Dandelions cause enormous problems for lawn cultivation and on golf courses, far outweighing their extremely minimal use for food and medicine.
Introduced earthworms are causing big problems in bothOhio and Minnesota.
In addition introduced earthworms are threatening the survival of some native earthworms, such as the Oregon giant earthworm.
If we’re talking environmental damage though, I’d guess that dandelions are far more benign than the giant monocultural expanses of bluegrass or fescue they “threaten”. Give it all over to the dandelions, I say 
You could make the same argument about any introduced pest of a crop plant. I don’t think anyone would consider that the introduction had “worked.”
Of course, crop plants “work” in the sense that they are beneficial to humans, while being detrimental to native species (which must be removed or controlled in order to cultivate them). However, crop plants don’t really fit the usual concept of introduced species unless they can survive without human care and can spread in the wild.
The OP is vague about what constitutes an introduction “working.” Some introductions have “worked” in the sense of being beneficial to humans, but few have done so without being at the expense of native species.
I left the definition of worked loose as I am just curious how often our plans have gone according to plan. I did a little google-ing and only found where the introduction of animals did not work out and got curious what cases did work.
All I’ve really heard about was the introduction of animals that have had bad consequences, Hawaii, Guam and Australia.
The reintroduction of the wolf into the continental United States worked but I don’t know if this qualifies as as an introduced species as it a reintroduction.
Thanks for all the interesting info! I never would have thought of earthworms as an invasive species. Please continue to fight my ignorance.
In the Middle Ages Old World peasants struggled through the long winters surviving on moldy grains and spoiled pork, a great thing happened at the tail end of winter, though, the wild greens came up everywhere, dandelion, mustard, docks, henbit, various nettles, Erodium, white man’s footprint, abundant and free fresh food full of restorative vitamins and minerals. I’ve always read these plants came to the New World in ship ballast and mixed with agricultural seed, but it’s striking that so many of the invasive plants we contend with were the spring tonics that kept our ancestors alive.
The dam guvmint, at various levels, introduced Johnson Grass, Kudzu, and Salt Cedar, all disasters. The U.S. Army, in the 1850’s introduced camels into Texas. Lt. Echols led an expedition from Ft. Davis through the Chihuahuan Desert on mixed mounts, mule, camel, and horse. The Camels outperformed the other animals, though they did have problems with their footpads splitting passing through the Desapoblado. The Army lost track of the camels with the Civil War approaching and there were reports of camels wandering the desert well into the 20th century (though this is historically an area of high tequila consumption).
The State of Texas introduced Aoudads into the Big Bend area last century, they have sustained a small population, one that unfortunately competes with the native Desert Bighorn which the state wants to reestablish in the same area.
Then there was the great Emu craze and bust of the 1990’s when many broke Emu ranchers turned their stock loose in the hills of central Texas. Luckily they all died in a hurry.
And now the Eurasian Collared Dove, the damn things are everywhere especially at my bird feeders…
The Eurasian doves definitely took off. Alas, in my neighborhood as their population went up the population of mourning doves dropped dramatically.
:smack: D’oh! Of course, mongooses. I’ve been away from Hawaii too long.
I do recall a cute little family of mongooses that lived by the little Manoa Creek or Spring that ran by the edge of campus. They’d sometimes pop out onto the sidewalks, where people would feed them.
The introduction (and continued stocking) of various sport fish species in the Western US has had the desired effect of creating some absolutely world-class fishing, and spawning (yuk yuk) a whole industry around it. I imagine in some places the now-ubiquitous rainbow, brooks, and browns have displaced some native fish but nobody seems too worried about it.
I once read that when the British navy started exploring the Pacific they often came across desert islands with no vegetation.
Thinking of the possibility that someday they might have a crew shipwrecked they began planting coconuts and other plants on the islands and that is why nearly all the islands have coconuts.
Banyun trees seem to have done well in Hawaii.
Potatoes are an introduced species to Europe and became a European staple.
The white-tailed deer, the muskrat and the pheasant are all introduced species in Finland, and work just as intended, filling ecological niches and hunters’ needs while threatening no native species or habitats. The Canadian beaver saved the beaver population of Finland in the 1800’s but now somewhat inhibits the European beaver’s comeback. The mink and the raccoon dog are a bit more problematic as opportunistic nest-robbers and unintended fur industry escapees, but still manageable.
Certainly incorrect. Coconuts float and are designed to withstand long immersion in salt water and still be viable. They would have naturally colonized even the remote islands, without the need for planting.
By the same token, however, coconuts are unable to disperse inland very far from the high tide line. Any coconuts growing inland from the shore have been planted by humans.
He’s wrong about coconuts, but from my understanding, the British Navy did actually release pigs and other animals (possibly goats, sheep, and rabbits, IIRC) on islands to feed future shipwrecked sailors.
Yes, they did, as did other mariners such as pirates to provide food on return visits. This undoubtedly resulted in many extinctions of species on remote islands, due to destruction of vegetation and of eggs of ground-nesting birds. In addition, rats were inadvertently introduced, which were even more destructive.
As I mentioned, the answer to what “worked” depends on what the “plan” was. Many introduced species have thrived in their new homeland, and sometimes have become food sources or provided other benefits to humans. But in many, probably most cases, this has been at the cost of native species that were out-competed or became food for the introduced ones. And in many cases the introduced species have thrived too well, and become directly detrimental to human interests. Also, a lot of introductions, like rats, have been unplanned.
There have been some game bird and song bird introductions that don’t seem to have caused too much negative impact on native species, such as Ring-necked Pheasant and Chukar, and House Finch in the eastern US. But these are the exception rather than the rule.
The problem is often because the introduced species have been brought in without the predators, parasites, or diseases that controlled their populations in their native lands. Without natural controls they spread unchecked.
The most “successful” introductions have been cases in which a natural enemy was introduced to control some other introduced species, like prickly pear cactus in Australia. However, these have been to correct an previous disaster so I’m not sure they constitute things “going to plan.”
Introductions have been particularly destructive on islands and island continents because their faunas and floras may be less resistant to competitors, herbivores, and predators because they have had to contend with a smaller number and range of other species in their limited land area.
I wouldn’t really count this, since the original ecosystem had been adapted to the presence of wolves, and their reintroduction merely moved it back toward what it had been before.
Apples?
The pigs they released deliberately and the rats they brought in unintentionally both helped kill off the dodo.
Aren’t cultivated lawns and golf courses environmental hazards in and of themselves? Pesticide runoff and what not?
I believe that introducing the cane toad to Australia was highly successful — for the cane toad.