Climate Change – Page 2 – Conservation Sense and Nonsense

Defining “Success” So That “Success” Can Be Achieved

I always attend the conferences of the California Invasive Plant Council (Cal-IPC) and the California Native Plant Society because I feel obligated to understand their viewpoint so I can accurately report on the controversies of invasion biology. Ironically, the more I learn about the native plant movement and the “restoration” industry it spawned, the less … Continue reading “Defining “Success” So That “Success” Can Be Achieved”

I always attend the conferences of the California Invasive Plant Council (Cal-IPC) and the California Native Plant Society because I feel obligated to understand their viewpoint so I can accurately report on the controversies of invasion biology. Ironically, the more I learn about the native plant movement and the “restoration” industry it spawned, the less sense it makes. The October 2024 Symposium of the California Invasive Plant Council has provided yet more evidence that attempts to eradicate well-established non-native landscapes and replace them with native plants are futile.

Tricks of the “Restoration” Trade

Every Cal-IPC Symposium has wrestled with the question of how to convert non-native grassland to native grassland. A study of 37 grassland “restorations” in coastal California answers that question. (1) It’s really quite simple. All you need to do is define success as 25% native plants after “restoration” and limit post-project monitoring to 5 years or less: “Monitoring is done ≤5 years after project-implementation, if at all, and rarely assesses the effects of management practice on project success.”

It also helps if public land managers in charge of the projects won’t allow the academic researcher to enter the land to conduct a survey of the results. 43% of the projects that were studied were “statutory,” i.e., they were mandated by laws such as county general plans or legally required mitigation for projects elsewhere that Environment Impact Reports determined were harmful to the environment. 30% of the managers of the statutory projects would not allow the academic researcher to survey their projects.

It is also easier to achieve success if the project goal is downgraded mid-project as were many of the statutory projects because they weren’t able to meet the original goal.

Project managers can also reduce their risks of failure by planting a small number of native species that are particularly easy to grow: “Ninety-two percent of restoration managers preferentially use one or more of the same seven [native] species.” Seven projects planted only one native species.

According to the study, the result of planting only a few hardy native plants is “biotic homogenization.” Call it what you will, but this risk-averse strategy is inconsistent with claims that the goal of native plant restorations is to increase biodiversity.

The study did not ask project managers about the methods they used to eradicate non-native plants or plant native plants. The study tells us nothing about the methods that were used or whether or not some methods were more effective than others. Since results of the projects were all very similar, should we assume that the methods that were used didn’t matter?

The presentation of this study concluded with this happy-face slide. (see below) It looks like a cartoonish marketing ad to me:

Harmless aquatic plants being pointlessly eradicated

A USDA research ecologist stationed at UC Davis made a presentation about the most effective way to kill an aquatic plant with herbicides, but that wasn’t the message I came away with.

Jens Beets told us about a species of aquatic plant that is native to the East and Gulf coasts of the US, but is considered a “noxious weed” in California, solely because it isn’t native. He said the plant is considered very useful where it is native. (see below)

Where Vallisneria americana is native, it is considered a valuable plant for habitat restoration because it is habitat for vertebrates and invertebrates and it stabilizes soil and water levels. The canvasback duck is named for this plant species because it is preferred habitat for the native duck that is found in California during the winter.

Vallisneria americana looks very similar to other species in the genus considered native in California. For that reason, native species of Vallisneria have been mistakenly killed with herbicide because applicators didn’t accurately identify the target plant as native. Jens Beets recommended that genetic tests be performed before plants in this genus are sprayed with herbicide.

This story probably sounds familiar to regular readers of Conservation Sense and Nonsense. The story is identical to the pointless and futile effort to eradicate non-native species of Spartina marsh grass in the San Francisco Bay. The species being eradicated in California is native to the East and Gulf coasts, where it protects the coasts from extreme storm surges and provides valuable habitat for a genus of bird that is plentiful on the East Coast, but endangered in California. The 20-year effort to eradicate non-native Spartina has killed over 50% of the endangered bird species in the San Francisco Bay.

Throwing good money after bad

Because the hybrid is indistinguishable from the native species of Spartina on the West Coast. 7,200 genetic tests have been performed in the past 12 years before hybrid Spartina was sprayed with herbicide. Taxpayers have spent $50 million to eradicate Spartina over 20 years. Recently, California state grants of $6.7 million were awarded to continue the project for another 10 years. A portion of these grants are given to the California Invasive Plant Council to administer the grants.

Plants are sprayed with herbicide because they aren’t native, not because they are harmful. Even if the target species is needed by birds and other animals, it is still killed and animals along with it. The target species looks the same as the native species and only genetic testing can identify it is as a non-native. The non-native is the functional equivalent of the native. It is only genetically different because natural selection has adapted it to the conditions of a specific location.

Pesticide regulation in the US is a hit or miss proposition

The final session of the symposium was a carefully orchestrated apologia for herbicides, a defensive tirade that suggested Cal-IPC believes its primary tool is in jeopardy. Two presentations were made by employees of regulatory agencies. Their assignment was to reassure the public that pesticides are safe because they are regulated by government agencies.

The fact that many countries have banned pesticides that are routinely used in the US does not speak well for our regulatory system. America’s pesticide regulators rarely deny market access to new pesticides. A recent change in policies of California’s Department of Pesticide Regulation made a commitment to the continued use of pesticides for another 25 years.

In 1996, Congress ordered the U.S. Environmental Protection Agency (EPA) to test all pesticides used on food for endocrine disruption by 1999. The EPA still doesn’t do this today. Twenty-five years later, the EPA has not implemented the program, nor has it begun testing on 96% of registered pesticides. In 2022, an organization that represents farm workers sued the EPA to conduct the legally mandated evaluation of chemicals. The lawsuit has forced the EPA to make a commitment to conduct these evaluations of chemicals for hormone disruption.

The Cal-IPC presenters got some badly needed push back from attendees. One attendee informed the audience that all the testing of herbicides is bought by the manufacturers, not the regulators who don’t do any testing. Another attendee pointed out that herbicides have not been evaluated for the damage they are doing to the soil, damage that makes it difficult to grow native plants in the dead soil. The “pesticide regulator” agreed with those observations.

Fire safety or native plant restoration?

The Interim Deputy Director of the Laguna Canyon Foundation was the final presenter for the Symposium, speaking on a Friday afternoon at 4:30 pm, when there were less than 100 attendees left of the 690 registrants. His presentation was about the blow back that his organization gets from the public about herbicide applications. Criticism of herbicides escalated after a wet year that increased vegetation considered a fire hazard. This photo (below) is an example of the visible effects of fuels management by Laguna Canyon Foundation using herbicides.

It seems likely that a fuels management project was selected for this presentation because it’s easier to justify herbicide use for fuels management than for eradicating harmless plants solely because they aren’t native.

I recently supported Oakland’s Vegetation Management Plan that will use herbicides for the first time on 300 miles of roadsides and 2,000 acres of public parks and open space in Oakland. Previously, herbicide applications were only allowed on medians in Oakland. I tracked the development of the Vegetation Management Plan for 7 years through 4 revisions to avoid nativist versions of fuels management such as leaving dead thatch after herbicide applications on grassland or destroying non-native trees, while leaving highly flammable bay laurel trees behind or destroying broom, while leaving more flammable coyote brush behind.

However, using herbicides for the sole purpose of killing non-native plants is much harder to justify. The irrational preference for native species has put us on the pesticide treadmill. Every plant species now targeted for eradication with herbicides should be re-evaluated, taking into consideration the following criteria:

Is it futile to attempt to eradicate a plant species that is deeply entrenched in plant communities?
Will the attempt to eradicate the plant species do more harm than good?
Is the targeted plant species better adapted to current environmental and climate conditions?
Is the targeted non-native plant making valuable contributions to the ecosystem and its animal inhabitants?

If these questions cannot be satisfactorily answered, the bulls-eye on the targeted plant should be removed. Limiting the number of plants now being sprayed with herbicide is the only way to reduce pesticide use. If the plant isn’t a problem, there is no legitimate reason to spray it with herbicide.

Pot calls kettle black

The Cal-IPC presentation was a detailed criticism of the public’s complaints about herbicides used in their community. The intention of the presentation was to arm herbicide applicators with defenses against the public’s complaints. Herbicide applicators were encouraged to recognize these arguments (below) and participate in the “education” of the public about the righteousness of their task.

The presenter then showed a series of slides making specific accusations, such as these: (see below)

Those who object to the pointless destruction of nature can also cite similar distortions and misrepresentations of facts (AKA lies) by those who engage in these destructive projects;

Nativists fabricated a myth that eucalyptus kills birds to support their demand that eucalyptus in California be destroyed. There is no evidence that myth is true.
Nativists also fabricated a myth that burning eucalyptus in the 1991 firestorm in the East Bay cast embers that started spot fires 12 miles away from the fire front. There is no evidence that myth is true.
Nativists exaggerate the success of their projects by setting a low bar for success, conducting no post-project monitoring, and restricting access to their completed projects.
The EPA justified the dumping of rodenticides on off-shore islands by inaccurately claiming that the rodenticides do not end up in the water, killing marine animals. There is ample evidence that island eradications have killed many marine animals because rodenticide lands in the water when applied by helicopters.
USFWS justified the killing of 500,000 barred owls in western forests by claiming they are an “invasive species.” In fact, barred owls migrated from the East to the West Coasts via the boreal forests of Canada. These forests were not planted by humans and have existed since the end of the last Ice Age, some 10,000 years ago. The arrival of barred owls on the West Coast was a natural phenomenon. Barred owls are therefore not “invasive species.” In a rapidly changing climate, many animals must move to survive.
Nativists claim that most insects are “specialists” that require native plants. That claim is a gross exaggeration of the dependence of insects on native plants, which are sometimes confined to a family of plants containing thousands of both native and non-native species.
Pesticide applicators also complain about “personal attacks.” They are not alone. I (and others) have been called “nature haters,” “chemophobes,” and “climate change deniers.” Pesticide applicators feel abused. So do I.

I could go on. The list of bogus claims of the superiority of native plants and animals is long and getting longer as more and more public money is available to conduct misnamed “restorations.” Suffice to say, there is plenty of misinformation floating around invasion biology and most of it is used to defend destructive “restoration” projects. The war on nature is also a war of words.

(1) Justin Luong, et.al., “Lessons learned from an interdisciplinary evaluation of long-term restoration outcomes on 37 coastal grasslands in California.” Biological Conservation, February 2022.

The Forever War on Non-Native Plants

I spoke to California’s Wildlife Conservation Board at their August 2024 meeting about the Invasive Spartina Project. I asked the Board not to fund the eradication of non-native spartina and its hybrid, using herbicide. This project, which began 20 years ago, had cost over $50 million by 2023. (1) Non-native spartina, native to the East and Gulf coasts (2), provides crucial habitat for Clapper rails (3), closely related to our endangered Ridgway rails.

Source: Cornell Laboratory of Ornithology

Non-native spartina grows taller, denser, and doesn’t die back in winter as native spartina does. Because early aerial spraying of herbicide eradicated most non-native spartina by 2010, Ridgway rail populations declined by 50% due to habitat loss. (4)

The project was temporarily paused in 2014 to plant native marsh plants and stabilize rail populations. When the project was resumed in most places the rail population continued to decline from 2018-2023. There were approximately 1,200 Ridgway rails in the Bay estuary before the project began. (5) The most recent survey in 2022 found about 500. (6)

Native pickleweed was planted based on the mistaken assumption it would benefit endangered salt marsh harvest mice. Recent studies show there are more mice in areas with less pickleweed and they eat both native and non-native plants. (7)

Source: *“Evaluating the plasticity of a ‘specialized’ rodent in a highly-invaded estuary,” Katie R. Smith, et.al., Presentation to California Invasive Plant Council Symposium, October 2023*

For the past 10 years, the focus has been on eradicating a hybrid of spartina, though it is indistinguishable from native spartina and 7,200 genetic tests were required from 2010 to 2022 to identify it. Hybridization is a natural evolutionary process that supports natural selection. (8)

Hybrid spartina could help to protect the Bay’s shoreline as sea level rises and extreme storm events cause erosion. Where it is eradicated, gaps in vegetation are difficult to revegetate because the herbicide (imazapyr) that is used is very mobile and persistent in the soil. Imazapyr is also a non-selective herbicide that kills both native and non-native plants growing closely together, as they do in the San Francisco Bay Estuary. (9)

Although others spoke with me, there were an equal number of people who spoke in favor of granting nearly $7 million to continue the project for another 10 years. Some of the funding is granted to California Invasive Plant Council to administer the grants. Several of those speakers (including Marin Audubon) actually claimed that the project is benefiting endangered Ridgway rails, despite the fact that the project has killed at least 600 of them by destroying their nesting habitat and probably contaminating the food they eat, such as crustaceans and mollusks.

You might wonder why an organization such as Marin Audubon, which is committed to protecting birds, would advocate to continue a project that has killed at least 600 endangered birds, until you remember that Marin Audubon is also supportive of the project that plans to kill 500,000 barred owls. Marin Audubon also wants the Barred Owl Management Strategy to be mandatory instead of voluntary as proposed by USFWS.

Source: Staff Report for Invasive Spartina Project, WCB Board Meeting, August 22, 2024

The Wildlife Conservation Board approved grants to the Invasive Spartina Project with one dissenting vote. The dissenting Board member voted, “Hell, NO!” Her term on the Board will end after the May 2025 meeting. She does not expect to be reappointed. Her departure will be the end of the effort to prevent the Wildlife Conservation Board from granting funds to projects that use pesticides. It’s another dead end for those who advocate on behalf of wildlife and against the use of pesticides on public lands.

Funding sources to continue the Invasive Spartina Project are the Greenhouse Gas Reduction Act and Climate Change Resilience fund. These funding sources are as inappropriate as the project itself. Destroying vegetation does not reduce greenhouse gas emissions. Destroying non-native vegetation that grows taller, denser, and doesn’t die back in winter does not make our shoreline more resilient as sea-levels rise and winter storms become more intense.

Invasive Spartina Project is typical, not unique

The Invasive Spartina Project is typical of other “restoration” projects in California that have been trying, unsuccessfully, to eradicate non-native plants for 20 years and more. Thanks to the California Invasive Plant Council (Cal-IPC), we now have survey data that tells us where these projects have been done and for how long. (10)

Cal-IPC sent more than 300 survey questionnaires to “practitioners” who had registered for Continuing Education credits for Cal-IPC classes and “land manager staff of organization throughout California.” Over 100 practitioners replied to the survey. This graph depicts their replies to the question, “Approximately how many total years have you applied herbicides throughout your career?”

Source: California Invasive Plant Council

Clearly, the Invasive Spartina Project is one of many “restoration” projects that have been applying herbicides for 20 years or more. And the Invasive Spartina Project has secured State funding to continue spraying herbicides for another 10 years. Spraying herbicides on public lands has created stable, life-long employment for an army of weed warriors.

The survey also tells us where herbicides are being sprayed:

Virtually all (89%) herbicide applicators are spraying herbicides in “natural areas”—which we assume are wildlands—where no attempt has been made to plant native plants. Most projects are more destructive than they are constructive. Nearly 50% of herbicide applicators are spraying in public parks. 70% of herbicide applicators spray in “restoration areas,” presumably to sustain the native plants that were planted. If they are using non-selective herbicides, such as glyphosate and imazapyr, they are probably killing native plants too.

There are many other revelations in this survey and the details are available in the Cal-IPC publication (10):

Only 1.9% of respondents had not used herbicides or been part of a project that used herbicides.
The top three application methods were spot spraying (100%), cut stump (87%), and broadcast spray (70%).
40% of respondents were not calibrating their herbicide use. “Calibration is the process of adjusting and measuring the amount of pesticide that a piece of equipment will apply to a target area. It’s an important step in the pesticide application process to ensure that the equipment is applying the correct amount of pesticide at the right rate and in a uniform manner.” (Google search)
28% of respondents had never received calibration training. 20% of respondents said they did not calibrate their herbicide application because “they did not know how.” Cal-IPC often claims that herbicides are being applied “judiciously.” If you don’t know how to apply herbicides, you are unlikely to apply them “judiciously.”

The Forever War on Non-Native Plants

Cal-IPC’s survey of “restoration” practitioners confirms our observations of their efforts in the past 25 years in the San Francisco Bay Area:

Attempts to eradicate non-native plants are a Forever War that has poisoned our public lands without eradicating non-native plants or restoring native vegetation, in most cases.
The war is futile because it is attempting to stop evolution, which is trying to help flora and fauna adapt to the changing climate and environment. Humans cannot stop evolution, nor should we try. The Forever War is a losing battle against evolution, which has sustained life on Earth for 3.7 billion years, without human “assistance.”
The plants that we are trying to kill are also adapting to the poisonous war we pointlessly wage against them. They have evolved and will continue to evolve resistance to the poisons we spray on them. Herbicides are less effective than they were 40 years ago and they will be continuously less effective.
We are poisoning ourselves and other animals in our futile attempt to kill the plants that feed them. Claims that wildlife eat only native plants is a fiction and a lie that sustains an industry with vested economic interests in that myth.
Many pesticide applicators are not properly trained or they are not following legally mandated instructions for pesticide applications on product labels. They are hurting themselves when they don’t wear legally required personal protection equipment. They are hurting the environment and everyone who lives in it when they use too much pesticide because they have not calibrated their applications as required by the product label. When they don’t post pesticide application notices in advance of their applications, they deprive the public of the opportunity to protect themselves by avoiding the area. Even when they do, such signs would not be helpful to wildlife.
The money that is wasted on this Forever War could be used to address a multitude of other pressing needs. For example, the lead pipes in Oakland that are delivering drinking water contaminated with lead to children in our public schools could be replaced with a fraction of what has been spent to eradicate non-native spartina marsh grass in the past 20 years. (11) It’s no wonder that the public does not trust the American government:

References:

San Francisco Estuary News, “The Battle for Native Cordgrass,” Jacoba Charles, March 2023
USDA Plant Database: Spartina alterniflora When the Invasive Spartina Project began, the USDA Plant Database map of this species indicated that the species was introduced on the West Coast. The current version of the map shows that this species is now native to the West Coast.
Clapper rail, Cornell Laboratory of Ornithology Status of Clapper rail is “Low Concern”
Adam Lambert et.al., “Optimal approaches for balancing invasive species eradication and endangered species management,” Science, May 30, 2014, vol. 344 Issue 6187
“Effects of Predation, Flooding, and Contamination on Reproductive Success of California Clapper Rails (Rallus Longirostris Obsoletus) in San Francisco Bay,” Steven E. Schwarzbach, Joy D. Albertson, Carmen M. Thomas, The Auk, 1 January 2006
2023 California Ridgway’s Rail Surveys for the San Francisco Estuary Invasive Spartina Project (page 9)
“Evaluating the plasticity of a ‘specialized’ rodent in a highly-invaded estuary,” Katie R. Smith, et.al., Presentation to California Invasive Plant Council Symposium, October 2023
San Francisco Estuary Invasive Spartina Project 2021‐2022 Monitoring and Treatment Report (Appendix II, page 3)
Journal of Pesticide Reform: https://assets.nationbuilder.com/ncap/pages/26/attachments/original/1428423389/imazapyr.pdf?1428423389#:~:text=Imazapyr%20can%20persist%20in%20soil,aerial%20and%20ground%20forestry%20applications
Dispatch, Newsletter of California Invasive Plant Council, Spring 2024 (page 10-11)
“In 2018, Oakland Unified School District (OUSD) estimated that it would cost $38 million to fix lead contamination in its schools. This included $22 million to replace water lines and $16 million to replace drinking water and sink fixtures. The OUSD blamed the aging infrastructure for the high lead levels and sought help from the state and federal government.” (Google Search)

Isle Royale: Long-term study of predator/prey dynamics

“Natural history might be much like human history — explainable, but not predictable.” – Isle Royale Wolf-Moose Project

Isle Royale is an island and US National Park in Lake Superior. It is 45 miles long and 9 miles wide. Big enough to be the home of many animals, but small enough to be intensively studied and well understood.

The closest land is 24 miles away, in Canada. Far enough away to limit opportunities for animal migrations and control public access to the island, but close enough that ice bridges from the land to the island have formed in the past that animals used to migrate to the island. It is isolated, but not totally isolated, which contributes to the dynamism of the ecosystem.

The animals at the top of the food web on Isle Royale are wolves and moose. Moose are said to have arrived via an ice bridge at the beginning of the 20^th century. Wolves arrived using another temporary ice bridge in the late 1940s. The predator/prey relationship between moose and wolves has been studied on Isle Royale continuously since 1958, making it the longest-running predator/prey study.

When the study began 66 years ago, scientists expected to find an equilibrium balance point between populations of wolves and moose that would be stable in the long term. That’s not what they found on Isle Royale. Instead, they observed continuous, unpredictable change, such as disease, tick outbreaks, immigrant wolves, severe winters and hot summers.

Scientists recorded the population dynamics of wolves and moose on Isle Royale for 66 years, as depicted in this graph:

*Source: 2023-2024 Annual Report of Ecological Studies of Wolves on Isle Royale*

As we would expect, moose populations increased when wolf populations decrease and vice versa. Scientists can explain the turning points in the population curves of both wolves and moose, but in many cases they could only do so long after the fact as they identified the causal factors:

Between 1958 and 1969, the moose population doubled, while the wolf population declined from 30 to 15.
Between 1969 and 1980, the wolf population increased as the moose population decreased until 1982, when canine parvovirus was introduced to the island by a visiting dog.
The wolf population decreased from 50 to 14 until parvovirus died out, but the wolf population did not rebound. The wolves had become inbreed because they were all descendants of a single breeding pair. The wolf population suffered spinal deformities that handicapped their hunting until a single new male introduced new genes in 1997.
Between 1982 and 1996 the moose population increased to an all-time high of 2,400 until 1996 when their over-population caught up with them. The population plummeted because of lack of forage, an increase in the tick population and a severe winter. Ticks cause moose to lose their hair during winter, at a time when they were already thin because of over-browsing of vegetation.
When the moose population plummeted in 1996, there was a corresponding decrease in the wolf population, until a new wolf arrived via a temporary ice bridge. In 1997 a single male wolf made his way to the island on an ice bridge during the extreme winter. He was very prolific and infused new genes into the wolf population that enabled the wolf population to rebound to 30 by 2005. The arrival of the new wolf was not identified by the scientists who study Isle Royale until 14 years later, as the result of genetic tests.
Between 2000 and 2005 there was a series of hot summers, which increased the tick population and suppressed the moose population, causing a corresponding decline in the wolf population.
Between 2005 and 2011, the moose population rebounded, but the wolf population continued to decline. By 2011 there were only 15 wolves with only 2 females and most males were without functioning packs. Inbreeding was probably contributing to the inability of the wolf population to recover.

In 2018, the National Park Service decided to take matters into their own hands. There were only 2 wolves left at that point and over-population of moose was taking its toll on vegetation on the island. New migration of wolves was no longer expected because the warming climate prevents the formation of new ice bridges to the island. NPS adopted an interventionist policy for the first time. They made a commitment to introduce 20-30 new wolves to the island over 3-5 years.

The first introduced female wolf arrives from Minnesota, 2018. Source: NPS

The graph depicts the arrival of new wolves on Isle Royale in 2018. The wolf population has increased and it is more genetically diverse because of the arrival of wolves from distant genetic pools. Greater genetic diversity will improve the resiliency of the wolf population. The moose population is decreasing in response to restoration of wolves to a population of 30.

Dueling bull moose on Isle Royale, 2001. Source: NPS

The dynamic predator/prey relationship between moose and wolves in Isle Royale will continue in unpredictable ways. Climate change is expected to play a bigger role. Hotter weather will increase tick populations and cause more moose mortality. Changes in the climate will effect vegetation. Balsam fir that are the preferred food of moose are being killed by spruce budworm. Ice bridges that bring newcomers to the island will no longer form.

Scientific Humility

However, the scientists who have studied Isle Royale for decades don’t want to leave you with the mistaken impression that they understand everything that has happened in the past or that they can predict everything that will happen in the future on Isle Royale. Their humility is refreshing:

“For 50 years, the focused purpose of the Isle Royale wolf-moose project has been to predict and understand a relatively simple natural system. But the more we studied, the more we came to realize how poor our previous explanations had been.” (1)

These scientists want us to understand the limits of our understanding of nature because if and when we don’t, we make serious mistakes:

“If we see Nature as a system whose future we can predict, then we will be confident in our efforts to control and manage Nature. If, in Nature, we are more impressed by its essentially contingent, and hence unpredictable character, then our relationship will be more strongly rooted in striving to live within the boundaries of Nature’s beautifully dynamic variation.” (1)

Readers of Conservation Sense and Nonsense know that I believe humans cannot control nature. We don’t understand nature well enough to control it and the forces of nature are far more powerful than we are. When we try, we often do more harm than good. The scientists who have studied Isle Royale for 66 years seem to agree with me. I am grateful for their work and their wisdom.

(1) Wolves & Moose on Isle Royale, Project Overview

Sources for this article:

              Wolves & Moose on Isle Royale, Project Overview
              Wolves & Moose on Isle Royale, Ticks
              Isle Royale National Park
              Isle Royale, Wikipedia

Mid-Summer Visit to the Sierra Nevada

We spent a few days in a small family-owned resort in Sierra City in mid-July. It’s an area we know well because we have visited many times in the past 25-years and taken many birding and geology courses at the nearby San Francisco State University Sierra Nevada Field Station.

It has been about 12 years since our last visit and we were expecting to see significant changes after a decade of drought. Our previous visits were also earlier in the summer, during nesting season in June, when birds are more active and vocal. As expected, the weather was much warmer than previous visits.

The Setting

Sierra City sits at the base of Sierra Buttes at 4,200 feet elevation. Sierra Buttes tower above at 8,560 feet. The Buttes are the remains of the lava flow of an ancient volcano. The soft rock surrounding the lava flow eroded away long ago and the harder rock has been sculpted several times by glaciers during past ice ages. The glaciers sculpted rocks on the valley floor into the basins of many lakes that remain today.

This area was occupied by a hunter-gatherer culture of Indigenous people for thousands of years. They migrated according to the seasonal harvests of plants and animals until Europeans arrived in 1850 to mine for gold. The first generation of the owners of the resort arrived as miners. When gold was exhausted, ranching became the family enterprise. When the recreational treasures of the area were discovered in the 1960s, the family converted the ranch to a resort in 1967. The economy of this area has evolved, just as its flora and fauna have.

Fire Hazard Mitigation?

The most significant change we observed since we were last in the Sierras is the massive timber operations. In the 12 miles from Sierra City to Yuba Pass at 6,700 feet, we saw roadside clearings created by cutting young trees. Huge piles of small-diameter logs and wood chips were stacked in the clearings (see below).

These clearings looked like fire hazard mitigation partly because of their proximity to the road and to campgrounds, but also because they destroyed small trees, which are more likely to ignite than big trees. On the other hand, the piles of logs and wood chips are more flammable than any living tree, big or small.

Thinning the forests is also a strategy to reduce competition for available moisture at a time of extreme drought. Extreme drought stress in the conifer forests of the Sierra Nevada is one of the primary causes of tree mortality in California in the past decade.

Commercial Logging?

When we reached the summit of the road at Yuba Pass, we saw another clearing that used a different strategy than those we had passed. The campground at Yuba Pass was entirely clear cut of all of its trees, big and small. Lonely picnic tables were surrounded by the stumps of large trees. Appropriately, the campground was closed and its bathroom locked (see below). No one would want to camp there now.

This destruction of the campground at Yuba Pass looks like a fire hazard mitigation project gone bad or a commercial logging operation at the expense of a campground at an important trail head that is used for winter cross-country skiing and summer hiking.

We visited the bar at our resort at the end of the day to get the perspective of the locals about these logging operations on Highway 49. We learned that they are controversial with the locals, but there is no vocal opposition to them in a small community of only 200 year-round residents. (The bartender said the community was more concerned about AT&T’s threats to disconnect their landline phones because the community does not have a cell phone tower.)

However, the public’s reaction to the destruction of the campground at Yuba Pass was much stronger than to the thinning of young trees. The rumor is that the contractor who clear cut the campground at Yuba Pass did not do what they were supposed to do. The Yuba Pass project is considered a rogue operation by the locals.

We also learned that the piles of logs and wood chips will eventually be hauled away to be used as biofuels to generate electricity. As the wood is burned, the carbon stored in the wood will be released into the atmosphere, contributing to greenhouse gases that cause climate change. Some of the dead wood has already been removed. Nine months after the trees were destroyed, much still remains to be removed. Meanwhile, the piles are clearly a fire hazard. Fire hazards are increased in the short term by dead wood and in the long term by contributing to global warming.

Tree Mortality

At Yuba Pass, we began to see first-hand the tree mortality in the Sierra Nevada we had been reading about in the media for years. We saw many dead red firs as well as one of the symptoms of more red fir deaths in the near future.

Adjacent to dead red fir trees, younger red fir trees were heavily loaded with cones, which are an indication that the tree is making a last gasp for survival of the species by trying to produce a big, new generation of trees (see above).

As we drove over the summit to the eastern side of the Sierra Nevada we could see the scale of the death of red and white firs. The eastern side of the Sierras is drier than the gently-sloping western side, which receives the moist air from the ocean. The Sierras drop steeply on the eastern side to the Great Basin, which extends into Nevada as a dry, hot desert. (see below)

Dead conifers at Yuba Pass in October 2022. Source: Sierra Nevada Conservancy

Until 2022, tree mortality in the Sierra Nevada range was confined to southern and central portions of the range and at lower elevations. An aerial survey of trees in the northern portions of the range in October 2022 found 28 million dead red and white firs at higher elevations. Red and white firs are higher elevation conifers and were therefore harder hit than lower elevation conifers in this portion of the range.*

Ecological “restorations” are never done

We visited a restoration project on the eastern side of Yuba Pass at Carmen Meadow. The project was done about 20 years ago. We wanted to see how it was progressing.

The meadow had been the home of rare willow flycatchers until it dried out, killing the willows that were home to the flycatchers. A berm had been built as the roadbed of a railroad. The berm diverted water into the creek, digging its channel lower than the meadow, draining water from the meadow into the creek. A check-dam was built to divert water channeled by the berm from the creek into the meadow, restoring water to the meadow. The flycatchers returned when the willows returned.

We had last seen Carmen Meadow over 12 years ago. Although willows remained, there were also young Jeffrey pines on the perimeter of the meadow as well as dotted throughout the meadow. Thus, natural succession from pond, to meadow, to forest is in progress. (see below) Restoration projects are never done because nature is dynamic and evolution is never done.

Must this natural succession of the Carmen Meadow be stopped? That is probably a matter of opinion. My readers know that my opinion is probably “NO.” In defense of my opinion, I offer my readers an alternative scenario.

Willow flycatchers are also rare in the Southwest, where the loss of water also caused the loss of willows that are home to the flycatchers. But, in Southwestern desert, the solution is not so easy and painless as diverting water into Carmen Meadow.

Water in the Southwest has been diverted from riparian areas for agriculture and drinking water for large and growing residential communities. As you might imagine, few are willing to divert water supporting human activities to support a rare bird.

In the Southwest, willow flycatchers solved their own problem by making the necessary transition from willows to non-native tamarisk trees that require significantly less water than willows. And in this case, native plant advocates resisted this transition by trying to eradicate tamarisk solely because they are not native trees. The birds were willing and able to transition to a non-native tree, but the nativists wouldn’t accommodate their preference.

The Message

We had a wonderful time on our brief trip to Sierra City at Yuba Pass. We hope to go again and we expect to see more changes when we do. We took these messages away with us.

Yes, the Sierra Nevada range is changing, but it remains beautiful. We encourage you to visit and if you have, visit again because it is never the same twice.
There is a fine line between fire hazard mitigation and commercial logging and it isn’t always clear what the objective is.
The short-term objectives of any landscape project are sometimes at odds with the long-term objectives.
Change is the only constant in nature.

*Sources:
https://www.sfchronicle.com/climate/article/california-tree-deaths-17770026.php
https://sierranevada.ca.gov/signs-of-a-new-tree-mortality-event-showing-up-in-the-sierra-nevada/

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.

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

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

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

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

Plant Evolution Timeline

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

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

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

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

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

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

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

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

Evolution of grasses

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

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

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

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

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

Native plant advocates in California have selected grassland as their preferred ecosystem because it was the dominant ecosystem prior to the arrival of Europeans at the end of the 18th century. They have consistently failed to convert non-native grassland to native grassland in California. Nor is it clear that there would be any benefit to the environment or to its inhabitants to return to the treeless landscapes of California that existed prior to settlement in the late 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 600 genetic tests are required every year to confirm their identification as hybrids before they are sprayed. The Invasive Spartina Project is a waste of limited conservation resources and it serves no useful purpose.

Evolution vs. Conservation

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

The use of pesticides by “restoration” projects is antithetical to the goal of conservation because they do more harm than good.
Migration is a means of species survival. Natural migration of plants and animals cannot and should not be stopped.
Humans cannot duplicate the forces of evolution. Natural selection is the most powerful, efficient, and effective method of determining the winners of competition.
Hybridization has the potential to improve adaptability of closely related plants and animals. Hybridization cannot and should not be stopped.
Resources being wasted in the attempt to stop the natural forces of evolution should be redirected to reducing greenhouse gas emissions causing climate change. Such efforts are appropriately called “conservation.”

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.

Update, July 2025: The Northwest Forest Plan has been amended. The amendment to the plan will enable more logging in the Pacific Northwest. Https://www.chronline.com/stories/proposed-changes-would-allow-more-logging-on-federal-land-in-the-pacific-northwest,372393

The amendment began during the Biden administration and was approved in May 2025. The point of the amendment is to “manage” the forest to reduce wildfire hazards. https://www.fs.usda.gov/r06/planning/northwest-forest-plan-amendment

The stated purposed of the USFWS plan to kill 500,000 barred owls was to save endangered spotted owls. The plan was created by the timber industry in the Pacific Northwest because killing barred owls on their properties enabled them to get permits needed to continue logging on their properties.

On October 30, 2025, the US Senate rejected an effort to halt the implementation of the Barred Owl Management Plan by a vote of 25-72: https://worldanimalnews.com/2025/10/30/stop-the-slaughter-450000-barred-owls-face-mass-killing-for-so-called-conservation/

However, The Trump administration has also cancelled some grants that funded the plan to kill barred owls in the Pacific Northwest: https://washingtonstatestandard.com/2025/07/22/plans-to-shoot-thousands-of-barred-owls-in-doubt-after-feds-cancel-grants/

Confusing, isn’t it? The plan lives, but some of the funding for implementation is gone. That’s my best guess.

There is some logic to this sequence of events. However, I doubt that logic was used to reach this conclusion. In any case, I am pleased that barred owls will be spared the planned massacre. However, the loss of federal funding to kill barred owls will not prevent private land owners from killing barred owls. The revision of the Northwest Forest Plan to enable more logging might make killing barred owls on private land unnecessary.

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

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