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  • Writer's pictureCalyx

The Discord of Invasion Ecology

The noble pursuit of conservation. We have been led to believe that without it, extractivism would destroy the precious landscapes that both inspire and sustain us as a species. In a time when the natural world seems to be being ruthlessly eroded, it is remittable to want to cling to what established safeguards we have in place. But is this narrative true?

The taproot of the modern field of conservation is colonialism. The false binaries that pervade our western worldview create conflict in every part of our lives. Spending your days training your eye to see what is directly in front of you, and not what you think you see, is a good way to instill the patience and humility needed to understand how these issues affect the field. Plants and people are inextricably tied to one another, and the mirror presented in the world of plants is not merely a metaphor for which we can judge our own human strife, but a very real and tangible set of issues that we cannot as a species survive without addressing.

Scientists pride themselves on being very factual and uninfluenced by emotion or anthropomorphism. But when it comes to conservation biology, and more specifically, invasion biology, the tables turn. The rhetoric takes on a very emotive tone, rife with wartime hyperbole. These emotions have their place, but it is not in the delineation of scientific research. This emotional articulation is not merely a byproduct of scientists passionate about their work - this type of language (and subsequent action) is a direct product of the foundation of invasion biology. What I mean to say is, this is not an error, it is the premise on which invasion biology was founded. And if it doesn’t seem very scientific, it’s because it isn’t. The vilification of plant species often has more to do with propaganda and regional folklore than it does science.

We think invasion biology is based on scientifically established data and baselines. We have been taught to equate “native” with good, benevolent, increased biodiversity, and “invasive” as bad, malevolent, decreased biodiversity. But this simply is not the case. The issue of invasive species is a complex one, but this makes it all the more important for us to study. It is a direct window into the many downfalls of western culture; the harms of binary, the dangers of imperialism, the frivolousness of static thinking, the way that capitalism dictates policy and action, the readily accepted biases that exist in scientific research, and so much more.

So let’s observe a few examples as we try to untangle the subjective and convoluted morass that is invasion biology.

The American Chestnut Tree Castanea dentata

How do we define a native species? How far back must we go before we ascertain a species’ native status? It is generally accepted by the scientific and governmental establishment that a native plant is one that has existed and co-evolved in a specific environment for hundreds to thousands of years. However, it is also asserted that only plants found in the United States prior to European colonization may be considered native to the U.S. Some also suggest that a native plant is one that exists in a particular region through non-human introduction of any kind. Plants that are non-native but aren’t injurious to the ecological balance of its introduced zone may become “naturalized,” but never “native.” This presents a myriad of problems including gross inaccuracies in the botanical record pre-colonization, issues with restoration attempts focusing on a vague and imaginary static period of time before settlement, as well as the problem that we’ve made it impossible for nativization to occur from henceforth (which might seem like semantics to some, but given how our perception is influenced and often built around language, especially in the context of science, we must tread carefully with our terminology and aim be as precise as possible with it).

The American chestnut is one of the most beloved native species on the East Coast. Let’s take a look at how it got there, and how it achieved its revered (and native) status.

If we look at the pollen record for the post-glacial period starting from about 20,000 years ago, the trees that began to move into the northeast and cover the landscape included Ash, Oak, Birch, and Ironwood arrived first. Maples moved in shortly thereafter, followed by Beech, and then Hickory at around 8,000-6,000 years ago. As the climate and habitat continued to change, the last major tree appeared, around 2,000 years ago: the American chestnut. The tree thrived and soon made up a substantial portion of the canopy. While some debate exists about how much of the population it made up (ranging from 3% to 25% on average, with some landscapes reaching upwards of 45% dominance [areas, I hypothesize, where indigenous populations stewarded their stands]), there is no debate about the profundity of the tree. 1

According to the American Chestnut Foundation:

“The American chestnut, Castanea dentata, once dominated the forests of the eastern half of the United States and southern Ontario, Canada. Numbering nearly four billion, the tree was among the largest, tallest, and fastest-growing in these forests. Because it could grow so rapidly and attain huge sizes, the American chestnut was often an outstanding feature in both urban and rural landscapes.” 2
Backcrossed American-Chinese Hybrid at the Connecticut Experimental Agricultural Station | Photo: J. Tignor

It was a tree valued for its strong and rot-resistant wood and as an incredibly abundant food producer for humans, wildlife, and livestock. When the chestnut blight Cryphonectria parasitica, a parasitic fungus native to East Asia, came and by the 1940s the American chestnut population had been reduced to “technical extinction,” as the American Chestnut Foundation puts it. The giant trees could readily grow over 100 feet tall with trunks 10 feet in diameter now can hardly make it past shrub status. The restoration efforts for this species primarily involve hybridization with the Chinese chestnut Castanea mollissima in order to create a genetically stronger, blight resistant chestnut tree. After 30 years of breeding, this effort has been relatively successful. 3

It is difficult to follow this summarization of the history of the American chestnut while ascribing to the strict definitions set out by invasion and conservation biologists without scratching your head. Under the modern definitions, imagine if a tree species moved from the south into our north eastern forests and spread so vigorously as to make up nearly 25% of tree populations of many forested regions. Would we not call it an “invasive species?” Well, it takes a long time for a species to move into an area and coevolve with the other species there in a way that is mutually beneficial (this may be true, but evidence is now demonstrating it may not always take as much time as we thought). So, how then is this different from any other aggressive non-native species we encounter today? If we give it enough time, who's to say it won’t naturalize, just at a different rate than say, dandelions?

This is what happens when you separate invasion biology from succession ecology. Succession ecologists are in it for the long haul: they are flipping through hundreds to millions of years to understand the dynamics of how ecosystems change and develop. Camels were originally inhabitants of North America, and were relatively recently introduced to the Middle East. If one tries to ask the question of where camels are native to now, and if they were reintroduced to North America today after a 13 thousand year gap would they be considered native, you’d likely get a myriad of answers.

If you're looking for an interesting case study on how cultural bias and colonization affects the answers to these types of questions, just take a look at the history of native horses on Turtle Island. Yes, native horses. Didn't think horses were native to North America? That's because the story of native horses was erased and rewritten from the colonial perspective. It has been a commonly accepted belief that horses were present in North America but went extinct during the last ice age. If you learned about the relationship of Indigenous Americans and horses in school, you were probably taught that this relationship began when the Spanish brought horses to the North American continent in the early 16th century. Neither of these statements are true. 4 The most recent evidence, which has long been corroborated by indigenous accounts, proves that horses did in fact survive the last ice age, and continued to be a presence in Indigenous culture in North America through first contact. However, the myth that horses are not "native" to this part of the world, or at least no longer are, continues to be perpetuated not only in modern education systems, but within academia as well as within the structures that manage the lands of the American west where these horses are today, namely the Bureau of Land Management. The BLM is appointed with the responsibility of maintaining a "thriving natural ecological balance on public lands." The Wild Horse and Burro Program has been mismanaged for decades 4, partially due to complete lack reliance of scientific analysis, as well as serious conflicts of interest in rangeland with cattle ranchers, but also due to the fact that horses are still viewed as an "invasive species" (in contrast with the actually non-native cattle that take up the vast majority of BLM rangelands - more on this distinction in the next section).

Most people, and certainly most invasion biologists, have a difficult time grasping the span of deep time (the timescale of geologic events). This is partially because we are, at least in western culture, driven largely by instant gratification, with a long-term focus of one or two generations at the most. This scope of time is also the focus of industrial practices, and the reason perpetual growth, not sustainability, has been the primary focus in the capitalist agenda, and it’s role in cultural conditioning is in large part to blame for the general population's lack of foresight. Right now we are living in a time when we have to make changes quickly in the face of climate change. We need to make decisions that will impact our immediate future. But are we making the correct ones, and are we looking far enough back in time (for example, to the most recent major climate shift) to understand what processes are occurring and are about to occur, so that we can be best equipped to cope?

If we move on and just accept that the American chestnut is indeed a native species, why are we hybridizing it with a non-native species? Does that not negate the entire premise of something needing to be native to be valuable? We are trying our darndest to preserve the American chestnut, even if that means making it less “American,” because it is a superbly valuable species- but moreover one that we have a historical relationship with. If you look closely, you will see examples of the cultural bias around labeling species as either native, naturalized, or invasive over and over again. In the end, though, the American Chestnut provides us with a tasty morsel of what the science and practice looks like when we cast the constructs of native and non-native aside and shift our focus to ecologically sound practices.

Wheat, Soy, & Corn

So, how do we define naturalized or invasive species, exactly?

This is a task that has never been accomplished with much precision, however the 1999 National Invasive Species Act produced these terms: “An invasive species is defined as a species that is 1) non-native (or alien) to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” 5

If we take corn, wheat, and soy into the equation, can we classify these as invasive species? If we don’t, why not?

The definition laid out by the Invasive Species Act is essentially asking the question: did introduced plants do what we wanted them to do? In the case of corn, wheat, and soy, none of these are native. They are responsible for ecological damage on a catastrophic scale. These are massive monocultures with little to no biodiversity (any biodiversity that does sneak in is quickly eradicated by herbicides and pesticides, which cause their own array of ecological harm in the soil and downstream). 97% of the native grasslands, one of our most rich and diverse ecosystems, in the U.S. have been replaced by these croplands. The primary reason why these three plants are not labeled as invasive is because “invasive” is culturally and institutionally defined, more so than it is scientifically.

The secondary reason why these crops are not labeled as invasive, is that most invasion biologists will add the adjunct to the definition that the species must be able to adapt and spread quickly. 6 This is predicated on the idea that invasive species spread more aggressively than native species. The science tells us that the seeds of non-native species spread at the same rate as native species, but germination and survival rates are what differ, which has more to do with conditions that allow for non-native species to thrive as opposed to native species (more on this later). Without humans, crops like wheat, corn, and soy would not cover so much of the land. But to make the statement that this means they are not inherently invasive categorically separates us from the equation. It divides humans, “us,” from ecology, “them.” But we are not separate: we are not only a part of the ecosystem but a keystone species within it. We disperse the seeds of corn, wheat, and soy, creating vast monocultures, just as other animals do, like birds spreading the seeds of Callery Pears. So while these crops may not be “invasive” in and of themselves given this definition, they do not exist in a vacuum. They were born out of human intervention and continue to exist alongside it. If the solution was as simple as saying “well, if we just stopped growing them, they’d just fizzle out on their own,” then I must ask the question, why don’t we? It is not simple in a land where economics and institutions dominate.

So while wheat goes on being defended as an exception to their rules, Starlings, on the other hand, are vilified as invasive “pests” because they consume large amounts of grain in crop and cattle lands 7. This threat to the economically valuable (but ecological destructive) industries is usually cited along with the claim that Starlings displace and threaten native bird species, but research has shown no correlation with the decline in native birds with the presence of starlings, and many of the native birds which they affect have already successfully adapted to the starling’s presence by changing their nesting behaviors. 8 Starling population numbers have begun to decrease over recent years, likely indicating a natural “evening-out” phase of their introduction or that they are being afflicted by the same things that are reducing native bird populations.

European Starlings | Photo: J. Tignor

The Lawn

The idyllic American lawn… pure, symmetrical, manicured… representative of the American dream. Originating from the southern English estate style landscaping that plantation estates were modeled after, perfectly manicured lawns were a status statement of aristocracy. They made the statement, “I am so wealthy, I can occupy this valuable land without growing an ounce of food on it.” Or as ethnobotanist Jonathon Robinson so eloquently puts it, “The lawn is an act of conquest.” The lawn is a symbol of colonization and of private property ownership, which are both subjects deeply interlinked with the topic at hand (an article for another time).

After World War II, an increase in private land ownership in America from suburban development combined with rapidly increasing production and application of chemical herbicides and fertilizers (a direct product of the military industrial complex) meant lawns were becoming more commonplace and more manicured. Lawns have become such a deeply culturally conditioned status symbol, that it is written into zoning laws and HOA bylaws that homeowners are required to maintain them to certain standards, and anyone letting biodiversity slip in can get fined (not to mention shamed by neighbors for not upholding their moral imperative).

The American lawn is a biodiversity wasteland. It is, if there ever was one, the definition of an invasive species monoculture. Look at the top five most common lawn grasses: Kentucky Bluegrass is not native to Kentucky, rather Europe, Asia, and Africa. Tall and Fine Fescue are native to Europe. Bermudagrass is native to eastern Africa. Perennial ryegrass is native to Europe, central Asia, the Middle East, and Africa. The most hated lawn weeds? White clover, dandelion, thistle, ground ivy, violets, smartweed, sorrel, deadnettle, chickweed. None of these are native either, but comparatively which ones provide more ecological benefits? How about human benefits? PennState Extension has numerous articles with instructions on how to control these pesky "weeds," primarily using herbicides like 2,4-D, triclopyr, dicamba, and several others. 9

Americans now spend over $30 billion annually to maintain these biodiversity wastelands. The same companies who manufacture the chemicals that help landowners eradicate every last terribly invasive dandelion, like Monsanto and Dow AgroSciences, are the same ones who are lobbying and influencing the restoration practices executed by agencies like The Nature Conservancy, The US Fish and Wildlife Service, the Bureau of Land Management, the National Audubon Society, the Invasive Species Advisory Committee, and many others. 10 It is no coincidence that these particular conservation organizations have taken the stance that ecologically damaging herbicides are frequently the superior method for controlling invasive species.

Purple loosestrife Lythrum salicaria

Purple Loosestrife

“A threat? In a harmless-looking plant with pretty purple flowers? Yes. Purple loosetrife's beauty is deceptive: it is killing our nation's wetlands. A wetland with lots of purple loosestrife is soon a wetland with little wildlife. Growing in dense thickets, loosestrife crowds out native plants that wildlife use for food, nesting, and hiding places, while having little or no value for wildlife itself.”

This is an excerpt from Penn State University Extension’s website. 11 But as it turns out Purple loosetrife’s standing as one of the most invasive plants in North America is not actually backed by science, but rather conjecture that was run away with by the media. Purple loosestrife has relatively minimal impact on the ecosystems where it resides, and the areas where it does form larger colonies tend to be areas with significant and harmful anthropogenic disturbance. 12 This is true of all invasive species: they enter the ecosystem and take hold in regions where the conditions are primed for them to do so, most often where anthropogenic harm has occurred.

Again, is loosestrife the problem, or a symptom of it?

Purple loosestrife does in fact provide a great deal of value to wildlife, but perhaps not in the way one might expect. While it is much appreciated by butterflies and other insect pollinators, loosetrife’s primary gift to wildlife is that it is a bioremediator that updates and detoxifies Polychlorinated biphenyls (PCBs) 13, endocrine disruptors that wreak havoc on both floral and faunal health.

As we race toward a future of highly polluted waterways, where plastics have infiltrated every artery on earth, bioremediation might become one of our most valuable types of ecosystem services. Though, it is certainly not the only one provided by non-native plants. It is easy enough to simply sweep ecosystem services (though I must say, as a citizen scientist endeavoring to decolonize myself how I do loath that term) under the rug, it isn't always practical. This is again evident in the case of non-native honeysuckles. The sale of non-native Lonicera species were banned in 25 states after they were deemed invasive by the USDA. In 2011, the University of Pennsylvania conducted a study illustrating that non-native honeysuckles were a key factor in supporting communities of native bird populations and biodiversity, which ironically, as it turns out, was the original purpose for why the honeysuckle species were introduced into the area in the beginning. 14 There are numerous studies that indicate that non-native species provide habitat and food for wild birds. In some cases, the removal of non-native species has caused bird populations to plummet because of the loss of nesting sites. Climate change is altering the timing of migratory birds, causing them to interact with more northern regions later into the season. Many non-native species fruit later in the in the season than native species, providing food in areas that would otherwise be slim-pickings. Most studies indicate that birds do not discriminate between native or non-native forage options. Many species deemed invasive are highly problematic due to their dispersal by birds, so to suggest they are not a wildlife food source is contradictory. 15 Multiflora rose, non-native Honeysuckles, Autumn olive, Chinese privet, Oriental bittersweet, Porcelainberry, English Ivy, and Callery pear are known for being favored by the birds and thus dispersed widely.

There is also the concern also that non-native fruits frequented by birds are much higher in carbohydrates and contain far less fat compared to native fruits. It is potentially of concern to see such a rapid shift in macronutrient selection, and it is unclear how this will effect the vitality of birds in the near future. There is evidence, however, that migratory birds increase their fat reserves more quickly by feeding on carbs than they do by feeding in fats. 16 It is possible that these birds will quickly adapt to their new diets. And make no mistake- this is their new diet, because even if we increase the abundance of native species, if they aren't fruiting late enough into the season, the birds will be looking for food elsewhere. Increasing temperatures may extend the fruiting period of some native species, but no amount of climate change will change the photoperiod that affects phenology. It is possible that in an effort to protect wild birds by eradicating non-natives, we are eliminating the food sources they need to adapt to their new migratory patterns. It is also important that we stop repeating the fallacy that invasive species are the reason why native species are in decline. Keeping in mind that it is habitat loss, not invasive species, that is the greatest threat to biodiversity, but more importantly is that in most cases it is habitat loss that is enabling invasive species to take hold and thrive. Many of the same factors contributing to habitat loss are also contributing to climate change.

Ecosystems are dynamic and adaptive. They will change, but the way in which they change is largely based on disturbance, which in ecology is a temporary change in the environmental conditions that had been contributing the factors needed to maintain that particular ecosystem. Disturbance is a normal, natural part of the dynamics of ecosystems. A disturbance could be something as small as a tree falling over to something as massive as a dam diverting millions of acre-feet of water... or releasing enough fossil fuels into the air to atmospheric changes leading to planet-wide climate change. The vast majority of invasive species are early- to mid-successional species- species that arrive after disturbance. Humans are creating massive disturbances on a perpetual basis that are not only causing native species to fail, but is also opening up habitat for certain non-native species to do what they're best at - move in and create the conditions needed for the next stage of the dynamic cycle of succession. If we take a moment to consider all of the contributing factors of habitat loss for native species (and habitat creation for non-native ones) perhaps we'd see our own culpability and be less likely to point fingers at the plants themselves. They're just doing their jobs.

The Mountain Pine Beetle Dendroctonus ponderosae

We’ve made the mistake of suggesting that native plants are morally superior to non-native ones. We assume that plants have always carried their status around with them and been judged accordingly, but these terms are recently attributed. When Hewitt C. Watson originally applied the terms "native," "alien," "denizen" (meaning naturalized), etc. to plants in the mid 19th century, he did so as a purely objective endeavor. 17 The preconceived judgements about whether those labels, which had been borrowed from English common law terminology, meant a plant was "good" or "bad" would come from others in the field not long after. A non-native species that demonstrates resilience in its new environment is readily named "invasive," which as you might be beginning to see, is not an actual indicator for a plant's actual destructiveness to its environment. And true "native" plants, by definition, are also rather hard to come by in our modern definition of the term when you acknowledge the issues of indigenous erasure and the long history of indigenous agriculture, trade routes, etc. As Emma Marris puts in her groundbreaking book Rambunctious Garden, "The label invasive species is recent, stretching back just a couple of decades, but human introduction sketches back into prehistory. We have moved species around for at least as long as we have been farming." 18

What if we did away with the concept of "invasive" entirely and simply approached each plant as an individual, and acted according to its actual impact on its environment as opposed to its assumed impacts? One would think scientists would be able to overcome the affects of war terminology on their objectiveness, but that has proven to not be the case. And if scientists cannot be objective while subscribing to this type of terminology, then how can we expect lay people to not feel a sense of grief or even terror every time the word "invasive" or worse, "alien invader" is uttered? As the authors of the review The Potential Conservation Value of Non-Native Species put it, "we believe it is prefer- able to distinguish species on the basis of how long they have been present with terms such as long-term resident species, recently arrived species, and new species (Pysek et al. 2004; Davis 2009). We surmise that species will increasingly be evaluated for reasons independent of their recent range distributions." 19 Given the current climate, it seems to be time to put the vernacular of H.C. Watson to bed.

It has been determined that, native species cannot, by definition, be invasive. This predicate precludes the possibility for the existing ecosystem in which that native species resides to change (are you sensing a pattern here?). Climate change has allowed the native mountain pine beetle to explode in numbers and allowed them to expand their range higher into subalpine elevations. 20 The pine beetle feeds on the phloem of the pine species, primarily lodgepole, ponderosa, and whitebark pines, but all pines in their range can be targeted. Once they begin feeding, the beetle releases pheromones which cause an aggregation of beetles to come and feed on the same tree. The beetles deposit a fungus into the tree that will serve to feed their offspring, and eventually this fungus kills the tree. Droughts have diminished the trees’ ability to produce resin to protect itself from beetle infestation. Besides climate change, forest fire suppression as well as the damage done by the logging industry, with its monocultural replantings after clear cuts, have also led to increased susceptibility to pine beetle mortality. 21

While you won’t catch a conservation biologist calling the mountain pine beetle an invasive species in its native range, they are managing it in a similar fashion, with infected tree removal and insecticides. 22 There is an acknowledgement that the beetles, like fire, do play an ecologically vital role of recycling pine forests (a sentiment you won’t come across when dealing with equally destructive non-native species, regardless of their capacity for providing ecosystem services). As native ecosystems become more and more unstable due to climate change, resource extraction, development, pollution, etc. we will begin to see more instances of these established native relationships fall out of kilter.

The Barred Owl Strix varia

Another example is the barred owl, Strix varia. Native to the Northeast, where they’ve faced a major loss of habitat due to fragmentation and deforestation. This owl is non-migratory and rarely leaves its nesting territory unless prey is scarce, but the pressure of habitat loss combined with the loss of Indigenous stewardship of lands on Turtle Island leading to "habitat bridges," created circumstances for the barred owl to expand its range westward. 23 (I'm taking this opportunity to remind you that it isn't human intervention that leads to ecological disruption, but rather unharmonious and ill-informed intervention that does so). It moved north and west into parts of the midwest, Canada, and the pacific northwest. The pacific northwest is also home to the northern spotted owl Strix occidentalis, a smaller cousin of the barred owl. The spotted owl has also suffered population losses due to habitat loss from deforestation, fire, and climate change. Habitat preferred by spotted owls is late-successional and old-growth forests - the preferred tree types for timber harvesting. It takes 120-200 years for forests to reach this stage of succession. The barred owl is larger and more aggressive, with a broader diet, and scientists have correlated a sharper decline to spotted owl populations with the presence of barred owls. The barred owls are competing for territory and resources, but they are also hybridizing with the spotted owls. The presence of the barred owl and its impact on the already destabilized spotted owl has led to an outbreak of appalling arguments from the logging industry. They claim that either barred owls must be destroyed or else they'll call for the removal of protections for old growth forests because they are no longer within the range of the spotted owl habitat. 24 Isn't this how stable species end up on the protected list to begin with?

The opinions of the timber industry are infiltrating the scientific community. Some scientists are saying that the spotted owl will go extinct if they do not eradicate the barred owl, citing research that has demonstrated the lethal removal of the barred owl (using 12 gauge shotguns) stabilized the spotted owl populations. It stabilized them- but populations did not grow. This means that even when barred owl numbers are decreased enough to prevent competition, the spotted owl still struggles to recuperate from the other, far more pressing perils of habitat loss. 25 In spite of this information and a complete lack of consensus on barred owl management, The U.S. Fish and Wildlife Service deemed the research “successful” and is working on developing a strategy for lethal removal of barred owls. Meanwhile the same agency just opened up 204,797 acres of land for timber harvesting that was identified as “critical habitat” for the spotted owl as recently as January 2021. 26 According to the Oregon Fish & Wildlife Service, “Although the listing of the spotted owl as threatened and the designation of critical habitat offer some protection for the spotted owl, past trends suggest that much of the remaining unprotected habitat could disappear in 10 to 30 years.” 27 The USFWS declined to uplist the spotted owl from threatened to endangered this year, a decision which many scientists believe was made as a handout to the logging industry.

While I certainly have no qualms with trying to protect and preserve the spotted owl. Beyond their own intrinsic value, the protection efforts for this bird have been a catalyst for many improvements in the scope and practices of the timbering industry- without the interventions put into place to protect the spotted owl the timber industry would have had free reign to continue destroying the old growth forests they call home. I do have many questions and concerns with the way folks are going about it. Without the prior removal of habitat, would the spotted owl currently be at risk from the presence of the barred owl? Is enough being done to re-establish habitat for the spotted owl’s numbers to actually increase once the mass-removal of barred owls begins taking place? What is being done for the barred owls of the east coast, who’s homelands were destroyed by industry? If the spotted owl does go extinct, what creature will fill that niche in the ecosystem there? How long would it take biodiversity to recover if that species happened to be the more-resilient barred owl, or barred-spotted owl hybrid? How does this all that much differ from breeding the American Chestnut with the Chinese Chestnut in order to create a more resilient species? As more and more species disperse from their native ranges under pressure from climate change and habitat loss, how will the conservationist movement cope and adapt?

As I see it, the barred owl is a scapegoat for the timber industry. And as long as the timber industry gets away with their wrongdoings, no less with the assistance of the USFWS, then perhaps we should consider which species are more resilient and likely to thrive after the chaotic destruction that timbering and climate change will reap on the landscape when we make efforts for the qualitative imperative biodiversity. Perhaps we should contemplate why a bird that normally never flies more than 6 miles from its nest has traveled 2,500+ miles away from its homeland of the east coast. If we could stop vilifying the barred owl for a moment, what could it have to teach us? These are lessons we have to learn, and learn quickly. If you go to the National Audubon Society's website you can view the ranges of the birds of North America as well as the way these ranges are predicted to change due to climate change. 28 The majority of species that are at risk have limited ranges, and as these ranges shift northward because of climate change it puts them at great risk. Many of these animals to have the necessary corridors to make these migrations. And when they do arrive, how will they be treated? If we consider these unassisted migrations as "invasions" of "non-native" species, we are shooting ourselves in the foot.

The examples illustrated in this article are just a few out of many. The concept of "belonging" vs. "invading" in regards to biota is subjective depending on the perceived and actual negative effects and benefits on its ecosystem that we deem noteworthy. As Matthew Chew and Andrew Hamilton put it in their essay The Rise and Fall of Biotic Nativeness: A Historical Perspective:

"It is remarkably easy to unravel the conception of biotic nativeness... None of the relationships comprising biotic nativeness is in an inevitable, permanent, or dependable object supporting a conception of belonging... Yet preference for nativeness permeates ecological thinking, supporting a multi-hundred article-per-year publishing effort. Ecologists can demonstrate that in a relatively small (if quite noticeable) subset of interactions, 'aliens' demonstrate fitness superior to 'natives'; but we cannot explain - in biological terms - how inferior fitness is consistent with superior belonging." 29

Novel Ecosystems: Looking Forward

Ranges are dynamic. Humans have been moving around the planet for 185,000 years (or if we're counting early humans, 2 million years), and everywhere they have gone they’ve brought plants with them. Prior to hominid intervention, novel ecosystems have been occurring and supplanting pre-existing ones since life emerged. If we look through the fossil record we see example after example of this. All ecosystems were once colonized by "invading" species. It is this process that drives evolution and speciation. In The Rise and Fall, Chew and Hamilton make the point, "Paleobiogeography is rife with redistributions and speciations that generated competition for space and resources, the stuff of natural selection."

The prevalence of a species is dependent on many factors, but in every ecosystem, if given enough time, both the existing and incoming organisms eventually reach a homeostasis. They co-evolve. In the process, certain habitats may change either as a direct result of that incoming species or, more commonly, as a result of the changes that occurred to allow that new species to come in and thrive in the first place. And consequently, certain species may struggle or even go extinct, and biodiversity may temporarily wane. 98% of all the species who have ever called this planet home have gone extinct. This is part of a natural cycle. As Tao Orion states in her book Beyond the War on Invasive Species, "...ecosystems, like all systems, are dynamic. They're characterized by constant change. Ecosystems, like any system, can sustain and even thrive with some level of perturbation, but at a certain threshold they are prone to complete transformation... An unrecognizable system isn't necessarily dysfunctional- it's just different from what it was." 10 We may perceive this as fundamentally competitive, but more and more scientists are discovering that nature is cooperative more than competitive. The competition that does occur is generally a short term occurrence which eventually co-evolves into a cooperation. The problem for us, according to conservationists, is that this process can take thousands to millions of years and we just don't have that kind of time (but these are the laws of nature, and the laws don't change just because they're inconveniently upending our plan to have unchecked dominion over the earth). The limitations of time on evolutionary adaptation are being challenged by scientific observation, though. Species are demonstrating major morphological evolution in very short time spans - under the right conditions within a few generations. This was previously thought to be possible only for simple organisms, but we now know that complex species can evolve rapidly. The draining of wetlands in the Everglades has caused the Everglade Snail kite (Rostrhamus sociabilis) to become endangered. This is a species endemic to Florida. The drained wetlands disrupted the native Florida apple snail (Pomacea paludosa), the Snail kite's primary food. A study published in 2005 showed the Snail kite evolved to be able to eat the non-native Island apple snail (Pomacea maculata), which is five times larger than the native Floridian species, in under two generations. Their bodies and beaks both grew in size, with a notable increase their relative bill to body mass ratio. 30 The commonly held belief that Darwin's finches differentiated themselves over the course of hundreds of thousands of years is being obliterated. These scientific findings alone are enough to challenge everything we're being told about the "dangers of invasives species."

There is also now evidence that plants did not evolve slowly over hundreds of millions of years, but instead underwent rapid evolution over the course of two bursts 250 million years apart, first with the development of seeds and second the introduction of flowers. Nature works cyclically. Looking back into earth's evolutionary history can give us the insight we need to create a livable future for our descendants but only if we view the past holistically and over the span of its many peaks and lulls. The only difference now and 10 million years ago is that we’ve arbitrarily decided that no species introduced post western colonization can ever become native. We’ve imposed static, civil labels for natural, dynamic processes and in our attempt to dogmatically obey these definitions we’ve created this chaotic pseudoscience that we now need to dismantle. We are an invasive species by our own definition, but our dilemma is that invasive species are an unproductive fabrication; they do not exist.

What does this mean for us in practical terms? While we can't throw all caution to the wind or fall into a heap of nihilism, declaring "what's the use?" We're humans: scientists, gardeners, healers, habitat transformers. How we view and interact with the landscape has very real consequences. But we cannot continue down the path we're on, pretending that invasive biology is a substantiated or unbiased scientific field, all the while basing policy on conjecture and encouraging landowners to pour on the glyphosate in the name of "biodiversity" (all the while obliterating the fungal and microbial biodiversity of the soil, which are ya know, is only the foundation of all life). How we can accept the mere existence of the "Northeastern Weed Science Society" is beyond me. How can one put "weed" and "science" in the same sentence with a straight face? It becomes less funny when you realize that this society is in association with both Monsanto and Penn State University. 31

The scientific community needs to come to terms with where they've gone wrong and start making better choices. We all do.

I do want to make it clear that I don't think there is anything inherently wrong with managing non-native species or encouraging and protecting native ones. Land management always facilitates selection of preferred biotic residents for a desired outcome (when done regeneratively this desired outcome takes into account all of the factors it influences, directly and indirectly, for at least the next several generations). The removal of non-native species may or may not be the optimal choice for the management of a particular section of land. In The Potential Conservation Value of Non-Native species, the authors suggest a more forward-thinking approach to land management:

"The management of non-native species and their potential integration into conservation plans depends on how conservation goals are set in the future. A fraction of non-native species will continue to cause biological and economic damage, and substantial uncertainty surrounds the potential future effects of all non-native species. Nevertheless, we predict the proportion of non-native species that are viewed as benign or even desirable will slowly increase over time as their potential contributions to society and to achieving conservation objectives become well recognized and realized." 18

I'm not suggesting we fall into the pit of dogmatism and take a hands off approach to ecological management. And I'm not suggesting that highly dispersive non-native species are not ever problematic. In many cases, these species are working to re-stabilize ecosystems and a war against them really is a war against ourselves. They are, in some select cases, problematic in terms of short-term biodiversity thus, our immediate ability to thrive as humans. But again, our management approach is ineffective because the invasive species are the symptoms of a deeper pathology. Ecological disruption and loss of biodiversity is problematic, and at the root of these pathological expressions are the etiology: the subsidized agricultural industrial complex, the military industrial complex, enclosure and privatization, capitalism and fabricated scarcity, globalism... and at the root of all of these lies colonization and the loss of relevancy, or rather awareness of the relevancy, of the "natural" world in day to day life for human beings. The "re-wilding" movement has made an attempt at reclaiming this relevancy, but like the conservation biology field, the rewilding movement falls flat in its failure to decolonize perspectives on human-land interactions, resulting in counter-productivity that actually further separates us from nature. Both these movements strive to return us to a mythological state of "pristine wilderness" as opposed to acknowledging our place within the ecological system. Unlike conservation biology, the rewilding movement rightly reframes our mindset to acknowledge that we, too, are mammals, but fails to see the complexity with which we have interacted with the land as mammals for millenia and perpetuates misinformation about what cultures they deem "hunter gatherer" looked like and how to go about emulating their practices as a means of species survival. But, in fact, our species survival is dependent on the co-creation of wild spaces as we reach the conclusion of what "wild" even means in an anthropogenic world. Until we can see the world as whole, until we can see "habitat" in the marginalized urban spaces and see ourselves within the "wilderness," we cannot heal. As desperately as we need uninterrupted corridors of habitat for wildlife, we need to recognize our inseparability from nature.

Succession is something that can be managed: we can harness the power of nature and utilize it, just as indigenous people have done for millenia. We can tend landscapes to reduce negative impact and promote biodiversity by selectively removing some plants, burning, planting, coppicing, etc. We can work within these ecological systems, as part of them. But we cannot stop succession entirely. We cannot force biota to obey our will when our will defies the laws of the system. This is what we are trying to do with herbicides- committing biological warfare in the struggle against a failing system. Just as the suppression of wildfire and the oppression of the Indigenous people who have long practiced cultural burning has led to an increase of out of control canopy fires and massive destruction of forest ecosystems, our management of invasive species is not only futile, it is causing iatrogenic harm and compounding our already dire situation. You cannot "fight" invasives species: a war against nature is a war against ourselves and will never be won. You can only work with it. The climate is changing, and we cannot deny the scars we have left and continue to inflict on the earth daily. We have upended the systems that we are trying to preserve. It is time for us to acknowledge the reality of the systems we are in. We have to adapt. It is within our ability as a species to rediscover our place within this dynamic system and work with those dynamics instead of against them. Traditional Ecological Knowledge offers a model for not only the land management practices that we can employ, but also for the shift in mind-frame and worldview necessary to move forward in a positive way. "Indigenous nations' invasive species work is generally underreported in the literature but includes communication and education initiatives, scientific research that tests new stewardship strategies, ecosystem restoration through Indigenous knowledge, and adaptation of cultural practices to account for changing conditions, including incorporating introduced species into Indigenous food systems." 32

We can be stewards of the land only if we listen deeply to the land.


  1. Edward K. Faison and David R. Foster. (2021, July 28) Did American Chestnut really dominate the eastern forest? Arnold Arboretum

  2. The American Chestnut Foundation (2021, November 10) History of the American Chestnut

  3. The American Chestnut Foundation (2021, May 25) Breeding

  4. (2013) A Review of the Bureau of Land Management (BLM) Wild Horse and Burro (WH&B) Management Program National Academies of Science, Engineering, and Medicine

  5. Executive Order 13112 - Invasive Species (1999)

  6. Native, Invasive, and Other Plant-Related Definitions | NRCS Connecticut Natural Resources Conservation Service Connecticut

  7. Impacts of European Starlings on Native Species: Looking Beyond Competition for Nest Sites – Research Highlights - US Forest Service Research & Development (2015) U.S. Forest Service

  8. Natalie Hofmeister (2021, April 2) Essay: Are Starlings Really “Invasive Aliens”? The Cornell Lab: All About Birds

  9. Turfgrass and Lawn Care Penn State Extension

  10. Tao Orion (2015) Beyond the War on Invasive Species: A Permaculture Approach to Ecosystem Restoration Chelsea Green Publishing

  11. Purple Loosestrife in Pennsylvania (2021, December 4) Penn State Extension

  12. Lavoie, C. (2009) Should we care about purple loosestrife? The history of an invasive plant in North America Biological Invasions

  13. Bush, B., Shane, L. A., Wilson, L. R., Barnard, E. L., & Barnes, D (1986) Uptake of polychlorobiphenyl congeners by purple loosestrife (Lythrum salicaria) on the banks of the Hudson river Archives of Environmental Contamination and Toxicology

  14. Gleditsch, Jason & Carlo, Tomás (2011) Fruit quantity of invasive shrubs predicts the abundance of common native avian frugivores in central Pennsylvania Diversity and Distributions

  15. Greenberg, Cathryn H.; Walter, Scott T. (2010) Fleshy Fruit Removal and Nutritional Composition of Winter-Fruiting Plants: A Comparison of Non-Native Invasive and Native Species Natural Areas Journal

  16. Araújo, P.M., Viegas, I., Rocha, A.D. et al. (2019) Understanding how birds rebuild fat stores during migration: insights from an experimental study Scientific Reports

  17. Nimal R. Chandrasena (2021, June 7) ‘Aliens’, ‘Natives’ and ‘Artificial Habitat’- Revisiting the Legacies of H.C. Watson and S.T. Dunn

  18. Emma Marris (2011) Rambunctious Garden: Saving Nature in a Post-Wild World Bloomsbury

  19. Schlaepfer MA, Sax DF, Olden JD (2011) The potential conservation value of non-native species Conservation Biology

  20. Why are some whitebark pine trees surviving climate-driven mountain pine beetle outbreaks? (2021, August 17) Northwest Climate Adaptation Science Center

  21. Roach, W. J., Simard, S. W., & Sachs, D. L. (2015) Evidence against planting lodgepole pine monocultures in the cedar-hemlock forests of southeastern British Columbia Forestry

  22. Gibson, K. E. (2004) Management Guide for Mountain Pine Beetle Forest Health Protection and State Forestry Organizations

  23. Spotted Owl and Barred Owl U.S. National Park Service

  24. Barnard, J. (2004, June 20) Barred owl inroad, hybrids complicate spotted owl review. The Spokesman-Review

  25. Owl vs. owl: Should humans intervene to save a species? (2019, October 15) AP NEWS

  26. Endangered and Threatened Wildlife and Plants; Revised Designation of Critical Habitat for the Northern Spotted Owl (2021, November 10) U.S. Fish and Wildlife Service

  27. Northern Spotted Owl Oregon Fish and Wildlife Office

  28. National Audubon Society

  29. Matthew K. Chew and Andrew L. Hamilton The Rise and Fall of Biotic Nativeness: A Historical Perspective (chapter from Richardson, D. M. (2011) Fifty Years of Invasion Ecology: The Legacy of Charles Elton (1st ed.) Wiley-Blackwell)

  30. Cattau, C.E., Fletcher Jr, R.J., Kimball, R.T. et al. Rapid morphological change of a top predator with the invasion of a novel prey. Nat Ecol Evol 2, 108–115 (2018).

  31. Northeastern Weed Science Society

  32. Reo, N.J., Whyte, K., Ranco, D., Brandt, J., Blackmer, E., & Elliott, B. (2017) Invasive Species, Indigenous Stewards, and Vulnerability Discourse The American Indian Quarterly

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