IUCN Standard to support global action on invasive alien species

Nowhere but they are listed under the injurious species list of Lacey act. I can understand a ban for import to island occupancies but to think that this Australian marsupial could survive ecosystems with wild cats in it requires fear driven lack of rationality. This is why the US will never have brush tailed possums in zoos.

The US has similar laws regarding the importation of mongoose and African rodents into the country. The reasoning is always due to the taxa in question having had a large negative impact on the ecosystem of some region of the country.

~Thylo
 
I’ll get you after work. I don’t disagree with you. But I do think the destructive effect of the Python is again, in a sense, exaggerated. I’m not saying the species does not effect the environment in which it is introduced, but I don’t agree that change is necessarily destruction.

There are native species on the brink of extinction due to the pythons...

~Thylo
 
I'd also love to know what you think of all those Zebra Mussels, Round Gobies, Sea Lampreys, ect. destroying the Great Lakes. And about Nile Perch in Lake Victoria?

Good points...but I did say terrestrial environments. And again, “destroying” is probably not the word I’d use...changing, altering, impacting...sure. To detriment of native species...sure. I understand that and agree. But...would it be “destroying“ the lake were it a natural (I.e. non-human facilitated) colonization. Or would it be change, with subsequent adaptation?

The difference is there and it’s within that difference that reasoned assessment should take place. Especially in less vulnerable habitats. And remember this as well, a lake is to the land, what an island is to a lake. So yes...it’s generally a bad thing to introduce a non-native species to such an environment. But....there is room to differ.
 
I’ll get you after work. I don’t disagree with you. But I do think the destructive effect of the Python is again, in a sense, exaggerated. I’m not saying the species does not effect the environment in which it is introduced, but I don’t agree that change is necessarily destruction.

I feel I do need to restate that my initial posts (and subsequent ones) on this subject acknowledged that islands, up to and including Australia, are exceptions to my generally held view on the subject.

I’m not a fan of free roaming house cats either.
Completely purging an entire ecosystem of mammals is "overblown"!!! :eek:
 
Good points...but I did say terrestrial environments. And again, “destroying” is probably not the word I’d use...changing, altering, impacting...sure. To detriment of native species...sure. I understand that and agree. But...would it be “destroying“ the lake were it a natural (I.e. non-human facilitated) colonization. Or would it be change, with subsequent adaptation?

Except it's not. That's the difference.

~Thylo
 
Good points...but I did say terrestrial environments. And again, “destroying” is probably not the word I’d use...changing, altering, impacting...sure. To detriment of native species...sure. I understand that and agree. But...would it be “destroying“ the lake were it a natural (I.e. non-human facilitated) colonization. Or would it be change, with subsequent adaptation?

The difference is there and it’s within that difference that reasoned assessment should take place. Especially in less vulnerable habitats. And remember this as well, a lake is to the land, what an island is to a lake. So yes...it’s generally a bad thing to introduce a non-native species to such an environment. But....there is room to differ.
The only thing that hasn't changed about the Great Lakes is that they are lakes, really - the ecosystem of them is completely altered, thanks to the large number of invasive species. On paper this is a net gain in biodiversity. Only three species lost, and plenty more gained. But I don't think any of the deepwater cisco species would agree with you there. Nor would all the other formerly common species in those lakes, like the Lake Trout or all of those freshwater mussels. Or any of the fishermen who are used to catching nothing but gobies or the occasional Sea Lamprey-covered salmon.
 
The US has similar laws regarding the importation of mongoose and African rodents into the country. The reasoning is always due to the taxa in question having had a large negative impact on the ecosystem of some region of the country.

~Thylo

Just to further what you have already said.

I guess that the Javan mongoose is already present as an invasive species and having some severe ecological impacts in some US overseas territory like Puerto rico, US virgin islands and Hawai'i (not sure if they are on Guam though..).

Consequently, I think the fear of importing this to the United States is a very understandable concern.
 
There is a lot going on here and as someone who has worked with invasive species for a few years there seem to be a lot of misunderstandings and oversimplifications here.

Scientists have tried for years now to predict what makes a species potentially invasive in a new country. There is a lot of noise in this data and by far the best predictor is that when a species has become invasive somewhere, it is likely to do so again.

From a cost-benefit perspective, early detection rapid response is by far the most cost-effective and beneficial way to deal with any new exotic species. Once a species has become invasive it is next to impossible to eradicate it completely from its new range and damage control is the best one can do (Rabbits in Australia, Stoats in New Zealand, but also plenty of examples with insects and plants). It is much cheaper and has much more long-term benefits to eradicate all 100 new arrivals than to wait and see how they will all behave. In all likelihood most exotic species will never reach invasion status (but there can be a extremely long time between settling in a country and spreading!), but the ones that do can do extreme damage. This damage is highest outside the most heavily developed areas (such as W-Europe) and there is evidence that pristine environments have a higher resistance (but are not completely resitant) than disturbed areas.

When saying that invasive species are just another change to a dynamic ecosystem and ecosystems will just change, that is a gigantic oversimplification with potentially disastrous effects. There are invasion denialists pointing at how species richness has increased in Hawai'i to show that it is a positive, but 50% of all species are non-native and on a global level species richness is lower, not to speak from how native forests are displaced and all the ecosystem services they deliver are diminished too... (not to speak about cultural values). If you look beyond the disappearance of many native species if successful invaders arrive, this often brings gigantic changes to the ecosystem itself. For example invasive pine, eucalypt and (mainly Australian) Acacia species in Mediterranean systems around the world not only endanger biodiversity hotspots (Southern Cape!), but also consume a lot more water than the original vegetation, which endangers drinking water provision to people among loads of other things (see working for water program in S-Africa).

It often seems that people need to experience the real damage an invader can do from up-close before they accept the problem. There are very few biomes with relatively few invaders (mountains and the Arctic being an exception). But research suggests that these are not immune either....
 
I think a lot of the hysteria regarding invasive species is overblown. Pigs in Europe are woodland engineers, but the same species in North America is destructively rooting and wallowing and befouling. Environments change. Few will agree...but I stand by it.

I would just like to add to the conversation by pointing out that the above is the exact same argument as "climate change isn't a problem even if it is manmade because environments change, we're just helping them change faster :) Get over yourself" and "humans are animals and we built tools to assist us so therefore taking a machine gun to an entire species is simply survival of the fittest and we need to erase the hysteria and dogma surrounding what is, in actuality, a natural extinction"

~Thylo
 
This damage is highest outside the most heavily developed areas (such as W-Europe) and there is evidence that pristine environments have a higher resistance (but are not completely resitant) than disturbed areas.

I would generally agree with that statement.

In Brazil there certainly seems to be a strong correlation between the biological invasion of invasive primate species such as common and black eared marmosets into remaining forest fragments and the widescale deforestation of the Atlantic rainforest and anthropization / urbanization of the landscape.

I think that in many cases (but obviously not all) the anthropization of landscapes is a strong enabler / facilitator of biological invasions, the eventual establishment of invasives and displacement or extinction of natives.
 
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