior to publication.  Most members of the Pentagon press corps refused to agree to these restrictions and have left their offices in the Pentagon.  Self-censorship is a more insidious threat because the public no longer knows when the media is pulling its punches to avoid retribution, which is the President’s modus operandi.

The legal profession has also been brought to its knees by the President’s threats of punishment if they participate in lawsuits that try to prevent the implementation of the administration’s policies.  Many major law practices have been forced to provide pro bono legal services for President Trump after being threatened with access restrictions to the judicial system.  Major law practices are refusing to represent plaintiffs who are trying to protect themselves from government prosecution, hoping to stay out of the line of fire.

California Responds

The same day that Americans re-elected Donald Trump in November 2024, California voters passed Proposition 4, the $10 billion bond that funds climate change mitigation and ecological restoration in California.  California’s bond funding will help to compensate for the loss of federal funding of ecological and climate mitigation projects in California. California Natural Resources Agency reported the cancellation of federal funding for these projects in California:

Source: California Natural Resources Agency, July 2025

Does California have enough money to compensate for the loss of federal funding of climate change mitigation and ecological restoration in California?  I don’t know, but I do know that federal funding is also being lost for many other purposes that are important to Californians, such as subsidies for health insurance and food assistance needed by many Californians.  Some municipalities are responding by raising sales and property taxes to backfill the loss of federal funding in many sectors of the economy.  While federal taxes are being cut, California’s taxes may rise.

Meanwhile, California is challenged by related issues such as the need to build more housing in order to reduce the cost and house our growing homeless population.  In July 2025, California responded to that issue by revising the California Environmental Quality Act (CEQA), which will remove many obstacles to building new housing and allow more aggressive fire hazard mitigation. 

The cost of gas in California has been consistently higher than in most states because of voters’ desire for clean air.  Regulations have made drilling for and refining oil in California costlier than in other states, which makes gas more expensive for consumers.  Refineries have responded to California’s restrictive regulations by leaving the state, which reduces supply, raises prices further and is expected to restrict availability of fuel. California’s Senate Bill 237, signed into law in September 2025, addressed these concerns by streamlining approval of drilling permits, including idle pipelines, in an “environmentally responsible and safe manner.” 

In other words, California has been forced to adapt to new economic and environmental realities. At the same time, California is aggressively fighting back.  As of October 1st, California has filed 46 lawsuits against the 2nd Trump administration, “contesting the Trump administration’s executive orders, agency decisions and even recent laws that Trump himself signed.”

Americans Shrug

Composite opinion polls reported a persistent negative approval rating of 11% for the Trump presidency until the government shutdown in October, when the approval rating dropped to negative 15% before returning to negative 11% when the government re-opened.  Over 40% of American voters still approve of the Trump presidency.  Many voters have made up their mind and are not responsive to the daily onslaught of alarming information.  I understand and am sympathetic to the public’s dilemma, summarized in a recent social media post:  “My desire to be well informed is presently at odds with my desire to remain sane.” 

Updated 12/10/25

For perspective, consider that President Biden’s composite approval poll on July 6, 2024 was negative 19.3%, just 15 days before Biden dropped out of the presidential race on July 21, 2024. 

The demonstrations I have attended are another window into the mood of the American public.  The NO Kings demonstration on June 14, 2025 is said to have drawn 5 million people.  The second NO Kings demonstration on October 18th claims to have drawn 7 million people.  Although these seem impressive numbers, they don’t add up to a change-making revolt.  The lack of young people participating in these demonstrations is dispiriting.  The future is in their hands, yet their commitment to democracy is lukewarm compared to my generation, the boomer generation that still feels a strong commitment to the peace and prosperity that democracy has delivered to us.

On the other hand, Democrats aren’t dead yet.  In November 2025, moderate Democrats won governorships in New Jersey and Virginia and a Democratic Socialist won the mayoral election in New York City.  In response to Republican gerrymandering of congressional districts in Texas, 64% of Californians voted to gerrymander congressional districts in favor of Democratic candidates.  A recent Marist poll indicated that registered voters in the US plan to vote for Democratic candidates for congressional seats in 2026 by a margin of 14%. 

Changes in the elected leadership of the Bay Area chapters of the Sierra Club are an indication of a change in the public’s commitment to the environment.  The San Francisco Bay Area Chapter is now led by activists who want more housing and more active recreational opportunities.  The old guard, who were committed to restricting recreational access in favor of native plant restorations in public parks, has been replaced.  The Lomo Prieta Chapter, which represents the South Bay, is now undergoing a similar transition to new leadership with new priorities.

Changes in the leadership of the San Francisco Bay Area chapters of the Sierra Club are symptomatic of the Club’s much broader decline on a national scale.  According to the New York Times, the Club has lost 60% of the 4 million members it had in 2019.  The Times attributes this loss of support to the change of the Club’s advocacy focus from environmental issues, most prominently climate change, to progressive social justice issues such as racial justice, gay rights, labor rights, and immigration rights. In 2019, one of the Board Directors objected to the proposed budget, but was voted down: “I said, ‘We have two F.T.E.s devoted to Trump’s war on the Arctic refuge, and we have 108 going to D.E.I., and I don’t think we have our priorities straight,’” Mr. Dougherty said.

Finally, wealthy American philanthropists are providing clues of a fundamental change in the political climate in America.  Bill Gates, former owner of Microsoft and supporter of global health initiatives, recently announced that it is time for a “strategic pivot” in the global climate fight from focusing on limiting rising temperatures to fighting poverty and preventing disease.  Gates still believes climate change is a serious problem, but it won’t be the end of civilization because he thinks scientific innovation will contain it.  Unfortunately, federal support for finding such scientific innovations has been withdrawn.  Gates’ message seems to be that we aren’t able to stop climate change, so we must cope with it.  It’s another way of accommodating the environmental policies of the Trump administration.

Looking Ahead

I am deeply troubled by the many threats to America’s treasured democracy.  However, many of the changes in environmental policies in the past year are aligned with the mission of Conservation Sense and Nonsense.  Since its inception in 2010, the mission of Conservation Sense and Nonsense has been the preservation of our predominantly non-native urban forest, opposition to the use of pesticides on public lands and advocacy for mitigating the causes of climate change.  Some of the changes in environmental policy in the past year are consistent with those goals:

  • Many projects that use pesticides and kill harmless animals and vegetation have been defunded by the federal government. The State of California is trying to compensate for the loss with state funding, but its ability to do so will be challenged by many other new demands on state resources, such as subsidies for health care and food.

When wildlife refuges and marine sanctuaries lost much of their funding and staff, many of their projects were abandoned.  Many of those projects may have been beneficial, but the plans to aerially drop rodenticides on the Farallon Islands to kill harmless mice is an example of a project that is better off dead.

  • Prevailing public opinion that native plants and animals are superior and the corresponding belief that non-natives are a threat to them is unlikely to change in the near-term.  I do not begrudge the horticultural preferences of home gardeners.  However, native plant advocates will have limited ability to demand that public land managers eradicate non-native plants if there is no public money available to fund landscape-scale “restorations.”
  • As public money for ecological “restorations” on public land dries up, the “restoration” industry and the jobs it creates will probably dwindle over time. As economic interests in “restoration” evaporate, the advocacy that supports it is likely to as well. College students are likely to make other educational choices with more promising career prospects, which will further reduce the labor force engaged in “restorations.”
  • When forest “restoration” projects that involve clear-cutting or removing healthy trees are defunded, existing carbon storage is preserved.  Every mature tree—native or non-native—sequesters carbon at a time when we need every available carbon sink to compensate for the loss of limits on greenhouse gas emissions causing climate change.
  • Climate change will accelerate as we abandon our efforts to reduce greenhouse gas emissions that cause climate change. The landscape that survives the changed climate will be best adapted to the changed environment.  When the climate changes, vegetation changes or dies.  No amount of human intervention can alter that ultimate reality because nature always bats last.

In 2026, Conservation Sense and Nonsense will continue to report major developments relevant to my mission.  In other words, I will continue to “hunker down and watch it play out.”  Guest posts consistent with my mission and civil comments, both pro and con, are always welcome here. Thank you for your readership. 

Happy Holidays and best wishes for a more peaceful year in 2026.

“Instead of ‘controlling’ non-native plants, perhaps we should practice more ‘self-control’”

Juian Burgoff

Julian Burgoff wrote a guest post for Conservation Sense and Nonsense about the undervalued functions of non-native aquatic plants in 2023.  Necessary Nuisance explained that non-native aquatic plants perform valuable ecological functions.  Attempts to eradicate aquatic plants deprive aquatic animals of valuable habitat.  The herbicides used to kill aquatic plants also pollute the water, harming aquatic animals and killing non-target aquatic plants. 

Julian Burgoff is an avid bass angler and aspiring fisheries ecologist from western Massachusetts.  He recently received a master’s degree with the Massachusetts Cooperative Fish and Wildlife Research Unit at UMass- Amherst where he studied juvenile river herring growth, diets and habitat use in coastal Massachusetts lakes and estuaries.  He is passionate about lake ecology and the management of aquatic vegetation in lakes and hopes to work in a field related to lake conservation and warmwater fisheries management in the future.

I am grateful to Julian for giving us another opportunity to publish an article about a specific project that is trying to kill valuable aquatic plants with herbicides.  Thank you, Julian.

Conservation Sense and Nonsense

Hydrilla and the Connecticut River: Falling into the “Invasive” Trap

If you spend time on the tidal Connecticut River in summer, you will likely see thick green mats covering its shorelines, coves and backwaters. This is hydrilla — a non-native aquatic plant that’s long been demonized by state agencies and lake managers across the country.

One morning during a summer internship performing fisheries related fieldwork on the river, I saw a young doe on the bank nibbling on a clump of hydrilla exposed at low tide. I laughed to myself — I knew it was good fish habitat, but even deer like the stuff!

The “official” position was that it was choking the river, outcompeting native species, and impeding recreational use of the river. But as a passionate angler and ecologist who studies aquatic ecosystems, I’ve learned that what we (as western scientists) think about non-native species and their impacts — especially in the world of aquatic plants — often turns out to be driven more by ideology than by scientific evidence.

The War on Hydrilla

Hydrilla arrived in the Connecticut River around 2016 and has since spread through the lower mainstem and its tributaries. In response, the Connecticut Agricultural Experiment Station (CAES) and the U.S. Army Corps of Engineers (USACE) have launched an aggressive herbicide campaign that seeks to “restore” native aquatic plant communities and study the efficacy of using a cocktail of various herbicides to treat the areas of the river where the growth of hydrilla is most prolific. Over the past few summers and into next year, private contractors plan to treat hundreds of acres of river coves with a mix of chemicals, including diquat and florpyrauxifen-benzyl.

On paper, this might sound like responsible ecological stewardship — reducing non-native plant stands such that their native counterparts can flourish. But in my view, it’s another example of what resource managers in Minnesota have referred to as “the invasive trap”: the belief that any non-native species must be “harmful”, and that launching management campaigns to kill them must be ecologically and economically beneficial.

The problem is that this assumption is not based on data, but on the dogmatic assumptions of invasion biology that underpin the world view of many western scientists and management agencies.

Unexpected Ecosystem Services: What the Evidence Shows

Across the country, hydrilla has often played the opposite role of what managers might expect. In the Chesapeake Bay and its tributaries, researchers found that hydrilla helped stabilize sediments, clear up murky water, and create habitat for fish and invertebrates — even helping native aquatic plant stands return. In Florida lakes, scientists compared lakes with and without hydrilla and found no major differences in fish, bird, or aquatic plant diversity.

In other words, hydrilla didn’t destroy these ecosystems where it was introduced. It filled open niche space, performed valuable ecosystem services, and is now integrated into the food web, for better or for worse.

That’s not to say hydrilla should be introduced to new water bodies or can’t impact ecosystems in ways that are perceived as harmful. Like many aquatic plants (native and non-native), hydrilla can grow in thick stands that interfere with swimming or boating, alter water chemistry and change physical habitat suitability for aquatic organisms. But many of these impacts are human nuisances, not ecological disasters, and should be managed as such. In large, dynamic systems like the Connecticut River, hydrilla’s role is likely far more complex — and possibly beneficial — than its label as “one of the world’s most invasive aquatic plants” suggests.

The Risks of Herbicide Use to “Restore” Native Plant Communities

Despite the lack of evidence that hydrilla is causing ecological “harm” to the Connecticut River, the proposed management intervention — widespread herbicide use — carries significant ecological risk.

Diquat, one of the main herbicides being applied, is what’s called a contact herbicide: it kills whatever plant tissue it touches (including native plant taxa). Florpyrauxifen-benzyl is a systemic herbicide, meaning it’s absorbed into plants and disrupts their growth. When a large quantity of aquatic plants rapidly die, they decay and release nutrients into the water, which can fuel algal blooms that reduce water clarity. If water clarity is significantly reduced, the very native plants managers aim to “restore” can’t regrow.

Ironically, hydrilla often bounces back first because it’s more tolerant of poor water quality than many native species. This can lock managers into a costly, never-ending cycle: herbicide use → temporary die-off → algal bloom → hydrilla regrowth → more herbicides.

Similar outcomes have been observed in Florida, where researchers found a large-scale florpyrauxifen-benzyl treatment sharply reduced hydrilla abundance in a Florida lake, but the plant regained dominance within a year as reduced water clarity from the treatment hindered native plant recovery.

Cascading Food Web Effects

As primary producers, aquatic plants are essential to the foundation of food webs — sheltering young fish, providing surfaces for invertebrates to live, and supporting wildlife like waterfowl. When herbicides are used to kill aquatic plants, there are often complex indirect impacts to the integrity of aquatic food webs.

Diquat is known to be toxic to not just plants (native and non-native) but invertebrates (the tiny animals that feed fish), such as amphipods. Even at concentrations lower than what’s used in field applications, diquat has the potential to impact these organisms which in turn may reduce available habitat for organisms higher up the food web like fishes.

Diquat also contains bromide, a compound that researchers have linked to a neurological disease killing bald eagles in the southeastern U.S. The disease develops when a particular cyanobacteria grows on hydrilla plants and interacts with bromide — forming a toxin that bio-magnifies as it moves up the food web. Ducks eat the hydrilla, eagles eat the ducks, and the toxin accumulates, damaging the eagles’ brains.

While this phenomenon hasn’t yet been documented in the Connecticut River, applying bromide-based herbicides in a manner that is likely to contribute to algal blooms (including cyanobacteria blooms) is not an ecologically sound management practice.

What We Don’t Know

Despite the confidence behind these large-scale management interventions, there’s little data showing how hydrilla has actually affected biodiversity or water quality in the Connecticut River. To prove that hydrilla is causing ecological “harm”, we’d need long-term monitoring — decades of data on aquatic plants, fish, wildlife, and water quality — collected before and after hydrilla became established. These data likely don’t exist at the scale needed to make an informed, unbiased assessment. Yet herbicide applications in the name of ecological “restoration” are moving forward anyway. The “post-monitoring” required by the project plan mostly focuses on the “efficacy” of the treatment (e.g. how much hydrilla biomass is reduced) not on whether algae blooms occur or how invertebrate and fish communities are affected.

This is a common phenomenon with herbicide treatments: the indirect effects of the management intervention are simply too complex and too costly to quantify. Based on the current “post-monitoring” protocol, if it’s found that hydrilla biomass is reduced and that native aquatic plant communities continue to exist following treatment, the project will be considered a success.

Less is More: Observation Based Management

Sometimes, the most ecologically mindful (and most cost effective) management decision is to pause to let species interactions occur unmolested and find their own equilibrium rather than impose an imaginary concept of what a given ecological community “should” be.

Where hydrilla interferes directly with human activities — say, blocking a boat ramp or clogging a marina — mechanical removal or small, targeted herbicide treatments could be reasonable management interventions. But broad, river-wide herbicide use is neither justified by science nor a long-term sustainable solution to non-native aquatic plant management.

With non-native species introductions, the truth is that there is no going back. Climate change, nutrient loading, and decades of physical habitat alteration via damming etc. have already changed this river beyond what it was a few centuries ago. Plants and animals are constantly being introduced and adapting to a new reality — one where species origins and “native” vs. “non-native” status matter far less than their role in maintaining ecosystem functions.

Rather than pouring more chemicals into the water, perhaps we should pour our efforts into observing, monitoring, and trying to understand why certain plants succeed and how ecosystems adjust to change over time. Instead of “controlling” non-native plants, perhaps we should practice more “self-control” and let nature heal itself without the imposition of the human ego and its desire to constantly fight the expressions of the natural world in the Anthropocene.

Julian Burgoff
Amherst, MA
jburgoff@umass.edu

The Post-Native World

Today, I’m publishing an excerpt of “The Post-Native World,” which was originally published by Ground Up, the Landscape Architecture and Environmental Planning Journal of the University of California, Berkeley. 

The author of the article, Mark Wessels, received his Master in Landscape Architecture at UC Berkeley. He is a licensed landscape architect and certified arborist.  He is a Senior Associate with PGAdesign in Oakland, California. 

Mark sent the following excerpt of his article in Ground Up to the members of the Oakland Urban Forest Forum, of which I am a member.  Mark’s article reflects my own belief that resilience of urban landscapes in a changing climate requires diversity, redundancy, and flexibility that can only be achieved with both native and introduced plants. 

Conservation Sense and Nonsense

Native ranges of trees in California’s urban forests. Source: Matt Ritter, Professor of Forestry, Cal Poly, SLO

CITIES AS HARBINGERS OF A POST-NATIVE WORLD
Native plant enthusiasts argue that native plants have evolved for thousands of years to be optimized for their environments. This is based on the assumption that environmental factors like soil type, climate, and ecological communities change very slowly, at the rate of geologic time. The fitness advantage of native plants depends on a relatively static, unchanging environment.

Yet cities are anything but static. Urban soils are altered by construction, compaction, and contamination. Impermeable surfaces and water infrastructure change urban hydrology. Urban heat island effect and microclimates affect soil and air temperatures. Cities are defined more by how urban they are than by where on the planet they are located. A tree adapted to urban environments, for example, is much more likely to flourish in San Francisco than one adapted to coastal dunes. In short, cities are post-native; they no longer reflect the environmental conditions for which native plants evolved. They are something new.

Cities are not the only places irreversibly altered by human activity. Human influence ripples out through resource extraction, food and energy production, and global climate change. Cities are already several degrees warmer than their historical temperatures, and many native plants cannot survive in this altered environment. Climate models predict several degrees of warming globally in the next 50 years. Native plants face challenges in urban settings today, and 50 years from now they will face challenges everywhere. As the effects of climate change spread beyond cities, landscape architects will need to move beyond geographic provenance to find plants adapted to a post-native world.

DIVERSITY OF APPROACHES VS. SINGLE STRATEGY
Globalization has irreversibly altered the planet, but it may also hold the key to surviving climate change. Designers today have unprecedented access to plants from around the world. For millennia, plants have been continuously evolving new, more efficient ways to survive in an astounding array of environmental conditions. In a post-native world, we will have to reconsider the idea that each plant is custom-evolved for a particular place on the earth, and instead think of global biodiversity as a library of adaptation. This library holds the key to successful planting in urban areas today, and hope for an uncertain future.

What I’m suggesting is that we embrace global biodiversity while we still have it; that our cities become hotbeds of plant species richness, hybridization, and cross-pollination; that we start a thousand divergent experiments, in small and controlled ways; and that we embrace this moment of globalization to produce an unprecedented explosion of diversity with which we can begin to replant and repopulate this irreversibly altered planet.

The resilience of natural systems lies in diversity, redundancy, and flexibility. Individual plants, and even individual species, die off frequently, but there is always another individual or another species to fill the void. Relying on a small set of native trees without embracing the redundancy and diversity of natural systems is a recipe for disaster.

Mark Wessels

A Walk in the Woods

We celebrated July 4th with a walk in the woods.  Huckleberry Botanic Regional Preserve in Oakland is a true remnant of native vegetation that is unique among the collection of 73 parks of the East Bay Regional Park District.  The trail guide describes the conditions that created this ecosystem and enabled its survival while other native ecosystems have not survived:

Huckleberry is “a relic plant association found only in certain areas in California where ideal soil and climatic conditions exist.  The vegetation association finds its roots in past climates and geologic history.  The plants originated in the distant past along the southern coast of California when the climate was more moist and tempered by the cool coastal fog.  Today, similar vegetation is found on the islands off the Santa Barbara coast and in isolated pockets on the mainland coast from Point Conception to Montara Mountain south of San Francisco.”

A view from Huckleberry Botanic Preserve of hills to the east. Source: East Bay Regional Park District

The preserve was created partly to protect an endangered species of manzanita, specifically pallid manzanita.  There are 107 species and sub-species of manzanita, of which 95 are native to California.  The ranges of most of these species are extremely small because manzanita hybridizes freely and therefore adaptive radiation has resulted in a multitude of species, sub-species, and varieties that are adapted to micro-climates.  Many of these species are locally rare and 10 species of manzanita have been designated as endangered, two of which are limited to the San Francisco peninsula:  Raven’s manzanita and Franciscan manzanita.

Manzanita is vulnerable to extinction partly because its ranges are small and partly because it is an “obligate seeder,” which means it can only be propagated in the wild from seed.  The seed of manzanita is germinated by fire.  However, the exact relationship between fire and germination is not known.  Many complex experiments have been conducted on the few viable seeds produced by Raven’s manzanita, which was designated as endangered in 1979.  Various combinations of fire, heat, cold, smoke, liquid smoke, etc., were tried and failed to determine exactly what triggers germination of manzanita seeds.  The suppression of fire in the past 150 years has contributed to the decline of small manzanita populations in California.

Some endangered species of manzanita are available in commercial nurseries because they can be easily cloned, which means they are genetically identical.  These commercially available manzanita species remain technically endangered because the criteria for endangered status requires that they be grown from seed in the wild to be eligible for removal of endangered status. 

Pallid manzanita in the Huckleberry Botanic Reserve are not doing well:

And some pallid manzanita is dead:

The sign explains that as pallid manzanita dies, it creates space in the understory for chinquapin and it predicts that more competitive huckleberry will eventually “overgrow and kill” chinquapin.  The sign describes this process as natural succession.  It doesn’t accuse huckleberry of being invasive.  If huckleberry were non-native, it probably would be considered “invasive.” 

Chinquapin has a distinctive nut, which is encased in a bristly shell.  My hiking companion said he and his brothers used to eat the tasty nut when camping in Mineral King in Sequoia National Park.  The bristly shell doesn’t make it easy to access the nut, but birds and wildlife find a way:

Huckleberry is appropriately the namesake of this botanic reserve.  In some portions of the narrow trail huckleberry creates tall, dense hedges on either side of the trail:

Because the Huckleberry Botanic Preserve is a relic of native vegetation that has been undisturbed by fire and development for hundreds of years, it is an excellent place to see huge native trees compared to much younger and therefore smaller native trees in other public parks in the San Francisco Bay Area. 

Mature bay laurel trees in Huckleberry Preserve are an opportunity to witness the competitive strategy of this tree species.  When it achieves some height as it grows, its branches fall over and often put down new roots that grow new vertical trunks.  This prostrate posture of bay laurels gives them a competitive advantage over other plants in the understory.  Mature bay laurels occupy huge expanses of space around them that create shade and make it difficult for other plants to become established in the shade.  The prostrate posture of bay laurels also makes it more flammable because the fire ladder to its canopy extends to the ground.  Crush a bay laurel leaf in your hands to smell its aromatic oils that also contribute to the flammability of bay laurels:

This madrone tree in Huckleberry Reserve is the biggest I’ve ever seen:

In early July some woody and herbaceous shrubs were still blooming. In this case, sticky monkey flower in the foreground and pink flowering current in the background:

Huckleberry Botanic Reserve is a unique gem in East Bay Regional Park District.  I hope you will have an opportunity to see it and that you will appreciate it as much as I do. 

Ideological vs. Scientific Definition of Biodiversity

Although there is broad agreement that maintaining biodiversity is necessary to achieve conservation goals, there is disagreement about the definition of biodiversity. Some native plant advocates believe biodiversity includes only native plants (example HERE). Most scientists include both native and non-native plants in measurements of biodiversity. I asked Claude.ai about this debate. 

Data source: Living Planet Report (2022). World Wildlife Fund (WWF) and Zoological Society of London.

I publish Claude.ai’s answer to my question as a guest post today. Claude.ai now has immediate access to internet sources, which makes answers to such queries more current and comprehensive.  Claude.ai has also provided links to the sources of the information provided. 

Conservation Sense and Nonsense

The ongoing debate about measuring biodiversity

Claude.ai:  Based on the available data, there’s a significant and ongoing scientific debate about whether biodiversity measurements should include non-native species. Here’s what the evidence shows:

Scientific Practice vs. Conservation Ideology

The Reality of Scientific Measurement:

In actual scientific practice, major biodiversity databases and assessment tools often do include non-native species. Research shows that “data used for biodiversity assessments and conservation planning should, initially, include all species” and that “including non-native species into the Biodiversity Intactness Index can lead to a 10% improvement in the index score” NihNCBI.

The Global Biodiversity Information Facility (GBIF), one of the world’s largest biodiversity databases, explicitly includes non-native species, stating that “information is the single most important variable necessary to support research, monitoring and management of alien and invasive species” GBIF.

Standard Biodiversity Definitions

Official Definitions Are Inclusive:

Scientific definitions of biodiversity do not exclude non-native species. As Britannica notes, biodiversity is defined as “the variety of life found in a place on Earth” and biologists most often define it as “the totality of genes, species and ecosystems of a region.” The most common measure is “species richness” – simply “the count of species in an area” BritannicaWikipedia.

The Convention on Biological Diversity (CBD) “emphasises the role of biodiversity in delivering benefits essential for all people and, as a result, seeks to safeguard all life-forms.” Research argues that “the absence of non-native species from biodiversity indices stands in contradiction to the CBD and Sustainable Development Goals {SDGs}” Do non-native species contribute to biodiversity? – PMC.

Scientific Consensus vs. Conservation Advocacy

The Evidence Shows Division:

A 2019 survey of 314 researchers found that “overall, a majority of respondents in our sample supported statements that the species-component of biodiversity should include all species (55%) or some types of non-native species” Diverse views among scientists on non-native species. This indicates significant scientific support for including non-native species in biodiversity measures.

However, there’s strong opposition from some conservation biologists. The IUCN argues it’s “misguided and potentially disastrous to consider native and non-native species as equal from the standpoint of both ecosystem services and conservation goals” Do non-native species count as biodiversity? – Crossroads blog | IUCN.

Practical Measurement Reality

How Biodiversity Is Actually Measured:

Standard biodiversity indices like Shannon diversity, Simpson diversity, and species richness simply count all species present. These indices “do not discriminate between species and communities with very different functionalities” and follow “a leading principle that ‘all species and individuals are considered equal'” 22.2: Diversity Indices – Biology LibreTexts +2.

Research shows that “the introduction of a non-native species increases the local species count (by one!)” and “because of the spread of non-natives, a general trend worldwide is that often local biodiversity (measured by a species count) is increasing even while overall global species numbers are in decline” Understanding and Defending the Preference for Native Species | SpringerLink.

Key Contextual Points

The Complexity of the Issue:

Scientists recognize this is “a broader social debate about what type of nature we need to ensure a good life for present and future generations.” The discussion involves “not only a scientific debate about the contributions of these species to society but also a broader social debate” Do non-native species contribute to biodiversity? – PMC.

Even in conservation contexts, scientists often use the term “alien species” rather than “invasive species” because “‘invasive’ suggests invasion potential and negative ecological effects, which is not necessarily the case for all alien species” Species data for understanding biodiversity dynamics: The what, where and when of species occurrence data collection – Petersen – 2021 – Ecological Solutions and Evidence – Wiley Online Library.

Conclusion

The available data clearly shows that:

  1. Standard scientific practice: Most biodiversity measurements and major databases include all species regardless of origin
  2. Official definitions: Neither CBD nor standard scientific definitions of biodiversity exclude non-native species
  3. Research consensus: A majority of surveyed scientists support including non-native species in biodiversity measures
  4. Conservation advocacy: Some conservation biologists argue for native-only measures, but this appears to be a minority position in the broader scientific community

The claim that “biodiversity only includes native plants” appears to be an ideological position held by some in the invasion biology community rather than the standard scientific practice for measuring biodiversity.

California’s Wildlife Conservation Board needs to hear from you!

Although I have stopped writing original articles for Conservation Sense and Nonsense, I am still actively engaged in local environmental issues.  When there are opportunities to influence public policies that affect the environment, I often participate. 

Today, I am sharing my public comment on the update of the strategic plan of California’s Wildlife Conservation Board (WCB) in the hope that it might inspire you to write your own comment on the draft plan, which is available HERE.  The deadline for submitting comments is May 16, 2025.  Comments may be sent to this email address:  wcb@wildlife.ca.gov

The mission of the Wildlife Conservation Board is to “protect, restore and enhance California’s spectacular natural resources for wildlife and for the public’s use and enjoyment…”  In service of that mission, WCB awards grants of millions of dollars every year for “restoration” projects.  According to WCB’s annual report for 2024, WCB awarded $93.5 million for “habitat restoration and enhancement of 5,000 acres” of land in California in 2024.

Source: “WCB 2024 Year in Review”

Over the life of the updated strategic plan, from 2025 to 2030, the Wildlife Conservation Board will distribute grants of $1.02 billion ($204 million per year) from funding made available by Proposition 4, the $10 billion “California Climate Bond,” which was approved by voters in November 2024.   Because most federal funding of climate and ecological restoration has been cancelled by the Trump administration (and being litigated, as we speak), the “California Climate Bond” will be one of the few sources of funding for these projects. 

This is my public comment on the strategic plan update for California’s Wildlife Conservation Board:

WCB Strategic Plan Update

Thank you for this opportunity to comment on the draft of WCB’s update of its strategic plan (SP).  I am writing to suggest that WCB consider the addition of a few over-arching principles that would apply to all of its programs.  These principles would enhance the plan’s stated goals of climate resilience and biodiversity protection by ensuring projects are evaluated based on their actual ecological outcomes rather than adherence to historical conditions.

  • All projects funded by WCB should be more constructive than they are destructive.  For example, a project that proposes to destroy more habitat than it creates should be less competitive than a project that will create more habitat than it destroys. A project that reduces carbon storage by destroying vegetation does not “reduce and remove carbon pollution,” as the SP proposes.
  • Projects that do not propose to use pesticides to destroy habitat should be more competitive than those that use pesticides because pesticides damage the soil and are harmful to wildlife and human life.   The success of projects is jeopardized by pesticide use.
  • Projects that apply for additional funding for a continuing project must address the fundamental question of the viability of the project.  In other words, if a project has been funded for 20 years, WCB should consider if the goals of the project are still realistic in a rapidly changing climate and environment (e.g., Invasive Spartina Project).
  • Projects should be consistent with the basic principles of science, such as:
    • The scientific definition of biodiversity includes both native and non-native plants and animals.
    • Hybridization is one of the tools of evolution that enables adaptation and speciation in response to changes in the climate and the environment.
    • The flammability of vegetation varies, but the variation is unrelated to the nativity of the plant.  Native plants are not inherently less flammable than non-native species.
    • The native ranges of California’s native plants have changed in response to the changing climate and they must continue to change if they are to survive.
    • Our changing environment dictates that historical landscapes cannot be replicated.  Humans cannot stop evolution, nor should we try.

I recommend that the WCB consider incorporating these principles into its project evaluation criteria to ensure that funded projects align with current ecological knowledge and maximize benefits for California’s biodiversity in a changing climate. Incorporating these principles into the SP would strengthen the plan’s objectives related to climate resilience (C2.1, C2.2), biodiversity protection (B1.1, B2.1), and program evaluation (D2.1, D2.2).

In support of these principles, I offer the following scientific studies for your consideration:

On pesticides damaging soil and harming wildlife and human health

  • Wan et al. (2025):  Pesticides affect a diverse range of non-target species and may be linked to global biodiversity loss. This study presents a synthesis of pesticide (insecticide, herbicide and fungicide) impacts on multiple non-target organisms across trophic levels based on 20,212 effect sizes from 1,705 studies. For non-target plants, animals (invertebrate and vertebrates) and microorganisms (bacteria and fungi), we show negative responses of the growth, reproduction, behavior and other physiological biomarkers within terrestrial and aquatic systems. Negative effects were more pronounced in temperate than tropical regions but were consistent between aquatic and terrestrial environments.  Results question the sustainability of current pesticide use and support the need for enhanced risk assessments to reduce risks to biodiversity and ecosystems.
  • Klein et al. (2024):  New Roundup formulations are 45 times more toxic to human health,on average, following long-term, chronic exposures. The study identified eight Roundup products in which Bayer has replaced glyphosate with combinations of four different chemicals: diquat dibromide, fluazifop-P-butyl, triclopyr, and imazapic. All four chemicals pose greater risk of long-term and/or reproductive health problems than glyphosate, based on the EPA’s evaluation of safety studies. Diquat dibromide and imazapic are banned in the EU. Diquat dibromide – present in all the new formulations – is 200 times more toxic than glyphosate in terms of chronic exposure and is classified as a highly hazardous pesticide.  New Roundup formulations pose significantly more harm to the environment. The chemicals replacing glyphosate in Roundup are significantly more likely to harm bees, birds, fish, earthworms, and aquatic organisms, on average. They are also significantly more persistent in the environment and more likely to leach down into groundwater, increasing the risk of contaminating waterways and drinking water.

On biodiversity including non-native species:

  • Schlaepfer et al. (2011): This pivotal paper challenges the automatic negative classification of non-native species by documenting their potential conservation benefits. The authors present evidence that some non-native species provide ecosystem services, habitat, and resources for native species, particularly in human-modified landscapes where native species may struggle. They advocate for conservation approaches that evaluate species based on their ecological functions rather than origin alone.
  • Mascaro et al. (2012): This study examines novel forests in Puerto Rico dominated by the non-native Castilla elastica tree. The research demonstrates that these novel ecosystems maintain key ecological processes such as productivity, nutrient cycling, and carbon storage at levels comparable to native forests. The findings suggest that novel ecosystems composed of non-native species can maintain essential ecosystem functions even after native tree species decline.

On hybridization as an adaptive mechanism:

  • Hamilton & Miller (2016): This paper reframes hybridization as a potential adaptive resource rather than a conservation threat. The authors present evidence that hybridization can introduce genetic variation that helps species adapt to changing environmental conditions, particularly relevant in the context of climate change. They suggest that conservation strategies should sometimes protect hybrid zones as sources of evolutionary potential rather than trying to eliminate them.
  • Fitzpatrick et al. (2015): This study examines how hybridization challenges traditional conservation approaches based on species preservation. The authors argue that hybridization is a natural evolutionary process that can generate biodiversity and adaptive potential. They present a framework for evaluating conservation value that considers genetic, ecological, and evolutionary factors rather than focusing solely on taxonomic “purity.”

On flammability unrelated to nativity:

  • Zouhar et al. (2008): This comprehensive technical report examines relationships between non-native plants and fire regimes. While acknowledging that some non-native plants can alter fire behavior, the report emphasizes that flammability is determined by plant structure, chemistry, and arrangement rather than nativity status. It provides detailed case studies showing both native and non-native plants can increase or decrease fire risk depending on specific traits.
  • Pausas & Keeley (2014): This study documents abrupt changes in fire regimes that occur independently of climate changes. The authors demonstrate that shifts in vegetation structure and fuel characteristics—which can be caused by both native and non-native species—are often more important determinants of fire behavior than plant origin. The research challenges simplistic assumptions about the relationship between native plants and fire resilience.

On changing native ranges:

  • Pecl et al. (2017): This influential paper documents how species are naturally shifting their ranges in response to climate change. The authors present global evidence of species redistributions across latitudinal, longitudinal, and elevational gradients. The study emphasizes that these range shifts are necessary adaptations to changing conditions and argues that conservation strategies need to accommodate these natural movements rather than trying to maintain historical distributions.
  • Bonebrake et al. (2018): This paper synthesizes research on climate-driven species redistribution and its implications for conservation. The authors highlight how traditional conservation approaches focused on preserving species in their historical ranges are becoming increasingly unviable under climate change. They advocate for more dynamic approaches that facilitate range shifts and species movements as adaptive responses to changing conditions.

On novel ecosystems and historical conditions:

  • Hobbs et al. (2014): This seminal paper introduces a framework for categorizing landscapes as historical, hybrid, or novel ecosystems. The authors argue that many ecosystems have been irreversibly altered by human influences and climate change, making restoration to historical conditions impossible in many cases. They advocate for pragmatic management approaches that focus on ecosystem functions and services rather than historical composition.
  • Stralberg et al. (2020): This study examines climate refugia in North America’s boreal forests. The research demonstrates that even supposedly pristine ecosystems will undergo significant changes due to climate change, with some areas serving as temporary refugia. The authors emphasize that conservation strategies need to recognize the transient nature of these refugia and plan for ongoing ecological transitions rather than static preservation.

In Conclusion

As you know, the mission of the Wildlife Conservation Board is to “protect, restore and enhance California’s spectacular natural resources for wildlife and for the public’s use and enjoyment…”  In addition, the Wildlife Conservation Board “envisions a future in which California’s wildlife, biodiversity and wild places are effectively conserved for the benefit of present and future generations.”  My suggestions for improvements in the draft strategic plan are consistent with the mission of the WCB. 

There was a time when academic scientists believed that the goal of conservation was to replicate historical landscapes by destroying plants and animals that were not here prior to European settlement.  Although many of these plants and animals found their way to California by natural means, without human assistance, they were perceived as “alien invaders” that didn’t belong here.  The assumption was that ecosystems can achieve an equilibrium state that represents an ideal that can be sustained by preventing change.  Science has long ago abandoned that notion in favor of acknowledging that nature is constantly changing in response to constant change in the environment. 

The belief that destroying such “alien invaders” would restore the landscape persisted for decades.  In many cases, no replanting was done after introduced plants were destroyed.  After poisoning our public land for decades, it has become clear to those who are not ideologically committed to historical landscapes that the original goal is not attainable because the plants and animals that survive are those that are best adapted to current environmental conditions, particularly the rapidly changing climate that is expected to continue to change.  In most cases, the newcomers are performing the same ecological functions of their predecessors and the harm that was presumed is usually balanced by benefits of their existence. 

Most academic scientists acknowledge this reality, but cultural lag has left the public behind as science has moved on.  Non-profit organizations that survive by the grace of their donors, have contributed to the pressure on public land managers such as the Wildlife Conservation Board.  Academic scientists are unwilling to participate in such grass-roots policy politics and their publications are often incomprehensible and inaccessible to the public and public land managers, leaving public land managers at the mercy of those with the least amount of information and the most amount of passionate belief.

The Wildlife Conservation Board has a responsibility to the public to inform itself of the consequences of conservation practices that are damaging the environment and are no longer realistic.  I respectfully ask that the WCB read the scientific studies I have provided and take them into consideration as it distributes over a billion taxpayer dollars made available by the passage of Proposition 4. 

Conservation Sense and Nonsense
May 1, 2025

References for cited studies

On pesticides harming soil and damaging wildlife and human health:

On biodiversity including non-native species:

  • Schlaepfer, M.A., Sax, D.F., & Olden, J.D. (2011). The potential conservation value of non-native species. Conservation Biology, 25(3), 428-437.
  • Mascaro, J., Hughes, R.F., & Schnitzer, S.A. (2012). Novel forests maintain ecosystem processes after the decline of native tree species. Ecological Monographs, 82(2), 221-228.

  On hybridization as an adaptive mechanism:

  • Hamilton, J.A., & Miller, J.M. (2016). Adaptive introgression as a resource for management and genetic conservation in a changing climate. Conservation Biology, 30(1), 33-41.
  • Fitzpatrick, B.M., Ryan, M.E., Johnson, J.R., Corush, J., & Carter, E.T. (2015). Hybridization and the species problem in conservation. Current Zoology, 61(1), 206-216.

  On flammability unrelated to nativity:

  • Zouhar, K., Smith, J.K., Sutherland, S., & Brooks, M.L. (2008). Wildland fire in ecosystems: fire and nonnative invasive plants. General Technical Report RMRS-GTR-42-vol. 6. USDA Forest Service.
  • Pausas, J.G., & Keeley, J.E. (2014). Abrupt climate-independent fire regime changes. Ecosystems, 17(6), 1109-1120.

  On changing native ranges:

  • Pecl, G.T., et al. (2017). Biodiversity redistribution under climate change: Impacts on ecosystems and human well-being. Science, 355(6332).
  • Bonebrake, T.C., et al. (2018). Managing consequences of climate-driven species redistribution requires integration of ecology, conservation and social science. Biological Reviews, 93(1), 284-305.

  On novel ecosystems and the impossibility of recreating historical conditions:

  • Hobbs, R.J., et al. (2014). Managing the whole landscape: historical, hybrid, and novel ecosystems. Frontiers in Ecology and the Environment, 12(10), 557-564.
  • Stralberg, D., et al. (2020). Climate-change refugia in boreal North America: what, where, and for how long? Frontiers in Ecology and the Environment, 18(5), 261-270.

Deforestation in San Francisco

I am publishing an article today that was published by the San Francisco Forest Alliance, with permission.  Many thanks to SFFA for reporting about the continuing assault on San Francisco’s urban forest. You can express your opinion about these tree removals by calling 800-801-2661 Ext 4.

Conservation Sense and Nonsense

Deforestation on Clarendon Avenue

Posted on March 31, 2025 by SF Forest Alliance

There’s a lot of deforestation on both sides of Clarendon Avenue, above the Laguna Honda, and on the slope below Laguna Honda Hospital. This time it’s courtesy of SFPUC –  San Francisco Public Utilities Commission (which our followers would recall is managed in the same way as SFRPD – San Francisco Recreation and Parks Department’s  “Natural Resources Division.”)

Indeed, Lisa Wayne, who for many years spearheaded the SFRPD effort, moved to SFPUC in 2021.

Note: All pictures in this post copyright Anastasia Glikshtern

SAN FRANCISCO FOREST ALLIANCE WROTE TO  SFPUC

San Francisco Forest Alliance is following up with SFPUC for evidence that the trees have indeed been evaluated as hazardous. We also pointed out that the bird nesting season has started on February 1 (it runs through August 31, 2025). It appears that the work continued through mid-February.

This forest added much to the beauty, privacy, and air quality of the neighborhoods around it. It’s historic: This charming article by Rex Bell described it in 2011 and compared it to the same places in 1896, where it was described as “A Genuine Old-Fashioned Country Road Within the Limits of the City of San Francisco.”

RISKS AND ISSUES

Quite aside from the historic beauty of this urban forest, and the many benefits of urban trees , there are issues of risk. One is slope stability – and we wonder if SFPUC actually assessed the risk of that steep slope above Clarendon Avenue being destabilized by this deforestation. The second is flammability. This is an area of the city that gets summer fog, and the fog moisture harvested by these trees kept the area below damp and cool. Now it will be dry and covered in fine fuels; we can only hope we do not face a hot dry summer any time soon.

Finally, since SFPUC uses herbicides as freely as does SFRPD’s Natural Resources Division, we can expect a lot more pesticides flowing into the groundwater.

San Francisco seems to have moved forward quickly with its war on trees. They have been felled everywhere where the urban forest exists in the city: Mount Sutro, McLaren Park, and now Clarendon Avenue. Ironically, they call it “Restoration.”

“Restoration” in progress
Formerly a beautiful tree