Climate Change – Conservation Sense and Nonsense

Flawed Data: Garbage in, garbage out

Even the most dedicated academic invasion biologists—such as Daniel Simberloff and Doug Tallamy—concede that not all introduced plants are invasive. However, they claim that all introduced plants have the potential to become invasive.

Early in the rise of invasive biology, over 25 years ago, much research effort was devoted to determining the factors that could predict which plants would become invasive. Theoretically, if we could predict an invasive future for an introduced plant we could make an early effort to eradicate them before they became entrenched, naturalized members of an ecosystem. At that point, most invasion biologists concede that landscape-scale attempts to eradicate non-native plants are futile.

The most recent attempt to identify the factors that contribute to “invasability” is a study led by Assistant Professor Moshen Mesgaran in the Department of Plant Sciences at UC Davis: “Invading plants remain undetected in a lag phase while they explore suitable climates.” (1) This study claims that it can take hundreds of years for non-native plants to become “invasive,” which the authors call “lag time.”

The study got my attention because it seemed obvious that the behavior of all plants, whether native or non-native, has changed greatly in the past 300 years, because of many changes in the environment, most notably climate change. What is described by the study as “lag time” between the time of the introduction of a non-native plant and its invasive behavior, seems primarily the predictable response of plants to climate and other changes that we should expect.

Source: https://scitechdaily.com/invasive-time-bombs-scientists-uncover-hidden-ecological-threat/

When I mentioned this study to one of my scientific advisors, he pointed out the most obvious flaw in the study, which casts doubt on the study’s conclusions. The study claims that plantain (Plantago lanceolata) had lag time of 177 years, the longest of any introduced plant in the United States: “Consider the common lawn weed Plantago lanceolata, otherwise known as ribwort or buckhorn plantain, which has the longest dormancy in the United States, according to the report. Noxious to livestock and native plants, the plant was introduced in the United States in 1822 and is found widely here.” (2)

In fact, plantain arrived in the US long before 1822 and was quickly widespread shortly after its arrival in the 17^th century. Plantain arrived first to the East Coast with early settlers, along with many other weeds. John Josselyn visited New England in 1638 and 1663 and made a record of English weeds in New England—including Plantago lanceolata—that was published in the 19^th century.

Native Americans of the Northeast also made a record of the arrival and spread of plantain in New England: Plantain “was called ‘Englishman’s foot’ by the Amerindians of both New England and Virginia, who believed in the seventeenth century that it would grow only where the English ‘have trodden & was never known to grow before the English came into this country.’” (3)

The arrival and rapid spread of plantain in the US is also immortalized by American popular literature. Henry Wadsworth Longfellow described the simultaneous arrival of white people and plantain, in the epic poem, Song of Hiawatha, published in 1855: “Wheresoe’er they tread, beneath them/Springs a flower unknown among us/Springs the White-man’s Foot in bloom.”

More recently, Daniel Mason described in his novel, North Woods, the arrival of plantain in the ballast of an English ship and its subsequent spread in the New World: “And there are seeds, uncountable, scattered in the humid loam: red clover, groundsel, spurrey, trefoil, meadow fescue, dandelion, hedge parsley, nonesuch, plantain. The voyage takes two months. On landing, the ballast is removed and dumped into the harbor. Much of it—the stones, the shells, the beads, the spectacles—sinks to the bottom of the bay. But the seeds, many of the seeds, enough of the seeds, rinsed loose of their swaddling earth, are freed into the breakers and float to shore.” (4)

Plantain arrived in the western US in the early 19^th century, when the Spanish brought many weeds to the West from Mexico along with their herds of cattle. Weeds from the Old World were noticed and recorded by John C. Fremont when he visited the Sacramento Valley in 1844. He also mentioned that his horses ate the weeds, and “even the squaws he met ate it [red-stemmed filaree].” (3)

English plantain “was one of the nine sacred herbs of the Anglo-Saxons, and Chaucer and Shakespeare cited its medicinal qualities. It grows wild today in all the continents but Antarctica, as well as in New Zealand and a number of islands. It rates as one of the very hardiest of weeds in the world, and it will be with us forever, apparently.” (3)

“English plantain is a major host of the buckeye butterfly from coast to coast, and in New York and perhaps elsewhere it is being used by the Eastern Baltimore Checkerspot, Euphydryas phaeton, previously considered monophagous on the wetland Scroph Turtlehead, Chelone glabra. This provided an escape from a very narrow niche!” (5) There are many instances of butterflies using plantain as their host plant in scientific literature (6)

We also question the characterization of plantain by Professor Mesgaran’s research team as a “noxious weed” that is harmful to livestock. English plantain is not listed as a “noxious weed” by the state of California (7) and its “invasiveness” is considered “Limited” by the California Invasive Plant Council. English plantain is not considered toxic to horses or cattle, according to the results of internet searches.

Plantain arrived in the New World soon after it was discovered by the Old World. It spread quickly and is now a valued member of American ecosystems, as well as most ecosystems all over the world. As we often say in defense of harmless non-native plants, “What’s the beef?”

Professor Mesgaran’s study used herbarium and climate data to analyze “over 5,700 time series (species × regions) in 3,505 naturalized plant species from nine regions in temperate and tropical climates to quantify lags and test whether there have been shifts in the species’ climatic space during the transition from the lag phase to the expansion phase.” (1) This source of information was clearly not accurate in the case of English plantain, which has been in the US over 400 years and immediately spread everywhere. I can’t speak to the study’s report of “lag times” in other global regions.

Putting aside the inaccuracy of data used by the study to report the “lag time” between the arrival of introduced plants and evidence of invasive behavior, I summarize the findings of this study:

The behavior of plants vary from one place to another because growing conditions vary.
When the climate changes, vegetation changes in response.

This study claims that it can take hundreds of years for non-native plants to become “invasive.” The concept of “lag time” seems to suggest that all introduced plants have the potential to become invasive. This is not a new idea among invasion biologists who consider all introduced species a problem even when there is little evidence that they are. That school of thought expects us to prevent all plant introductions because they assume that all of them will be a problem in the future. The contrarian view is:

It is impossible to prevent all introductions of non-native plants because most are dispersed unintentionally or naturally.
The damage that is done to the environment by futile attempts to destroy non-native species is worse than the theoretical risks that some of them will eventually become a problem.
The resources used in the attempt to eradicate non-native species could be put to better use to benefit the environment, such as addressing the causes of climate change.
Every non-native plant contributes to biodiversity, which creates evolutionary opportunities to adapt to the changing environment. There is far more opportunity lost when harmless non-native plants are eradicated compared to their potential to contribute to biodiversity.
Many non-native plants are beneficial and are frequently functional substitutes for native species that are no longer adapted to the changed environmental conditions and climate.

Unfortunately, what might have been a straight-forward study (embedded in arcane jargon and complex statistical analysis) is flawed by inaccurate information about the “lag time” of specific plants in specific countries. The study claims that it took 177 years for plantain to become “invasive” in the US. In fact, plantain spread everywhere immediately after it was introduced in the 17^th century and there is no evidence that it has done any harm where it lives. If we learn anything new from this study, it is that herbarium records are not a reliable source of information about the arrival and dispersal of introduced plants.

Much like the fossil record, herbarium collections can establish that a plant or animal lived in a specific place at a specific time, but they cannot provide negative evidence that the plant or animal wasn’t there or elsewhere prior to the time the specimen was collected. In any case, when plantain arrived in the US, there were few herbarium collections available to record its arrival.

This is not to say that herbarium collections are not useful for botanical research. Here are two specific examples of how herbarium collections have been used appropriately by scientists:

Angela Moles, an Australian scientist, used the collection of a university herbarium to measure the changes in plants that were introduced to Australia. The herbarium had samples of the same species of plants collected over a 60 year period from the same location. Professor Moles found that the plants had changed in significant ways. In a sense, they were becoming Australian plants in response to the biotic (other plants and animals) and abiotic (climate, soil, etc.) conditions of their new home. She predicted that if they weren’t yet genetically distinct from their ancestors, they soon would be. Professor Moles made a TED presentation 11 years ago about her findings that is available HERE.

Scientists used seeds in France’s National Botanical Conservatories collected in the 1990s and early 2000s to study how the plant had changed over a period of less than 30 years. The plant species they studied was capable of both self-pollination and cross-pollination by insects and other animals. They germinated the old seeds and compared their flowers with those now growing in the French countryside. They discovered that self-pollination by that plant species had increased 27 percent since the 1990s, probably in response to the significant decline in bee populations. That study was described by the New York Times.

No amount of obscure jargon and statistical analysis can compensate for flawed data: garbage in, garbage out.

“Invading plants remain undetected in a lag phase while they explore suitable climates,” Mohsen B. Mesgaran, Nature Ecology & Evolution, February 6, 2024
https://scitechdaily.com/invasive-time-bombs-scientists-uncover-hidden-ecological-threat/
Alfred Crosby, Ecological Imperialism, Cambridge University Press, 2004 (second edition). The source of the quote within the quote of Crosby is from the published writings of Reverend John Clayton, a Parson with a Scientific Mind.
Daniel Mason, North Woods, Random House, 2023
Email communication with Professor Emeritus Arthur M. Shapiro (UCD) with permission
“Matthew and Jonathan Douglas explicitly record oviposition on plantain in “Butterflies of the Great Lakes Region” (2005). I’m sure there are earlier such mentions.” Email communication with Professor Emeritus Arthur M. Shapiro (UCD) with permission
https://www.cdfa.ca.gov/plant/ipc/encycloweedia/pdf/CaliforniaNoxiousWeeds.pdf

Assembly Bill 2509 has the potential to reduce pesticide use, IF it is revised

Below is my letter to California Assemblymember, Ash Kalra (District 25, San Jose), asking him to consider revising Assembly Bill 2509 so that it will reduce the use of pesticides in California to eradicate harmless and useful non-native plants. Please consider making this suggestion to your elected representatives in the California Legislature. AB2509 has the potential to reduce pesticide use in California if we make an effort to revise it as needed to accomplish that goal.

Dear Assemblymember Kalra:

AB2509, your bill being considered by the California Legislature, will define “Integrated Pest Management” (IPM) and “invasive species.” The bill has the potential to reduce pesticide use in California’s parks and open spaces, but only if it is revised to accomplish that purpose. AB2509 is also an opportunity to improve the success of ecological restorations that begin by eradicating non-native plants considered “invasive,” by narrowing the target to those few species that are actually doing any harm.

In its present form (April 4, 2024), AB2509 defines invasive species, “to mean nonnative organisms that cause, or are likely to cause, economic or environmental harm, excluding humans, domestic livestock, specified domestic or domesticated species, and nonharmful nonnative organisms.”

That definition is based on Federal Executive Order 13112, which was passed 25 years ago, in 1999. We have learned a lot in the past 25 years about invasive species and the attempt to control them:

The climate has changed a great deal since 1999, and with it the environment, including the plants and animals that live in it. The native ranges of many plants and animals have changed and will continue to change.
We have learned that many introduced plants are often functional substitutes for native plants that are no longer adapted to the changed environment.
We have learned that insects are capable of rapidly adapting and evolving to make use of introduced plants.
We have learned, after trying to eradicate them for over 25 years, that most naturalized introduced plants cannot be eradicated.
We have learned that the herbicides being used to eradicate introduced plants are doing a great deal of harm to the environment and the animals who live in it. We now know that herbicides damage the soil, making it difficult for new plants to survive in sterilized soil, devoid of beneficial microbes and fungi.
We have learned that native plants don’t necessarily return after introduced plants have been eradicated. The damage done by eradication projects is often greater than the anticipated benefit.
Despite dire predictions to the contrary, there is no evidence that any introduced plant species has caused the extinction of a native plant species in California.

We need a new definition of invasive species that reflects these changes and accommodates the movement of plant and animal species needed for survival. We need a definition that does not attempt to stop adaptation and evolution. Like dynamic nature, our attempts to conserve nature must constantly evolve in response. We need a definition that distinguishes between actual harm and theoretical predictions of harm. We need a definition that does not require us to poison our public lands unnecessarily.

Please consider revising the definition of “invasive species” in AB2509 to reflect what we now know about introduced plants, such as:

“AB2509 defines invasive species to mean pathogens, diseases, and insects that are known to cause harm to plants and animals, including humans.”

In its present form, AB2509 also defines Integrated Pest Management as: “’Integrated pest management’ means an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment.”

Integrated Pest Management (IPM) is not a new concept. Most public land managers have had IPM programs for over 25 years. Some have resulted in reduced herbicide use in developed areas, without corresponding reductions in public open space and wildlands.

San Francisco’s IPM program has significantly reduced herbicide use on developed public land, but herbicide used to eradicate non-native plants in one-third of park acreage known as “natural areas” has changed little, as shown in this graph:

*Source: San Francisco Integrated Pest Management Program*

East Bay Regional Park District has also reduced its use of herbicides in developed areas of the park, such as parking lots, picnic areas, and playgrounds, without reducing their use in wildlands where non-native plants and trees are eradicated:

*Source: EBRPD 2022 Annual Integrated Pest Management Report*

If we want Integrated Pesticide Management Programs to reduce the use of pesticides in our public lands, we must define IPM to achieve that purpose by:

Changing the definition of “invasive species” to focus only on those introduced species that are known to cause actual harm. The expectation of “likely” harm without evidence of actual harm should not be used to justify pesticide use.
Explicitly defining the “guidelines” that determine if pesticides are needed in order to prevent their use on harmless and beneficial plants.
Avoiding the use of vague terms that can be interpreted differently from different perspectives, such as “use of resistant species.” Resistant to what? In whose opinion?
By not making empty promises such as claiming that pesticides can be used on non-native plants without doing any damage to non-target species. Because of drift, persistence, and mobility of pesticides in the soil, it is not possible to make such assurances, which give the public the mistaken impression that herbicides can be used without unintended consequences

Please consider a revised definition of Integrated Pesticide Management that will reduce pesticide use and preserve the vegetation that is capable of growing in today’s environment, such as:

“’Integrated pest management’ means an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, and modification of cultural practices. Pesticides are used only after harm is documented, benefits of existing vegetation have been identified and weighed against harm, the health risks and environmental damage caused by herbicides is considered, and the outcome of eradication is determined to be positive, on balance.”

In conclusion, I will briefly describe my interest in invasion biology and the ecological restoration industry it spawned. My interest began over 25 years ago when my neighborhood park was designated a “natural area” by San Francisco’s Recreation and Park Department. When I moved to the East Bay, I learned that the native plant movement is equally committed to the eradication of introduced plants and the pesticides needed to accomplish that goal. I have visited many of these projects all over the Bay Area and elsewhere in California. I read the publications and attend the conferences of California Invasive Plant Council and California Native Plant Society so that I am as informed of their objectives and beliefs as I am of the academic criticism of invasion biology. I have had a website since 2010 that reports to the general public what I have learned about specific projects and the scientific evaluations of them. I invite you to visit my website to help you evaluate the advice I am sending to you today about AB2509. I can provide references for every statement I make in this letter, on request.

Thank you for your consideration and for your effort to reduce pesticide use in California.

Sincerely,
Webmaster, Conservation Sense and Nonsense

CC:
Patty Clary, Californians for Alternatives to Toxics
Damon Connolly, Assembleymember, District 12
Jay Feldman, Beyond Pesticides
Angel Garcia, Californians for Pesticide Reform
Doug Johnson, California Invasive Plant Council
Megan Kaun, Sonoma Safe, Ag Safe Schools
Melinda MacNaughton, El Granada Advocates
Margaret Reeves, Pesticide Action Network
Jane Sellen, Californians for Pesticide Reform
Nancy Skinner, Senator, District 9
Buffy Wicks, Assemblymember, District 15
Wildlife Conservation Board

Update, April 24, 2024:

The Assembly Agriculture Committee voted unanimously to pass AB2509 to the Appropriations Committee with no amendments.

Doug Johnson, Executive of Cal-IPC and Marc Landgraf, Santa Clara Valley Open Space Authority, spoke in favor of AB2509. Johnson claimed that only “small amounts of pesticide are used.” Landgraf said most plants are killed by grazing, mowing, and volunteers pulling my hand; herbicides are used only “when needed.”

Damon Connolly was the only committee member to speak. He expressed concern that AB2509 not conflict with his continuing support for AB99, which has the potential to reduce roadside spraying of herbicide by Cal Trans.

There were no speakers in opposition to AB2509. There was no acknowledgment of the public’s concern about AB2509 or of the public’s concern about herbicides being used on our public lands.

Let Evolution Lead the Way to Adaptation and Survival of Life

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

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.

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 18^th 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.

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 hundreds of genetic tests are required 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.”

Thomas Halliday, Otherlands, A Journey Through Earth’s Extinct Worlds, Random House, 2023
https://www.nytimes.com/2024/01/04/science/flower-sex-evolution-bees.html?searchResultPosition=1
https://en.wikipedia.org/wiki/List_of_C4_plants
Erik Lundgren et.al., “Functional traits—not nativeness-shape the effects of large mammalian herbivores on plant communities,” Science, February 2, 2024
David Yih, “Land Bridge Travels of the Tertiary: The Eastern Asian-Eastern North American Floristic Disjunction, Arnoldia, 2012

For US Fish & Wildlife Service “Management” Means Killing

“It makes me sad, but range expansions are a part of natural systems. We just happened to be watching when one occurred. Even if [we’re to blame], we’re probably going to have to live with it.”
Eric Forsman, US Forest Service

US Fish & Wildlife Service (USFWS) proposes to kill 470,000 barred owls in the next 30 years in an effort to save the northern spotted owl (NSO) and a closely related sub-species in California. The deadline for making a comment on this proposal is January 16, 2024. Instructions for making comments are available HERE.

Today, I will tell you about this proposal, how it came about, and why I am opposed to the proposal. I provide links to the source documents so you can read them yourself. I hope this information will help you reach your own conclusions about the plan and submit a public comment.

USFWS Barred Owl Management Strategy

The purpose of the Barred Owl Management Strategy is protection for the dwindling population of northern spotted owls (NSO) in the Pacific Northwest (Washington, Oregon, and Northern California). NSOs were classified as a threatened species by USFWS in 1990. The first Recovery Plan for NSO, published in 2011, identified habitat loss and barred owls as the primary threats to NSOs. The most recent Recovery Plan has added “past habitat loss, continued timber harvest, and wildfire” to the list of threats to NSOs.

The Barred Owl Management Strategy also proposes “management” of barred owls to protect the California spotted owl (CSO), which is a subspecies of NSOs. Although endangered status for CSO was proposed in February 2023, endangered status has not been granted. Yet, USFWS proposes to extend the same lethal removal measures used to protect NSOs to CSOs. In addition to the threats to NSOs, California spotted owls are also threatened by fragmented habitat and forest mortality caused by drought and correlated disease, which have killed over 300 million conifers in California in the past 10 years.

*Source: Barred Owl Management Strategy*

Despite the many threats to spotted owls, the Management Strategy intended to protect them addresses only one of those threats: barred owls. It makes no proposals for improving or expanding habitat or addressing the impact of climate change on forests.

The Barred Owl Management Strategy is a voluntary plan. Federal agencies in spotted owl territory (Bureau of Land Management, US Forest Service, and National Park Service) will be “encouraged” to implement the plan. If state, commercial, private property, and tribal land owners choose to participate they will be granted the same “take” permits required by the Migratory Bird Treaty Act that federal land managers will be granted, so long as they agree to follow the protocol for “removing” barred owls from their properties.

The word “removal” in the context of the Management Strategy means “lethal removal.” The protocol requires that barred owls be found by playing a recording of their distinctive call (described as “who cooks for you?”) and shooting the owl as it flies toward the call and the shooter. If guns are not allowed where barred owls are found, they must be captured and euthanized. Hybrids of barred owls and spotted owls will also be killed, despite the fact that accurately identifying hybrids is considered difficult, particularly in subsequent generations.

Because the Management Strategy is not mandatory, the total number of birds that will be killed can only be estimated. If all property managers choose to implement the Strategy, approximately 470,000 barred owls would be killed in the next 30 years. Although the Strategy covers only a 30 year time frame, “barred owl management will be required at same level for the long term” because “Their populations will continue to produce young that can disperse within and beyond the current range of barred owls.” (1) The estimated current population of barred owls in study areas of the Management Strategy is only 102,000. Clearly the lethal removal of barred owls is not expected to keep pace with the reproductive success of barred owls. The killing of barred owls will continue forever, although there is no expectation that they will be eliminated.

*Source: Draft Environmental Impact Statement for Barred Owl Management Strategy*

How were barred owls selected as the scapegoat?

When northern spotted owls were designated as “threatened” in 1990 it triggered the legal protections conferred by the Endangered Species Act. In 1994, the Forest Service and the Bureau of Land Management published the EIS for the Northwest Forest Plan. It created 24 million acres of reserve areas where logging was prohibited to preserve spotted owl habitat. The reserve areas protected approximately 80 percent of the remaining old growth forests in the Pacific Northwest from timber harvesting. Obviously, the plan had a negative impact on the timber industry and those who were employed by the industry. Between 1980 and 1998, 23% of logging jobs were lost, triggering the Timber Wars.

The rate of decline of spotted owl populations in the Pacific Northwest decreased when most logging in old-growth forest was stopped by the Northwest Forest Plan, but began to accelerate again in about 2008. USFWS attributes that increase in the rate of population decline to competition from barred owls and that theory is supported by several studies.

Barred Owl. GNU Free Documentation License

Barred owls are native to North America. They have been migrating from their historic range in the north and south east of the US to the west coast of North America since about 1900. Barred owls were first seen on the west coast of North America in British Columbia, Canada around 1959. They were first documented in Washington in the 1970s and have continued moving south from there.

Barred owls have successfully competed with spotted owls in their expanding territory because they are larger than spotted owls, they eat a wider variety of prey, they have greater reproductive success, and they are able to live in forests where spotted owls cannot. Spotted owls are restricted to old-growth forests with large trees and dense canopies, while barred owls often live in second-growth (previously logged) forests and even wooded urban areas.

The Management Strategy speculates that the omnivorous diet of barred owls will devastate the food webs in the new territory they occupy, although the Strategy offers no evidence to support that theory. In fact, as barred owls expanded their territory through the Canadian boreal forest, such devastation was not reported. Barred owls are not considered “invasive” in Canada.

The impact of barred owls on spotted owls was first observed by Lowell Diller, a wildlife biologist who worked as a consultant to Green Diamond Resource Co., a logging company managing timberland in Humboldt and Del Norte counties in Northern California. Mr. Diller was also an adjunct professor in the Department of Wildlife at Humboldt State University.

Owls, including barred owls, are protected by the Migratory Bird Treaty Act. Mr. Diller applied for permits to kill barred owls on the property of Green Diamond Resource Co. as an experiment to determine the impact of barred owls on spotted owls. He described his project in an article in the Marin Independent Journal: “In 2009,…Diller set aside patches of timberland to remove barred owls. In other patches, he did nothing. After four years, he would see how northern spotted owl numbers differed in the areas with and without barred owls…The study is the first to prove his treatment works.” To be clear, his “treatment” was to shoot barred owls. Mr. Diller also described how upsetting it was to kill birds.

Green Diamond applied for permits and has continued to kill barred owls on its property. That commitment has ensured that Green Diamond’s current rate of logging can continue. The Green Diamond spokesman explained: “’When you can protect and sustain a business and jobs and also conserve the northern spotted owl,’ he said, ‘why not do it.’” (Marin Independent Journal)

Sierra Pacific Industries is also killing barred owls on its property. Sierra Pacific Industries in Shasta County is the largest private land holder in California and the second largest lumber producer in America.

On the basis of the success of Diller’s study, USFWS approved a pilot project to kill barred owls in other places where spotted owls live. The pilot project killed about 3,000 barred owls. When the project was completed in 2021, they reported, “The removal of barred owls had a strong, positive effect on the survival of northern spotted owls and a positive, but weaker, effect on recruitment of spotted owls.” (2) The Barred Owl Management Strategy is based on the success of the pilot study.

In other words, killing barred owls has enabled the timber industry in Northern California to continue their logging operations. It has also removed the pressure to expand reserve areas to protect spotted owls, even though many scientists believe such expansion would be more effective than killing barred owls to save spotted owls: “’The bottom line is that extinction rates went down when the amount of habitat went up,’ U.S. Geological Survey biologist Katie Dugger, lead author of the 2015 demographic study, said in a presentation on the findings last fall. ‘Spotted Owls cannot exist without old-growth forest. And now we’re talking about two species trying to use the same space, so in fact we need more of it.’” (3)

Specific Flaws in Barred Owl Management Strategy

The Barred Owl Management Strategy is based on several outdated notions about nature that have been cast in the concrete of American law. The Endangered Species Act is based on assumptions about nature that were conventional wisdom at the time the law was passed 50 years ago, in 1973. Evolution was considered a series of events that occurred in the distant past and is no longer actively changing plants and animals. At the time the ESA was passed, evolution was not believed to occur within a time frame observable by humans. Nature was perceived as reaching an “equilibrium state” that was stable over long periods of time. Early conservation efforts were therefore based on the assumption that once achieved, an equilibrium state could be sustained if left undisturbed in nature preserves. (4)

We now know that these assumptions are mistaken. In the past 50 years, climate change and advances in paleontology have taught us that nature is inherently dynamic and we are usually powerless to stop it from changing even when we try. When a law is designed to control nature, we should expect some conflict between static law and dynamic nature. Fifty years after the Endangered Species Act was passed, that conflict is becoming progressively more apparent and problematic.

These are the specific flaws in the Barred Owl Management Strategy that are the result of mistaken assumptions about nature:

Barred owls should not be considered “invasive” on the west coast of the US because the expansion of its range is a natural phenomenon that cannot and should not be stopped.

USFWS designates barred owls on the west coast as “invasive” by fabricating a story about the route barred owls took from their historic range in the east to their expanded range in the west that is not consistent with the facts. Although USFWS admits that the route that facilitated expansion is “not well documented,” they claim there is evidence of anthropogenic change across the Midwestern Prairie that supports that specific route: “…the historical lack of trees in the Great Plains acted as a barrier to the range expansion and that increases in forest caused by the anthropogenic impact of European settlement enabled the westward extension of the barred owl range. These include anthropogenic impacts such as fire exclusion and suppression, bison and beaver extirpation, deer and elk overhunting, establishment of riparian forests, and extensive planting of trees and shelterbelts in the northern Great Plains…” (2) Although that is an accurate description of anthropogenic changes in the Midwestern Prairie, it is irrelevant to the expansion of the range of barred owls, because that wasn’t the route they took to the west coast.

The legal definition of invasive species enables USFWS to designate barred owls on the west coast as “invasive” based on their claim that the expansion route was through the American Midwest as a result of anthropogenic change. If non-indigenous humans are considered the cause of a change in ranges of plants and animals, the species is considered “invasive” where it did not exist prior to the arrival of Europeans. Labelling any plant or animal “invasive” makes it a target for eradication. However, the theory of a midwestern expansion route for barred owls is not consistent with the facts:

This map clearly shows that the route used by barred owls to expand their range to the west coast was through the boreal forests of Canada, which were not the result of anthropogenic change. The boreal forests of Canada have existed since the Ice Age ended 10,000 years ago. The map does not show the historic or current existence of barred owls in the American Midwest.

The expansion route of barred owls to the west coast through Canadian forests is also consistent with the record of their arrival on the west coast. They were seen first in the west in 1959 in British Columbia, Canada, at the northern edge of their current range. They were first seen in the US in Washington in the 1970s. Their range expansion continues to the south. This sequence of events is not consistent with the claim that they arrived on the west coast via the American Midwest.

Claiming that barred owls are “invasive” enables USFWS to justify their extermination, as many of their eradication projects do: “Yes, wildlife removal has been used as a management tool by many agencies across the country to control invasive species such as invasive carp, Burmese python, feral hogs, rats, mongoose, and nutria. Invasive species can thrive in areas where they do not naturally occur.” (1) That list of animals being killed by USFWS is far from complete.

This is not a trivial matter. Climate change requires that plants and animals move to find the conditions needed for their survival. Preventing the migration of plants and animals as the climate and the environment change will doom them to extinction. Designating barred owls on the west coast “invasive” has dangerous implications for many plants and animals that must move to survive in a rapidly changing climate. The Management Strategy should not set this dangerous precedent.

Interbreeding of spotted owls and barred owls is a natural phenomenon that cannot and should not be stopped. Hybrids of spotted and barred owls should not be killed.

Hybridization is not only common, it can result in the creation of new species more rapidly than other forces of evolution, such as mutation and natural selection: “Hybridisation also offers shortcuts on the long march to speciation that do not depend on natural selection at all.” (5)

More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. Yet there are currently around 8.7 million species of eukaryote (organisms whose cells have a membrane-bound nucleus) globally. (Wikipedia) Biodiversity on Earth has increased partly because of hybridization, which has often enabled adaptation to changed environmental conditions.

There are many important examples of hybridization among animal species, most notably the history of hybridization of our species, Homo sapiens. Humans are now the sole surviving species of genus Homo. Our genome contains the relicts of the genes of other members of our genus that are now extinct, which indicates hybridization with other hominoid species. The modern human genome contains 1-4% of Neanderthal genes. (5)

There are also many examples of hybridization of plant species that contributed to biodiversity. In a recently published study of the evolution of oaks, scientists traced the 56 million year evolutionary history of roughly 435 species of oak across 5 continents where they are found today. Hybridization was instrumental in the formation of oak species and the ability of oaks to survive in different climate conditions. The article in Scientific American about the genetic study of oak species concludes: “A firm grasp of when, where and how oaks came to be so diverse is crucial to understanding how oaks will resist and adapt to rapidly changing environments. Oaks migrated rapidly as continental glaciers receded starting around 20,000 years ago, and hybridization between species appears to have been key to their rapid response. The insights we can gain from elucidating the adaptive benefits of gene flow are critical to predicting how resilient oaks may be as climate change exposes them to fungal and insect diseases with which they did not evolve.”

The bias against hybrids is a reflection of nativist ideology in the natural world. Nativists call hybridization “genetic pollution.” Unfortunately, hybridization is seen by nativists as the loss of a “pure” native species rather than the potential for a new species that is better adapted to changing environmental conditions. The proposal to kill hybrids of barred and spotted owls is a symptom of the nativist bias that is typical of most public agencies.

Barred and spotted owls are closely related. They are in the same genus, just as Neanderthals and Homo sapiens were in the same genus. Their interbreeding is both predictable and potentially beneficial to spotted owls because barred owls are better adapted to current conditions. The hybrid has the potential to produce a new species that is better adapted to compromised forest conditions than the spotted owl. Although there is risk in hybrids, in the case of spotted owls the risk is worth taking because many scientists predict that the northern spotted owl will soon be extinct. Hybridization may be more helpful to the spotted owl species than killing barred owls.

The Barred Owl Management Strategy should not be extended to California spotted owls.

The Barred Owl Management Strategy depends on the legal protections of the Endangered Species Act. Both barred owls and spotted owls are protected by the Migratory Bird Treaty Act. Therefore, “take” permits must be granted to kill barred owls. The protected status of northern spotted owls justifies take permits, but should not be extended to California spotted owls (CSO) that are not legally protected. Issuing take permits to kill barred owls to save California spotted owls makes a mockery of both the ESA and the Migratory Bird Treaty Act. It implies that USFWS can find loopholes in environmental laws intended to protect nature, whenever they wish. It undermines the public’s faith in government when public agencies are perceived as arbitrary and capricious.

Killing barred owls in CSO territory cannot be justified because there are few barred owls in their territory and threats to the CSO population are unrelated to the existence of a few barred owls. (See map of barred owl distribution in California below.) Shooting barred owls will not stop the wildfires, droughts and diseases killing their habitat. The proposed Management Strategy is irrelevant to the survival of CSO.

*Source:* *Spotted Owl Observation Database, California Department Fish and Wildlife, 2019*

There is no reason to kill barred owls in Marin and Sonoma counties in the San Francisco Bay Area because the population of Northern Spotted Owls is stable and there are very few barred owls.

The Marin/Sonoma County Management Zone designated by the Management Strategy includes all lands within the named counties. Conditions in Marin and Sonoma County are substantially different from the rest of the northern spotted owl range. This is the only portion of the northern spotted owl range where barred owls are very uncommon.

The recently completed survey of northern spotted owls in Marin County reports that the population is stable. The survey found nesting pairs of NSOs in all 48 inventory sites. A small decline in nesting success was not statistically significant. Two unpaired barred owls were detected on or near Marin County Property or Marin Watershed Property in 2023. One was removed, the other was not detected a second time. (6)

*Source:* Northern Spotted Owl Monitoring on Marin County Parks and Marin Municipal Water Department lands, 2023 Report, Point Blue Conservation.

Despite the lack of evidence that northern spotted owls are threatened by barred owls in Marin County, the Barred Owl Management Strategy considers it the highest priority to kill the few transitory barred owls detected in Marin County. This is unnecessary overkill that should be removed from the Management Strategy. It contributes to the public’s perception that the strategy of USFWS is extreme and inconsistent with environmental laws that protect nature.

In conclusion, the Barred Owl Management Strategy is a reflection of the extreme nativist bias of USFWS. Like many of their projects, USFWS has selected an animal scapegoat for the declining population of northern spotted owls that are not well adapted to changed forest conditions. Selecting an animal scapegoat enables timber companies to continue logging and it is an easy way to avoid addressing the much more complex reasons for challenges to northern spotted owls. For example, killing barred owls won’t do anything to reduce the greenhouse gases causing climate change or restore logged or burned forests. The Barred Owl Management Strategy will employ an army of snipers, but is unlikely to benefit the environment or its inhabitants. USFWS cannot stop evolution, nor should it try.

Although I have low expectations that 2024 will be more peaceful than last year, in the spirit of hope, I wish you Happy New Year. Thank you for your readership.

Redefining Ecological Restoration

“Urban Jungle is breathtaking in its scope, both geographic and temporal… I can say I probably learned more per page in Urban Jungle than in any other book I have read at all recently.” –Professor Art Shapiro

As climate change makes many places uninhabitable, there is a new urgency to restore natural habitats damaged by human activities.

After a lengthy and contentious battle, the European Union narrowly voted to make a commitment to restore 20% of nature areas on land and sea within their borders. Farmers were the primary opposition to making this commitment, claiming it would severely reduce their ability to produce sufficient food. 6,000 scientists from several countries disagreed: “They argued that in the long term, it was climate change and nature degradation that constituted the highest threat, and that the proposed policy would ensure sustainable food production.” (1)

The Biden administration has issued an executive order to conserve 30% of US lands and oceans by 2030. This 30X30 commitment has been funded by the State of California and is in the early stages of implementation. In the US, the commitment to “restore” land is often interpreted as a commitment to destroy non-native species with pesticides with the goal of restoring native plants and animals.

“Restoration” could mean something entirely different and a recently published book, Urban Jungle: The History and Future of Nature in the City, invites us to redefine restoration in a very different way. In a nutshell, Urban Jungle proposes to let nature heal itself without a preconceived goal to replicate historical landscapes that aren’t adapted to the climate and the challenging conditions of the urban environment. Left to its own devices, nature creates novel ecosystems, plant communities that are biodiverse and self-sustaining.

World War II created a case study of novel ecosystems

When World War II ended in 1945, the Potsdam Agreement determined that Germany would be occupied by the allies that won the war: United States, United Kingdom, France, and Soviet Union. The map of post-war Germany (see below) shows the division of Germany among the allies. The white portion of the map was administered by the Western Allies and the gray portion of the map by the Soviet Union. Berlin (in red) was deep in Soviet controlled East Germany and was likewise divided into East and West Berlin. The Soviet Union did whatever it could to isolate West Berlin by restricting access routes to West Berlin and ultimately building a wall around it in 1961.

Source: **https://en.wikipedia.org/wiki/GNU_Free_Documentation_License**

Berlin was heavily bombed during the war and was largely a pile of rubble at the end of the war. While other European cities were able to clear the rubble within a few years, West Berlin could not because the Soviets would not let them dispose of rubble outside city limits.

The physical isolation of West Berlin and the restricted access of the population to the countryside turned West Berlin into an ecological island. Scientists in West Berlin, with few other opportunities to pursue their interests in botany and ecology, studied and recorded the transition of many tons of building rubble into novel ecosystems populated by whatever plants could find their way there and survive the challenging conditions. West Berlin was physically isolated from 1945 until the reunification of West and East Germany in 1990, creating a unique opportunity to study natural succession in an urban setting when nature is left alone for nearly 50 years.

One of the first pioneer plants in West Berlin arrived with the Ukrainian army in the hay brought to feed their horses. Salsola collina, a tumbleweed, is native to southern Russia and central Asia. Its arrival was a preview of what was to come, a landscape that would be radically different from the pre-urban landscape. The plants best adapted to the harsh conditions of the ruined city were hardy non-native species.

Non-native plants that thrived in West Berlin were more tolerant of higher temperatures in an urban setting, where hard surfaces absorb more solar radiation, buildings block the wind, and greater pollution traps heat. This is known as the heat island effect. By the 1960s, the temperature in Berlin was on average over 4⁰F higher than the surrounding countryside.

Südgelände Nature Park in Berlin was a railway yard that was abandoned in 1952 as a result of the division of East and West Berlin. By 1984 there were 334 ferns and flowering plants and many animals, birds, and insects living in the park. It is a novel ecosystem that was shaped by human activities then left to natural processes. It remains as a nature park today because the people of Berlin fought against developing it into a train station again. They had come to love its wild beauty during their long confinement during the Cold War and they weren’t willing to give it up. Source: Südgelände Natur Park

The naturally evolving novel ecosystems in West Berlin were also surprisingly biodiverse. Where natural succession was allowed to occur over many years, 140 different plant species and 200 insect species were found in the 21^st Century. In nearby Tiergarten Park, which is carefully maintained as a park, only one-quarter as many insects were found in an area of comparable size. By the end of the 20^th century, 1,392 naturalized plant species were growing in Berlin, compared to 822 in the 18^th century.

21st Century equivalent to World War II

Climate change is the 21^st Century equivalent of World War II in its potential to cause death and destruction. Climate change will create similar requirements to restore environments that are destroyed. Urban settings will be particularly vulnerable to the consequences of climate change because they are population centers and they are already compromised by urbanization.

Tidal estuaries and wetlands are one of many ecosystems that are threatened by climate change, as sea-levels rise in a warming climate and intensity and frequency of storms increases flooding. These threats are greater in urbanized areas because most of our largest cities were built on coastlines and rivers at a time when transportation and shipping was easier by water than by land.

Historically, cities were protected from storms by surrounding marshlands that filtered and cleansed runoff from the land, polluted by human waste. But as cities grew, marshlands were often destroyed to create more land. In many cases, the landfill was composed of the garbage produced by city-dwellers.

The closure of urban garbage landfills and the restoration of wetlands to buffer the city from the rising sea and extreme weather events is another opportunity to redefine restoration as a natural process that uses the healing powers of nature. Urban Jungle uses Fresh Kills Landfill in New York City as an example of restoring nature by leaving it alone.

Historical map of Freshkills Park in 1912, before it was a landfill garbage dump. Source: https://www.nycgovparks.org/park-features/freshkills-park/about-the-site

Fresh Kills was a tidal estuary and marshland on the west side of Staten Island in New York City. It was opened as a landfill to accept residential garbage in 1948. By 1986 it had reached peak volume, receiving 26,000 tons of residential garbage per day. When it was closed in March 2001, the garbage was from 90 to 225 feet tall, weighing 150 million short tons. It was reopened in September 2001 to accept about one-third of the rubble from the collapse of the World Trade Center on September 11, 2001. It was the largest garbage landfill in the world when it finally closed.

Fresh Kills Landfill is now in a 30-year process of being restored as a park, renamed Freshkills Park. The garbage was capped (see below) and methane produced by the decomposing garbage is being captured and used to heat about 22,000 homes on Staten Island.

Source: https://www.nycgovparks.org/park-features/freshkills-park/about-the-site

The productive wetland ecosystem that was destroyed by the landfill cannot be restored. Instead, a new ecosystem will slowly emerge on top of the toxic garbage. The process began by seeding the slopes of garbage with fast-growing plants that were then plowed repeatedly back into the soil to add organic matter. Then tough native grassland species were planted to provide habitat for initial colonizers, such as insects, small mammals and birds. Now that basic conditions for life have been established, what happens next is in the hands of nature: “Freshkills Park will be reclaimed by whatever species are attracted to the foundation of grasses. Nature will do the bulk of the work, not human beings. Biodiversity will steadily build as winds and birds bring seeds to the site. This process of spontaneous successional growth is how nature rebounds from natural disasters such as forest fires, earthquakes, volcanic activity and climate upheaval. Only in the case of Freshkills Park, the disaster was humanmade.” (2)

View of Downtown Manhattan from Freshkills Park. Licensed by Creative Commons

Getting off the pesticide treadmill

Allowing nature to heal the places humans have damaged is also an opportunity to get off the pesticide treadmill. The natural process of succession does not require the use of herbicides to eradicate non-native plants that arrive naturally on the wind, in water currents, and in the stomachs of animals and birds. When all plants are welcome, there is no need for herbicides and there is more biodiversity that supports more animals and is more resilient as the climate changes in unpredictable ways.

In a place like Freshkills Park, it would defeat the purpose of turning a toxic landfill into a park public to use herbicides, insecticides, or rodenticides. New York City banned the use of most pesticides in its public parks in 2021.

In 2019, France banned the use of glyphosate-based herbicides for non-agricultural use. The French city of Blois imposed the ban before the national ban was adopted: “A study published in 2019 found more than 300 species of urban plants sprouting out of the pavements of the French city of Blois, which had recently phased out glyphosate weedkiller.” (2)

Allowing nature to “manage” our public parks, makes them safer for us and for wildlife as well as more biodiverse than human management that wages a never-ending war on so-called “invasive” plants. There are more bees and bee species in cities than in surrounding countryside because there is more available food in its diverse vegetation: “Analysis of honey from a bee in Boston, Massachusetts, found it had pollen taken from 411 different species of plants; nearby country honey contained traces from just eighty-two plants. Cities are islands of biodiversity compared to rural monocultures, with a bigger and more diverse source of nectar even than nature reserves and forests…” (2)

The takeaway message

Successful restoration of damaged land will take these facts into consideration:

Many hardy non-native plants are better adapted to challenging urban conditions than native plants: “If native plants can’t hack it in the metropolis, their place should be taken by specialist species drawn from around the world that find niches in the various microclimates of the concrete jungle.” (2)
A diverse landscape of native and non-native plants is more resilient in a changing, variable, and unpredictable climate.
Novel ecosystems created by natural succession are more biodiverse than their historical predecessors.
When pesticides are used to kill non-native plants, disturbed land is damaged further and is even less likely to support a native landscape. Killing non-native plants with herbicide also reduces biodiversity.

(1) https://www.nytimes.com/2023/07/12/climate/europe-nature-restoration-law.html?searchResultPosition=1

(2) Urban Jungle: The History and Future of Nature in the City, Ben Wilson, Doubleday, 2023

Going Toe to Toe with Doug Tallamy

In June 2023, Washington P ost p ublished an opinion piece advocating for the use of herbicides to kill non-native plants, in which Doug Tallamy was quoted as saying that spraying herbicide on non-native plants is “chemotherapy,” equating non-native plants with cancer and pesticides with medical therapy. Tallamy. and more broadly his viewpoint, received some blowback from Conservation Sense and Nonsense and others.

Thomas Christopher and Doug Tallam y collaborate on their shared mission of promoting the use of native plants and the closely related goal of eradicating non-native plants they consider a threat to native plants and insects. In October 2023, Tom Christopher (TC) gave Doug Tallamy (DT) an opportunity to respond to criticism of native plant dogma on his Growing Greener podcast that is available HERE. Christopher also invited listeners to send him feedback on the podcast. Professor Art Shapiro, whose work was central to the interview, has responded separately and his response is available as a footnote. Conservation Sense and Nonsense (CSN) sent Christopher an email, which I hope he shared with Tallamy. The following is an excerpt from that email.

Hi Tom, Thanks for the air time for opposition to eradicating non-native plants in your interview with Doug Tallamy and for this opportunity to respond. I’m flattered that criticism of native plant dogma has attracted some attention on the East Coast. I’ve transcribed most of your interview with Doug Tallamy as best I can and provided some feedback to Tallamy’s viewpoint. I sent Art Shapiro the podcast and he has responded separately.

TC: Some people say that non-native plants are just as effective as natives in supporting food webs. For example, buddleia that is spreading throughout the East and West is used by butterflies.

CSN: Buddleia davidii is on California’s list of invasive plants, but it is not considered invasive in California. It was put on California’s list because it is considered invasive elsewhere, making the point that invasive plant behavior varies depending on local conditions, such as climate. Sweeping generalizations about invasiveness are rarely accurate. If gardeners are concerned about the potential for invasive behavior, they can plant a cultivar of buddleia that does not reproduce.

DT: We shouldn’t call all insects pollinators. Just because an insect visits a flower for nectar doesn’t mean it’s pollinating that flower. There are more visitors to flowers than there are pollinators. Butterflies visiting buddleia are just there to sip nectar.

Euphydryas chalcedona — Variable checkerspot. Photo by Roger Hall

CSN: Buddleia davidii is native to Central China. Non-native buddleia is used by a butterfly species that is native to California and other states in the Western US.

The first actual observation of checkerspot butterflies breeding spontaneously and successfully on buddleia was in Mariposa County, California in the Sierra Nevada foothills. Checkerspot bred there successfully on buddleia in 2005 and in subsequent years. This colony of checkerspot on buddleia was reported in 2009: “We conclude that buddleia davidii [and other species of buddleia] represents yet another exotic plant adopted as a larval host by a native California butterfly and that other members of the genus may also be used as the opportunity arises.” (1)

In 2017, a gardener in Mendocino County, California also reported the use of buddleia as the host plant of checkerspot: “By now I am questioning how it was that butterfly larvae were using my butterfly bush as a host plant, completely against everything I’d ever heard. How was this possible? I emailed Art Shapiro, a very well-known butterfly expert and author, sending him a pic. He wrote back to confirm they were butterfly larvae, but added, ‘These are not mourning cloak butterflies. They are checkerspots. And the only time I’m aware this has happened [like, ever, except one in a lab in 1940…] is in Mariposa County.’” (2)

Buddleia is available as the host plant of checkerspot butterflies with a native range from Alaska south along the Pacific Coast through California and Arizona to Baja California and Mexico; east to Montana, the Dakotas, Wyoming, Colorado, New Mexico. This is a clear case of a widespread native butterfly choosing a non-native plant as its host.

Arthur M. Shapiro and Katie Hertfelder, “Use of Buddleia as Host Plant by Euphydryas chalcedona in the Sierra Nevada foothills, California,” News of the Lepidopterists’ Society, Spring 2009
http://plantwhateverbringsyoujoy.com/never-pull-up-and-discard-what-you-cannot-identify/

DT: Most bees that people see in their gardens are honeybees that are there to get pollen and sometimes nectar. These are generalist bees but specialist bees that require pollen from particular plants (always native plants) can’t be supported by those at all.

CSN: Specialization of insects is exaggerated by Tallamy. For example, he would probably call a squash bee a specialist. As its name implies, its host plant is squash plants in the squash family, with 98 genera and 975 species. The squash bee is considered an excellent pollinator of zucchini and butternut squash, both native to Central and South America. However, they do not usually visit melon plants, according to Wikipedia. Again, we are reminded to avoid broad generalizations when describing the complex and diverse natural world.

Likewise, the native alkali bee is a particularly effective pollinator of alfalfa, which is native to the Mediterranean region. Alkali bees also pollinate members of the large legume family with over 16,000 species that are native all over the world. If you are interested in such associations, you can find an exhaustive list of native butterflies and their many non-native host plants in Art Shapiro’s butterfly guide for Central California and the Bay Area. It is not true that bees Tallamy considers “specialists” require pollen from only native plants.

DT: Sometimes butterflies adopt a new host plant as a caterpillar host. For example, black swallowtail butterflies caterpillars eat carrots or parsley or dill. What’s going on? There are two different kind of hosts: 1) The caterpillar has not adopted a new host at all because it was already adapted to that particular host. 2) Actual host switching from one plant to another is very rare. It happens on a time-scale of thousands of years. It requires a mutation or an adaptation to chemical defenses of new host plants.

CSN: Tallamy tries to make a distinction to avoid acknowledging that insects make use of introduced plants because they are chemically similar to the native plants they have used in the past, which in some cases are no longer available. The butterfly has, in fact, adopted a new host, a plant that wasn’t there before and is now hosting the caterpillar. There are many cases of rapid evolution that enable such transitions, but both cases are clearly transitions from native to non-native plants. If the original native host is still available, it isn’t necessarily abandoned in favor of a non-native. Such transitions are useful because they increase the population of available insect hosts and are essential if the original native host is no longer available.

TC: Pushback from California cites research of Professor Art Shapiro reporting that spontaneous spread of non-native plants has benefited native butterflies. He reports that 82 of 236 California native butterfly species (34%) are laying their eggs on introduced plant taxa, so caterpillars feed on them and many more butterflies use introduced plants as nectary sources.

DT: Great! These are host range expansions. Agriculture in California has eliminated the host plants of a lot of butterflies and it’s a good thing we had close relatives of natives so butterflies could expand their host range and use them. But if 34% of native butterflies are using introduced plants that means 66% are not. If all plants were introduced, we would lose 66% of butterflies in California. This is not the direction I want to go. I would choose 60% rather than 34%.

CSN: Christopher and Tallamy seem to have read one sentence in the abstract of Shapiro’s study without reading subsequent sentences: “Interactions with introduced plant taxa are not distributed evenly among butterfly species. Alpine and desert butterflies interact with relatively few introduced plants because few exotic plant species have reached and successfully colonized these habitats. Other California butterfly species are specialists on particular plant families or genera with no exotic representatives in California and have thus far failed to recognize any introduced plants as potential foodplants. Some California butterflies have expanded their geographic ranges and/or extended their flight seasons by feeding on exotic plants.” In other words, where there are more introduced plants and some are closely related to native plant hosts, more native butterflies use introduced plants.

TC: What do you say to the claims that introduced plants stay greener longer than native plants adapted to wet or dry seasons so that introduced plants give rise to extra generations of caterpillars?

DT: This is only true if caterpillars can use those plants and in host range expansions they can. Shapiro is also right about extending availability of nectar. For example, monarchs that migrate need forage along the way. The minus is that we’ve been so hard on native flora. These insects were doing just fine before we brought in non-native plants. It’s a Band-Aid we’re putting on an environment that has been ravaged by taking out native species that were here before. Let’s put native species back too.

CSN: The claim that non-native plants are driving native plants to extirpation or extinction goes to the heart of the controversy. Native plant advocates believe that accusation, although there is little evidence to support it. The greatest threat to native plants and insects is habitat loss, particularly converting wildlands to agricultural fields. The second greatest threat is the pesticides that are used by agriculture. Remember that Tallamy is an enthusiastic promoter of herbicides to eradicate non-native plants. He calls it “chemotherapy” in a recent opinion column in the Washington Post. Pesticides kill both plants and the animals that feed on them, they are anathema to biodiversity and the food web that Tallamy believes he is supporting.

Marcel Rejmanek (UC Davis) is the author of the most recent report on plant extinctions in California, published in 2017. At that time there were 13 plant species and 17 sub-species native to California known to be globally extinct and another 30 species and sub-species extirpated in California but still found in other states. Over half the globally extinct taxa were reported as extinct over 100 years ago. Although grassland in California had been converted to Mediterranean annual grasses by grazing domesticated animals decades before then, most of the plants now designated as “invasive” in California were not widespread over 100 years ago.

Most of the globally extinct plant species had very small ranges and small populations. The smaller the population, the greater the chances of extinction. Most of the globally extinct plants were originally present in lowlands where most of the human population and habitat destruction are concentrated. Although there are many rare plants at higher altitudes, few are extinct. Plants limited to special habitats, like wetlands, seem to be more vulnerable to extinction. The primary drivers of plant extinction in California are agriculture, urbanization and development in general. Non-native plants are the innocent bystanders to disturbance.

“Invasive species” are mentioned only once in the inventory of extinct plants published by California Native Plant Society and only in combination with several other factors. However, the identity of this “invasive species” is not clear. Rejmanek suggests that the “invasive species” rating refers to animal “invasions” by predators and grazers. He says, “Indeed, one needs quite a bit of imagination to predict that any native plant species may be driven to extinction by invasive plants per se.” (Marcel Rejmanek, “Vascular plant extinctions in California: A critical assessment,” Diversity and Distributions, Journal of Conservation Biogeography, 2017)

TC: 90% of all insect species are specialists that have evolved in concert with only one or a few plant lineages. How can they cope with the loss of native plants?

DT: Native plants are adapting in evolutionary time. Specialization is a continuum. Few insects are confined to a single plant species, some are confined to one or two genera, and others are confined to one or two families of plants. But if you are looking at the number of plants available to them, only about 7% of plants they are adapted to are available to them. 93% of available plants are not viable hosts for insects. Everything is a specialist on one level of another.

CSN: That sounds like an argument for a diverse garden, with many plant species that offer more food sources for insects. That doesn’t seem a sound argument for eradicating non-native plants.

TC: I understand that some native plants are more useful to insects than others?

DT: These are the keystone species. Many native plants don’t support insects because plants are well-defended against them. Keystone species are making most of the food for the food web. Just 14% of native plants across the country are making 90% of food that drive the food web. 86% of the native plants are not driving the food web. Insect food comes from the big producers, like oaks, black cherries, hickories, and birches.

CSN: That is a mind-boggling admission!! Earlier Tallamy complained that non-native plants are hosting only 34% of butterflies in California. Now he says that only 14% of native plants are useful to insects. He asks home gardeners to plant only native plants as well as limit our plantings to a small subset of native plants.

Tallamy’s ideology is antithetical to the goal of biodiversity, which could be the salvation of ecosystems in a changing climate. Since we can’t predict the climate of the future, biodiversity provides more evolutionary options, which increases the chances that some species will survive. Tallamy asks us to put a few eggs in the huge basket of our ecosystems, reducing their ability to survive the challenges of our changing climate.

For example, in Oakland, California, where I live, there were approximately 10 species of native trees prior to settlement. In 1993, there were 350 tree species in Oakland. (David Nowak, “Historical vegetation change in Oakland and its implications for urban forest management,” Journal of Arboriculture, September 1993) The recently published draft o f Oakland’s Urban Forest Plan reports that there are now over 500 tree species in Oakland. I can’t fathom why Oakland would want to limit the planting of trees to only 10 native species.

I agree with Tallamy that many native plants are not useful to insects. I attend the annual conference of California Invasive Plant Council to give native plant advocates every opportunity to convince me of their viewpoint. At the most recent conference at the end of October, Corey Shake of Point Blue Conservation made a presentation about his project to “Evaluate native bee preference for common native and exotic plants.”

He designed 16 hedgerows around agricultural fields in Yolo County to determine if native bees have a preference for native plants or exotic plants, by controlling for availability of native plants compared to exotic plants. Here is his abstract:

“Farm edge restoration monitoring in Sacramento Valley highlights native bee use of some exotic plant floral resources. Corey Shake. Point Blue Conservation Science. cshake@pointblue.org

“Research of native bee preference for native versus exotic plant floral resources in California’s Sacramento Valley has shown mixed results. No studies have demonstrated a preference for exotic plants by native bees there, but some have highlighted the importance of exotic plant floral resources in plant-pollinator networks and expressed concern that rapid removal of exotic plants without restoring native plant populations could have negative impacts on native bees. We have been collecting native bee flower visitation, plant species, and floral abundance data on 16 farm edge restoration projects in Yolo County, California since 2019, which will allow us to assess bee preferences for some key native and exotic plants relative to their floral abundance. In our preliminary analysis, we see some important trends: (1) relative to their floral abundance in our plots, some native plant species are more frequently visited by native bees than other native plants that are infrequently or rarely visited, and (2) there is significant native bee visitation to some exotic plants relative to their floral abundance. We will further evaluate these data as well as our butterfly diversity and abundance data to provide plant-species specific insights to restoration practitioners and weed management specialists to help them reduce harmful impacts to native pollinators when executing restoration projects and managing weeds.”

In other words, not all species of native plants are useful to native bees and some species of non-native plant species are useful to native bees. Tallamy’s sweeping generalizations about the usefulness of native plants to insects are not supported by empirical or field studies. Although the characteristics of plants vary widely, the variation is unrelated to the national origins of plants.

From Micro to Macro Perspective

I recognize my voice in the questions Tom Christopher asked of Doug Tallamy, as well as Art Shapiro’s. Speaking for myself, not for Art, this interview misses the point of my criticism of native plant ideology. I like native plants as much as I like any plant and I encourage everyone to plant whatever they prefer. I only object to the pointless destruction of harmless non-native plants that thrive because they are best adapted to the conditions where they have naturalized. Non-native plants do particularly well in the wake of disturbance. Where they have replaced native plants, the natives were destroyed by disturbance, not by the hardy non-native plants that can tolerate disturbance. Non-native plants are a symptom of change, not the cause.

I object to destructive eradication projects because they poison the soil with herbicides, making it even less likely that non-native plants will be replaced by fragile native plants. I object to the loss of biodiversity which is a hedge against extinction in a rapidly changing climate. We don’t know which plants will be capable of surviving in the changed climate. We should not be taking cards out of the deck while we gamble with the future of the environment and everything that lives in it.

Unfortunately, native plant advocates take offense when anything positive is said about introduced plants. A positive statement about a non-native is routinely interpreted as a negative statement about native plants. It shouldn’t be. The emphasis on the negative assessment of introduced plants results in harmful land management decisions. The pros and cons of all plants should be considered before we condemn non-natives with a death sentence. Like our justice system for human society, all plants should be presumed innocent until proven guilty.

Thanks again for airing this debate on your podcast. I hope you will forward my email to Doug Tallamy

Webmaster, Conservation Sense and Nonsense

shapiro-brief-polemic Download

Gardening with the help of nature

Juliet Stromberg is a plant ecologist who specialized in wetland and riparian ecosystems of the American Southwest. Her friends call her Julie and I will presume to do the same. She has retired from her position at Arizona State University, but her husband, Matt Chew, is still teaching ecology from a historical perspective at ASU. He is very much her partner in their 20-year project to restore 4-acres of dead citrus grove and an 80-year old Spanish colonial house, long abandoned and derelict. The property came with water rights, without which their project would not have been possible.

In her recently published book, Bringing Home the Wild: A Riparian Garden in a Southwest City, Julie tells us how she and her partner transformed—with the help of natural processes–this dead patch of land in South Phoenix, Arizona into the oasis that it is today. The first step was to restore the irrigation system, which immediately brought much of the dormant seed bank back to life.

Julie & Matt’s garden is in the center of this aerial view

Using the riparian vegetation of the Salt River—the source of their water—as her reference, she chose a half-dozen tree species as the foundation of their garden, such as Fremont cottonwood, Gooding’s willow, and velvet mesquite. Twenty years later, there are now 300 trees, sheltering a community of plants and animals. How did they get there?

The seeds of some trees such as blue elderberry and mulberry were brought from neighboring gardens by birds and small animals. Julie and Matt have seen 157 species of birds in their garden, so we can assume birds have done some of the planting. The seeds of some plants are aerodynamically shaped and were blown in by the wind, adding to the diversity of the garden.

*Tropical milkweed seeds ready to be launched by the wind from a neighbor’s front yard. Conservation Sense and Nonsense, Oakland, CA, October 2023*

Many of the trees are American in origin, but others are not. Regardless of the method of dispersal, most introductions are welcome in Julie’s garden. She spares her readers the tedious recitation of which plants are considered native and which are not. The Southwestern desert is not an ecosystem with which I am familiar. I was glad to have a tour of Julie’s garden without irrelevant information about the nationality of every plant. For the same reason, I like to travel in distant places where I can’t distinguish natives from non-natives. Everything looks great to me and nothing brings me down more than a guide who wants to inform us of what “belongs” and what doesn’t.

Julie and Matt also planted a fruit orchard and a vegetable garden that bring more birds, insects, and animals to the garden as well as providing food for their table. Eating the fruits of our labors in the garden deepens our respect for what plants do for us and establishes our working relationship with the land.

Managing a wild garden

In keeping with Julie’s opinion that ecological restoration is a form of “glorified gardening,” she actively manages her garden. A few plants that annoy members of her community of plants and animals—such as puncture vine and tumbleweed—are not welcome.

When the delicate balance between predator and prey becomes unbalanced, some protective measures are necessary. If coyotes and dogs can’t keep up with the rabbit population, it’s sometimes necessary to put vulnerable plants into cages to protect them. The root balls of some plants are covered in wire mesh to protect them from hungry gophers.

Plants also assist in their own defense. Where mesquite is grazed by cattle, the tree responds by growing longer thorns to repel the cattle. When plants are attacked by plant-eating insects, some emit a toxin to render themselves inedible. The scent of the chemical wafts to neighboring plants, alerting them to the arrival of predators. These natural defenses are an important line of scientific inquiry that has potential to substitute nature-based solutions for synthetic chemicals.

The population of roof rats in Julie’s home is kept in check with liquid birth control, lest they chew on electrical wires or build nests in car engines.

Gardening with the help of friends

Julie’s is not a manicured garden, but it requires constant pruning to keep trails clear and provide light and space for plants to thrive. The annual scouring of the flood plain by spring floods is one of the natural processes that Julie and Matt could not use to restore their land because irrigation water is channelized and confined by concrete. Julie has come to appreciate the flies and other insects who are the decomposing crew, helping to reduce the accumulation of debris in the absence of annual scouring floods. Sixty-six species of flies assist with decomposition as well as pollination in Julie’s garden.

Julie is happy to have coyotes in her garden, but her dogs disagree. Violent and fatal confrontations between these closely related species required building a wall that confines dogs close to the house at night, while coyotes safely roam most of the garden.

Dogs are an important part of Julie and Matt’s life. Early in the book’s introduction Julie warns readers that they should put her book down “NOW!” if they don’t want to hear dog stories. Julie has walked thousands of dogs in a nearby animal shelter. In addition to her own 4 dogs, there are also occasional foster dogs who need to recover from traumatic experiences to be adoptable. In Julie’s refuge, these traumatized dogs learn to trust again.

Peaceful co-existence

Julie is a recovering academic scientist. Before she retired, she felt that her focus on the accumulation of data needed for scientific analysis was causing her to lose track of the big picture. She needed to stop and smell the flowers, so to speak.

She received her graduate education during the heyday of invasion biology. Julie slowly shifted away from native purism based on her experiences in the field. She has rejected that doctrine, and regrets teaching her students to fear “those who came from somewhere else.”

Julie has a vivid memory of the first step she took on that journey to her gardening ethic of peaceful coexistence. She had been instructed to pull tree tobacco from land along the Salt River that was being restored. The nicotine in the plant was making her feel sick, which seemed to bring her to her senses. She began to wonder what she was doing, “following orders to kill creatures she barely knew.”

Fly on desert tobacco. Photo courtesy Juliet Stromberg

Part of Julie’s skepticism about such eradication projects is based on her understanding of how little we know. She realizes that the harm done by non-native species is exaggerated and their benefits are underestimated. Given the limits of our knowledge, we should be obligated to give introduced plants the benefit of the doubt before killing them. She now appreciates the beauty of tree tobacco, which also feeds birds, fixes carbon, and stabilizes the soil. Its seeds were naturally dispersed to Julie’s garden and tree tobacco is welcome there.

Imperatives imposed by climate change

Julie says, “The preoccupation with provenance diverts conservationists and gardeners from critical issues,” such as climate change, food security, and extinction (which, studies show, are not caused by introduced plants). Living in the Southwest, Julie has a front row seat on climate change. It’s always (within the context of our lifetime) been hot there, but now it is blisteringly hot during summer months. She watches hummingbirds in her garden seek shelter in the shade, close to the irrigation drip. She watches dogs panting, birds gasping for breath and plants wither and die in the heat. And she knows that both native and non-native plants store carbon that would otherwise contribute to greenhouse gases causing climate change. Carbon storage varies according to certain plant characteristics, but those characteristics are unrelated to the nationality of plants.

Those who insist on replicating the landscape that existed 200-400 years ago in America are depriving nature of the evolutionary opportunities that will enable survival. We don’t know what life will be capable of living in the climate of the near-future. Nature needs as many alternatives as possible to find the species that can survive. Plants and animals are blameless in this struggle of survival of the fittest. The least we can do is to get out of their way as natural selection finds the life that is adapted to the current and future climate.

Showing respect for nature

Julie does not use any pesticides in her garden….no herbicides, fungicide, or insecticide. She is concerned about the pesticides used by her neighbor across the road who grows cotton. She notices the blue cotton seeds scattered on the ground and surmises that they were coated in insecticide or herbicide that will infuse pesticide into the plant as it grows. The poisoned seed can kill seed-eating birds and other animals and the plant itself will be poisonous as it grows. The dust from the cotton field blows into her property when the field is plowed and after the cotton is harvested because no cover crops are grown to tamp down the dust and prevent the loss of carbon stored in the soil. Julie can see firsthand the damage caused by industrial agriculture and is confirmed in her commitment to avoid using pesticides.

Julie shows her respect for everything living in her garden by her choice of pronouns to describe them: “who” not “what,” “she/her” not “it.” She asks her readers to show the same respect for plants and animals, regardless of their nationality. Avoiding the use of pesticides in our gardens is another way to show our respect for the plants and animals on which we depend, with the added benefit of not poisoning ourselves.

Thank you, Juliet Stromberg, for telling us about your garden and congratulations for what you have accomplished and learned from the experience of nurturing it back to life with the help of nature.

Oakland’s Vegetation Management Plan Is Headed in a Destructive Direction

Oakland has been trying to adopt a vegetation management plan (VMP) to mitigate fire hazards since November 2016. The plan has been drafted three times in 2018, 2019, and 2020 and a draft Environmental Impact Report was also published in 2020. All three versions of the plan were acceptable to me and many others. Every version would have removed dead trees and thinned non-native trees on 2,000 acres of public land and 300 miles of roadsides in Oakland, leaving the tree canopy intact so that the forest floor would be shaded, suppressing the growth of weedy vegetation that ignites easily and keeping the forest floor moist, which retards fire ignition.

Unfortunately, none of the proposed vegetation management plans were acceptable to native plant advocates who want all non-native trees in project areas in Oakland to be destroyed and the land replanted with native plants and trees. The plan they are demanding is a native plant restoration, not a wildfire hazard mitigation plan. Since they have successfully prevented Oakland from addressing wildfire hazards for eight years, we might assume they aren’t concerned about wildfire.

A fourth version of the plan and a new Environmental Impact Report are expected to be published in September 2023 and there will be a new public comment period in October. Based on written and oral public comments at public hearings, we predict that the revised plan is likely to be far more destructive than previous drafts of the plan. Based on that prediction, I am alerting you to the need to read the revision and write a public comment. Please ask to be notified of the publication of the plan by sending an email to info@oaklandvegmanagement.org .

Update: The revised Oakland Vegetation Management Plan and revised Draft Environmental Impact Report were published on September 20, 2023. These documents are available HERE. There will be a public hearing by the Oakland Planning Commission on November 1, 2023. The deadline for public comment will be November 4, 2023. Comments can be submitted by email DEIR-comments@oaklandvegmanagement.org or by mail to Montrose Environmental, attention Ken Schwarz, 1 Kaiser Plaza, Suite 340, Oakland CA 94612.

When I have read the revised plan and its revised EIR, I will post a draft of my public comment on the draft by October 1^st.

– Webmaster, Conservation Sense and Nonsense, September 20, 2023

What do opponents of previous plans want?

There is a wide range of opinions about a vegetation management plan for Oakland. I will use the public comment of the California Society of American Foresters (SAF) on the third version of the VMP as a representative opinion and the best available predictor of where the fourth revision is likely headed. The entire comment of the Society of American Foresters (SAF) is available HERE and here are some of the revisions SAF is asking for:

“Ecological restoration should be a goal of the VMP, including the establishment of native plant species where nonnative species dominate…Thinning of dense stands of nonnative tree species should only be done as part of an overall strategy of restoration, i.e., the goal of any tree removals should always be to eventually convert these stands to native tree or vegetation cover in order to build greater ecological resiliency.”
“In concert with the goal of ecological restoration, adaptive management in light of climate change should guide management practices and restoration plans. Adaptive management strategies that incorporate new information and changing conditions will be critical to ecosystem restoration. Annual grasslands may become more dominant, oak woodlands less so in the planning area in the future as climate changes. Management targets in many cases will have to be based on anticipated future conditions.”
“However, if thinning is kept as the desired practice, we ask that you design each entry to be sufficiently intensive to assure that tree crowns will not close before the next thinning entry (10 years from now?) and indeed is sufficiently thinned to allow work towards establishing native vegetation in these stands.”
“The use of prescribed fire as a vegetation maintenance tool should have been considered and included in the VMP especially on ridges where fire moving from adjacent jurisdictions might occur, or along power-line transmission corridors.”
“The vegetation management zones along roadsides, especially along routes of egress, should be modified to extend 100 feet from roadside edges and should include any trees with underlying structural or health conditions that are tall enough to fall onto streets and roads. This may in some cases require looking outside of the 100-foot roadside clearance.”
“It is important that the use of triclopyr herbicides is included to treat cut stumps in eucalyptus to prevent sprouting. Glyphosate herbicides will not be effective in treating eucalyptus stumps and will result in resprouts.”
“There should be an Ecological Restoration Guide added to the appendices…This new appendix would outline the City of Oakland’s current ecological restoration efforts, identify stakeholders (e.g., city departments, Oakland Wildlands Stewards, etc.) and their roles…”

Native plant restoration, NOT wildfire hazard mitigation

The Society of American Foresters (SAF) is asking the City of Oakland to make a commitment to eradicating all non-native trees in project areas and replacing them with native plants. Such a plan would not reduce wildfire hazards in Oakland because native vegetation is not inherently less flammable than non-native vegetation. Most wildfires in California occur in native chaparral and native conifer forests.

The plan proposed by the Society of American Foresters (SAF) is a native plant restoration plan, NOT a wildfire hazard mitigation plan. Their proposal would destroy much of Oakland’s urban forest, which would not be replaced by native trees:

Non-native trees were planted in Oakland in the 19th century because there were few native trees: “Vegetation before urbanization in Oakland was dominated by grass, shrub, and marshlands that occupied approximately 98% of the area.” (1) Non-native tree species in the East Bay are adapted to soil and microclimate conditions that are not suitable for native species.
Grassland was the dominant vegetation type of pre-settlement Oakland partly because of the land management practices of Native Americans and the stock grazing of early settlers: “Native Americans played a major role in creation of grasslands through repeated burning and these disturbance-dependent grasslands were maintained by early European settlers through overstocking of these range lands with cattle and sheep. Twentieth century reduction in grazing, coupled with a lack of natural fires and effective suppression of anthropogenic fires, have acted in concert to favor shrubland expansion.” (2)
Grassland in California is not native to California. Mediterranean annual grasses were brought to California in the early 19^th century by the grazing herds of Spanish-Mexicans. California’s native bunch grasses are not adapted to heavy grazing by herds of domesticated animals. The grassland of California is about 99% non-native (Allan Schoenherr, A Natural History of California, UC Press, 1992). Attempts to convert annual grasslands to native bunch grass have not been successful. A team of scientists at UC Davis spent $450,000 and 8 years trying to convert 2 acres of grassland to native bunch grasses without success. Grassland that will replace our urban forest will not be native.
Grass is easily ignited and fires move quickly through grassland, particularly in a wind-driven fire. The deadly, destructive fires in Maui, Hawaii are a case in point. When agricultural fields of sugar cane, pineapple and other tropical fruit left Maui they were quickly succeeded by non-native grass that was considered a factor in the spread of fire. (3) Dormant, dry annual grassland in the East Bay Hills will be more flammable than the living vegetation that native plant advocates want to destroy.
A small redwood grove was the only pre-settlement exception to the otherwise treeless Oakland hills: “…for thousands of years [the Oakland hills] were treeless meadows, visited seasonally under Indigenous management…The one exception was the redwood groves of the southern Oakland Hills, a restricted forest that extended a few miles eastward from upper Dimond Canyon over the ridgetop to the outskirts of Moraga.” (4) Much of this grove still exists today because coastal redwoods are vigorous resprouters when they are burned or cut down.
SAF also predicts a vegetation type-conversion from forest to grassland: “Annual grasslands may become more dominant, oak woodlands less so in the planning area in the future as climate changes.” Grassland will naturally succeed to shrubland without regular burning, which SAF recommends to reduce fuel loads.
Prescribed burns in densely populated urban areas are rarely approved by Bay Area Air Quality Management District because they pollute the air and often cause uncontrolled wildfires. California law regarding liability for damage caused by prescribed burns was revised in 2022 to provide legal protections for those who manage prescribed burns. The revised law lowers the standard for liability to gross negligence from a previous standard of simple negligence. (5)

Consequences of landscape conversion to grass and shrubs

Destroying thousands of trees will increase air pollution and reduce air quality. Destroying thousands of trees will increase greenhouse gas emissions causing climate change by releasing the carbon stored by the trees that are destroyed and reducing carbon sequestration going forward because the destroyed forest will not be replaced by a forest of native trees.

There was little biodiversity in Oakland’s pre-settlement forest: “Oakland’s original species composition has increased from approximately 10 tree species to more than 350…Today [1993], only 31% of existing trees are native to Oakland, the plurality of trees (38%) are native to Australia/New Zealand.” (1) Destroying thousands of non-native trees in Oakland will reduce the biodiversity of our forest. A more diverse forest is more resilient, particularly in a changing climate, with extreme and variable weather conditions.

Increasing 300 miles of roadside clearance from 30 feet (as proposed by the 3^rd version of the VMP) to 100 feet (as proposed for the 4^th version of the VMP) will produce wood debris on a scale that cannot be disposed of. We know what the outcome will be because of a similar project on Claremont Ave, where eucalyptus was clear cut 100 feet from the north side of 1.1 miles of the road in fall 2020. Below are pictures of the piles of wood chips and logs that remained along that stretch of road for about 9 months while project managers tried to figure out what to do with the wood debris, which was eventually dispersed throughout the hills. UC Berkeley implemented the project with funding from Cal-Fire.

The north side of Claremont Ave. was clear cut 100 feet from the road. The south side of the road was not cut because the trees are native. There is a creek flowing at the bottom of the canyon that creates the moist conditions needed for native trees, which will not grow where non-native trees now grow. Photo by Doug Prose, courtesy Hills Conservation Network.

One of many piles of logs, Claremont Ave, November 2020. It took about 9 months for the logs to be dispersed along roads in the hills. Photo by Doug Prose, courtesy Hills Conservation Network.

One of many piles of wood chips, Claremont Ave, November 2020

The roads in the East Bay hills are now lined with logs, preventing people from pulling off the road. No native plants or trees were planted after the trees were destroyed. Three years later, the clear cut roadside is vegetated with non-native annual grasses and coyote brush, a pioneer native shrub.

The project on the property of UC Berkeley was very small in comparison to the Oakland vegetation management plan that will clear cut 300 miles of roads, producing at least 300 times the amount of wood debris. What will Oakland do with the wood debris that is produced from the destructive VMP that native plant advocates demand? Tons of wood debris lying on the ground is far more flammable than living trees, which is another indication that the VMP that native plant advocates demand is not about mitigating fire hazards. It’s about their preference for a native landscape that is not less flammable than the landscape they demand be destroyed. Like all Mediterranean climates, our native vegetation is fire adapted and fire dependent. A significant number of our native species will not regenerate in the absence of fire. Most wildfires in California in the past 5-10 years have occurred in native chaparral and native conifer forests.

NY Times reported that 150 homes burned in this wind-driven fire in San Diego in 2003, but the eucalyptus surrounding the neighborhood did not burn. The flammability of eucalyptus trees is exaggerated to justify their destruction. NY Times photo

The more trees that are destroyed, the more herbicide will be required to prevent the trees from resprouting. SAF is correct in saying that tricopyr will be needed to kill the roots of the trees to prevent them from repsouting. Glyphosate will not accomplish that task. Triclopyr is more toxic than glyphosate. Triclopyr has a signal word of “warning” and glyphosate has a less toxic signal word of “caution.” Triclopyr kills the roots of woody plants by traveling from the cut stump to the roots of the plant in the soil. Triclopyr is known to kill mycorrhizal fungi in the soil, which are essential to the health of plants growing in the soil. The more herbicide that is used to kill the roots of destroyed trees, the less likely a newly planted native landscape is to survive. All the more reason to assume that the destroyed forest will not be replaced by a native landscape.

In Summary

The landscape that native plant advocates demand for Oakland will be predominantly non-native annual grasses.
Native trees will not replace the trees that are destroyed because they are not adapted to most places where non-native trees now live and because there is no available funding to purchase native plants, plant them on thousands of acres of public land, and irrigate them until they are established. Similar fuels management projects done by East Bay Regional Parks District, East Bay Municipal Utilities District, and UC Berkeley have not planted a native landscape to replace trees that have been destroyed.
Non-native annual grasses will naturally succeed to shrubs in the absence of frequent fire. Shrublands are more flammable than the existing urban forest because fire travels on the ground, unless wind-driven fire ignites tree canopies. In that case everything burns, both native and non-native trees. The wind-driven fire in Oakland in 1991 spared no trees in burned areas, whether native or non-native.
The project would produce many tons of flammable wood debris that has no commercial value and no place to be safely disposed of.
The loss of our urban forest will increase air pollution in Oakland, contribute to greenhouse gas emissions causing climate change, and raise temperatures in a city that is already a heat-island.
Herbicides needed to prevent the urban forest from resprouting will poison the soil and suppress the growth of a new landscape.

If you live in Oakland City Council District 4 or 6, you are likely to be directly affected by Oakland’s vegetation management plan. The most effective way to influence the VMP is to express your opinion to your representative on the City Council, as well as our at-large representative on the Council. Contact information for members of the Oakland City Council is available HERE.

(1) David Nowak, “Historical vegetation change in Oakland and its implications for urban forest management,” Journal of Arboriculture, September 1993
(2) Jon E. Keeley, “Fire history of San Francisco East Bay Region and implications for landscape patterns,” International Journal of Wildland Fire, September 2005.
(3) https://www.nytimes.com/2023/08/13/us/hawaii-wildfire-factors.html
(4) Andrew Alden, Deep Oakland: How geology shaped a city, Heyday, 2023.
(5) https://kion546.com/news/2022/01/04/new-california-law-changes-liability-for-out-of-control-prescribed-burns/

The Great Lakes: A story of man-made invasions

I’m reading about the Great Lakes in preparation for a cruise on the Great Lakes from Chicago to Toronto. (1,2) It’s a story of continuous invasions of aquatic creatures, one after the other, with many more expected in the future. Every one of those invasions was caused by the removal of natural barriers from isolated bodies of water to accommodate human activities such as shipping of goods.

Connecting the Great Lakes to the Atlantic Ocean

The St. Lawrence River is the natural gateway into the Great Lakes from the Atlantic Ocean. The salty water of the ocean and the fresh water of the lakes was part of the natural barrier that protected the lakes from invasive species because, for the most part, the marine creatures that live in salty water are different from those that live in fresh water.

The St. Lawrence River was steep and narrow, creating white-water rapids that limited travel from the ocean to the lakes (or vice versa) in anything but a birch bark canoe that could be carried around the rapids. The natural barrier was penetrated by building the St. Lawrence Seaway in 1959 that widened the river and used locks to climb the steep incline of the river into Lake Ontario.

The St. Lawrence Seaway was instantly obsolete because of the unforeseen container revolution that transformed global shipping. The transition from traditional to container shipping was instantaneous because the advantages are so great. Container ships are huge in comparison to the small ships that had been loaded by hand for centuries. The St. Lawrence Seaway is too narrow to accommodate container ships. The loans given to the builders of the seaway by Canada and the US were eventually forgiven because the tolls on the seaway will never pay for the expense.

But the damage was done, although much of it could have been avoided. The ships that start their voyage in fresh water ports on rivers take on their ballast water when they start their voyage and with it freshwater aquatic creatures that don’t live in the Great Lakes. When they arrive in the Great Lakes they dump their ballast water to take on their cargo. The dumping of ballast water in the Great Lakes could have been regulated in 1959, but it wasn’t. Only very recently have ships from fresh water ports been asked to exchange their ballast water in the ocean, before entering the Great Lakes and those regulations weren’t mandatory until 2021. Such is the power of commercial interests that the consequences of introducing new species into the Great Lakes were not considered.

The second natural barrier that protected the Great Lakes was Niagara Falls in New York with a vertical drop of 160 feet. That steep cliff across the Niagara River prevented the movement of marine animals from the Atlantic Ocean, through Lake Ontario and into the other four lakes. It was one of the first barriers to be penetrated by the Erie Canal in 1825 and the Welland Canal in 1829. The Erie Canal connects the Hudson River that flows into the Atlantic Ocean to Lake Erie, bypassing Niagara Falls and creating a gateway from the Atlantic Ocean into the Great Lakes. The Welland Canal connects Lake Ontario to Lake Erie, which also bypassed Niagara Falls and created another gateway from the Atlantic Ocean to all of the Great Lakes.

Connecting the Great Lakes to the Mississippi River Basin

The St. Lawrence Seaway, Erie, and Welland canals opened the front door of the Great Lakes to salt water creatures in the Atlantic Ocean and the ships that brought foreign aquatic animals into the Great Lakes. The reversal of the Chicago River that connected Lake Michigan to the entire Mississippi River basin, opened the back door to the Great Lakes to all of the freshwater aquatic animals that live in the vast Mississippi River basin, east of the Continental Divide.

When Chicago was built, it dumped its sewage into Lake Michigan and it also took its drinking water from Lake Michigan. As the population of Chicago grew it became more vulnerable to typhoid epidemics caused by the polluted water Chicago was drinking. The Chicago River had sent a dribble of water into Lake Michigan from its headwaters not far west of Chicago before it was reengineered.

In 1900, Chicago built a huge sanitary canal that connected Lake Michigan to the Mississippi River. The sanitary canal carried Chicago’s sewage into the Mississippi River and created a shipping lane to the Mississippi River while giving Chicago a clean source of water from Lake Michigan. The sanitary canal reversed the flow of the Chicago River, which now flows out of Lake Michigan.

The Consequences

The first invasive predator of native fish arrived in the Great Lakes via the canals built early in the 19^th century. The sea lamprey is a parasite that attaches itself to the bellies of fish and slowly sucks the blood out of it. Its suction-cup mouth is the stuff of nightmares.

Lampreys, like salmon and sturgeon, are born in freshwater rivers and streams before living in the ocean and finally returning to their freshwater birth place to spawn and die. They are capable of living in both fresh and salty water. In the Great Lakes lampreys did not need to migrate to the ocean as their ancestors had because there was sufficient food in the lakes.

As late as the 1940s commercial fishermen in the Great Lakes were harvesting 100 million pounds of native fish, such as lake trout and whitefish, annually. Lampreys were first reported in Lake Michigan in 1936. By 1950, the commercial fishery had all but collapsed as the lamprey population reached its peak.

Lampreys met their match when a graduate student at University of Michigan wrote his Ph.D. thesis about the life cycle of lampreys. He spent several years stalking lampreys in Lake Michigan and its tributaries, finding out where and when they spawn and at what point in their life cycle they become parasites of fish.

The lamprey population had been so vast that it was impossible to target an attack on them. An understanding of their life cycle enabled the development of a strategy to eradicate them. More than 5 of their 7-year lifespan is spent burrowed in the gravel of small streams that feed into the lakes. At that stage they are not yet fish predators.

Armed with the knowledge of when and where lampreys were most vulnerable, the strategy was to build mesh barriers that prevented the lampreys from returning to the streams to spawn. There was some success with the barriers, but not sufficient to reduce the huge population.

The final solution to lamprey control was the use of a chemical that would poison lampreys without killing native fish. Finding the chemical that would do the job was a classic case of trial-and-error without regard for the consequences of using poisons in the environment. Chemicals were solicited from all over the country and the world for study as candidates. The tests, done in uncontrolled environments with no safety precautions for low-level workers, consisted of dumping hundreds of different chemicals into three jars, one containing a lamprey, another native lake trout, and a third native blue gill. After hundreds of trials, a chemical that killed only the lampreys was selected for the job of eradicating the lamprey population. No thought was given to the possible effect on all the other native fish in the lakes—such as whitefish and sturgeon—or humans, or plants. (3) The same chemical is still used today to control the lamprey population, which remains but is no longer considered a problem.

There are many invasions into the Great Lakes. The lampreys were followed by alewives, a species of small fish. The population of alewives boomed at first, then busted, resulting in massive rafts of millions of dead alewives. Finally, the population of alewives stabilized and now are considered the primary prey of salmon that were introduced in the 1960s to serve the sport fishermen who are the backbone of Michigan’s tourist industry.

Zebra and quagga mussels proved to be one of most damaging of the invaders in the Great Lakes, partly because of how widely they spread. They were brought to the lakes in the ballast water of ocean-going ships. The open back door of the Great Lakes into the vast Mississippi River basin enabled the inevitable spread of quagga mussels throughout the country, eventually crossing the Continental Divide into western states. Those who tried to prevent that spread, spent many years imposing strict regulations about decontaminating and moving boats into places where mussels weren’t yet found. Today, places like Lake Powell have given up enforcing the regulations.

The mussels are filter feeders of phytoplankton that is food for creatures at the bottom of the food chain, depriving them of food, as well as their predators higher in the food chain. The mussels have turned sandy beaches into foot-slicing no-go zones. They improve the water clarity of the lakes, but that’s a mixed blessing for other inhabitants of the lakes.

Quagga and zebra mussels are now part of the food web. Populations of diving ducks have increased where mussels are found. A species of non-native fish—the goby—thrives on quaggas. And native whitefish, yellow perch, and chub have slowly developed the ability to digest quaggas, a story not fit for the squeamish. Whitefish don’t have the jaws needed to crack the mussel open, so they swallow them whole and leave it to their digestive system to deal with it: “the typical whitefish has an anus about the size of a ‘swizzle stick.’ But the fish excrement, a paste of crushed mussel shell thick as unset concrete, stretched the whitefish’s underside orifice to the diameter of his pinky.” (1)

The latest arrival is Asian carp via the Chicago River and sanitary canal from the Mississippi River into Lake Michigan. Asian carp were introduced to the Mississippi River to eat sewage pollution drained into the river by many rural communities. The prediction is that Asian carp will decimate the commercial fishery of the Great Lakes, though it is still early in that story.

Moral of the Story

Problems in the Great Lakes were caused by humans who were accommodating their own needs. The aquatic animals blamed for the problems were only symptoms of the changes made by humans. They were not the cause. Eradicating them will not prevent new invasions in the future, so long as the gateways to other bodies of water remain open. And over time, many of the species that cause problems at first will enter the food web and become contributing members of the ecosystem. We fear change, but in many cases that is because our time frame for evaluating change is too short.

We should assume that similar problems have occurred wherever isolated bodies of water have been connected to serve human activities. The Suez Canal connected the Mediterranean Sea to the Red Sea in 1869. The Panama Canal connected the Atlantic Ocean to the Pacific Ocean in 1914. I can only imagine the consequences of removing the impassable barriers between those vast bodies of water.

To be clear, I don’t regret the building of most of the canal passages, with the possible exception of the St. Lawrence Seaway. However, it is not realistic to expect that the environment will not be altered by removing impassable barriers on water or land and it is pointless to blame the plant and animal species that are merely responding to the changes we have made.

(1) Dan Egan, Death and Life of the Great Lakes, W.W. Norton & Co., 2017

(2) Jerry Dennis, The Living Great Lakes, St. Martin’s Press, 2003

(3) The pesticide 3-trifluoromethyl-4-nitrophenol (TFM) is used to control sea lamprey (Petromyzon marinus) populations in the Great Lakes through its application to nursery streams containing larval sea lampreys. TFM uncouples oxidative phosphorylation, impairing mitochondrial ATP production in sea lampreys and rainbow trout (Oncorhynchus mykiss). However, little else is known about its sub-lethal effects on non-target aquatic species. The present study tested the hypotheses that TFM exposure in hard water leads to (i) marked depletion of energy stores in metabolically active tissues (brain, muscle, kidney, liver) and (ii) disruption of active ion transport across the gill, adversely affecting electrolyte homeostasis in trout. Exposure of trout to 11.0 mg l^− 1 TFM (12-h LC₅₀) led to increases in muscle TFM and TFM-glucuronide concentrations, peaking at 9 h and 12 h, respectively. Muscle and brain glycogen was reduced by 50%, while kidney and muscle lactate increased with TFM exposure. Kidney ATP and phosphocreatine decreased by 50% and 70%, respectively. TFM exposure caused no changes in whole body ion (N a⁺, Cl⁻, Ca^2 +, K⁺) concentrations, gill Na⁺/K⁺ ATPase activity, or unidirectional Na⁺ movements across the gills. We conclude that TFM causes a mismatch between ATP supply and demand in trout, leading to increased reliance on glycolysis, but it does not have physiologically relevant effects on ion balance in hard water.” (Oana Birceanu, et.al., “The effects of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) on fuel stores and ion balance in a non-target fish, the rainbow trout,” Comparative Biochemistry and Physiology, March 2014)

Dana Milbank: “How I learned to love toxic chemicals”

Dana Milbank is a political commentator for the Washington Post. Like many city dwellers, Milbank moved his family from Washington DC to the Virginia countryside during the Covid pandemic.

His new home inspired him to become a native plant advocate with the usual corresponding hatred of non-native plants. He announced his new hobby of killing non-native plants in April 2023, as described in thi s response to his article by several defenders of the natural world as it exists, rather than as some might wish it to be.

In a more recent articl e, Milbank expressed his frustration at the failure of his early efforts to destroy non-native plants on his property without using herbicides: “When last I wrote about my battle of the brush, I was losing, badly, to the invasive vines and noxious weeds that had turned forest and field at my Virginia home into an impassable jungle. I’d cut them back, but they would return in even greater numbers.”

And he explained how he “learned to stop worrying and love chemicals.” He is now both a native plant advocate and a promoter of herbicides (specifically glyphosate) which is typical of most native plant advocates.

He justifies poisoning both his property and the Shenandoah National Park near his home by turning to advisors who tell him what he wants to hear, people who make their living using herbicides to eradicate non-native plants.

Of course, renowned native plant guru, Doug Tallamy, is one of his advisors. Although Tallamy advised residential gardeners against using herbicides in his book, Nature’s Best Hope, published in 2020, he has now changed his mind about herbicides. In Milbank’s article, Tallamy says that herbicides are an “essential tool:” “‘I think of it as chemotherapy,’ said Doug Tallamy, a University of Delaware entomologist and guru of the native-plant movement. ‘We have ecological tumors out there. If we don’t control them, we have ecological collapse. We have the collapse of the food web.’”

Poisoning the soil

Milbank admits that glyphosate (Roundup) is toxic and he wears protective gear when applying it, including a respirator (which is not required for glyphosate applications by California’s pesticides regulations). He describes his application technique: “My preferred technique is ‘hack and squirt.’ With my hatchet, I cut gouges around the circumference of the invading tree, then spray the poison inside. For smaller invaders, I can chop the whole thing down and apply the chemical as a ‘cut stump’ treatment.

I read most of the over one thousand comments on Milbank’s article to determine the public’s reaction. Although many commenters express reservations about the use of herbicides, the majority of commenters are supportive of the use of herbicides. The manufacturers of pesticides are definitely winning the public relations battle regarding chemical safety. When supporters reply to doubters of herbicide use, they defend Milbank’s application technique as “surgical.”

Cut stump and hack and squirt application methods are less likely to disperse chemicals in the air, but they increase soil contamination. These application methods work by applying herbicide shortly after the woody plant is cut, while the cambium layer (between the bark and the heart wood) is still functional. The cambium layer delivers the herbicide to the roots of the plant to kill the roots. The application may appear to be “surgical” from the standpoint of above-ground contamination, but the damage is being done in the soil, the plants growing in the soil, and the animals that eat those plants.

Source: https://www.acompletetreecare.com/blog/what-are-the-layers-of-a-tree-trunk/

There are many consequences of poisoning the soil:

Because the roots of plants are intertwined as well as connected to one another by fungal networks in the soil, non-target plants are harmed and often killed. It is not possible to poison one plant without poisoning others. HERE is an example of a forest of native trees that was damaged by spraying herbicide under the trees.
Herbicides kill beneficial microbes and fungi in the soil that contribute to plant health. (1) For example, fungal networks that are killed by herbicides transport moisture and nutrients from the soil to the plants. Whatever vegetation remains or is planted in the future is handicapped by the loss of this living support system.
Glyphosate binds minerals in the soil, preventing essential nutritional minerals such as iron and manganese in the soil from being taken up by plants. (2) Glyphosate is so widely used that it is found in the blood and urine of most of the population, including children. Could glyphosate be a factor in widespread iron-deficiency anemia in adolescent girls and young women? (3)
Glyphosate is a well-known anti-microbial agent. These effects raise concerns regarding glyphosate’s influence on human health and behavior through secondary means, such as our gastrointestinal microbiome, given what is now known regarding the gut microbiome and its influence on human health and disease. (4,5)

Source: https://symsoil.com/soil-food-web-soil-cities/

Who are the climate change deniers?

Milbank repeats his accusation that those who believe the threat of non-native plants is exaggerated, are climate change deniers. He turns to the Executive Director of the federal Invasive Species Council for confirmation, who calls the threats of non-native plants “settled science.” Science is, by definition, never settled. Science is a process, not a conclusion. Every scientific hypothesis is constantly tested and usually refined or overturned as new knowledge and methods are available. Many scientists are testing the hypotheses of invasion biology and questioning their validity in a changing climate.

The only issue about invasion biology that is “settled” is that it has created a multi-billion dollar “restoration” industry that relies on and benefits the manufacturers of pesticides, as well as creating vested interests that perpetuate the industry.

Milbank also quotes one of his advisors who claims that native plants are better adapted to the changed climate than non-native plants: “The natives have the best ability to adapt — they’ve been adapting for tens of thousands of years in these areas — so they’ve got the ability to change as the climates and the landscapes have been changing.” This statement seems comical, given that the topic is the extreme difficulty of eradicating non-native plants and the fact that they are out-competing native plants. There is zero evidence that native plants are better adapted to the changed climate than the non-native plants that have replaced them. 500 million years of geologic history on Earth has informed us that when the climate changes—as it has many times–the vegetation changes.

All plants, whether native or non-native, convert carbon dioxide to oxygen and store carbon. Destroying them contributes to greenhouse gases causing climate change by releasing their stored carbon into the atmosphere and reducing the capacity of the landscape to absorb more carbon in the future. To deny that fact, is to be a climate change denier.

Reality trumps unrealistic hopes

Milbank describes the landscape he hopes to achieve with the help of herbicides. It is the landscape that existed in the distant past, in a different climate, before the environment was altered by the activities of humans. I am reminded of one of the presentations at the most recen t conference of the California Native Plant Society, an event where the audience hopes and the speakers douse the audience’s hope with the reality of their unsuccessful efforts. The presenter described a 20-year effort at the Santa Rosa Plateau Ecological Reserve to convert non-native annual grassland to native grassland, using annual (sometimes bi-annual) prescribed burns. Many different methods were used, varying timing, intensity, etc. The abstract for this presentation reports failure of the 20-year effort: “Non-native grass cover significantly decreased after prescribed fire but recovered to pre-fire cover or higher one year after fire. Native grass cover decreased after prescribed fire then recovered to pre-burn levels within five years, but never increased over time. The response of native grass to fire (wild and prescribed) was different across time and within management units, but overall native grass declined.” The audience was audibly unhappy with this presentation. One person asked if the speaker was aware of other places where non-native grass was successfully converted to native grass. The speaker chuckled and emphatically said, “NO. I am not aware of any place where native grasses were successfully reintroduced.”

(1) “Glyphosate kills microorganisms beneficial to plants, animals, and humans,” Beyond Pesticides, October 2021.
(2) “Glyphosate, a chelating agent—relevant for ecological risk assessment?” Environmental Science and Pollution Research International, 2018
(3) “Prevalence of Iron Deficiency and Iron-Deficiency Anemia in US Females Aged 12-21 Years, 2003-2020,” Journal of American Medical Association, 2023
(4) “Is the Use of Glyphosate in Modern Agriculture Resulting in Increased Neuropsychiatric Conditions Through Modulation of the Gut-brain-microbiome Axis?” Frontiers in Nutrition, 2022
(5) “Toxic Effects of Glyphosate on the Nervous System: A Systematic Review” International Journal Molecular Science, 2022

Category: Climate Change