Well it's heating up out here with our first "heat wave" and/or "heat advisory" of the summer. It's just about in the nineties and I'm happy enough to stay indoors after 9a.m. or so for the duration.
Still, it's a great time to get out and see the babies and all the other birdies attending them.
Maybe the early bird gets a worm or two, but the afternoon bird also seems to do just fine. Honestly, we have a lot of worms. When it rains, the sidewalks are pretty much an endless bird buffet of slugs, snails and wormies.
And there are all manner of delicious things on the ground. Some of them better camouflaged than others.
Cedar waxwings are new to the territory. They are distinct birds, sporting a smart little black mask, waxy orange wingtips, and a splash of yellow at the end of the tail.
Our very first cowbird fledgling was bawling for food from their white crowned foster parents.
Cutest of all by far were the crow fledglings. They're more in their gawky toddler phase. Hopping around awkwardly, making their funny begging cries and baring their bright red little mouths. Blinking their dopy blue eyes. They are darling!
So, it's been a fun time in our little medium-urban housing environment. I am amazed how little of all this bustle I noticed in previous years. That's the amazing thing about "nature" - it's just always right there
And on that note, may I present to you... A book report! Sort of!
So, a while back I went on a lil rant about the ugly side of conservationism: the occasionally vituperative hostility towards invasive species like house sparrows and starlings (getting pleasure out of hurting a fucking bird because you've decided its evil is fucked up, I hold strong on that).
In doing some research about the plight of the bluebird and the guilt of the house sparrow, I was tipped off to a book called The New Wild: Why Invasive Species Will Be Nature's Salvation, by Fred Pearce. It took me a while to come up on the hold line, but I've finally just read it.
It's a lot of preaching to the choir, so it wasn't exactly edifying, but many of the questions I raised and spots I was coming around to were highlighted in bold bloody red in this book. An environmental journalist, Pearce looks with a scrutiny that reminds us why liberal arts remain important in a STEM world. And he brings plenty of science and expert input to back it up. I do want to investigate opposing points of views and read more but it definitely gave me a lot to think about and confirmed some places of unease for me.
Consider this a tl;dr to the book. It's still long. But you know, it's not 190 pages long?
Invasion biology, as described by Pearce, is the conservational biology framework that brings us "invasive bad, native good." Coming from this premise, it looks at ecosystems as finely balanced co-evolved systems of native plants and animals who each fill a crucial role. It sees invasions as devastating and catastrophic.
To me, its lineage is the pre-Darwinian belief that God endowed each animal with the perfect traits to serve their purpose on earth. Nowadays, instead of Eden, we have deeply fragile and simultaneously perfectly balanced ecosystems honed by capital C and capital E CoEvolution.
Especially in an anti-intellectual age it's very important to recognize that "science" done with certain pre-conceptions will often go along confirming those pre-held biases and even rigorous studies can misrepresent the greater truth about an issue when the scientists are narrowly selective about what they choose to study. Data is data, but it needs to be interpreted and humans are certainly able to import unconscious biases even when they are convinced of their objectivity.
This is one of many reasons it's so important to replicate research. It's one of many reasons that the ones replicating the research should be different and come from different angles than the original researchers.
We've seen myriad instances where social biases colored scientific orthodoxy. Much of what we thought we knew about medicine was derived by studying white men, for instance. Victorian misconceptions about the roles of men and women obscured the role of female sexual choice and the broad range of "female" behaviors. Invasion biology unavoidably incorporates xenophobia and Christian. mythology. Purity conservationism creates a sort of before-the-fall paradise and separates mankind from nature (We did eat that damned apple after all). Some conservationism seeks to reclaim a virgin wild that never truly existed and can never persist.
Little side note
As time goes on the conception that any particular feature or quality defines humans as separate from animals seems to diminish. Myriad animals exhibit problem solving, reasoning, tool usage, self-recognition, emotional complexity, understandings of basic linguistic elements, complex social dynamics, social learning, artistic and musical sensibility, and the ability to learn from previous memories.
The degree to which any other animal may exhibit a feature once thought uniquely human is debatable, and it's further questionable if humans ought to be the markers or any sort of grand end point anyways. But the distinction between non-human animal and human animal is not as clear cut as previously envisioned.
Animals even seem to display some basic agriculture. Ants, snails, and termites cultivate particular fungi. Damsel fish similarly culivate algae in specific plots. Aphids basically herd honeydew producing bugs. Similarly, we've seen penguins practicing something akin to prostitution (and running a scam by promising favors they refuse to act on after receiving their pebbles).
Humans may do a lot of quirky things compared to other animals, but we are less unique than we think. We are a part of the ecosystems we inhabit, even as we alter them substantially.
It's crucial to acknowledge that many early conservationists were vocal eugenicists, white supremacists, and - yeah we're gonna go there - a lot of the ideas of invasion biology echo ecological eugenics in NAZI Germany. Many used dubious interpretations of Darwin's concepts to create both racial and ecological hierarchies. The Redwoods even became a mascot tree of the Eugenics movement.
If you actually look at the violence of the language, you can start to see it -aliens explode, they overrun, they devastate, they assault, they flood and they invade. There is a declared "war on invasives"! It's also notable that the most visceral reactions to non-native plants and animals often occur shortly after a war, invasion, or terrorist attack. There is something innately psychological underlying invasion biology.
These premises are also, often, built on shaky ground as Pearce goes to great lengths to illustrate.
As I've speculated, the presence or even aggression of an invasive species at the site of a decline or degradation does not prove it is the cause.
“In Australia,” says Mark Davis of Macalester College, “declines in the native species typically began decades before introductions of species . . . that have been reported to have contributed to the extinctions.” Sometimes, aliens can simply survive in places natives can't. Human activity can invite invasives and blame them for the whole shebang.
When we simply focus on the plant or animal we miss the underlying problem that may have brought them there in the first place. When we approach from a battle mindset instead of seeking understanding, we often cause more trouble than we solve.
After considerable study, Davis concluded invasion biology was based on a false proposition. With exceptions, the introduction of non-native flora and fauna actually tends to increase biodiversity in a given location. Species rich environments accommodate more introduced species than species-poor communities. Often introduced species lay the groundwork for a return of native species and become valuable to native animals. This develops to a point where extirpating invasives has a far greater negative impact on native species than keeping the invasive.
Snail Kites
Change triggers amazing feats of evolution. One well known instance occurred with snail kites in Florida. Populations were plummeting, in large part due to habitat decline and significant droughts. The native apple snail, their main food source, had become rare. But while the native apple snails declined precipitously, a non-native apple snail that was several times larger began to inhabit the area and breed quite successfully. The kites initially continued to decline, as the new snails were too large for them to eat.
However, in under ten years, there was a dramatic resurgence. Birds often experience evolutionary changes on a shorter time scale because they reproduce often, allowing generational shifts and new mutations to occur more quickly. In this case, bill size and body mass are a heritable trait, and so most surviving snail kites have beaks large enough to eat the new snails.
#NotAllAliens
One of the limitations of invasion biology is that it disproportionally focuses on the small percentage of invasives known to have significant impacts. A 2008 study of papers published in invasion biology journals found that only 49 species had been the subjects of 10 or more studies. Out of thousands, these have an overwhelming focus in the study of invasives. And yet, "it is an accepted rule of thumb that at least 90 percent of invaders quickly disappear, and of the remainder only around 10% cause any trouble." Similarly, most studies focus on small islands that have been most heavily impacted. The studies, in effect, do not capture the larger picture as they center on the most extreme cases.
The representation is misleading. We do not all live on small islands with endemic populations. Most of the world is messier. Most non-native species have a marginal impact. Even though that do have clear and measurable impacts can have a much more mixed balance sheet when you really look at it. And sometimes, we just trust our guts so much we don't bother to look at it.
Kudzu
Pearce spends the beginning of his book investigating some of the most famous invasions and suggests we haven't seen the whole picture even here.
Kudzu, for instance was once enthusiastically brought into the United States. A beloved plant in Asia, it provided nitrogen for the soil, made cheap and easy livestock fodder, helped stabilized soil in drought. And then, as we know the story, it spread like wildfire. By the 1990s it was listed as a noxious weed. What changed, according to Pearce is American expectations of the land. As agriculture turns away from grazing, kudzu grows un-checked, which is suboptimal in a farmland environment.
But, Pearce asks... "Is it bad for nature? The claim is often made, but when I searched for information about how much ecological harm it does, I found that nobody seemed to know." The anecdotal record is long, but somehow the actual scientific record is weak.
He quotes Irwin Forseth of the University of Maryland as saying there simply is not good research. "The idea that it is bad seems to have become so entrenched among Americans that nobody saw the need to test the claim."
On the other side, Derek Alderman of the University of Tennessee, who believes kudzu could have untapped economic value as a textile, medicine and nutrition. Others believe it could serve as a potent sustainable resource, medicine, and source of biofuel.
Subsequent to The New Wild's publication, conservationist Bill Finch raised further questions about the mythology of kudzu. Unlike the common belief that kudzu is a super-spreader, covering more than 7-9 million acres, the latest survey by U.S. Fish and Wildlife found it covered only 227,000 acres of the 200 million acres of Southern Forest. This is substantially less than Asian privet, and one third of the spread of roses in the same area.
While it is expected to spread, it's projected to do so at a rate of 2,500 acres a year versus the oft quoted 150,000 acre spread. Another non-native actually seems to be limiting its spread - the Japanese kudzu bug infestation is associated with an estimated 1/3 decrease in kudzu biomass in under 2 years.
"The myth of kudzu has indeed swallowed the South, but the actual vine’s grip is far more tenuous."
Contrary to reports that kudzu is turning the American South into a monoculture, the South harbors the most diversity in the Eastern US and possibly all of the United States. The threat of kudzu is far less severe than imagined and the source of the scaremongering was largely a mix of confirmation bias (kudzu thrives best in areas where people are likely to see it) and poor science.
Like Pearce, Finch points out the risk in blaming invasives for deeper issues: "Our obsession with the vine hides the South. It veils more serious threats to the countryside..."
Tamarisk
Meanwhile, tamarisk (salt cedar) may have been blamed largely for showing up in the wrong place at the wrong time and being just a little too good at surviving. In the 1940s, it was maligned as a water guzzling plant, choking out the area and drying up rivers. Hydrological studies change the picture. After extensive eradication of Tamerisk along the Pecos River, studies have shown no evidence of any greater flow in the river. Its water consumption, on study, is only on par with native cottonwood or willow. More recent studies show that it does not, in fact, compete particularly aggressively against native plants. In fact, the presence of Tamarisk boosts soil fertility.
Meanwhile, the endangered southwestern willow flycatcher has begun to nest in tamarisk almost exclusively. At this point, eradicating tamerisk would present a substantial risk to a vulnerable species.
Zebra Mussel
And then there's the notorious zebra mussel. This is one of the most aggressive and famous invasives and there are definitely documented downsides of its presence. Notably, there are economic impacts on humans. They clog water pipes, mess up boats, and can impact property values. So, yeah, they are gonna be a hard sell on the positive side. It's also been assumed that they are devastating for the local environments. And it's true that they change everything up with significant winners and losers. But is this a question of framing?
The zebra mussel moved into the heavily polluted Great Lakes in the late 1980s. They were the only filter feeders able to swallow the gunk in Lake Erie and they did in fact remove significant pollutants from that lake. This is both a potential positive and negative, as doing so changed the entire food web. Invasion biology would immediately categorize that as bad.
But perhaps it's simple equivocal? While mussels, clams and shrimp are declining due to competition with the zebra mussels, smallmouth bass, birds, and the endangered lake sturgeon, all of whom are rebounding due to the increased clarity of the water. Erie is now the world's premier smallmouth bass fishery. There has also been a return of migratory wildfowl who feed on the mussels. As always, winner and losers.
"A new ecological environment is rapidly emerging in the lake, with its own checks and balances. We cannot quite tell how it will work out. The revival of the ancient sturgeon may limit and perhaps even reverse the proliferation of zebra mussels. Some ecologists say that if humans hadn't hunted the sturgeon almost to extinction, the zebra mussels would never have got such a grip... but surely this is all better than the "dead" lake."
What we do know is that you can look exclusively at the negatives of this particularly impactful alien species, but this might involve overlooking at least some countervailing benefits. The USGS's Great Lakes Science Center admits that "Zebra mussels," which have spread to all the great lakes and into Chicago and Mississippi, "have had positive impacts on parts of the Great Lakes ecosystems." Other studies have shown a twofold increase in diversity of invertebrates where zebra mussels have colonized a seabed
The idea that invasives cause more damage than natives is also understudied. Rob Marrs of the University of Liverpool looked at the prominence in the National Woodland Survey of three local plants —bramble, bracken, and ivy—and three invasives —rhododendron, sycamore, and Himalayan balsam. He found that the locals caused four times more damage to local woodland biodiversity than the aliens.
But let's looks at some heavily cited claims:
In a 2004 paper, David Pimental (a foundational conservation biologist/entomologist) said in passing that “in other regions of the world, as many as 80% of the endangered species are threatened and at risk due to the pressures of non-native species.” This has been quoted relentlessly by conservationist groups and other scientific papers.
Pimental was in turn referencing another paper that concluded this. But upon a small amount of research, Pearce fond that this paper was referring specifically to plants in the Fynbos area of South Africa. A subsequent UNEP study quoting a report from South African scientists (among them van Wilgen, the author of the cited paper) says that just 750 of the 8,574 native plant species of the Fynbos “are currently facing extinction [as a result of] pressure from invading species.” This turns out to be less than 10 percent.
Possibly, invasives do cause more threat, but this figure is repeated everywhere and it is based on an inaccurate and misleading citation. Given how foundational it is, why has nobody questioned it or tried to replicate that number from real data? Pearce suggests "sometimes a story is just too good to check".
Likewise, it's often said that the annual cost of alien species to the global economy is more than $1.4 trillion. That number is quoted widely and indiscriminately. This again goes back to work by Pimental. In this case, he attempted to calculate the costs himself but his choices, on analysis, are "rickety at best".
Pearce applauds the effort, but when he gets into the weeds he finds many of the choices to be problematic.
"For instance, rats, mostly brown and black rats, are listed as responsible for just over half the environmental losses from alien species in his six countries, at $56 billion a year. Almost half of the rats’ bill, $25 billion, comes from India, where local estimates put the rat population at 2.5 billion." And yet, black rats are actually native to India. In other words, damage he attributes to "invasives" is actually being caused by natives to some extent.
Beyond this, no invasive species is credited with any positive impact to balance the final tally. While native and non-native pests cause damage, non-native cats kill them and provide valuable pest control in doing so. Even just the smell of a cat will deter rodents from a property! There's no credit for this service even though it has real impact and the cost of other forms of pest control is considered in the invasive debits column
Much of the agricultural (and other) pollination in our country is now down by non-native European honeybees. While you might have mixed feelings about that, our economy depends on this, not to mention the value of honey produced.
Our entire farming system, a huge swathe of our economy, is based on non-native plants and animals.
Meanwhile, cats are given a "per-bird-death" dollar debit. Some birds, being non-native, are tallied both as a cat-death cost and a cost for staying alive and needing to be eradicated by some other pest control measure. Starlings naturally are blamed for eating crops without any recognition that - if they truly were chasing off native species - a native bird would likely have incurred that cost without the starlings' interventions.
And again, these are non-native crops being protected with pest control. As Pearce puts it, "it does seem odd to include among these negative impacts the billions of dollars spent on pesticides to protect one set of alien species from another!"
Another common quote is that invader species "have contributed to 40 percent of the animal extinctions that have occurred in the last 400 years." Pearce tracked this down to a paper written by David Wilcove, published when he was working for the Environmental Defense Fund. His actual paper was arguing that 49% of extinction threat to endangered species came from invaders. This claim only applied to the United States.
However this argument is extrapolated almost exclusively from evidence collected in Hawaii, a particularly vulnerable island ecosystem that in no way should be reflective of the greater US: Hawaii makes up 0.3% of the area of the US, and was responsible for 2/5 of all endangered birds and plants in his data. Wilcove was very clear about how limited his data was, emphasizing there were "few quantitative threats to species."
When Pearce asked him if it was appropriate for others to cite his work to claim the 40% figure for animal extinctions, Wilcove said he had no idea where that number for animal extinctions came from.
Yet another widely cited paper turned out to be a four paragraph "paper" that claimed invasive species were a known factor in 54% of animal extinctions and the only known factor in 20%. Upon checking this, Pearce found the authors had based their information on IUCN's database on known extinctions and checking notes about the extinctions. They admitted that only 25% of the listed extinctions had any notes to check, meaning 3/4 of the extinct species were not included in this analysis at all. Nor was the database particularly comprehensive, listing only 680 extinctions. This means 170 extinctions had notes that they interpreted as caused by invasives.
When Pearce tried to analyze for bias this by looking at the database, he was unable to get much information. The authors could not explain how they decided invasive species were a causal element. Nobody has replicated this analysis.
This short 4 paragraph paper was a response pointed to another paper in the same journal. This article explicitly said "available data supporting invasion as a cause of extinctions are in many cases anecdotal, speculative, and based on limited observation." They pointed out that arriving in the same place at the same time that natives are declining does not prove cause and effect.
Which is to say, invasion biology rises from uncritical foundations and there is so much we do not actually know. There are studies that do show tangible damage in specific cases, but they tend to focus on very specific species that make up a small percentage of invasives and are conducted with pre-conceived bias against these species.
"There are no virgin forests out there, says Kathy Willis, director of science at Kew Gardens in London."
Not only is the estimate of the "damage" of invasive species somewhat shaky, the very concept of Eden we hark to is apocryphal.
The more "unspoiled" wildernesses are explored, the more we find evidence of early man's presence. As it turns out, "nature" has been resilient from the start. When farmed areas stopped being fertile, they were abandoned. Left untended, forests rebuilt themselves with whatever components were available at the time.
Forests regrow within a few centuries to the point where it's almost impossible to tell they were ever anything else.
There is also a myth that ecosystems have delicately evolved to a point of divine interdependence. That a single niche out of place will despoil it eternally. This is based on misconceptions of evolution that imagine a single elevated end to the process.
In reality, evolution is faster, messier and far more chaotic than it is divine or balanced. Any change in environment prompts a flurry of adaptation that can happen within generations. Darwin's finches evolve in one way to have thicker beaks and then another to have smaller beaks in response to droughts and floods within brief generations. Pesticides, herbicides, and antibiotics prompt extremely rapid evolution in their target species. Everything is changing all the time.
Coevolution happens (see ravens and wolves, crows/pigeons/house sparrows and humans), but ecological niches are not set in stone. Where one animal fills a niche, other animals develop other niches as specific as necessarily to avoid direct competition. When one animal/plant is removed, others fill it. It's the wild west of nature almost all the time.
"Most change is random. The result is not optimum—certainly not some preordained perfection—but a workable mishmash of species, constantly reorganized by a throw of the dice." - Stephen Gould
Nor has there ever been a solid or consistent ecosystem. Not only are flora and fauna changing, but they are moving. Constantly. The concept of native is abstract at best. Everything came to a new location at some point. And rarely all together in a solid ecosystem. And with the changes of climate coming now, they will continue to move.
"Looked at from this perspective, the spread of alien species today is merely a continuation of a natural process of the colonization begun when the ice retreated. A broad time horizon shows there is no such thing as a native species. All lodgings are temporary and all ecosystems in a constant flux, the victims of circumstance and geological accident."
Pearce concludes fairly convincingly that there are no true natives and no stable ecosystems. Instead of seeking perfection, conservation would benefit by looking at the places flora and fauna thrive. Often in the least expected places.
I think it's important to emphasize that Pearce doesn't proclaim that non-native species are never a problem. His main point is that our actual understanding is very limited and that many times we cause more damage attempting to eliminate them than simply allowing them to be absorbed into the greater ecosystem.
There is a need for weighting the costs and benefits. Especially when a plant (native or otherwise) impacts human economies or well-being, intervention may be appropriate. But the bias has to be addressed and understood. And it serves us to look beyond.
If nothing is wilderness, then what does it mean to be a conservationist? What and how do we conserve?
Nature was never "over there" while we were "over here". If you look in your backyard, the floorboards of your home, or an abandoned building, wild is always with us. We spend millions trying to keep wildlife out of our homes and fight losing battles trying to control what's in our lawns. We may want to believe we have control, but wild never goes away entirely.
"Nature" (that balance of intersecting lifeforms) rebounds when we simply let it do so. We've shaped our land to be more welcoming to "weeds" that love upended soils. So here they. We are attended by animals who have evolved to live with us in our cities and homes. Everywhere we let it, "the wild" comes with us and stays with us.
And remains where we once were. Chernobyl is populated by radioactive animals who continue to live their lives with winners and losers and adaptations to continue surviving there.
David Edwards of James Cook University in Australia found that 75 percent of bird and dung beetle species remained across a large logging concession covering 2.5 million acres in Sabah, Borneo, even after the entire concession had been logged over twice.
“Secondary forests of all ages should be protected. They are a hugely valuable safety net for biodiversity,” says Robin Chazdon of the University of Connecticut.
In other words, we should look deeper. We should look in unconventional places (other researchers have found that golf courses are actually amazing hotspots of biodiversity). And we need to find ways to be more thoughtful about promoting biodiversity and protecting human interests.
Pearce allows that humans will care about some species. We have our "favorite mascots" like the panda and the condor. And that's ok. We are allowed to change the environment to preserve what we love. But striving for perfect virginity and crystalizing a moment in time will hinder growth and ignore the true wild around us.
"In a world of climate change, where the old wild is hemmed in by human activity, these ecosystem islands will increasingly resemble museum pieces, time capsules, and experimental labs for scientists. They will not be wild in any true sense. On the other hand, the novel ecosystems, the make-do-and-mend places, will be the ones able to stand on their own two feet. They will be the new wild"
He doesn't quite say so, but I don't think he cries in his soup much about the animals that didn't make it. His story ends with speculation about the massive speciation and migrations that global warming will trigger. And while he may express some concern for those animals ill-suited to their environment, he strongly points to the many new ones that will emerge if we allow them to.
( He does however raise a quick concern for the decline of the same animals I championed previously - if the house sparrow, pigeon and starling are struggling, we should likely by concerned for ourselves.)
My complementary thought on this is that humans are a part of nature, but part of our human nature is having a mind with a moral sense. Most likely an adaptation that allows humans to live more successfully in groups, a moral sense frequently includes an element of avoiding causing unnecessary. I think what we call necessary will vary by how we rationalize, but I also think it alone can be a fairly natural reason to not kill cruelly or excessively (I won't say for pleasure, because hunters are actually quite active and successful conservationists). I think perhaps it's simply natural to express horror at the eradication of the passenger pigeon and the great auk because it didn't need to happen and it reflects on the unsustainable urges of humanity to consume beyond replacement.
Beyond but related to this, yes, nature will persist. Indubitably. If humans overextend their reach, they will hit a max die off and nature will carry on just as it did in Chernobyl. Conservation problem solved. As a human, though, that's a suboptimal outcome. Not only is that morally unappealing, but it's just straight up unappealing to us in the masses who'd likely be part of the die off. And so human interest certainly and unsurprisingly centers itself in the human practice of conservation.
And on that note, I quite love that we end with a message of qualified hope. The world is always changing and nothing can stop that, but we have some discretion in how we respond to that. I'm down with just enjoying the danged starlings as long as they aren't shrieking outside my window at midnight (I have my limits with all creatures!)
And on that note, I wish you all a very toasty little world cup weekend!
