How often do Introduced Species work?

See posts #23 and #24.

As already said, cultivated plants don’t really count as introduced unless they survive and spread in the wild. And domesticated varieties of apples don’t do so very much.

House finches are non-native to the US? :confused: Hunh. I thought I was better than the average bear about knowing details about invasive non-natives. Learn sumpin’ new every day. Thanks for dispelling one tiny bit of ignorance in one teensy corner of the universe, Colibri.

House Finches are native to the western US. They were introduced in the New York area as escaped cage birds in the 1940s. They eventually spread west and their range is now continuous across the continent.

One wonders what kept them from spreading eastward before.

I see from the article that the House Finch seems to have caused a decline in the Purple Finch in the areas to which it has been introduced, although much of the Purple Finch range is farther north.

The list should also include watermelon (originally from Egypt IIRC), potatoes, wheat, maize, coffee, apples, blackberries… there’s an enormous amount of cultivated vegetables and flowering plants which are being grown outside their original habitats. A problem I have with defining “no, they must be growing in the wild in those areas as well” is that then we need to define a complete scale: less than X amount of growth in the wild is not succesful, but more than Y is a pest.

Cane toads (as mentioned), ditto rabbits and damned camels in Australia.

o we count animals introduced that have since gone feral? Such as goats, cats and pigs?

I think the introduction of salmon in Lake Michigan has worked out great. Not only providing great sportsfishing but also eliminating the nuisance of dead alewives on the beach.

As I’ve already mentioned, domestic crops are not normally considered introduced in the meaning indicated in the OP.

The distinction isn’t that hard to make. Very few domesticated crops, especially modern highly specialized versions, can survive and spread in the wild.

Those have all become pest species in many areas where they have been introduced. Which definition of “worked” are you using?

A couple of years ago in WI, a bill was introduced in the legislature allowing people to shoot feral cats. So their population has apparently grown large enough to make them pests.

I dunno, does that make them failures?

Indeed, coconuts in Hawaii are thought to have predated the first Hawaiians.

Per the OP, did they work as planned by humans?

I’m willing to read about introduced species that are considered to have not worked and consider this thread similar to a conversation that started in one area and has expanded. I find a lot of this information very interesting.

I only recently learned that eastern wild turkeys once were not plentiful in NH, having been completely hunted out in the 1800s. Apparently they released 25 turkeys into the wild back in 1975 and now there are better than 40,000 of them.

The problem is defining “worked”.

Species like buffel grass worked perfectly, insofar as they did exactly what they were intended to do: provide lots of feed for domestic grazers. they may have caused substantial ecological problems, but they have caused no economic problems, so by that standard they are perfectly successful.

The same is true of the introduction of goats or rabbits to remote islands: they did provide food for passing ships. Nobody cared at the time if they killed all the native species, so long as they survived. So by the standard definition they worked perfectly. The fact that some people centuries later think that the effect they have is negative doesn’t mean that they didn’t work exactly as originally intended.

I would suggest that the standard for “work” should be “Would the people who made the introduction be happy with the result today, to the extent that they would do it again if they could?” By that standard, the examples listed above worked. It seems that saying that a plan only worked if every human being for the rest of time agrees with the results is very presentist. By that standard, no plan has ever worked.

I can understand arguing that, say, rabbits in Australia or starlings in the US didn’t work because even the people who introduced them would be aghast at the damage they ended up causing. They failed even by the standards of the people doing the introduction.

But arguing that some introduction didn’t work solely because people 300 years later don’t like the effect is like arguing that vaccines don’t work because someone living in Sparta 3, 000 years ago wouldn’t like the effect. The effectiveness of a plan can only be judged based on the criteria used to formulate it. If a plan has to be judged a success by every human culture throughout all of time and space then no plan has ever worked. By such a standard, ‘‘not’’ introducing these species also failed.

Cane toads here are now having a rough time, the Cuban frog invasion seems to be working out pretty good for the Cuban frogs.

I hear they’re doing well in Hawaii.