Guest Post by Willis Eschenbach, title from a Paula Abdul quote
The backstory for today’s adventure is that this is the first scientific question I seriously researched. It is also the reason I don’t trust the “experts” or the “consensus”. In 1988, E. O. Wilson, an ant expert with little knowledge of extinction, made a startling claim that extinction rates were through the roof. He claimed there was a “Sixth Wave” of extinctions going on, and that we were losing a huge amount, 2.7% of all the species per year. This claim quickly went viral and soon was believed by everyone. So back in 2003, a decade ago now, I researched the question, found that Wilson was wrong by orders of magnitude, wrote it up, sent it around to the journals to see if they would publish it, and … well, let me just say that I was not received kindly. I was a voice crying in the wilderness. They didn’t give me a look-in, I was challenging the consensus. As far as I know, I was the only one saying that Emperor Wilson had no clothes … and as a result, I was not encouraged to continue publicizing my views.
But the world goes on, and three years ago I simplified and streamlined my work and published it as a post on WUWT entitled “Where Are The Corpses“. In it, I argued that there was no “Sixth Wave” of extinctions, that Wilson’s numbers were wildly exaggerated, and that current extinction rates (except in isolated islands and Australia) are not unusual in any way. Dr. Craig Loehle rewrote and developed the ideas, and he got it peer-reviewed and published in Diversity and Distributions, available here. Craig wrote about it in a post entitled “New paper from Loehle & Eschenbach shows extinction data has been wrongly blamed on climate change due to island species sensitivity“. Title says it all …
Figure 1. Stacked graph of total historical bird and mammal extinctions by year. This charts of the spread of European species (foxes, cats, rabbits, dogs, humans, weeds, diseases, etc.) to Australia and the islands. The earliest extinctions are from the time Europeans arrived in the Caribbean. There is a second wave of exploration and settlement in the 1700s. Finally, the spread of empires in the 1800’s led to the peak rates around the turn of the last century. Since then, the rates have dropped.
Having written so early and so extensively to try to debunk the claims of massive extinction rates and the bogus “sixth wave of extinction” hyped by the alarmists, I was pleased to receive a note from Anthony pointing out the publication of a new study in Science magazine (paywalled, naturally) entitled Can We Name Earth’s Species Before They Go Extinct? It’s gotten lots of media attention, mostly due to the fact that in the Abstract, they say that estimates of extinction rates are way overblown. My emphasis:
Some people despair that most species will go extinct before they are discovered. However, such worries result from overestimates of how many species may exist, beliefs that the expertise to describe species is decreasing, and alarmist estimates of extinction rates.
I must say, seeing that phrase “alarmist estimates of extinction rates” in Science made me smile, it was a huge vindication. However, I fear that they still have not grasped the nettle. I say that because at the end of the paper they say:
Conclusion
The estimates of how many species are on Earth (5 ± 3 million) are now more accurate than the moderate predictions of extinction rates (0.01 to 1% per decade). The latter suggest 500 to 50,000 extinctions per decade if there are 5 million species on Earth.
Why do I think that their conclusion is so badly flawed?
Like many modern scientists, rather than trying to find the most probable, they simply assume the worst. So they give their calculations assuming a 1% decadal extinction rate. Here’s the problem. That’s no more believable than Wilson’s 2.7% per decade rate. There are about 3,300 mammal species living on the continents (excluding Australia). If we assume that one percent of them go extinct per decade, that would mean that we should be seeing about 33 continental mammal extinctions per decade. It’s worse for birds, a 1% extinction rate for birds would be about 80 continental birds per decade. We have seen absolutely nothing even vaguely resembling that. That’s only slightly below Wilson’s estimate of a 2.7% extinction rate, and is still ridiculously high.
Instead of 33 mammals and 80 birds going extinct on the continents per decade, in the last 500 years on the great continental landmasses of the world, we’ve only seen three mammals and six birds go extinct. Only nine continental mammal and bird species are known to have gone extinct in 500 years. Three mammals and six birds in 500 years, that’s less than one continental mammal extinction per century, and these highly scientific folks are claiming that 30 mammals and 80 birds are going extinct per decade? … once again I’m forced to ask, where are the corpses?
This kind of world-blindness astounds me. I’ve heard of living in an ivory tower, but if you were making the claim that it’s raining, wouldn’t you at least look out the ivory windows to see if water were actually falling from the sky? How can you seriously claim that we’re losing dozens and dozens of species per year when there is absolutely no sign of that in the records?
Because the reality is that despite humans cutting down the forests of the world at a rate of knots for hundreds and hundreds of years, despite clearcutting for lumber, despite slash-and-burn, despite conversions to cropland, despite building hundreds of thousands of miles of roads and fences, despite everything … only nine continental mammal and bird species have gone extinct.
That gives us actual, not theoretical but actual, estimates of the historical extinction rates for continental birds and animals. For continental mammals that works out to 3 extinctions per 3,300 continental mammal species per 50 decades equals 0.002% per decade, somewhat below their low estimate of 0.01% per decade. For birds, it’s 6 extinctions per 8000 continental species per 50 decades, which is only slightly lower. If we assume that we’ve missed four out of five of the historical extinctions, very unlikely but I suppose possible, it still works out to only about 0.01%.
So their very lowest estimate, that of an extinction rate of 0.01% per decade, turns out to be a maximum estimate of what we’ve seen on the continents over the last five centuries.
Now, this does not include the islands and Australia. Rates there have historically been quite high. But the high historical rates there, as shown above in Figure 1, are the result of what might be called “First Contact”—the first introduction of numbers of European plants, animals, and diseases to previously isolated areas. But in 2013, there are few islands on the planet that haven’t seen First Contact. As a result, the extinction rates on the islands and in Australia, while still higher than on the continents, are extremely unlikely to have another peak such as they had at First Contact.
Finally, let me say that the low extinction rates should not be any cause for complacency. What my studies have shown is that the real threat to mammal and bird species is not habitat reduction, as incorrectly claimed for the last couple decades. The real extinction threat to birds and mammals is now and always has been predation, either by humans, or by imported “alien” species, particularly on islands. Hunting by humans threatens bonobo chimpanzees and other primates, as well as tigers, rhinoceros, and other mammal and bird species. Hunting is the extinction threat, not habitat destruction, and always has been, whether the hunters were animals or humans.
CODA
People are always giving me grief about how I’m not getting with the picture, I’m not following the herd, I’m not kowtowing to the consensus. I have no problem doing that, particularly given my experience regarding extinctions. For years I was the only person I knew of who was making the claim that E. O. Wilson should have stuck to his ants and left extinctions alone. Wherever I looked scientists disagreed with my findings. I didn’t have one person I knew, or one person I read, who thought I was right. Heck, even now, a decade later, the nettle still hasn’t been grasped, people are just beginning to realize that they were fools to blindly believe Wilson, and to try to manage a graceful climb down from the positions they took.
What I learned in that episode was that my bad number detector works quite well, that I should stick to my guns if I think I’m right, and that I should never, ever, ever place any faith in the opinions of the experts. They were all wrong, every single last swingin’ Richard of them, and I was right. Doesn’t mean I’ll be right next time, I’ve been wrong plenty both before and since … but it has given me the courage to hold on to some extremely minority positions.
It is my strong belief that I will also be vindicated in my claim that the earth’s temperature is regulated, not by CO2, but by a host of interlocking and mutually supportive homeostatic mechanisms that maintain the temperature within a fairly narrow range … time will tell. In my opinion, the experts in the climate field have shown that they don’t know a whole lot more about the real underpinnings of the climate than E. O. Wilson knew about extinctions … but that’s just me, and YMMV.
The very finest of a lovely day to you all,
w.
One “Rexx Vernon Shelton,” like me, is cross posting about this, here
http://www.volokh.com/2013/01/26/exaggerating-species-extinction-the-sequel/
at an environmental law prof’s blog.
Willis is described as a “crank” who can be dismissed (presumably by law students).
Only late in the discussion at volokh.com are commenter’s addressing biologists elastic notions of “species.” I don’t care is they have rationales; I only care that they are consistent or inconsistent, as Willis shows us this to be the precise problem.
trafamadore says:
January 26, 2013 at 7:19 pm
Thanks, tralf. I had to do a search to make sure exactly what the “100x” means. It relates to what you said above.
trafamadore says:
January 26, 2013 at 8:18 am
Let me go over this again. I explained it above, but it didn’t seem to take.
Your claim is that we are losing some 1,000 species per million species per year (100 x 10). That’s one species per thousand going extinct per year. There are about 3,300 mammals living on the continents. You say that the extinction rate is one per thousand species per year, or about 330 mammals going extinct every century on the continents. That works out to about 1,600 continental mammal species that should have gone extinct in the last 500 years, according to your figures.
Now, let’s compare that with reality. We now (including the Red-Bellied Gracile Mouse Opossum, declared extinct in 2008) have four mammal extinctions on the continents in the last 500 years.
SO … your claimed extinction rate would result in 1,600 continental mammal extinctions in 500 years.
We have seen 4.
So that shows your rate is orders of magnitude high for the continental mammals. For the continental birds, it’s worse. By your claimed extinction rate, we should have seen the extinction of 4,000 continental birds in the last 500 years … and we’ve seen six. And these are the very groups that Wilson said would be the hardest hit by his claimed extinctions from habitat reduction. Since their extinction rates have not been affected by habitat reduction, we have no reason to assume the extinction rates of other species are affected. Thus endeth my demonstration that your 100x is way too large.
Now, you may be claiming that the extinction rate has recently increased by 100 fold, but we just haven’t seen the extinctions yet … but that is exactly the same claim E. O. Wilson made a quarter century ago, so I’m afraid that claim is well past its use-by date. I went over those numbers in my original post.
You see, the problem with claiming that the extinction rate went up recently is that Wilson claimed the increase was due to habitat reduction, particularly in forests. He wasn’t talking about introduced species on the islands. He said that forest loss was the cause of the “Sixth Wave of Extinctions”. But we’ve been reducing forest habitat for centuries with no visible effect on the extinction rate, so the claim that we just haven’t seen it yet can’t be sustained.
I know what my conclusion from these numbers is, tralfie. I conclude that on the continents, 96% of the land area of our astounding planet, your claimed extinction rate is not 100x too high, it is 1000x too high. I also conclude that Wilson didn’t know what he was talking about regarding habitat reduction, and that there is no “Sixth Wave of Extinction”.
I can’t even begin to guess what you might conclude from these numbers, however, and I’m fairly sure I don’t want to know …
w.
PS—Does this prove anything about the extinction rates of e.g. the creatures surrounding the deep-sea hot smoker vents?
Nope, not one single thing, never said it did … but then, I’m talking about Wilson’s predicted extinctions and historical extinctions as they apply to birds and mammals facing habitat changes, not hydrophilic shrimp living in an environment unchanged for billions of years …
S. Meyer;
So why are we arguing? I just don’t like name-calling.
>>>>>>>>>>>>>>>>>>
Because respect is earned, not demanded. People with differing opinions may encounter a frosty reception here, but if they back their position with facts and logic they get respect. If they argue by assertion and condescension and refusal to even acknowledge points of view that they cannot refute with facts and logic, then they are just a troll and deserve to be treated as such. I think that Willis has been remarkably patient under the circumstances, and tramafadore has gotten off rather lightly. But she’s made rather a fool of herself in the process and at some point there is little value in failing to call a spade a spade.
Definitely worth another; ummmm…
Traffy; you really do your homework don’t you; NOT!
Just because in today’s world there are dense jungles in the tropics with plenty of critter &, plants doesn’t mean they’ve been jungles forever. http://news.mongabay.com/2005/1017-amazon.html.
Name a jungle. Are there ruins there? Most likely. Man has thrived in tropical conditions and suffered localized extinction events themselves. Odd isn’t it that all these jungle type of areas grew back and repopulated.
In America the Native American used to burn the undergrowth and fallen wood out every few years. An untouched virgin forest is danged hard to traverse; what with all of the undergrowth and fallen debris.
In the midwest, Native American burned acreage for several reasons; to form controlled food collection points gathering the fleeing animals, also to keep that difficult woody growth from interfering with all of that grassland. Bison ranged across North America and originally biologists believed that Eastern bison were a separate species and were driven extinct. Now it is believed the bison that ranged the Eastern woods were Eastern wandering bison. Only it is hard for ruminants to thrive in heavy forest. The original colonists didn’t hunt a lot of deer or bison; mostly they ate squirrel and birds. The deer thrived after the woods was cut down; bison probably would have if they weren’t already et.
The Amazon is believed to have supported a large sedentary population with large areas deforested. All that lime the South American natives used had to be kilned somehow…
Anyway Traffy; people here have put up with your incessant troll type whining. If you’ve paid any attention, you should’ve learned a lot…
Only, learning doesn’t seem to be your purpose in visiting WUWT. Nor is debating science; It is a puzzle why you are here as you consistently nit pick non-issues, off topic points, bizarre takes on plainly spoken logic and just forever harping about how inferior our logic, data and deductions are… You’ve certainly haven’t been able to demonstrate nor elucidate better science at any level.
Well Traffy, it all goes to prove how it isn’t a good idea to feed trolls. Trolls are a lot like pigeons, they crowd the font, bully others, crap all over and then leave without a “thank you” or care in the world. Only trolls, much like your visits here, are far worse than pigeons and I feel bad for sullying the pigeons.
If by some sad and disappointing inference you are that Trenbbbbb fellow, go find some more travesties. We’ve a little full up with your current travesty attempt here.
PS I hear there are deep warm pools of water caused by global warmbats in the Congo; maybe you should visit there and check it out…
Willis:
In response to your talk at ICCC7 (which I liked so much — thanks to Canman for posting the link): I think the extinction of the slide rule was not a good thing.
I was one of last few schoolchildren who were still taught to use it, and I totally didn’t get it. It was pure magic, and I did not like magic. Plus, I was one of the first schoolchildren on the planet with an electronic calculator in my pocket, so I totally missed the significance of the slide rule.
I believe the mistake on educators’ part that lead to the demise of slide rule’s (and much else, as a consequence) was to make it an object of learning. As such, it was not terribly interesting. If instead it was used as a means to teach mathematics in general — number theory, algebra, operations, projections, and probably a whole lot of other useful abstractions (as well as the art of making abstractions itself), we would probably be a much more numerate society today.
Come to think of it, there is no other object you can hold in your hand that materialises so many key ideas in mathematics. I only realised how great a teaching aid it was when my own children grew up enough to be challenged with the same ideas, and they didn’t like magic any more than I did. We started by playing with the “additive slide rule”, which was just a pair of regular rulers (or just strips of cardboard, which I later found to be better than pre-graduated rulers because you can mark them any way you want). With that, you don’t have to strenuously wrap your brain around questions like how much -1 – (-1 – 1) will be. I claim, you use more of your brain (and the more powerful parts of it) while playing with a pair of rulers to solve that problem than when you do it as a purely mental exercise, as the school wants you to do. In passing, you discover (or reinforce) the ideas of identity (zero distance) and negation (if you can travel a certain distance forward, you can then go back the same distance). With numbers visualised as distances and materialised as marks on real objects, additive algebra becomes a screaming fun. I actually had to stop my children once I knew they had got it, so we could go to the next stage (same with many more children I introduced to the slide rule later — it was too much fun).
The next step captures the gist of the “multiplicative” slide rule that engineers use(d). You take the graduated strips of cardboard we played with earlier and simply rename their divisions, like so: 0 -> 1, 1 -> 2, 2 -> 4, …, and hand them to your students without saying a word. What follows is a bliss. They typically have to be prompted to do this renaming trick (I have not seen a single child yet who would discover it by chance), but once presented with the renamed version, they immediately understand its purpose:
“Wow, multiplication is just addition by other name!”
“Now I need to put 1/2 on the other side of 1, where -1 was.”
“Let’s make another pair of rulers for number 3.”
“That’s way cool! Can we now have 2 and 3 on the same ruler?”
After a few iterations and a few more cardboard strips in the waste bin, they make a passable slide rule that can do 3 / 2 = 1.5 or 7 * 5 = 35. When they reach that stage, you pull your dad’s slide rule out of the closet and hand it to them. It is mesmerising to watch what they do with it.
I believe the slide rule must be made a protected species. We’re missing too much fun without it.
“Man, I can now see where 6 is, 1/6 and 1.5!”
take it to the end, all by themselves, and within an hour or two of unbounded fun you see them make a decent slide rule with, after a few iterations, they have a
Mr. Eschenbach:
I presume the six continental bird species to which you refer include the well-known cases of the Labrador duck, great auk (also from islands, of course), passenger pigeon & Carolina parakeet. To these I would add three or four Latin American species–the Colombian grebe & Bogota sunangel (probable), Atitlan grebe of Guatemala & slender-billed grackle of Mexico–for a total of seven or eight extinctions in the past few hundred years.
There are another 19 or so instances of possible or probable extinction of non-island, non-Australian birds, but either the species are dubious or there’s a chance they might still exist, like the ivory-billed woodpecker of Arkansas & imperial woodpecker of Mexico.
In any case, your thesis is valid. The numerous island & Australia extinctions skew the record.
Trafamadore, you say, ” from Traf: Our children will never see them. Never. They might as well be the dinosaurs, except we know what color their skin was and that they didnt have feathers”….”
So let me get this straight you blithering fool, evolution should stop right now, in 2013 so you children can see them. Absolutely pathetic.
atheok says: “Just because in today’s world there are dense jungles in the tropics with plenty of critter &, plants doesn’t mean they’ve been jungles forever.”
First, I really dont remember arguing this. And next, the species diversity in the Tropics is many many times that in temperate regions. And, maybe people were clearing jungle long ago, but the Congo and Amazon jungles are 10s of millions of years old, old enuf to have their own fish, animals etc (long before people/chimps _ancestors_ existed). Compare that to the Great Lakes, almost a ecological desert by comparison, only 10000 years old.
No such luck. I figure the climbdown is going to be effected without anyone ever really admitting that Wilson had his head up his anomaly and fooled just about everyone.
So write a comment/letter to Science. Their editors will be more or less obligated to publish it. The paper appears to make an unreferenced claim for extinction rates; you have a prior claim supported by data and a short, cogent argument.
Let me make the counter-argument, not as an expert, but just for the grins of it. Note that estimates for the number of species vary wildly and are constantly changing, in part because it is difficult for even the biologists to decide what is a different species and what is simply a variant of an existing one. This question is subtle, because species can often freely interbreed. As an example, note that all dog breeds are one species, where finches that to the eye are far more identical and that can equally well interbreed (and that have the same number of chromosomes etc) are not. If biologists from an alien planet arrived on Earth, would they consider the Chihuahua and Great Dane the same species?
This isn’t just my imagination. See:
http://en.wikipedia.org/wiki/Species_problem
This problem lies at the heart of the issue, because without an accepted solution nobody will ever agree on the baseline numbers or rates, will they?
When one counts the species (by any measure), the numbers of species diverges the farther down the phylogenetic chain one descends. Tens of primate species, thousands of mammal species, tens of thousands of bird species — a crude count is given here:
http://en.wikipedia.org/wiki/Species
Note that they count only 60,000 odd thousand vertebrates combined, another 1.3 million invertebrate animals, 4 or 5 hundred thousand plants and lichens and algae and then the numbers get really interesting — 10 to 30 million insects (say what?). 1.5 million fungi? A million mites? 5 to 10 million bacteria?
Then look at the chart on the right. These numbers include vast, vast numbers of species that supposedly exist but are undiscovered. Out in this genetic terra incognita anything could be true, so how can any claim be falsified? If there are nine to twenty-nine million undiscovered insect species, how can any claim of species extinction rate be falsified? Even if, in fifty years, we find that there are only two million species of insects discovered after looking very, very hard for new species, that could only mean that in the intervening interval we killed off as many as twenty-eight million of them in the greatest extinction event of all time!
The situation with bacteria is even worse, because new species are very probably constantly emerging and going extinct that far down the chain. Again one gets into difficulties with the term “species” — how much divergence is required for a variation on a prevalent green monkey disease to count as HIV? How much variation is there between MRSA (antibiotic resistant staph aureous, bred in our hospitals with great care) and the old non-resistant SA, compared to variations between other staph species? These are subtle questions, although in the end mapping all of the genes of all proposed distinct “species” may render the questions moot. There very likely is no sharp line here, only a blurring and accumulation of small discrete mutations that eventually push a centroid of sorts outside of the range of “natural” single generation variation.
The final thing that contributes to the enormous range of variation in the estimates of extinction rates is localization. In very specific areas of the US and Canada there is a melanistic subgroup of the Eastern Grey Squirrel, the Black Squirrel:
http://en.wikipedia.org/wiki/Black_squirrel
They are common in the suburbs of Detroit, for example. In North Carolina I’ve never seen a black squirrel, although we’ve a ton of grey ones. Nothing between the ones in Detroit and NC but miles of trees. Black squirrels are not considered different species (although once they might have been, and the question of how space aliens would count them still applies) but they tend to live in small enclaves and breed true. Reportedly, black squirrels were once the dominant kind of North American squirrel and enjoy certain survival advantages over the grey subgroup, but deforestation and human pressure supposedly shifted the evolutionary selection in favor of the greys as European settlers cut down all the trees and found squirrel (black or not) very tasty.
Insect species are far less mobile than squirrels, and spiders that live on one particular mountain can easily be isolated from spiders that live two mountails away (separated by several streams). Variations that started out no more significant than that of a grey vs black squirrel can easily build up over hundreds or thousands of years to the point where a naturalist, eager to have a species named after him (the reward of discovery, after all) claims a discovery of a new species because the two variations have a very slightly different pattern of spots, or average size, even though the two species, placed on a single mountain in between, would cheerfully interbreed and there is no real survival advantage or structural difference and even the DNA is only trivially different.
Comes the day when the forest on the first mountain is all cut down for timber, killing every last spider living on it, did the Earth lose a species? Suppose that mountain held the world’s last reserve of black squirrels? How about then? There might be far more practical and visible variation between black and grey squirrels than between the two supposedly different spiders, but killing off every black squirrel will not make Eastern Grey Squirrels extinct (and being mobile, they will be much harder to kill off anyway).
This is where complexity and counting become very important — and difficult. If one counts “every” geographically localized variation of bacteria, insects, fungi, fish, and so on as different species (including ones that are far less obvious than the difference between a Chihuahua and a Great Dane or grey versus black Grey Squirrels without a clear definition of species and with a huge career incentive for the discovery of new species (many claims for which will necessarily go unchallenged because there is no profit in challenging somebody else’s claim, only in making a new one yourself) then one can make almost any claim you like about the rate at which undiscovered species are or will go extinct and it can never be falsified.
A million species of insect might have been wiped out during the settlement of the US and nobody could prove it or prove that it didn’t happen. Two million species of bacteria could be wiped out by a two degree centigrade warming — or not — and without an actual count of and clear definition of ten million presumed species of bacteria who will ever know?
The right way to answer this question would be to first of all come up with a hard definition of species, one that creates a clear boundary at the level of DNA. This is almost impossible, as hybrids occur between widely different species and often are not sterile — nature is far more variable than we might have once thought, so the simple criterion of being able to interbreed and not terminate in sterile “mules” is not adequate (and of course inapplicable to bacteria and yeast and fungi) but without a quantitative definition the question can never be answered in an objective way although a reformed version of the question — how fast is the genetic variability of various phylogenetic divisions of living beings changing, how is the volume of genetic phase space changing — may be.
Then one could at least formulate statistical estimates of rates by sampling what goes on in the various phyla.
This is where Willis’ estimate comes up short (again, remember that I’m playing the Devil’s Advocate here). Mammal extinction rates and bird extinction rates are no more than noise on the overall extinction rates one expects. Mammals only rarely fill narrow, geographically isolated niches. Birds are similarly highly mobile and remarkably tolerant in the range of habitat that will support them. Spiders, however, may be differentiated hill by hill, mesa by mesa, valley by valley. Ants, mites, fungi — how different do they have to be to really be different? Is it reasonable to consider a variation of spider to be “made extinct” if it dies off on its localized hillside when one or two hills over a very close cousin is perfectly capable of filling precisely the same niche and not even be noticed as being “different”?
With all that said, I agree with Willis’ general suggestion that mass extinction is very probably an exaggerated claim, even by the second Science article. But in a claim for precedence in a letter to Science, it might be worthwhile to avoid the argument based on mammals and birds and focus on the big money, bacteria and insects.
“The estimates of how many species are on Earth (5 ± 3 million) are now more accurate than the moderate predictions of extinction rates (0.01 to 1% per decade). The latter suggest 500 to 50,000 extinctions per decade if there are 5 million species on Earth.”
“Like many modern scientists, rather than trying to find the most probable, they simply assume the worst. So they give their calculations assuming a 1% decadal extinction rate. Here’s the problem. That’s no more believable than Wilson’s 2.7% per decade rate. There are about 3,300 mammal species living on the continents (excluding Australia). If we assume that one percent of them go extinct per decade, that would mean that we should be seeing about 33 continental mammal extinctions per decade. It’s worse for birds, a 1% extinction rate for birds would be about 80 continental birds per decade. We have seen absolutely nothing even vaguely resembling that. That’s only slightly below Wilson’s estimate of a 2.7% extinction rate, and is still ridiculously high.
Instead of 33 mammals and 80 birds going extinct on the continents per decade, in the last 500 years on the great continental landmasses of the world, we’ve only seen three mammals and six birds go extinct.”
Good demonstration.
Also one may note, as the above highlights implicitly albeit not explicitly, the “millions of species” comes predominately from a supposed number of invertebrates, such as the number of theoretically technically slightly species-defining distinctions amongst bugs in jungles, etc. (so difficult to even notice or for many people to care to try to count that their figure is 5 ± 3 million, as in some nebulous number imagined to be easily anywhere from 2 to 8 million; the “Red List” mainly doesn’t bother to include insects, but only by predominately invertebrates can figures of millions of species be generated).
For what most people more ordinarily think of and care about as significant species, the total is more thousands than millions. From that, look at the limited percentage and smaller number in extinction risk, and sufficient millions of dollars each if needed to save / breed them would be trivial next to the world economy which is hundreds of trillions of dollars (hundreds of millions of millions of dollars) a decade, in contrast to activist attempts to use species extinction as an excuse to demand decimating civilization in general. Different plant species are somewhat more numerous but cheaper still to preserve each.
As for the multitude of subtle insect variations hypothetically at risk of extinction, most are concentrated in a few rain forest areas (jungles); such can be an argument for wilderness preserves there (as often exist), but human activity in the bulk of the world is simply irrelevant to them, like there is no huge multitude of insect species at risk from economic development in South Dakota.
My anecdotal observations show improvement in many species over the last decades.
Whitetail deer — increased to the point of overpopulation
Wild turkey — encroaching now into suburbs
Canada geese — again, to the point of overpopulation in some areas
Great blue herons — never saw any in the Appalachian mnts until recently, now there’s even a “regular” that patrols my border-stream in all seasons
Green herons along my stream
Bald eagles — see them regularly now in the watershed of the south branch of the Potomac river in WV
Hawks
Barred owls — encroaching even into suburban areas
Fish in small Appalachian streams — mostly introduced brown trout and blue-gills. State regulations enforcing “green-borders” along wetlands have benefited them
Chorus frogs, tree frogs and spring-peepers (frogs) in low, moist forests & streams
Pileated woodpeckers — again, encroaching into suburban areas
Sugar maples invading southeastward into formerly all oak-hickory-tuliptree forests
Alot of this has to do with human cultural changes, but it demonstrates the insignificance of supposed “climate-change” compared to other factors.
milodonharlani says:
January 27, 2013 at 6:39 am
If you have to ask that, I presume you have not done your homework. Go read the underlying documents referenced in the head post, and come back when you know what we’re talking about. I specified and discussed each species that has gone extinct.
Thanks,
w.
Gene Selkov says:
January 27, 2013 at 5:33 am
I agree wholehearted, otherwise, it’ll be just another victim of the fabled Sixth Wave of Extinction …
w.
rgbatduke, thanks as always for a reasoned and interesting comment.
You point out the vagueness of the boundary between species, and you are correct. Additionally, you are correct to point out that we could have wiped out a whole host of bacterial species when Europeans colonized the US, and we could not tell either way.
Finally, you say that the extinction rates of birds and mammals is not representative of other groups, which is also true.
However, there are a couple of related and significant issues.
First, ever since I was a kid, the estimate of the number of species has been steadily dropping. There were suppose to be hundreds of millions when I was young. Then it went down to tens of millions, and then to ten million (the figure used by E. O. Wilson), and in this paper it has dropped down to 5 ± 3 million, or perhaps as few as 2 million.
So I’d be very cautious about a Wikipedia claim that there are “10 to 30 million insect species” … that one is a serious outlier.
Second, while it gets kinda vague down in the basement morass of archaea and bacteria viruses and fungi and the like, there is a clear difference between say an eastern and a western cougar on the one hand, and an eastern cougar and an elephant on the other hand. The concept of “species”, while somewhat vague down in the basement, works fairly well here in the upper floors.
And while the original definition (a male and female of the same species can have fertile offspring) often doesn’t work down in the basement, by and large here on the upper floors it does provide a bright-line definition. As a result, if the algerian gazelle and the red-bellied gracile mouse opossum both go extinct, we can be damn sure they are not the same species, and that there are no red-bellied algerian gracile gazelle opossums running around anywhere.
Finally, let me return to the reason I began this study. E. O. Wilson used a simplistic method, called the “species-area relationship”, to estimate the rate of extinction of species due to the reduction of forest habitat. I have not tried, for obvious reasons, to determine if it is true about amazonian spider-mites … because there is no way to establish that one either way.
Instead, I focused on the group that E. O. Wilson claimed would show the highest rates, birds and mammals. His is a reasonable claim, given that the average lifespans of mammal and bird species are at the shorter end of the scale for species in general, and thus they must be easier to drive extinct than many other species.
Clearly, as you point out, my method has shortcomings. But I would argue that we simply do not have the data to calculate the extinction rates of other species. But given that bird and mammal species are known to have short species lifespans, and that we have put huge hunting pressure on both birds and mammals which we have not put on other groups, I think that using them as the canaries in the mine is fully justified.
Care to join me in writing a letter to Science? If it is signed by a PhD it’ll get more traction. I have not had good luck with such letters in the past, but past performance is no guarantee of future results, like the stock brokers say …
Thanks as always, I never fail to both enjoy and learn something from your comments.
w.
> And while the original definition (a male and female of the same species can have fertile offspring) often doesn’t work down in the basement, by and large here on the upper floors it does provide a bright-line definition.
Just to elaborate a bit on Willis’s “by and large” remark: it does not work for the so-called “ring species”, some of which include frogs.
Orson Olson says:
January 26, 2013 at 10:45 pm
Thanks, Orson. I went there, can’t find it. I find the article, but no comments … what am I missing?
w.
Gene Selkov says:
January 27, 2013 at 11:57 am
Thanks for the clarification, Gene. You raise an interesting issue. Here’s a definition of “ring species”:
Since the citation says “we can observe two species and the intermediate forms connecting them”, I fail to see how they are not using the standard definition of a species. When they say “two species”, they are calling them two species because the two groups of frogs can’t interbreed.
Yes, they are connected by intermediate forms that can interbreed … and? All that does is recapitulate the usual temporal history of speciation (gradual change over time until interbreeding is impossible) in one location. Or as Ernst Mayr observed, he called ring species not a disproof of speciation, but ““the perfect demonstration of speciation”.
So even in the ring species, the ones that can’t interbreed, they are calling two species that can’t interbreed “separate species”. Yes, you are quite correct that ring species do make the lines somewhat fuzzier. But any two given critters either can or cannot interbreed, and on that basis, if they can’t interbreed people call them different species.
Now, when you get to creatures without sex, where are the species lines? When you get to creatures that swap genes horizontally, where are the species lines? Hows about creatures that do both? In those situations, the idea of a “species” doesn’t have much meaning.
But for the overwhelming majority of the creatures that we deal with on a daily basis, they do exist in different species, there are (fairly) bright lines dividing the species, and for those beings, the concept of a “species” is quite useful and productive.
My thanks to you for raising the issue.
w.
Willis,
This statement you quote from Wikipedia:
• At one location in the ring of populations, two distinct forms coexist without interbreeding, and hence are different species.
.contains what I think is a misstatement as applied to a general case, unless that “one location in the ring” includes the lab setting where individuals are tested for their ability to breed. Normally, you see “two distinct forms” when you pick the individuals from the opposite ends of any diameter, but not from any short segment of the ring. It is the fact that you can pick any pair of the not-so-distant neighbours and see them breed, but not if they are distant enough, that makes it really fuzzy. In other words, the interbreeding relationship is only locally transitive.
Mr. Eschenbach:
You did discuss the species which qualified according to your view, but you did not consider the many “continental” bird species that arguably could or should be considered extinct, detailing why you reject them.
For instance, the great auk bred on offshore islands in historic times (unclear about prehistory), but it fed in continental shelf seas, so close to land that it was exploited by humans for millennia. The Cozumel thrasher lived on an island, but very close to land (probably attached to the mainland during glaciations), as opposed to the oceanic islands which have seen such devastation due to human activities. Cuba & Puerto Rico however are far enough from land IMO to be considered uncontinental, despite their prehistoric human occupations.
The Bogota sunangel hummingbird was considered a possible hybrid until DNA analysis in 2009 showed it to have been a distinct species, now assumed extinct. Similarly, a study has found the coppery or Letitia’s thorntail a species rather than subspecies or hybrid. Another presumably extinct South American hummingbird, the turquoise-throated or Godin’s puffleg, has been considered a hybrid or subspecies.
To the species problem must be added the “continental” birds probably extinct but awaiting surveys of every last possible little bit of habitat, including such well known cases as the two North American woodpeckers I mentioned & the Eskimo & slender-billed curlews. The Himalayan quail, for instance, hasn’t definitely been sighted since 1876, but is still listed as critically endangered rather than extinct. Same goes for the hooded seedeater (reported in 1823), Rueck’s blue fly-catcher (last seen in 1918), Tachira antpitta (1956), Korean crested shelduck (1964), white-eyed river martin (1980, but possibly more recently), Red Sea cliff swallow (1984), Bachman’s warbler (1988 in US, but wintered in Cuba), Tana River cisticola & glaucous macaw. At least some of these rare birds are likely in fact to be extinct.
Doubling, tripling or quadrupling the number of qualifying extinctions wouldn’t affect your argument much, but IMO some discussion of such considerations would be proper.
rgbatduke says:
”Is it reasonable to consider a variation of spider to be “made extinct” if it dies off on its localized hillside when one or two hills over a very close cousin is perfectly capable of filling precisely the same niche and not even be noticed as being “different”?”
That seems to me to be a much more important question if we’re trying to determine if we’re in the throes of a mass extinction or not. What characteristic marks the previous mass extinctions? Did they not leave vast arrays of vacant niches? For example, the 65 MA event that did in the dinosaurs (except birds) left niches available for mammals to evolve to fill ultimately giving rise to us. Trying to figure out whether we’re in a mass extinction event by counting species seems to just get bogged down in trying to separate the wheat from the chaff, which Willis does a decent job of by excluding all but continental mammals and birds but perhaps could be improved upon by analyzing niche availability instead.
It has been suggested that there are a finite number of niches: http://www.jstor.org/discover/10.2307/2423567?uid=3739848&uid=2129&uid=2&uid=70&uid=4&uid=3739256&sid=21101594178651
If so, couldn’t we potentially survey available niches to determine if extinction rates are leaving an unusual amount of resources unutilized, i.e. vacant niches?
Mr. West:
The number of ecological niches is certainly finite, but not constant.
Ecosystem complexity generally increases with time, except for epochs in the wake of great mass extinction events. Cambrian niches were fewer than Ordovician & especially than Silurian or Devonian, after green plants evolved & animals began to colonize terrestrial environments.
The spread of grasslands & diminution of forests in the Cenozoic both created new niches & reduced others.
Willis @12:59: “The figure of 99.9999% of all species being extinct is likely an exaggeration, my calculations put it at about 99.8% of all species being extinct.”
Thanks, Willis. You have laid out some reasonable calculations for the figure. I would add just two caveats:
First, the number is based on estimates which are then extrapolated. The number is not based on actual counts in the fossil record. Now to be sure we could argue that the fossil record is not expected to show but a miniscule fraction of extinct species due to fossil degradation, lack of preservation of soft bodies, shifts in the Earth’s crust, and other obscuring forces. And we might even be correct in all these assumptions. But it is a somewhat ironic situation when we are supporting our theory, not on the basis of empirical evidence, but because our theory predicts that there won’t be empirical evidence. We may be right, and our calculations may accidentally be spot on, but I believe my point stands: the numbers typically thrown about are not based on actual physical observations, but on assumptions and extrapolations. The assumptions and extrapolations may turn out to be right (even a stopped clock is right twice a day), but I like to at least acknowledge that they are assumptions and extrapolations and may not be correct.
Second, the question of extinction rate in the context of the number of existing species raises the related and very interesting question of species formation rate. If, to use your example, we have 5M species today and had, say, the same number of species 500M years ago, then the species formation rate would have to have at least matched the species extinction rate. Indeed, if we go back in time far enough to a point when there were few species we are inevitably forced to the conclusion that the species formation rate must have greatly exceeded the species extinction rate at least for a meaningful portion of the Earth’s history. I submit that there is little concrete evidence that the species formation rate is this rapid (we certainly don’t have evidence that 100 new species have formed in the last 20 years, for example; I’m obviously talking about new formations, not new discoveries of already existing species). Now we could postulate a theory that although observed species formation rates are typically incredibly low, species formation usually happens in quick bursts in places and at times that aren’t preserved in the historical record (let’s call it, say, ‘punctuated equilibrium’). Again we might be right. But someone might be forgiven for noticing that, yet again, we have proposed a theory, the support for which comes not from actual evidence in the fossil record but from an absence of evidence. Yes, we can do our best to extrapolate and assume and guess, but it is important to acknowledge that this is what we are doing.
milodonharlani says:
January 27, 2013 at 12:47 pm
Yes, I did detail why I rejected them. Take the Great Auk. I said in “Where Are The Corpses” that I divided the birds between continental and islands “based on where the birds breed”. Since the Auk bred on the islands, it was classified as an island bird.
As to whether I should have considered the list of birds that have not been declared extinct, like the curlews and the host of species you list that have not been seen in a while, let me remind you of what you obviously glossed over in the original post:
Was that unclear?
Next, you point to the difficulty of determining species. Yes, it is hard. I have not attempted to get into that food fight. As I said, and I will say again, my study was of “the actual extinction of species as confirmed by the relevant authorities”. If you wish to get into the details, you’ll have to talk to the Red List or CREO.
For an example, take the Bogota sunangel hummingbird. You claim it is extinct, but as I said, I don’t deal with claims. I want it confirmed by the relevant authority, which in this case is the Red List. Regarding the Bogota Sunangel, it says:
So the Red List does not claim it is extinct as you say, or even “critically endangered”, but “Data Deficient”. This is quite reasonable when you consider that we have no complete holotype (the first specimen collected of a given animal), and that the only evidence of the existence of this bird is from one skin purchased, not collected but purchased, in 1906 … we don’t even know which country it lived in, and you want to bust me for not explaining why it is not on my list? It’s not on my list because we know next to nothing about it, and the relevant authority has not classified it as extinct.
You have provided an excellent example of just why I did NOT try to do what you recommend, to try to detail why I did not include every single species imaginable—because I would be picking the spitballs off the wall for a hundred years. Instead, I gave the bright-line definitions I used regarding inclusion (breeds on the continent and not on an island, not a subspecies, not “almost extinct”, etc.) and left people to do their own homework …
Finally, you are correct when you say that finding even three or four extinctions wouldn’t change the situation. We’re missing hundreds and hundreds of claimed extinctions, not one or two.
w.
I noticed that one of my favorite blogs, Maggie’s Farm, has linked to this article.
Eric Anderson says:
January 27, 2013 at 1:52 pm
Thanks, Eric. I’m sorry, but this is totally untrue. Do you think the scientists just pick a number and extrapolate? The extinction estimates are based on the fossil record and very little else. Take a look at e.g. “The Currency and Tempo of Extinction” for one example among many. It also covers the issues you raise further down in your post concerning how to calculate the effects of the uncertainty of the fossil record.
Regards,
w.
Ever notice the stories trumpted by the Lame Stream Media are almost always about extinctions.
What about the number of new species that are discovered every year?
Is there an ongoing accounting that reconciles extinctions with newly discovered species?