BAD REPUTATION: Kimberley Toadbusters catch and kill invasive cane toads in Western Australia, but some scientists think fighting exotic species can be a waste of time and resources
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Invasive Species Don't Get No Respect
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Last November, Mark Davis spoke at a special meeting in South Africa to honor the 50th anniversary of Charles Elton's seminal book, The Ecology of Invasions by Animals and Plants. From Asian kudzu conquering the U.S. South to brown tree snakes wiping out birds on Guam, the ecological havoc wrought by exotic plants and animals has become—along with habitat destruction and climate change—one of the most talked about problems in species conservation.
But as Davis took the podium, he let his sport coat swing open to reveal his flip-flopped necktie, the skinny end stretching to his belt buckle—a not-so-subtle jab at the late Charles Elton, a notoriously inept dresser.
Though he may have earned a few chuckles from the in-joke, Davis's shenanigans did little to loosen up a crowd of scientists who viewed him as an exotic species, an alien and, perhaps, an invader. Davis is a plant ecologist at Macalester College in St. Paul who has spent the past 15 years challenging the most cherished principle of restoration ecology: that nonnative species should be eradicated from the landscape.
[Slideshow: Invasive Species Don't Get No Respect]
Earlier this spring, he published a bombshell of a book with Oxford University Press called Invasion Biology. Davis claims that alien species have been demonized and resources wasted on purported "invasives" could be better spent protecting habitat. More than that, he disputes the maxim that invasive species are the second-leading cause of species endangerment after habitat destruction, impacting some 42 percent of threatened and endangered species. Such concerns are particularly timely as ecologists debate the risks of relocating species to save them from climate change. In June, one reviewer wrote that Davis "dares to touch the third rail of invasion biology," slaughtering some of its "sacred cows."
A contrarian is born
Mark Davis was not always a contrarian. In the early 1990s he was the chair of the environmental studies department and spoke with the head of facilities at Macalester to suggest that the campus plant only native Minnesotan species. But as he began to think more carefully, the distinction between native and nonnative species no longer made biological sense. Instead, he realized it is more reasonable to talk about "undesirable and harmful" species, particularly when one considers that half of all agricultural pests are homegrown.
In his book Davis picks apart the claim that invasive species are the second-leading cause of extinctions. He traces that meme back to a 1998 paper by Princeton ecologist David Wilcove and colleagues in the journal Bioscience, which he derides for being based on the "opinions" of field researchers. Moreover, most species said to be imperiled by invaders were located in Hawaii and on other islands, not the mainland U.S., where he is skeptical that alien species can gain a foothold. "There have been thousands of nonnative species introduced in the United States," he says, "and they have not caused one native species to go extinct."
Davis is not alone in his call for reason: In South Africa he shared the stage with another invasion biology gadfly named Matthew Chew, a researcher at the Center for Biology and Society at Arizona State University in Tempe. Chew has made it his duty to restore dignity to the much-maligned tamarisk tree, aka salt cedar. Initially introduced in the U.S. Southwest for erosion control, the salt cedar rapidly established itself along desert waterways and was soon vilified for displacing native vegetation, sucking up scarce water resources, and releasing salt into the soil.
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43 Comments
Add CommentOne can only wonder but there's no reason to doubt that extremists in any field can do a lot of damage. But extremists do at least cause re-evaluation of "established facts."
Reply | Report Abuse | Link to thisAs for invasive species: I too have a hard time accepting that invasive species are "okay." When an organism invades, it alters the environment - a thing which is often hard to adapt to "as is." Ironic: humans are the epitome of invasive species. And we brag about it -calling our invasions "colonists" or "pioneers."
I grew up in a rural area close by a small town. We kids used to spend hours exploring and observing the natural environment. Some went on to become well informed on such topics as herpetology, biology and, yes, ecology.
The most stark lesson in ecology we learned? It was when real estate developers bulldozed all the woods and fields to build tract housing. Today that "town" is a large-area city which has very few parks and almost no natural areas. Man, the Top Invasive Species, obliterated all:forest, field, ponds, foxes, skunks, quail, frogs, snakes and untold insect species - including butterflies.
As per usual in discussions of this nature I find very few people, whether scientists or not, willing to admit when they are in over their heads. The chaotic nature of selection is not something any one of these people can predict.
Reply | Report Abuse | Link to thisThe fact is, the introduction of any alien species is imprudent provided special protection is the priority. Thus are we defined, as a species. I have carefully chosen these words to reflect the serious position we are in presently.
The work being casually discussed in this article should well have been coldly understood before we embarked on far reaching experiments in the genetic manipulation of plants, insects, or any living thing. Reflecting on environmental loss or effusively flying fish in hindsight is not made palatable by the absence of actual extinction. Extinction of endangered species might well have resulted from any of these cases.
Moreover the adaptations to changes such as sighted with the toad eating snake represents, not only a reduction in the capability of this animal to select prey, but an extinction, if you will, of the genus of the larger headed snake.
Mankind, at its worst is an agent of universal entropy, and at best preserves not only the immediately useful but the irreplaceable at risk. Intelligence that does not serve intelligent ends does not exist.
BuckSkinMan and WRQ9 are both absolutely right. The most invasive species on Earth is the human race. Indeed, a case can be made that mankind is a disease organism, and human civilization constitutes an infection of the planet. I guess we should be thankful that no one has shown up with a cure, a la "The Day the Earth Stood Still", at least so far.
Reply | Report Abuse | Link to thisAnd of course many if not most of these harmful "invaders" didn't really invade at all; they were brought in by human activity. I agree that harmful exotics like the zebra mussel, brazilian pepper, kudzu and of course our little problem with pythons in the everglades are very undesirable, I am amused that so far none of our "native life" activists, including my wife, have been able to explain why we regard human migration and migration of other species in exactly opposite ways.
And how does one define "native"? Several of our local species are dying out and probably not salvageable, for the simple reason that human activity has so changed the local environment that they are no longer adapted to it. If they go extinct, and a new species arrives that is adapted to the new environment, is the newcomer an "invasive species" or a "new native" species? Does it matter?
In the end, though, I guess all of these considerations will be moot. Given the current rate of human population growth, the widespread ignorance (even disdain) of science, and the political inability to address global warming, the issue of exotic versus native will become a secondary concern. I wish I could see a more optimistic outcome, but I don't.
Almost all species are capable of migrating. As the climate constantly changes species need to adapt, move or die. I agree with the previous posters to a certain extent, and I beleive that the human population growth is slowly killing our planet and must be addressed. But logic tells me that without this population growth...I WOULDN'T BE HERE. And I wouldn't get the joy of my one precious daughter. If you are willing to go all the way in your thinking, you should kill yourself for the sake of the native species. And I'll go a step further and say that since my people have been on this continent for over 10,000 years, Native Americans have the right to kill every immigrant for the sake of preserving our native species.
Reply | Report Abuse | Link to thisHere in Colorado, invasive tamarisk uses a disproportionate amount of water. Water that my government says we must give to Nevada and California. Now we have introduced beatles that eat the tamarisk. When the tamarisk is all gone, the beatles will either die or eat the "native" plants. In the end, extinction is simply a part of evolution. Sometimes we make it happen and sometimes it happens to us. Witness the near extinction of my people 2 centuries ago. Thank you for reading my rants and raves.
With respect, notslic, I only quibble with your proposition, "If you are willing to go all the way in your thinking, (then) you should kill yourself..."
Reply | Report Abuse | Link to thisNotice that I specifically start out with a warning about extremists. Others at least do not explicitly endorse such "all the way" thinking or sentiments in their posts.
I argue also with the logic which concludes: "without this population growth... I WOULDN'T BE HERE." No one knows the "probability" of their own existence except to say that it's a "miracle" - like the Universe itself. You can be grateful only post facto. I too have one precious daughter (really) and believe that she changed me for the better just by arriving in my life. But it's just as reasonable to argue that not having a life and therefore no daughter would be something I'd never be aware of because of my non-existence.
It's another thing entirely to advocate self-restraint when it comes to reproduction. To do otherwise is like refusing to obey traffic laws or refusing to stop smoking: it violates the rights of others and damages the common interest we all have.
In closing: I certainly hope you are not offended by my use of an"Indian Name" - this was given to me by a friend who is a full-blood Lakota who is a Pipe Carrier. He gave it to me in recognition of a gift and some assistance I gave him some years ago and I carry it proudly. I take very seriously the past and any present mistreatment of native North Americans, regardless of what other wasichu have done to your people.
Also, I do not see notslic "ranting and raving" - notslic is taking his turn at the council circle and nothing more or less.
Notslic, I hear the "kill yourself" counter-solution often, but if you give it a little thought, this has the opposite effect of that desired. If the only people who realize the population is so out of whack that it's net destructive, kill themselves when they realize it, then you are left with no people who are aware of the problem, and no one to help the breeders understand that there are consequences to their actions. People don't have to kill themselves, they'll die off soon enough. If they can control their basic biological instincts to breed uncontrollably, and have one or less offspring, the problem recedes.
Reply | Report Abuse | Link to thisUnfortunately, we're saddled with religions, all of which have been successful this long because (atrocities aside) they're each largely a manual for ensuring successful biological reproduction.
Also, I'd just like to point out, that while I am a great admirer of First Nation people and their heritage, they're immigrants and invasive as well. Even the earlier clovis people were immigrants. Humans are technically an invasive species outside Africa, and one that has altered the environments and wiped out more species than anyone.
Buckskinman and Hotblack...RESPECT. Thank you. You both have depth.
Reply | Report Abuse | Link to thisThank you, Notslic, for acknowledging what I always hoped would be common among all peoples. I merely learned (often "the hard way") that it pays to first show respect for others as well as expecting it for myself. Without blabbering on about it, I will only add that I found several examples of this "attitude" which proved its value to me. Benjamin Franklin is my favorite example. Also, the lesson has been reinforced by the culture of respect found among Native Americans.
Reply | Report Abuse | Link to thisThis discussion about "native" vs. "invader" species relates to most all humans as well. There is nothing "native" about a Native American. They too are imigrants on this continent. But again, at what point do we say that a species has the privelige of being refered to as "native" or not?
Reply | Report Abuse | Link to thisYou don't know the difference between MIGRATION and IMMIGRATION. The same holds true for migrating species and introduced species (whether on purpose or not).
Reply | Report Abuse | Link to thisHello Mhykael,
Reply | Report Abuse | Link to thisYou make a valid point about the way humans define themselves and other groups. Only, the topic we're discussing is non-native invasive species such as Cane Toads and Brown Tree Snakes.
The key phrase in the article's introduction is, "Mark Davis wants them (conservationist fighting invasive species) to reassess their missions." That's not too alarming - but I think what troubles some of us is his apparent casual attitude toward such (human introduced) species as that toad and snake.
The Cane Toad was intentionally introduced: making us wonder "what were they thinking?!" (in Australia): since previous species introduction efforts by the Australians have produced whopping unintended consequences. The Brown Tree Snake is a hitchhiker - but still "human introduced" because it arrived on boats and even aircraft.
I disagree with Davis about these creatures: by consensus, they are considered harmful and pose proven threats to humans as well as (truly) indigenous wildlife.
If humans are a disease as you say, then for argument's sake, would it not be prudent for you to see fit that you do not propagate? You would do Earth, other living organisms, and us (the remaining humans that do NOT buy into that BS) a whole lot of good.
Reply | Report Abuse | Link to thisI find it par for course that those who think humans are the problem for everything really mean that everyone ELSE but themselves.
Reply | Report Abuse | Link to thisLife here on Earth has endured far worse than humans. Earth can not be killed by humans. We, ourselves, would perish long before such an event would take place. An all-out nuclear conflict would not destroy Earth. It would take time, but life would renew. Any traces of such destruction would be erased in time.
Reply | Report Abuse | Link to thisThose regions that have a financial impact due to invasive species is quite undestandable. In MT, a great amount of monies from out of state is due to hunting and fishing. I understand Gov. Switzer's concern for the term he uses, "Bucket Biologist". He is refering to those who bring in foreign species that eventually outcompete the native species forwhich MT tourisms relies. How valid his claim is, I cannot say. I think he overstates this problem, but I am sure it does happen. I cannot see someone regularly and intentionally trucking in species from other parts of the country.
Reply | Report Abuse | Link to thisIs there anything "native" about any species? Life did not arise all over the planet at once and each population of lifeforms stayed in those places in perpetuity. All things move from one place to another. Sure, we are moving things now, but that's really not much further from what was already happening. It's just that instead of it happening slowly, it happened quickly. But life adapts and life goes on.
Reply | Report Abuse | Link to thisEh, who is this "you" you're referring to?
Reply | Report Abuse | Link to thisIf your comments are directed at someone, it just makes sense to identify whom you're addressing.
But since you do refer to the idea that humans are the most outstanding example of "invasive species" - it's appropriate that one of us respond and I will give it a try.
First - no one on this thread has said that humans are "a disease" - this is a term which originates with you in this instance. No one has taken the extreme position that you seem to think we have. And you also say that we should consider "not propagating" - while the only thing advocated so far is RESTRAINT in propagation to mitigate OVER population. You ignore the plain evidence: two of those posting (notslic and myself) have already said we have only one child. In fact, those who advocating restraint of population growth rightly say that anyone should limit themselves to having two children - to STABILIZE by obvious mathematical fact world population.
So your grand overview doesn't even apply to the statements made by others on this forum. WHO are you contending with?
Statements like "Earth will outlast humans" are nonsensical: since it is humans who are discussing the issue and the obvious goal is to preserve human life without damaging (not "destroying" as you have it) the Earth's biological balance.
Just FYI: On average any given species persists for at least 20 million years before becoming extinct. Humans, by all evidence to date, have existed only about 200,000 years. We're just getting started on our "alloted time" - so give us a break, we're only trying to meet or maybe break the average a bit.
Lastly, I don't know what Montana's governor says about invasive species and you say you don't know either. Check it out and get back to us with something substantive, won't cha?
Nathaniel,
Reply | Report Abuse | Link to thisWhat you say is true but does not apply to the matter we're discussing. What we are discussing is specific instances where species have been transported (on purpose or by accident) to places where they are doing substantial harm.
Zebra Mussels: arrived thanks to the "habit" of ocean freighters of waiting to dump their (water) ballast IN the Great Lakes. Now Zebra Mussels are spreading to inland waters (by attaching to recreational boats which are towed from place to place). Their presence is impacting power plants and water treatment AND significantly cutting down the sports fishing industry which is an important part of the Great Lakes states economies.
Zebra Mussels are native to Europe - they never "migrated naturally" anywhere. The ocean freighters made it possible. So - yes, this is MUCH DIFFERENT than what naturally occurs. The same applies to the other species mentioned in the article (snakes, toads and purple loosestrife).
Finally: Canada and the U.S. have mandated that ocean freighters now dump their ballast out at sea. The ocean freight companies have willingly complied. BUT - no way has yet been found to eradicate Zebra Mussels and several other water-dwelling invasives which continue to have negative impact on THE ECONOMICS of the region.
So, for this contrarian "ecologist" to claim that invasive species are no more than "something new and different" is inaccurate and ingenuous (because he knows better).
Davis has decided to ignore all the species that have gone extinct all over the planet. It hasn't happened as much in the U.S. in recent years because we have the Endangered Species Act (go ahead and read it on Wikipedia--send to any doubters that think species will not go extinct without conservation efforts). And how can he say that no species has gone extinct when not all the species have even been classified?
Reply | Report Abuse | Link to thisMost Australians remember what introduced rabbits and other invasives did to the physical structure of the land and to the diversity of plants and animals in the areas where the invasive species spread. So they have prudently chosen to spend some time and money controlling cane toads to protect what's left of their natural heritage. Davis is apparently a poor historian as well as a poor ecologist. Most people believe because they want to believe, not because of the evidence, which is how you get people ignoring vast amounts of evidence and clinging to bits of baloney that make them feel better. It just goes to show that having extra letters after your name does not protect against delusions, logical fallacies and confirmation bias.
Davis has decided to ignore all the species that have gone extinct all over the planet. It hasn't happened as much in the U.S. in recent years because we have the Endangered Species Act (go ahead and read it on Wikipedia--send to any doubters that think species will not go extinct without conservation efforts). And how can he say that no species has gone extinct when not all the species have even been classified?
Reply | Report Abuse | Link to thisMost Australians remember what introduced rabbits and other invasives did to the physical structure of the land and to the diversity of plants and animals in the areas where the invasive species spread. So they have prudently chosen to spend some time and money controlling cane toads to protect what's left of their natural heritage. Davis is apparently a poor historian as well as a poor ecologist. Most people believe because they want to believe, not because of the evidence, which is how you get people ignoring vast amounts of evidence and clinging to bits of baloney that make them feel better. It just goes to show that having extra letters after your name does not protect against delusions, logical fallacies and confirmation bias.
2ndSkeptic wrote:
Reply | Report Abuse | Link to this"Davis is apparently a poor historian as well as a poor ecologist. Most people believe because they want to believe, not because of the evidence, which is how you get people ignoring vast amounts of evidence and clinging to bits of baloney that make them feel better. It just goes to show that having extra letters after your name does not protect against delusions, logical fallacies and confirmation bias."
I disagree only with the idea that Mark Davis "is apparently a poor historian." In my personal experience, people who are obviously well informed on a given topic will sometimes "surprise" us with their seeming lack of information. It took several repetitions of this puzzling phenomenon before I realized that they have "other motives" which causes them to "play dumb." The pattern is: First they contradict what you know to be true (and can prove to be true), then they take the "trademark" stance of a contrarian, just as Davis has done.
Often as not: the next thing they start talking about is conspiracy. Always, this conspiracy they describe (to help explain their unexpected "ignorance") is carried out by... whichever political ideology is opposite to their own. Then they're not only posing as contrarians, they're asserting their role as "truth givers" and "debunkers" and "revelationists."
This is where Mark Davis stands out - he's already into the contrarian and debunker role. "Confirming our suspicions" that Science has been taken over by alarmists (always alarmists in the other ideological camp).
Science Fiction writer, Michael Crichton, is the most famous example. He started going around the country giving speeches to certain well-defined groups (who were paying him very well), then he started writing "op-ed" in national magazines: always saying that the scientists who were reporting FACTS about the trend toward global warming were exaggerating alarmists. Well - he never was outed, he died before that could happen.
Every time I've checked on the "facts" put out by such people, they turn out to be either still open questions or outright misrepresentations. Everyone trusts 'national figures' like Michael Critchton - so they naturally believe what these people say. This makes still-living Mark Davis a dangerous "authority figure."
I'm always amused at the underlying assumption in all these discussions, whether it be species invasion or climate change, which is namely that the current situation is the ideal situation and any shift away from it will result in apocalypse.
Reply | Report Abuse | Link to this"Notslic, I hear the "kill yourself" counter-solution often, but if you give it a little thought, this has the opposite effect of that desired. "
Reply | Report Abuse | Link to thisWhich is why the eventual goal of the ecopriests will be to kill someone else. They're too important to be lost, because they truly understand the problem.
Eh, I don't know what you mean by "underlying assumption" - I for one posted clear specific facts which demonstrate the desirability of the "pre-invasives" state of our environment.
Reply | Report Abuse | Link to thisBut go ahead and claim that the Great Lakes are now "better" or that they're in YOUR PREFERRED state after the introduction of Zebra Mussels and other aquatic invaders.
In terms of geologic time, we are putting the biosphere in a blender. We have to presume that on a time scale of thousands of years or longer, any species that can be introduced, will be introduced. Despite our best efforts, exotics will sneak through our inspections, slip past our inspection stations, hide in cargo holds and fuselages, get stuck in shoe soles and crevices in people's skin, or be spirited in by people who think it's too cute or pretty to pose a risk.
Reply | Report Abuse | Link to thisSo far, I see no evidence that anyone who has commented here has actually read Mark Davis's book -- so any comments about Davis, what he thinks or why he thinks it are evidently based purely on a 10 minute investment in reading one human interest article. Very American. Not very Scientific.
Reply | Report Abuse | Link to thisExtremists are always dangerous...whether political, social, religious, economic or ecological (Earth First for example). Nearly all decisions we make affect others. Therefore, our decisions must be tempered by logic, rationality and intelligence.
Reply | Report Abuse | Link to thisI witnessed the plague of mixomatosis in Australia. The problem is compounded by ranchers killing the dingos, which may have eaten the rabbits to a sustainable level if they wouldn't have also eaten the sheep and calves. The ranchers provide wool to the world and killing wild dogs to preserve their livelihood is their first interest, and a reasonable one to them, considering the harsh climate. They had already made extinct the marsupial tiger, along with the native Tasmanian Aboriginals.
My point is that we must do what we can to preserve native flora and fauna. But there may be worse unintended consequences from our further meddling in things that we don't have enough knowledge about. What if the mixomatosis mutated and affected native lizzards or birds? What if the zebra mussels help negate the effects of a deadly bacteria? If we introduce a predator species or disease to control the harmful invasive species, we may be compounding the problem in the future.
Very true, Native Son! Since I am not a biologist, ecologist or any other form of scientist by schooling or trade, I can't comment myself on the validity of one opinion or another posed here.
Reply | Report Abuse | Link to thisI can say, as one who knows Mark Davis as a friend not a colleague, he is naturally inquisitive, questions his own assumptions and, ultimately, offers views of the world based on thoughtful consideration of both fact and opinion.
Nice job, Mark! Where may I get my hands on one of those nifty ties?
This is one of the best discussions I've read, and I hope to use it in my class of honor students to illustrate intelligent discussions.
Reply | Report Abuse | Link to thisGood ideas are stated, often with a link to the "backup" information, and rebuttals are clear and not "hostile" on a personal level. It would be easy to search for revant data that relate to the interpretations.
In science, particularly the science of complex systems (mathematically defined), the way data is interpreted can shift "like a turn of the kleidoscoope" as the chips of glass fall and rearrange into a new semistable state. When we interprete data in this nature, "scientific proof" becomes an oxymoron. Ponder the physical model that could predict the next arrangement of chips in the kleidoscope. It is interesting that tenuous explanations are useful for the near future, while only a "sense of the future" is possible in our experiential time and with our active "knowledge." The reward is not another consistent result to the expectations, but an "outlier" result that suggests a new kind of experiment or explanation. From this perspective of "reality" dynamic new theories are constructed.
When I was a graduate student sharing an office with a few others, we spent most of our time "debating" a topic of interest. At times one of us would "tire" or their position, and we'd exchange perspectives. We all knew that any perception (opinion) was built on incomplete understanding of "tenuous generalizations" of oversimplifications. As immature scientists, we knew that there is no final answer, and that a single experimental result could weaken or destroy the foundation of any explanation. Confidence was built on an ongoing effort to find the logical "weak link" with a new technique or "better data" that could revise the way other data had been interpreted. These "gedanken experiments" were our intellectual fodder for the next research proposal or experimental technique invention.
This seems to be an ongoing discussion feeding on this intellectual cuisine.
Thank you.
Native Son,
Reply | Report Abuse | Link to thisI suppose we could preface each of our statements with "If Davis is represented accurately in the article..." but we are "daring enough" to think that the article isn't slanderous and to just take a chance that it does state his premise (which is that he wants those working to control / eradicate invasive species to reconsider their conclusions and efforts.
If we all did take the time to first find and then buy and then wait for delivery and then read Davis's book: there would be no immediate discussion.
In other words, for practical purposes, we believe Davis's position (that of a contrarian) is clearly stated and are discussing what he advocates. Anyone who HAS read his book (which at this point I don't think includes you) may jump in and present any corrections, if needed. Being mistaken is not something desirable, so such corrections would be welcome.
Perhaps most noteworthy is that you're the third person to drop in here at the Scientific American forums to offer your negative opinion of those who are discussing a putative scientific controversy. If you wish to offer only opinions about people you disagree with for unspecified reasons, perhaps you might try and find a more suitable venue for your opinions. There may even be a publication like, Unscientific American Critics, which you'd surely approve of.
Wanting to be equable, I'll modify my stance as follows:
Reply | Report Abuse | Link to this1. I have taken the trouble to look at Professor Mark Davis's background as educator and researcher and see nothing to indicate he is politically motivated.
2. I am still skeptical of what I perceive to be his proposition. But as notslick pointed out, there are examples of human interventions against an invasive species which created more problems than were originally present. If THAT kind of compounding mistake is what Professor Davis is arguing against, then I think everyone agrees - in an ironic, "Ya really think so?!" fashion.
3, I restate (with little fear of contradiction) that there are extremist elements in natural conservation. I believe it's obvious that they do more harm than good. I also agree with others who've already said that extremism taints and makes vulnerable legitimate groups and individuals in many areas.
4. As far as I can see: fairness dictates that we might do well to let the picture develop further before drawing firm conclusions about Professor Davis's argument.
Regards to All.
The comment in the article that not one native species has gone extinct is very interesting. With the hemlock wooly adelgid (HWA), an invasive insect of asian origins now killing the eastern hemlock, the USFS says they will all be gone in a decade, like the American Chestnut die-off from the chestnut blight of last century. The USFS, National Park Service, and state park agencies are treating trees in the region with Merit, which kills honeybees and others life forms, following the USFS claim that the hemlocks will be gone in less than 10 years. Soil drenching this toxic poison (Imidachloprid) around the hemlocks, which live along streams, is a big 'environmental' cause in the southern Appalachian mountains. The Blue Ridge Parkway has been treated, for instance. See the bee die-off article for the consequences. Meanwhile, in the name of saving this tree species, we are having our land and water poisoned, and countless other species poisoned by this effort. Many countries have banned the chemical; the US de-regulated it for sale at hardware stores.
Reply | Report Abuse | Link to thisWhy not change our terminology to describe the community dynamics rather than a characteristic of a species? We cannot know an absolute like "native" and "non native" except in a fixed, often arbitrary or unknown time? "Increasers" and "decreasers" describe what we see in an observable period, and if we study the details, we may learn the features that are behind the dynamics observed. I believe the term "invasive species" gained a reputation from economic factors of marketing technology to "stop the invasion," which was an emotion laden term to increase sales by fear mongering, rather than knowledge of a species and community. This idea can be checked by a time overelay of the term and the development of pesticides. In any case, as a scientist, a term needs to be low on emotionality and high on descriptive content.
Reply | Report Abuse | Link to thisSad to see some in this discussion diverge to discomfort regarding pro and con, although discussion is substance of inquiry. I have the book you refer to, have used it in class, and find much food for thought. That is the substance of dialog (seeking to understand) compared to debate (seeking to convincc). Science is much more about dialog than debate. Terminology is a matter of clarity of meaning in science, and substance is about data and testing the system. This focus is on terminology, and clarity of meaning is lacking.
Reply | Report Abuse | Link to thisNative v invasive is really a meaningless concept. It depends on what each does. In the U.S horses, cows, wheat and apples are clearly invasive. Yet we want them.
Reply | Report Abuse | Link to thisNature is flexible but it doesnt have a plan. Besides, there is no longer ANY place in the world that is natural, if you define that as free of human management or influence. The ancestors of the American Indians probably wiped out the native mega fauna and they certainly changed the landscape radically by their regular burning of forests and fields. The environment that greeted the English settlers at Jamestown in 1607 was very unnatural , but it was sustainable. That is what we need.
With climate change happening, the concept of native and invasive will become completely untenable. If conditions in Maine in 2050 become more like those of Virginia today, which sets of wildlife and forest species are the ones best suited? Spruce trees just dont grow well on the Virginia piedmont. Maybe the best native species will be loblolly pine, oak and tulip-poplar.
So lets replace the concept of invasive with that of sustainable. Many of the plants and animals we call invasive are indeed bad, from our point of view, since they displace desirable local species. But it is only from our human point of view. Nature doesnt care. In the great sweep of geologic time, things like this have happened many times before.
Honey bees, BTW, are not native to North America. The wild ones could well be called invasive. But since we like them, we call them beneficial.
Reply | Report Abuse | Link to thisLoss of the hemlocks is a problem. But they may be back along with the chestnuts through breeding programs. You notice the American elm has returned to city streets within the last few years. The road is not always a one-way trip to perdition.
Thank you dickr...the reason that this discussion is so civil is that the god squad chose not to interfere. Their purpose is to disrupt scientific discussion, even when it makes them look silly, and the discussion usually falls to the lowest denominator. I come here to learn, and occasionally add if I can. Sometimes I fall into the trap. Please look at the discussions regarding Darwin to see examples of non-intelligent discussion.
Reply | Report Abuse | Link to thisSorry John Matel, but the issue is HARMFUL invasive species.
Reply | Report Abuse | Link to thisI believe that the whole discussion is about HOW we define harmful. There are plenty of native bugs and animals that we might be better off w/o.
Reply | Report Abuse | Link to thisHi John...The fact that the species are here in the first place means that they have a place in the system. Sometimes the system is very localized and sometimes it is as big as the Pacific. These species have survived and adapted and been mutated. I do get your point, but just because we don't like being bitten by mosquitoes, and they can carry potentially deadly disease, doesn't mean that they don't have a place in the system. We really need a LOT more knowledge before we mess with things. I see your point that WE are describing a system and what is native or invasive to that system. Maybe our interference is simply evolution in action. Thanks.
Reply | Report Abuse | Link to thisIndeed WE are describing the system. Nature doesn't have an opinion. It is a little arrogant to believe that we really have the power to harm of help nature in the macro sense. The universe is very big and we are very small.
Reply | Report Abuse | Link to thisI understand that we need to be very conservative and cautious when dealing with long established natural systems. We can never understand all the relationships. But just because something is around does not mean that it is optimal or necessary. I don’t have a religious faith that nature has always got it right. A natural system is just the current adaption and there is no qualitative difference between a plant or animal that has arrived “naturally” i.e. by means of random chance, rather than one that has been deliberately or accidentally brought over by humans. The only problem is that humans do a lot more of it and have accelerated the process.
I reiterate that climate change is making the distinction between native and invasive irrelevant, as environments change due to the macro-climate. Our "hands off" option is now gone. We now have only the choices of wise or unwise management. We will need to redefine our ideas about what it ‘natural” and what is “man-made.”
Dear Notslic,
Reply | Report Abuse | Link to thisIt is a myth that Tasmanian Aboriginals are extinct - the several thousand people who identify themselves as such have struggled for decades to overcome this falsehood.
Also myxomytosis is a virus that has not spread beyond rabbits in 50 years in Australia, incredibly unlikely that it could mutate to infect non-mammalian species, meanwhile the rabbits have long since developed resistance to 'myxo' as we Aussies affectionately call it.
We have many disastrous introduced species in Australia - rabbits, foxes, cats, camels, pigs, my particular nasty is the European carp which has devastated our native freshwater fish populations. And of course plants such as prickly pear, lantana etc etc.
We will gain our revenge though, the eucalypt is a very prolific tree and conquers all. In a few centuries those seemingly benign gum trees will have taken over many forested areas thorughout the world - and then 'Killer Koalas' ; you have been warned.
Why do humans try to play god and control evolution? No matter what we do every species will go extinct at some point in time. Even we will evolve into another species and humans will go extinct. So anything we do now is just a temporary fix really. Survival of the fittest i say! if you cant adapt as a species your doomed simple as that so why not now. We need to stop trying to save everything and let nature run its course. We try to stop species from invading other habitats multiplying and ruining the ecosystem there. But we get to do it??? No matter what happens life will level itself out and create a new ecosystem over time. If any animal needs to be controlled its us. In my opinion if a species cant adapt let it go extinct thats life get used to it. We want to keep certain species around because we are selfish really but no matter what its all temporary anyway. So who are we to decide when something goes extinct or if it should be in a certain area of the world. I think we should try to limit how many animals we kill but there has to be some limit to our involvement in the evolution of ecosystems. Like the panda for instance... its a stupid animal let it go extinct... They only eat bamboo a non nutritious plant thats there first mistake second they never breed and when they do the offspring rarely make it to adulthood the so let them die out who cares. Its going to happen eventually. What are we going to have test tube pandas 50 years from now? What try and save them so they can be slaves in zoos for us? Waste of time and money!
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