It’s easy for us to tut-tut, and to wring our hands about all the species that humans spread around the world:
- Pigs and rats, as humans spread around the South Pacific
- British folks trying to recreate British fauna during the reign of the British Empire (in Australia, and in other places)
- Etc.
But I think the 100+ replies above show that there are shades of gray . . .
SoFla (South Florida, in the USA) is one of the most interesting places in the world for introduced (and sometimes invasive) species, due to a combination of factors:
- A relatively rich population that can afford pets from around the world
- A large population centre, which creates a high demand for non-native plants and animals
- A subtropical climate that allows many escapees to survive
- A climate that is prone to hurricanes, which can allow captive animals to escape their pens, and can also “spread things around”
- A shipping hub that receives cargo shipments from around the world, which may be “contaminated” with non-native plants and animals
You can read about some of the non-native organisms found in Florida here:
https://en.wikipedia.org/wiki/List_of_invasive_species_in_Florida
Do you have any favourites on that list? 
