Humanity likes to ignore the fact that nature is a nearly mathematically perfected system. It is always in the process of refining itself, so remains deliberately imperfect, with a battle between randomness through mutation and outbreeding competing against optimized high-performance genomes, like the mythical battle of “evil” and “good.”
This means that the rules in nature are not arbitrary, nor locked into symbolic games like financialization — ensuring that monetary instruments cover all fiscal needs — and administration, or the art of moving people around so that they go through a rote procedure in a manner that produces the appearance of desired function.
While our solipsistic advanced monkey brains find this appalling, the grim fact of life is that whatever we intend to do, it makes sense to look at what nature is doing first because it has encountered the problem before. This does not mean “back to nature,” because of course, nature also wants to kill us (and eat us) if it can.
That tells us that we can see our own diversity pattern in the destruction wrought by invasive species who essentially genocide native species by having lower standards:
Residents who have lived in this area for more than 20 years can well remember when green anole (Anolis carolinensis) were numerous. They would run across porches and display their jewel colored fans as they rested upon porch railings and screen doors.
At that time, they inhabited all areas around houses, foraging among the plants and shrubs. It was not uncommon to find a small white egg laid at the base of your favorite geranium or other potted plant, or to see an anole rush across the patio in pursuit of a cricket or other insect.
This has changed. Although green anoles are very territorial, the invasion of the brown anoles have chased the natives into the treetops. The brown anoles, having few enemies, have taken over the former habitat of the greens, forcing them into new territories and farther from our sight. In addition to taking the natural territories from them, the brown anoles, especially mature males, will actually kill and eat the baby green anoles. Their populations are greatly reduced from former numbers.
The brown anoles are off the radar of the predators, less discerning about what they eat, and attack young green anoles whenever possible. Maybe they have BLM riots of their own, drink Modelo Especial, chant “Allahu Ackbar,” and invent Abrahamic religions to enslave their host population to the individualistic doctrine of the mixed-race.
Invasive species always follow this pattern. They behave as generalists, the category of animals like rats and squirrels that are not specialized to a food source and environmental niche, and by doing so, out-compete the natives and replace them with a less specialized species which is of less use to the ecosystem.
Sometimes we see contrary examples, like natural evolution, where a more specialized species overtakes the generalists and drives them out through greater proficiency, instead of numbers like the generalists do. Specialization like most things is a cyclic spectrum with a range of sweet spots between the extremes.
Whatever group then proves the most violent and unpredictable dominates because the other withdraws, causing it to lose ground because it cannot conduct the activities it needs to thrive and reproduce. In the case of lizards, the more intelligent group backs off and loses territory:
We find that interference competition is asymmetric in favor of A. sagrei, which are more likely to display and less likely to retreat than A. carolinensis. Concordant with their arboreal tendencies, male A. carolinensis also trend toward retreating upward more often than expected by chance. These asymmetries are prevalent despite the almost complete absence of physical attacks, suggesting that interspecific signaling and avoidance behavior by A. carolinensis resolve most potential conflicts before they escalate to combat.
While avoiding conflict makes sense on the individual level, it fails the group, since over time they are less able to reproduce while their opposition has more opportunities along those lines. In the face of the invasive species, individuals of the host species choose self-preservation, causing a disorganized retreat.
After that, the invasive species possesses more territory and this allows it to increase its numbers, accelerating the decline of the native species. Over time, the native species vanishes, and the less-competent but more aggressive invasive species takes over:
In recent years, populations of our only native lizard have declined primarily because of the increase in brown anoles. Brown anoles have taken over green anole territories, and adult males occasionally prey upon green anoles. Pesticide use has contributed to population loss as well.
Invasive species tend to be those which have been introduced to a new environment and as a result, exist in a type of existential panic which translates to maniacal aggression and fecundity. They are the single-issue voters of the animal kingdom: they want to survive and do not care as much about quality of life, since they have nothing.
Established species on the other hand have found niches and have an elegant relationship to their environment, so they are many-issue voters, meaning that they are not just concerned with survival, but quality of life, and maintaining their niche. This complexity makes them stronger in the long term but weaker in the short term.
They do this by inducing the animal equivalent of “white flight” in the native species, since it has more to lose by engaging in aggression with newcomers, and therefore retreats instead of going into constant combat, even if that would drive out the invasive species.
Pushed from its most prosperous environments, the native species begins to falter and be replaced as it confronts an aggressive and numerous competitor which has none of the burdens of adaptation:
Being invasive, Cuban anoles reproduce in great numbers. Where they arrive, they quickly become very abundant. I just mentioned the story of the local nursery. Prior to Hurricane Michael I remember making stops at rest areas along Interstate 10 heading to Gainesville. Not one of them was free of this lizard. Possibly introduced on landscaping plants, they were very abundant. As you walked to the restroom you could see them scattering and running everywhere across the ground.
When the Cuban anole is introduced to a habitat where the Green anole already exists, the competition begins. The Green anoles are often forced higher in the shrubs, trees, and buildings – Cuban anoles are not great climbers. However, once Green anoles are “up there” they have fewer resources and fewer opportunities for breeding. They will usually move to another neighborhood or begin to die off from the lack of resources. Cuban anoles are also known to consume the eggs and young of the Green anoles. So, we see a decline of the native and an increase of the non-native.
In this way, invasive species bully their way into a dominant position at the expense of the ecosystem. They take over territory, bully out the natives, and out-reproduce them, driving the native species into less desirable territory where its numbers slowly decline until inbreeding takes it out.
It may be that in nature, this shows the invasive species is ironically in greater decline. A restless burst of reproduction and new territory succeeds at first, but then the lack of niche starts to beat it down when crises occur. At that point, the native species is long gone and the invasive species suffers a crash.
Most of our examples of invasive species result from human introduction because only such a radical change could introduce invasive species in large enough numbers to make a beachhead and have a chance of dominating. For example, human affinity for housecats causes them to dominate:
The team sequenced and analyzed both wild and domestic cats, including 48 modern individuals and 258 ancient samples excavated from 85 archaeological sites over the last 8,500 years. They then assessed the patterns of hybridization after domestic cats were introduced to Europe over 2,000 years ago and came into contact with native European wildcats.
The results of the studies demonstrate that, since their introduction, domestic cats and European wildcats generally avoided mating. About 50 years ago in Scotland, however, that all changed. Perhaps as a result of dwindling wildcat populations and a lack of opportunity to mate with other wildcats, rates of interbreeding between wild and domestic cats rose rapidly.
Jo Howard-McCombe from the University of Bristol and the Royal Zoological Society of Scotland explains, “Wildcats and domestic cats have only hybridized very recently. It is clear that hybridization is a result of modern threats common to many of our native species. Habitat loss and persecution have pushed wildcats to the brink of extinction in Britain. It is fascinating that we can use genetic data to look back at their population history, and use what we have learnt to protect Scottish Wildcats.”
Hybridization destroys the original species. Each species has a genetic framework, or complex network of traits selected by time, and when it hybridizes, that rolls the dice on each of these traits. As a result, they no longer support each other, and so the offspring have few specializations and abilities.
With interbreeding between the hybrid offspring, the trait network is further hammered down to the most general, resulting in an animal of lower ability but higher aggression and reproduction. One wonders if many invasive species displacing their relatives did not first hybridize with those relatives.
It turns out that invasive species often spell ecosystem doom because unlike the niche-bound natives, they thrive as generalists, producing excess that was never natural in that system:
For instance, in a recent field experiment in the US, scientists deliberately started a fire that killed about 10% of the longleaf pine trees in the area studied.
But in areas where an invasive grass—cogongrass, an Asian native—was allowed to establish itself alongside the pines, the fires had more fuel and were larger, hotter, and burned for longer.
Where the scientists had added rain shelters to simulate drought conditions, the grass dried out further and the fires became much more lethal. A combination of drought and the invasive species meant longleaf pine mortality soared to 44%.
In the case of the anoles, for example, the green anoles developed traits that allowed them both to find prey and to survive predators. This helped them endure when predator numbers surged during one year or another. When replaced, they are overtaken by a new species which has none of this resistance.
Even more, it no longer serves the role that they did in their niche by specializing in the prey that are most abundant and therefore need the most predation in order for the system to stay balanced. Like a society in the grips of diversity, an ecosystem with an invasive species becomes unbalanced and starts to come apart.
When humans look back over our history on this planet, we will see that our desire for easy answers produced many such crises and that we ignored them because we value our desires over the needs of reality. Like all catastrophes, this appears negligible at first but eventually creates a full-blown disaster.