Tag: nature

Environmentalism in the Rear-View Mirror

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

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

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

America Accommodates

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

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

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

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

California Responds

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

Source: California Natural Resources Agency, July 2025

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

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

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

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

Americans Shrug

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

Updated 12/10/25

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

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

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

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

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

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

Looking Ahead

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

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

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

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

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

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

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

Juian Burgoff

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

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

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

Conservation Sense and Nonsense

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

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

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

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

The War on Hydrilla

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

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

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

Unexpected Ecosystem Services: What the Evidence Shows

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

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

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

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

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

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

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

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

Cascading Food Web Effects

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

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

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

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

What We Don’t Know

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

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

Less is More: Observation Based Management

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

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

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

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

Julian Burgoff
Amherst, MA
jburgoff@umass.edu

The Post-Native World

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

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

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

Conservation Sense and Nonsense

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

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

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

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

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

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

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

Mark Wessels

A Walk in the Woods

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

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

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

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

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

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

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

And some pallid manzanita is dead:

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

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

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

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

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

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

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

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

Native Trees and Their Close Relatives

Over 10 years ago, Mark Speyer wrote one of the first guest articles for Conservation Sense and Nonsense about mulberry trees, one native to North America and the other introduced by American colonists because it is the host plant of silk worms.  That article was a hit!  It has been viewed by over 8,600 readers.  It is still entirely relevant to the mission of Conservation Sense and Nonsense and I recommend it to you.  You will find it HERE.

Mark Spreyer

I am grateful to Mark for giving me this opportunity to publish his guest article about willows, some native to North America and one introduced.  As in the case of introduced mulberry trees, some willow species are native to China. 

Much of China and North America have been in the same latitude since the evolution of angiosperms.  As a result of climate similarity and geographic proximity, many of our plant species considered native in Eastern North America are also native to 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.). 

They are different species from their Chinese counterparts because they have been separated long enough to change as a result of genetic drift and in response to a new environment, but are in the same genus and plant lineage and therefore chemically similar. These plant species made their way from China to North America by natural means, such as being carried by birds, animals, wind and ocean currents. 

In contrast, Chinese species of mulberries and willows were intentionally introduced to North America.  Mulberries were brought with the hope of making silk and weeping willows were brought to grace our gardens with their beauty.  Some say they don’t belong here because they were brought by humans.  Others say that is a meaningless distinction.  Whether brought by birds or brought by humans it is a distinction without a difference because humans are as much a part of nature as birds.

Mark Speyer is the Executive Director of the Stillman Nature Center in Barrington, Illinois.  He can be reached at:  stillmangho@gmail.com. 

WILLOWS IN THE WIND ©

       I’ve been writing nature columns for many years and I hope to write them for years to come but sometimes, the writing doesn’t come easy. The other evening, was one of those difficult times.

      As I reached for a bottle of aspirin to alleviate a headache, it hit me– willows.

You see the scientific name for the willow genus is Salix and the main ingredient in the original 1899 aspirin was salicin, an extract from willows.

      I’m not going to attempt to sort through the dozens of North American willows and their confusing hybrids. I don’t have enough aspirin for that. I’d like to concentrate on two of the willow trees, weeping and black, as well as a few of the willow shrubs.

Weeping Willow (Salix babylonica)         

      Unlike black willows, weeping willows aren’t native to this continent. The scientific name is somewhat misleading. This species originates from northern China, not the Middle East. Examples of Salix babylonica can be found growing along the famed Silk Road trade routes between China and Europe. The weeping willow arrived in Europe around 1730. It traveled to N. America courtesy of colonization. The weeping willow also landed on the W. Coast via Japan.

Weeping willow along a highway in suburban Chicago. Photo by Susan Allman

      Its graceful, long, slender, drooping branches makes the weeping willow an easy tree to identify. This pendulous growth habit earned this willow its common name. Not surprisingly, the tree is a popular choice for landscapers and gardeners. It is also the choice of pollinators such as specialized bees and butterflies. If planted in full sun, this rapid grower can reach a height of sixty feet.

           In addition, weeping willow tolerates soils that are somewhat acidic to alkaline. Finally, it thrives in low areas and wet spots where other trees might drown.  Decades ago, my father and I planted two weeping willows in a sunny wet pocket on the property. They grew fast and sucked up the water, just as we had hoped. You see they are designed to do just that.

         Like all willows, weeping willows are easily started from a sprig. Just stick it in some water and watch the rootlets sprout. When you think of where willows grow– along rivers, streams and other places prone to flooding– this asexual method of reproduction is a handy adaptation.

      If a flood washes away a bank and the willow that grew on it, odds are one of its branches will end up on a spit of mud or in a shallow pool downstream. With the passage of time, that branch will take root and a new willow will be on its way.

      In this country, most weeping willows are male clones and thus produce no fruit. Since reproduction for a willow is as easy as dropping a twig in running water, these clones can be found growing where no human planted them.

Black Willow (Salix nigra)

      Rather plant a native species? Then, this next tree is for you. While some may appreciate the graceful form of a weeping willow, give me the craggy old coot of the willow family, the black willow. One of the world’s largest willows, it varies in appearance with where it is growing. Along an eastern seaboard stream, it is a tree reaching a height of forty to fifty feet. In the southern reaches of the Mississippi River’s floodplain, a black willow can reach a height of 100 feet in a mere forty years.

Two black willows near the Fox River in northern Illinois. Photo by Susan Allman.

      Here at the Stillman Nature Center we had a couple of sprawling specimens of our own. They had large forks, beginning low down, each fork leaned outward giving the tree a “slouching picturesqueness” as Donald Culross Peattie wrote.

      Black willow has many alternate names such as American, brittle, and, a favorite of mine, scythe-leaved willow. I like it because the botanical term for willows’ long narrow leaves is lanceolate or lance-shaped. Lances and scythes belong together, don’t you think?          

       Brittle is another appropriate name. Its slender reddish-brown twigs are flexible at first. As they age, the twigs become darker and brittle at the base. Anyone who has sat at a picnic table or parked a boat under a large black willow, will soon find these items decorated with fallen black willow twigs.    

   Unfortunately, willows are short-lived, rarely living past 85. But, as I’ve watched our willows here at Stillman, I have some questions about that figure.

     For example, one of our largest black willows came down in a heap some years ago. After the chainsaws were done, all that was left was the short, thick trunk and a few feet of each main branch that the trunk divided into.

      Was the tree dead? Not quite. As the years passed, flexible yellow branches grew from one of the large “dead” arms. Nutrients and water were obviously flowing from the roots and through the tissues of this “goner.”

      So when is a tree dead? A newspaper story provided an answer that fits our willows. The article was about the fate of a sequoia. At the time, the tree was at least 2,500 years old, “We don’t know if it’s dying or not,” said an interpretive ranger at Sequoia National Park, “One branch with green leaves connected by live tissue to one root is all that’s needed for a tree to be considered alive.”

      Of course, the Sequoia’s trunk remained standing unlike our willow’s old trunk that was down and decomposing.

               Shrubby Willows

      Most willows don’t have large trunks since they exist as shrubs. This is not the place to sort through them all. A partial list would include goat, Bebb, narrowleaf, sandbar, and, the florists’ favorite, pussy willow.                     

Pussy willow in spring. Photo by Lara Sviatko.

      The native pussy willow (Salix discolor) is a boreal species that can occasionally be found growing in northeastern Illinois. As you might have guessed, it inhabits wet areas such as floodplain forests, marshes, and shrubby swamps.

      Because willow thickets are within reach, deer, elk and domestic livestock will feed on willow leaves and twigs. This brings me back to where I started.       Peoples from N. America to ancient Greece made teas and other medicines from willow bark to treat joint pain and other ailments. So, are animals eating willows just to fill their stomachs or to ease their aches and pains as well? The next time I run into a talkative deer, I’ll ask.

Mark Speyer, Summer 2025

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

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

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

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

Source: “WCB 2024 Year in Review”

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

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

WCB Strategic Plan Update

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

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

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

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

On pesticides damaging soil and harming wildlife and human health

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

On biodiversity including non-native species:

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

On hybridization as an adaptive mechanism:

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

On flammability unrelated to nativity:

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

On changing native ranges:

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

On novel ecosystems and historical conditions:

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

In Conclusion

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

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

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

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

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

Conservation Sense and Nonsense
May 1, 2025

References for cited studies

On pesticides harming soil and damaging wildlife and human health:

On biodiversity including non-native species:

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

  On hybridization as an adaptive mechanism:

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

  On flammability unrelated to nativity:

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

  On changing native ranges:

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

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

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

“Speaking for the Trees, No Matter Where They’re From”

When I announced my intention to quit publishing articles on Conservation Sense and Nonsense in December 2024, I invited like-minded allies to send me guest posts for publication.  I also recommended several trusted sources of information about invasion biology and related issues.

I am publishing a guest article by one of those trusted sources today, with permission.  Kollibri terre Sonnenblume is the author of “Speaking for the Trees, No Matter Where They’re From,” available on Substack.  He introduces himself on that website:  “Writer, photographer, tree-hugger, animal lover, occasional farmer, cultural dissident. Author of several books on ecology, human culture, and their intersections. Podcaster on the side.”

For readers who love all plants, both native and non-native, I recommend the Substack of Kollibri terre Sonnenblume.  His articles are deeply researched, informative, and beautifully written.  His knowledge of plants far exceeds anything I have learned about plants because he works directly with them as an integral part of his life and he is an astute observer. 

Conservation Sense and Nonsense

What is a “native” plant in a changing world?

California Fan Palms in Anza-Borrego State Park in California (Photo by author)

The term “native plant” has become a common one, and many people probably assume that the definition is clear cut. However, like many other seemingly simple designations, that’s not the case.

It was in the UK in the mid-19th century where the concept of “native” as opposed to non-native was first proposed by Hewett Coltrell Wallace, who borrowed the terms “native” and “alien” from British immigration law. His definition of “native” also included “naturalized” species, which humans had introduced but that have come to live without them unaided.

Nowadays, whether a given plant is considered “native” where it is found growing is dependent on the interpretation of the interrelation of three factors: time, place and human involvement. There is no agreed-upon global definition.

So currently in the United States, a plant is generally considered native only if it grew here before European colonization. On the East Coast, that’s the 1500s and in California, that’s 1769. Plants introduced since then, whether deliberately or by accident, are labeled “non-native,” “introduced,” “exotic,” or in some cases, “invasive.”

In the UK, though the year 1500 is often cited too, some would set the date at the end of the last glacial maximum, 16,000 years ago, others at ~8000 years ago, when rising sea levels made those landmasses islands, and still others at the Roman invasion in 43 CE. Species introduced by the Romans can also be called “archaeophytes,” which inhabits a middle ground.

Other countries have their own cut-off dates, or, like China seem to still be working it out. Some have none at all, defining “non-native” only in terms of whether the species was introduced by humans, but not when. South Africa has a designation of “native-alien” referring to species that are native to one part of the nation but not to others.

Given that the term is so unstandardized, it’s impossible to make generalized statements about “native species” at the international level.

Plants on the move

The “native range” of any plant is not a static thing. Historically, plant ranges have always been in flux, often in response to climatic shifts, a process which continues in the present day more rapidly because of climate change. Had European colonization never occurred in the Americas, the ranges of plants today would not be the same as they were in 1492, which is a fact that’s not often considered in these discussions.

Fossils and phytogenetics are two things that can show us where plants used to live and where they came from. For example, when Spanish colonists arrived in California in the 18th Century, Coast Redwoods (Sequoia sempervirens) grew in a strip nearly 500 miles long and 5-47 miles wide from what is now Monterrey County in the south to Curry County (Oregon) in the north. Since then, over 95% of them have been cut down. The grievous sin of destroying so many Redwoods in California is compounded by the fact that much of their former habitat is now so altered by land use conversion and ecological changes like erosion that it won’t be home to these grand trees for the foreseeable future.

Only 10,000 years ago—a blip in geological time—Redwoods grew as far south as Los Angeles, and five million years ago, they were found in Europe and Asia. The species has also been spread around the world by humans, including to New Zealand, where a 15 acre grove has been growing for over a century. Due to favorable differences in soil and rainfall there, the trees happen to grow faster there than on the US West Coast.

We can ask, then: how should we define the current “native range” of Redwoods? Are the degraded places where they recently grew but now won’t still part of their “native range”? What about portions of the Oregon Coast immediately north of their most recent range, which they would naturally be moving into because of climate change, both anthropogenic and natural? What about New Zealand where the tree is thriving because the conditions for the tree are so appropriate? Is a Redwood grown today within its historic range in Europe truly “alien” or is it just coming home? By the narrowest definition of “native” these questions are absurd, but of course definitions too are always in flux.

For many, the salient point is “human interference” as opposed to “natural dispersal.”

In this way of thinking, the Creosote Bush (Larrea tridentata), the dominant and emblematic plant of the US Southwest’s Mojave Desert is native even though it arrived from South America as recently as 14,000 years ago, because its means of conveyance over those many thousands of miles was non-human; possibly in the tail feathers of migrating plovers.

But this way of thinking also tends to ignore an important element: the influence of indigenous humans over history, which definitely impacted the “native ranges” of many plants and animals.

Indigenous Land Management Practices

Controlled burns by Indians on the Great Plains expanded prairies at the expense of forests, which led to the spread of Buffalo.

Similar techniques on the West Coast maintained Oak Savannah and suppressed the growth of Firs and Hemlocks.

Seeds, bulbs, corms and other plant material for propagation were collected, transplanted and traded far and wide among tribes in North America. Some species (such as certain Mariposa Lilies in the genus Calochortus) may have dwindled in number to the point of being endangered these days in part because they are no longer actively tended by humans.

The case of the California Fan Palm is particularly intriguing. For years, it was believed that the iconic species was a millions-of-years-old relict, left over from when its current desert home in southern California was much moister. However, phytogenetic analysis proved that the species emerged quite recently, since the last glaciation period 11,000 years ago.

It’s long been known that Indians made use of Fan Palms and their groves for food, craft material, and as places to live. They planted trees and they also set fire to them to clear away the dead leaves so they would be easier to climb to collect the dates. (Fan Palms are fire tolerant.) However, it also appears that they might have been responsible for introducing them to the majority of locations within their “natural range” beyond the small area in Baja California where they originated. (See my Did Native Americans introduce Fan Palms to California?)

If this is the case, then the groves that remain are not the result of “natural dispersal” as that term is usually understood and are more akin to abandoned agricultural sites than to “wilderness.” What, then, is the best way to treat them? I mean, if we’re not going to allow tribes to maintain and use them as they did which is obviously the right answer? Burning is prohibited, as is harvesting and planting the fruits when the trees are on public land. Our current policy aims to protect the trees (which is understandable) but perhaps the actual result is neglect.

California Fan Palms are not the only trees that humans have moved around. In Asia, the “native range” of the Carpathian Walnut coincides with the route of the Silk Road. The distribution of food plants within the forests of the Amazon are anthropogenic. Polynesians brought plants with them as they made new homes on islands throughout the Pacific Ocean. In eastern North America, the “native ranges” of Black Walnut, Pawpaw, Persimmon, Chestnut, and Shellbark Hickory and other food plants are also the result of indigenous human influence. (h/t to Zach Elfers for this info.) They are all considered to be “in the right place” because that’s where they were before a particular calendar date.

Point being, ecosystems that we consider to be “wild” or plant ranges we consider to be “natural” are in many cases human-made or human-impacted. Some would go so far as to say that the very concept of “wilderness”—as in “untouched by humans”—is tantamount to indigenous erasure.

We are a plant-moving species, like many other animals. That settler-colonialism has wreaked havoc on the ecosystems of the Americas is all too clear but to conclude that all the introduced plants who live here now “don’t belong” because “we” brought them here is, I would argue, a step too far, much in need of nuanced examination. The idea that they should be eradicated purely on the basis of place of origin is not merely misguided, but dangerous, given the collateral damage that such efforts inevitably cause, such as disrupting beneficial relationships between native and non-native species that have since formed. Fortunately, the conversation does not need to be so limited.

“Novel Ecosystems” & Ecological Succession

Often, native plants are valorized and non-natives villainized in a reflexive manner that belies the facts on-the-ground. How well an introduced plant has integrated into its new setting is rarely considered by many people (though some invasion biologists do). Or the question of whether plants can become “native.”

“Novel ecosystems” are mixes of native and non-native species. Though formerly ignored by most researchers, they are now garnering more attention because it’s recognized that they operate like any other ecosystem, with their constituent species interacting and adapting and filling different roles just like happens anywhere else.

In California, approximately 1/3 of native butterfly species now use non-native plants as food sources and as egg-laying sites. The range of some of these butterflies has expanded as a result. (See: “Exotics as host plants of the California butterfly fauna“) This has been fortunate for the butterflies, since so much of the habitat that previously provided for them has been destroyed by human activity since 1769, through activities including agriculture, ranching, deforestation, mining, urban sprawl and—most recently—industrial-scale “green” energy installations. The butterflies are adapting to novel ecosystems.

Saltcedar/Tamarisk (Tamarix sp. and Russian Olive/Oleaster (Elaeagnus angustifolia) are oft-maligned as “invasive plants” that should be eradicated. But in the western United States, these two trees are now the third and fourth most frequently occurring woody riparian plants, and the second and fifth most abundant species along rivers. To kill them all would entail destroying a significant amount of healthy vegetation (with no small amount of collateral damage to other flora) and would incur an ecological cost. Their prevalence is due mostly to the thousands of dams that have disrupted most riparian areas in the West, making them less hospitable to the original natives like Cottonwoods and Willows. Novel ecosystems are emerging.

Fifty kinds of birds nest in Tamarisk, including the Southwestern Willow Flycatcher, which is endangered because of habitat loss. At least 44 kinds of birds, as well as various native mammals, eat Russian Olives as winter hardy food. Given the prevalence the introduced trees now, and the dearth of the natives, many animals are now dependent on them. Spraying the trees with herbicides has not, and will not, change the fact the dams are responsible for the altered landscape, not the trees themselves.

At some point, do we recognize that the Tamarisk and the Russian Olive are de facto “native” even if they’re not de jure? For what it’s worth, all those birds have already cast their vote. Additionally, from a taxonomic perspective, hybridization among various introduced Tamarisk species have produced fertile offspring that may be declared a new species, Tamarix americana [reference]. Since this species is found only in the US, isn’t it “native” here?

Additionally, “novel” aspects might be temporary after the process of “succession” advances. “Succession” is a common ecological process in which the dominant flora of a landscape changes over time due in part to the ways that landscape is changed by the flora itself. So, after a disturbance—such as a landslide or the building of a road—the first wave of plants (which are sometimes called “pioneer species”) are often annuals that quickly fill the space. They will produce a profusion of flower that attract pollinators and seeds that feed animals. Such pioneers can be thorny, which is nature’s way of saying, “Keep out while I fix this!” A hallmark of this stage is the rebuilding fertility in the soil.

The annuals might be followed by shrubs, including berry bushes, which attract yet more animals, including birds. The scat left by these animals enriches the soil more. The bushes provide shelter for trees to germinate, and in time, the trees shade out the berries.

There are cases where disturbed landscapes “invaded” by non-native plants have been left untouched, and the exotics have ended up doing nothing more than fulfilling the role of pioneer species, and the area has returned to “natives” over time. So, when “invasives” are constantly beaten back in a given location, it’s possible that this interference is holding back the natural process of succession and ironically working against the intended goal of bringing back natives.

Novel ecosystems demonstrate nature’s inherent resilience. What we need to do is recognize them as ecologically legitimate and work with them from there. As time goes on, we’ll certainly have more opportunities.

Climate Change

According to National Geographic, “Half of All Species Are on the Move.” This is because, as the climate changes, so do ecosystems. With temperatures rising, species are moving further north or higher in elevation. As time goes on, this means that more and more species will migrate “outside their natural range” thereby becoming “non-native” or even—to some—“invasive.”

Those that can migrate, that is. Many plants will become, as wildtending guru Finisia Medrano used to say, “refugees without legs,” unable to flee fast enough and far enough to find safe haven. If that’s the case, then we must help them, Finisia repeatedly counseled.

The biologists call this “assisted migration” and it’s a topic that coming up more frequently as time goes on. Some of the strongest arguments against it come from the anti-“invasive” crowd, but many native plant lovers are in favor.

Does It Matter?

The term “native” can have utility; it tells you that a plant was well-adapted to a given place in a given time period because of the conditions that existed there then, and this can be helpful in understanding a species or an ecosystem. But it’s not an ancient, universal concept among all humans by any means, and ultimately it’s just a label of no account whatsoever to the big mover and shaker of life, Mother Nature.

Kollibri terre Sonnenblume

Malibu, California: A model for grassroots opposition to pesticides

“How could intelligent beings seek to control a few unwanted species by a method that contaminated the entire environment and brings the threat of disease and death even to their own kind?” – Rachel Carson

I am pleased to publish a guest article about a grassroots effort to reduce the use of pesticides in Malibu, California, a community of about 10,000 on the coast of Southern California.  Malibu is famous as the residence of Hollywood celebrities and executives and surfers attracted by 21 miles of beaches with world-class surfing conditions. 

City of Mallibu. Wikipedia – Creative Commons

The author, Kian Schulman, and her husband, Joel Schulman, are founding members of the Malibu-based nonprofit Poison Free Malibu, a group that has had much success protecting local wildlife, children and pets in the Santa Monica Mountains and throughout California by educating the public and policy makers about the dangers associated with pesticides.

I hope the impressive accomplishments of Poison Free Malibu will inspire readers to participate in such efforts in your community in 2025. 

Happy New Year!  Best wishes for a more peaceful 2025. 

Conservation Sense and Nonsense

Grassroots Power is a Strong Voice!

In the fight against harmful pesticides, the coastal community of Malibu, California is a model for the power of grassroots activism and persistent community engagement, which has significantly reduced the use of pesticides in Malibu. 

Chemical companies like Bayer (Monsanto), Dow, Syngenta, and others have expanded beyond agricultural markets, targeting “invasive” and “non-native” species in nature preserves with toxic pesticides. The Santa Monica Mountains surrounding Malibu are replete with “invasive species,” targets for eradication with herbicides, downplayed by claims of so-called Integrated Pest Management policies. 

The Santa Monica Mountains are wildfire prone. In December 2024, the Franklin Fire threatened the campus of Pepperdine University in Malibu, burned over 4,000 acres, multiple homes, and displaced many residents.  Various methods of fuels management are available, but herbicide is the primary tool because it is the cheapest method. I ask, “What is the price tag to our health and the entire ecosystem?”  

The Pesticide Problem

The impacts of pesticide exposure on our health are profound. Pesticide exposure has been linked to a rising tide of serious health problems, including cancer, Parkinson’s disease, diabetes, reproductive failures, developmental disorders, and autism. (1)

Pesticides and other chemicals can persist in soil for decades, contaminating soil and watersheds with toxic breakdown products.  In 2021, Scientific American published an article about a meta-analysis of nearly 400 studies that examined 275 soil organisms and 294 different pesticides. In 70% of those experiments, pesticides were found to harm the organisms that are critical to maintaining healthy soils.  Tens of thousands of subterranean species of invertebrates, nematodes, bacteria and fungi are filtering our water, recycling nutrients, and helping to regulate the planet’s temperature.  The EPA, which is responsible for approving chemicals for the market, is not presently required by law to test the effects of chemicals on the soil. 

The widespread use of these poisons are also harming wildlife. Rodent poisons used to kill small rodents don’t stop there.  Other non-target animals are often killed as well, either by eating the bait directly or eating the poisoned rodents.  Many top predators, such as mountain lions and bald eagles, have been killed by rodent poisons that work their way up the food chain. 

Market size of rodenticides in the US, 2014 to 2025 (in million US dollars)

Malibu’s Transformative Journey

In 2012, local activists began investigating the city’s pesticide use, discovering a shocking reality. Malibu’s parks and public spaces were being treated with a cocktail of toxic chemicals, including glyphosate (RoundUp), 2,4-D, triclopyr (Garlon), pre-emergents and others, often applied in areas where children and pets play.

RoundUp being sprayed in a Malibu public park while child cycles nearby.

Protecting Wildlife

Poison Free Malibu was activated in 2012, after a mountain lion was found dead in a local park with rodent poison detected in the autopsy.  Reducing rodent poison exposure has always been one of our primary objectives.  All top predators of rodents are at risk of rodent poisoning:  “The vast majority of bald and golden eagles in the United States are contaminated with toxic anticoagulant rodenticides…” (2) 

Poison Free Malibu addressed this issue in a variety of ways:

  • We asked local businesses selling rodent poisons to quit selling them.  No stores in Malibu now sell rodent poisons.
  • We asked businesses and organizations to remove bait boxes from their premises. 
  • We approached 10 neighboring cities to suggest that they pass resolutions banning the use of rodent poisons in their communities.  Animals are on the move, so broader protections are needed for them.
  • We helped pass three state bills to prohibit the use of 3 specific rodent poisons in California.  Unfortunately, these laws have exceptions, including one for using rodent poisons on off-shore islands to kill rodents. The pesticide industry was quick to respond to the new restrictions by promoting other, still allowed but extremely dangerous rodent poisons such as bromethalin and cholecalciferol.  Both of these have NO antidote, endangering wildlife and pets. According to the National Park Service, bromethalin was detected in 10 out of 16 mountain lions tested in the Santa Monica Mountains from July 2020 to August 2022.
  • We helped to pass a Dumpster Lid Lock Ordinance in Malibu.  In both commercial and residential areas, this ordinance was key to eliminating rodent issues.

Changing Public Policy

As we learned about the extensive use of a wide range of pesticides in Malibu it became clear that a broader effort was needed.  We petitioned our city for an Earth Friendly Management Policy, which bans the use of all toxic chemical pesticides in EPA 1, 2, and 3 categories of toxicity.  The city now relies on organic solutions, environmental enrichment, and “Expel, Deter, and Repel” tactics.

There is a National Park and a State Park in Malibu that also use pesticides on our public lands.  We had to negotiate directly with those organizations that are not subject to our city policies.  Following numerous meetings with State and National officials, we reached an agreement to establish hand weed-pulling events. This initiative has proven highly successful.

Public Education

The support of the public is needed to achieve changes in public policy.  Educating the public about the dangers of pesticides is therefore an important part of our strategy:

  • We reached out to school systems, other local cities, and counties, to bring these issues to their attention. Many have adopted pesticide-free policies, most recently Ojai just on December 10, 2024.
  • We received grants from our city and county to help us with our outreach efforts, such as developing coloring books, distributing hundreds of yard signs, and putting up billboards throughout Los Angeles.

Not the end of the story

Despite these many important accomplishments, our work is never done.  Legislative hurdles to our progress exist because of opposition from various government agencies, such as the Wildlife Conservation Board, the Department of Pesticide Regulation, the Environmental Protection Agency, CalTrans, and the California Department of Food and Agriculture.  There is regrettable opposition from many non-profit organizations that champion the use of pesticides to kill so-called “invasive” species, such as the California Invasive Plant Council and the American Chemistry Council, a trade association representing manufacturers of chemicals.

Our work is never done, but the grassroots movement in Malibu proves that collective action can transform seemingly insurmountable challenges into opportunities for positive change.

Kian Schulman, RN, MSN
Director, Poison Free Malibu
Contact: PoisonFreeMalibu@gmail.com | 310-456-0654
Website: PoisonFreeMalibu.org

(1) “Wide Range of Diseases Linked with Pesticides,” Pesticides and You, Summer 2010

(2) https://beyondpesticides.org/dailynewsblog/2021/04/study-finds-eagle-populations-experiencing-widespread-rodenticide-exposure/

Invasion Biology: “We can do whatever we want”

Macaylla Silver discovered Conservation Sense and Nonsense on Facebook.  We instantly recognized one another as kindred spirits, battle scarred by our attempts to protect nature from pointless destruction in service of the ideology of invasion biology and the native plant movement it spawned. 

When confronted with the destruction of wild places we love, our reaction was very similar, and responses to our efforts were also similar.  First we turned to public policy for protection:  Are they really allowed to poison our public lands with pesticides to destroy harmless plants? With a few targeted “exceptions” to policy, the answer was always, “We can do whatever we want.”

Then we both decided the best course of action was to become experts about the “science” that is used to justify destroying harmless vegetation with herbicides.  And so, we took to the books and armed ourselves with the science that refutes invasion biology.  Once again, we hit the brick wall of “We can do whatever we want.”

And there Macaylla’s experience as an activist diverges with mine.  He has successfully stopped the poisoning of Leverett Pond (for the time being) by showing the neighbors of Leverett Pond with videos, the consequences of poisoning the pond. 

However, he concludes his story with the astute observation that stopping the destruction of Leverett Pond is unlikely to be the end of the story.  Life in the pond will continue to evolve, as it must.  As long as people continue to believe that evolution must be stopped, the futile attempt to prevent change will continue. Macaylla is hopeful that mistaken belief will fade.  I hope he is right.

We thank Macaylla for his efforts.  We wish him luck in preventing more herbicide applications in Leverett Pond.

Conservation Sense and Nonsense

“Let the Pond Be a Pond”

Massachusetts Wetlands Protection Act was created for the protection of the state’s wetlands. The goals of the law are to prevent pollution, maintain habitats for plants and wildlife, and protect groundwater, public and private water supplies.

Our Town Bylaws in Leverett, Massachusetts also included a ban on the use of herbicides for any use outside of domestic and agricultural use since 1973.

There are five colleges in the area. The town is filled with highly educated academics and retired academics. Leverett is quite ecologically minded in my opinion, this hill town of 2,000 people.

Leverett Pond, circa 1860-1880, Erastus Salisbury Field.  Public domain.

One day back in 2018, I found that the large body of water at the town’s center, Leverett Pond, was under ecological attack. Somehow, some way, a handful of land abutters on the shallow side of the pond were trying to rid the pond of “noxious weeds.”  This included floating leaved Waterlilies and Watershield, plants such as rootless carnivorous plants like Bladderworts, submerged weeds like Coontail, Waterweed and Milfoils.  Even Cattails and other plants growing on the pond’s edges were considered for removal.

Act One:  Isn’t there a law against this?


I thought I could stop this. I thought once the town’s people knew what was happening they would be outraged. I thought the state would step in, prevent the further destruction and maybe even fine the people who were poisoning the area and dredging large sections, all so they could in their words “have crystal clear water to look at.”

I thought it would be easy.  I have never been so wrong in my life. 

It was five years of continual meetings, letter writing, publishing newspaper letters and articles, and a large portion of the town thinking that somehow I was just trying to cause trouble. Or maybe they didn’t think I knew what I was talking about. Sure, I saw the destruction, but I was misinformed. They believed in their intent and factual details of why they were on a campaign of eradication.

The details of destruction used to convince the town’s Conservation Commission, Select Board, and state agencies came from two retired professors, neither with a degree in Environmental Ecology. Their plan contained the curveball of being designed to show off knowledge of several obscure subjects unknown to nearly everyone:

1.Limnology: The science of fresh water systems
2.Pesticides and their application to aquatic environments
3.The botany and identification of aquatic plants

Act Two:  Countering Pseudoscience with Science


While the wordsmithing of the two PHDs had merit and flow, my own research quickly showed that they had only a surface understanding of subjects.  In order to counter their statements and proposals, I decided that I would deeply learn all I could about limnology, pesticides and the life of aquatic plants. I would become an expert, the old fashion way: I would purchase books. Lots of them. I read extensive science based articles on pesticide families, collecting hard data and staying away from anything that was too opinionated. 

People began to realize that I knew more than expected, so much more that it was easy to forget that the vocabulary was rarely understood. I presented myself on equal footing with proponents of the project.  I asked the community and its policy makers to consider that dumping herbicide on the pond might not be the best thing, creating aporia, lingering doubts that this handful of lakefront owners may have hidden motives.

Act Three:  Invasion Biology at Work

Then came the videos. I purchased two kayaks, an underwater camera, and I used cameras I had purchased for bird photography. The videos contrasted the “before and after” of the years of degradation in 2019, 2020 and 2022. The videos got the state involved.   The state permits for dredging that the project applied for in 2010 were never received. This meant that the project had to reapply for permits for any further work after 2020. 

Up to this point, I thought I was fighting against ignorance and arrogance from a few landowners who came late to the pond’s available real estate and bought lots that were undesirable because of their shallowness and large amounts of aquatic flora and fauna. I would have been in heaven if I bought such an area, but they looked to “improve it.”  So they had set out to “manage” the water’s surface.

The two professors contacted a professional who specialized in finding ways around what was allowed by the Wetlands Protection Act. Leverett’s Conservation Commission reviewed the law and found that there were no ways around the law because the plant abundance, oxygen levels and fish life were all healthy, vibrant. Graphs, data, reams of older regurgitated documentation pointed to the same conclusion I had reached: Let the pond be a pond.

To show the reason why no further “management” permits would be issued to continue the project, the head of the Conservation Commission submitted his own reason: the project violated Town Bylaws. Clearly. 

Then it happened. Three members of the Conservation Commission had what I thought were very strange ideas about conservation.  One had a pesticide license. One looked at the pond for recreation purposes rather than an interest in environmental issues. Another felt strongly about eradicating plants that they couldn’t identify if asked.  One said, in defense of using pesticides, the blithe motto “If you can choose it, you can use it,” while the other two nodded in agreement. “We have to stop the growth of these plants before they destroy the pond. It will reach a tipping point where there will be no return,” said one, with great conviction.  “It could in the future make the fishery less healthy,” said another, without a shred of data.  I had no idea why such people would be put on such a Commission. 

The Conservation Commission voted three to two to allow the project to continue for another five years. The state admonished but did not intervene. I had been angry at the professors and their allies for their lack of concern. Now the Conservation Commission had let me, and the pond, down.

The decision of the Conservation Commission gave the pond abutters cover, so they could remove all the plants they wanted. The Commission gave herbicide sprayers a welcome mat in Leverett to earn big money for the applicators and companies that make a variety of toxins.

The decision gave the Conservation Commission, not its local intended use, protecting wetlands and freshwater, but a zealous conviction that they were acting on a world saving mission.  It was Invasion Biology at work, masquerading as “restoration,” AKA the “native plant movement.” Invaders needed to be destroyed, regardless of recklessness, collateral damage, complete destruction.

So destroying acres of plant life, to get at one plant, that is okay now.  They were Crusaders with a capital “C.” And like all crusades…it rarely ends well.

Act Four:  Pictures are worth thousands of words

In 2022, the herbicide sprayers came back, on a very windy day, on an airboat. It appeared that the targeted areas were being sprayed, yet large amounts were misted and blowing in the air as the airboat itself churned the water’s surface. It was, in a word, sloppy.

From my kayak, I videoed the spraying of the pond with herbicides from an air boat: the before, during, and the after of floating masses of dead vegetation. I got the resulting video shown to many. It had few words, an eerie soundtrack that suited the unreal transformation, from living beauty to full degradation, death and decay.  (see below)

Leverett Pond after herbicide spraying in 2022. Entire video available HERE.

For the next year, and the next they stopped spraying. Sure, they hired an aquatic harvester to clean around the area of their docks, but that was it.

In 2024, the promoters of the deadly project were apologetic. They promised that “no herbicides” would be used. Even an attempt to hand pull marginal plants failed.

The pond will continue to respond to changing climate conditions, as it must.  Plants are likely to return and the fear-mongers are likely to demand their destruction again.

Fear of so-called “invasive species” is being used as an excuse to use herbicides in the futile attempt to freeze ecosystems that replicate historical landscapes.  As climate conditions continue to change, the fantasy that humans can prevent evolution is likely to fade.   Perhaps the restoration movement will begin to realize the folly of trying to sort plants and animals into two simplistic groups:  native vs. non-native.

As Charles Mackay said in a book written in 1841, ” Men, it is said, think in herds; it will be seen that they go mad in herds, while they only recover their senses slowly, one by one.”

Macaylla Silver
Leverett, Massachusetts
Contact:  artargentia@gmail.com

Nature’s Best Hope? Nope!

On November 16, 2024 I attended a conference at the Oakland Museum of California, where I live, sponsored by Bringing Back the Natives Garden Tour and featuring Doug Tallamy as the key note speaker.  The conference was sold out.  Two hundred enthusiastic native plant gardeners attended the conference.  Although a native Coast Live Oak is the crown jewel in my garden, I don’t consider myself a native plant advocate.  I listened quietly.

I have heard Doug Tallamy speak several times and I have read his books, so there were few surprises in his talk, except for this slide:

The cited study for this slide was published by Matthew Forister (and others).  Professor Forister is an academic entomologist who is a specialist in lepidoptera (moths and butterflies).  I have read several of Forister’s studies and I respect his research, so I was surprised that he would reach the conclusion claimed on Tallamy’s slide. 

I read the study (available HERE) and I was unable to find a conclusion in the study that was consistent with Tallamy’s interpretation of it.  Hmmmm, I said to myself, does Tallamy’s slide accurately represent Forister’s study? 

I asked Claude.ai to compare the study with Tallamy’s brief summary of the study.  Claude’s response was: 

“After carefully reviewing both the original study and Professor Tallamy’s summary slide, I find that his statement represents a somewhat oversimplified interpretation of the study’s findings…While Professor Tallamy’s statement captures the general spirit of the research – that most insect herbivores are specialists – it appears to be a simplified interpretation that makes stronger and more specific claims than what’s directly supported by the study’s data. The “90%” figure and the explicit connection to evolutionary history, while perhaps derived from other research, aren’t directly demonstrated in this particular study.”

Forister’s study found a continuous distribution between specialists and generalists, not a strict dichotomy, as Tallamy’s slide claims.  For example, an insect that is confined to plants in a genus is more specialized than an insect that is confined to a plant family.  Insects that are confined to a single plant species are extremely rare because they are often an evolutionary dead end. 

Professor Forister’s study is interesting.  It found that dietary specialization of insects varies by latitude and that specialization is greatest near the equator, where diversity of plant species is greatest, creating more opportunities for ecological niches in which specialized insects can find what they need with less competition.   

The same principle applies in the temperate zone, where we live.  That is, greater diversity creates more opportunities for insects to find what they need.  The scientific definition of biodiversity includes both native and non-native species.

The relationship between plant species in the Apiaceae family and the anise swallowtail butterfly evolved in the distant past, eons before individual members of the family evolved into different genera and species.  The association between an insect and its host plant is chemical rather than being a connection to a specific plant species.  In other words, anise swallowtail butterflies co-evolved with fennel. 

Likewise, monarch butterflies co-evolved with tropical milkweed, which is native to Mexico and Central America.  Both tropical milkweed and local native plants in the same genus contain the chemical that monarchs seek, a chemical that renders it unappealing to its predators because it makes them sick.  Again, this similarity is fortunate because tropical milkweed is evergreen and local natives are deciduous, making it available for monarchs to breed in winter months in a warming climate. Winter breeding of monarchs is recent and may not benefit the monarch population because fewer food sources are available in winter months. (2)

With the help of genetics, we can understand why individual members of a family of plants are closely related.  Plants and animals with a common ancestor are dispersed around the globe in a variety of ways, of which many are natural and long precede the advent of humans around 300,000 years ago.  Plants are carried by ocean currents, rivers, wind, storms, birds, animals, etc. 

When plants arrive in a new home, they quickly begin to change, partly because of random genetic drift and partly because they respond and adapt to the specific environment in which they have landed.  Over time, the change in the plant becomes great enough to be considered a new species, but its chemical properties remain similar to its ancestors in most cases.  Exceptions abound because nature is complex and our understanding is limited.

Why does it matter?

I attended this conference because native plant advocates are unhappy about Oakland’s Urban Forest Plan.  I support the plan because it will improve Oakland’s urban forest by addressing hazardous tree conditions, expanding the forest with diverse tree species, and more equitably distributing Oakland’s forest resources to neighborhoods that have been short-changed in the past.  I expected the plan to be discussed at the conference.  It was.

Native plant advocates want Oakland to plant more native trees and fewer non-native trees.  Opinions vary, of course, but some want a forest of exclusively native trees because of their belief that native trees support wildlife and non-native trees are not useful to wildlife.  There are many reasons why a diverse urban forest best serves Oakland and every animal that lives here:

  • The pre-settlement vegetation of Oakland was 98% grass, shrub, and marshland.(1) There were only 10 species of trees that are native to Oakland:  coast live oak, bay laurel, coast redwood, madrone, big leaf maple, holly leaf cherry, toyon, willow, buckeye, redbud.  There are now over 500 tree species in Oakland.
  • The goal of the Urban Forest Plan is to increase the population of street trees.  Most of the trees that are native to Oakland are not suitable as street trees.  Some are too big.  Some are shrubs rather than trees.  The branching habit of some native trees are too low to be street trees, which must not obstruct sidewalks or streets. 
  • Some shrubs can be pruned into trees, but that would be very costly and Oakland is broke!  A shrub that has been severely pruned into a tree is not stable.
  • Growing conditions where trees are needed in Oakland are often not suitable for native trees. That’s why they didn’t grow there prior to settlement.  Oakland’s urban forest is predominantly non-native because they are adapted to our growing conditions.
  • Climate change requires a diverse urban forest because a more diverse forest is more resilient.  Sudden Oak Death has killed millions of oaks throughout California for the past 25 years. We can’t predict which tree species will survive the warming climate.  Therefore, we must hedge our bets by planting a diverse forest.

As expected, the first question the audience asked of Doug Tallamy was why Oakland Tree Services is telling native plant advocates that Oakland can’t plant exclusively native trees because they aren’t adapted to the challenging conditions that street trees face.  Doug Tallamy replied that Oakland’s Tree Services is mistaken.  He showed this slide of the many native alternatives that he believed would be suitable street trees:

This list is predominantly shrubs.  Some are not native to Oakland.  Some plants native to Oakland are missing from the list. At least one—Himalayan blackberry—is a notorious invasive non-native that most public land managers have been trying to eradicate for decades.  Himalayan blackberry is, however, an extremely useful plant for wildlife.  The list is a mixed bag, but it won’t create an urban forest.  

Update:  The Public Works & Transportation Committee of the City of Oakland approved the Urban Forest Plan for Oakland today, December 10, 2024.  Eleven people spoke in support of the plan.  No one spoke against the plan.  

Dan Kalb, City Council representative for District 1, asked why Oakland is planting non-native trees, which he claimed are breaking sidewalks and destroying the foundations of people’s homes by sending their roots into their yards.  David Moore, the head of Tree Services, handled these questions well and Kalb did not pursue the issue further. No speaker objected to non-native trees in Oakland.  

I have a native Coast Live Oak in my front yard, which damaged the foundation of my home, destabilizing the house and doing extensive damage inside the house.  To save the tree, we had to repair the foundation by suspending the new foundation over the roots from two steel-reinforced piers that are 10 feet deep at each end of the foundation.  In other words, although there is some variation in the configuration of tree roots, the variation is unrelated to the national origin of the tree species. 

Given the budget deficit in Oakland, it was necessary to reduce the goal of the plan to maintain the tree canopy rather than increase it.  No one objected to that change in the goal.  We all understood that the change was necessary.

On the bright side

I enjoyed two presentations by native plant gardeners who transformed their yards from barren places into lovely native plant gardens.  One started her project by digging up concrete covering her back yard.  The other began by digging up a front lawn.  Of course, their new gardens are an improvement over their predecessors.  They are more beautiful and they serve more wildlife. 

However, would these new gardens be even more beautiful and useful to wildlife if they were more diverse?  Would they be more resilient as the climate continues to change in unpredictable ways?  Maybe.

Thankfully, there was little talk of destruction in either of these inspiring presentations.  One exception was an anecdote about the visit of a native plant advocate to the garden of a fellow gardener.  The gardener asked his visitor where agapanthus in his garden is from.  When told it was from South Africa, he promptly pulled it out of the ground. The audience was very amused by the story.

When traveling in distant places, I don’t want to know which plants are native.  Don’t ask, don’t tell.  It’s a pleasant break from the “good” plant, “bad” plant dichotomy. 

Tallamy advised against using insecticide, but he made no mention of using herbicides. 

I have no quarrel with these gardeners.  I firmly believe that everyone should be free to plant whatever they wish in their gardens.  I respect everyone’s plant preferences and I ask that they respect mine. 

However, our public parks and open spaces belong to everyone and our tax dollars are used to maintain them.  I ask only that public land managers quit destroying healthy trees and landscapes, especially with herbicides. 

(1) David Nowak, “Historical vegetation change in Oakland and its implications for urban forest management,”  Journal of Arboriculture, September 1993

(2) Professor Emeritus Arthur Shapiro sent the following “qualifiers” in an email.  The article has been revised accordingly.  “…a couple of qualifiers. First, zelicaon cannot breed all year because it has a seasonal pupal diapause (dormancy) in winter which is photoperiod—T mediated. Its native wetland hosts (Cicuta and Oenanthe) support breeding March-October. It is unclear that it had any native hosts at all in upland, dry habitats. It was probably a tule marsh species in pre-European CA (below about 4000′), just as its close relative machaon is a fenland species in the U.K. Second, monarchs didn’t breed in winter until recently, again because of photoperiod-T induced reproductive (adult) diapause. Tropical milkweed has been cultivated in CA for well over a century but was not bred on in winter, even in SoCal. I hypothesize that warming T is responsible for the change. It is NOT advantageous to breed in winter. Because curassavica is the only plant available, it gets reused over and over again and becomes contaminated with high levels of an infectious protozoan parasite that causes significant morbidity and mortality. The butterfly might be better off if it didn’t try to breed in winter.” November 21, 2024.