"Invasive" Ambystoma mexicanum?

I usually hang out in the axolotl forums, but I got to wondering, and this forum seem a more appropriate one to ask.

Is there a risk of axolotls becoming an invasive species? Or maybe a better question is, how big is the risk?

Is there a real risk of them hybridizing in the wild with other ambystoma? Which ones would be the highest risk?

They are a lot more temperature tolerant than I realized when we first got some. Reading on the axolotl forum, people have kept them in outdoor containers that occasionally freeze over. If they can survive that, they can survive winter in temperate climates around the world.

Knowing that people can (and do) dispose of unwanted aquatic pets by dumping them in the nearest body of water makes me wonder if there may be problems in the future if there aren't already.

Hello,

It's very difficult to answer such a question.

I suppose we can say the risk is not zero.
North America (and Europe) is huge and provides different climatic conditions, some of them possibly compatible with axolotl life. I've had axolotls in outdoor tanks for about 10 years. On the other hand, most captive-bred axolotls may be genetically very different from their wild counterparts.
Now, as a neotenic form, this species needs at least permanent ponds without fish.
In France, axolotl has not yet been noted in the wild but other amphibians like Xenopus frogs now thrive well in a large part of the country.

As for hybridization, anticipation also seems very difficult. Ambystoma californiense and A. mavortium readily hybridize, which constitutes a threat for A. californiense.

So the possibility is open.
That's why I find your question very interesting and very responsible.

That is why they are illegal in NJ. To keep them from being released where endangered Eastern Tiger Salamanders are found. To take hold anywhere you would need to find fish less pond that stayed cool and didn't dry up. Any place like that could be a risk

The whole Ambystoma genus is illegal in CA to protect against hybridization with A. californiense. The ban was mostly to prevent more introductions of A tigrinum but in cooler areas further north Axolotls could definitely become a problem.

Coastal Groovin said:

That is why they are illegal in NJ. To keep them from being released where endangered Eastern Tiger Salamanders are found. To take hold anywhere you would need to find fish less pond that stayed cool and didn't dry up. Any place like that could be a risk

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In N.J. it is illegal to have any gilled salamander. Their approach to legislation is "the shotgun approach."

A scientific literature search turned up no repost of invasive axolotl populations. Axos are notoriously susceptible to fish predation, which could be one factor. About cross-breeding with closely related ambystomatids: when cross breeding of Ambystoma tigrinum and Ambystoma mexicanum was tried years ago at the IUAxolotl Colony, they had to resort to artificial insemination. I don't know whether this was an environmental issue (no natal pond) or difference in courtship behavior. I've had a few metamorphosed axos that tried to court my blotched tigers. The tigers were not interested.

Wouldn't extinction be more likely than invasion in this case? Heck, we might be having to construct artificial habitat for them soon just so we can say there are still wild populations.