I did some reading about various introduced populations of fish, reptiles, etc and a suprising amount of them have yet to be posted here on iNaturalist. This is strange because most invasives are in places with higher population densities, especially in the US where there are the most amount of people using the app.
Here are some examples:
The Western green lizard (Lacerta bilineata) in Topeka, Kansas. This population is located in a major city so it is weird that it still hasn’t been posted to this website, especially being that they are large noticeable lizards. I guess it is due to the small area they live in and that most (or all) of it is on private property.
Eastern fence lizard on Staten Island. They were introduced by Carl Kauffeld in 1942 into what is now the Clay Pit Ponds State Park Preserve but I cannot figure out if they are still there or not. All the information on them is vague and there isn’t any definite proof in the form of publications or images.
Asian swamp eels in New Jersey. Back in 2008 a population was discovered in Silver Lake in Gibbsboro and although there was some short lived uproar like with snakeheads a few years before, the eels seem to have been forgotten. I did find some PDFs from the NJFWS which show they are still monitoring the population and removing eels from the lake, but there isn’t much else on them. Silver Lake is technically private property and fishing is prohibited but people still do it, and I know there are lifers out there who would want to catch a new species for their list so I would have thought people (other than FWS workers) would have caught them by now.
Rhamdia quelen in Miami, Florida. This is a species of South American catfish that is aquacultured on that continent and was presumably brought to Florida for the same reason. The weird thing though is that there is very little information on them as is, and there is next to nothing on them in Florida. I found out about them through life listers on instagram, but other than that there is no other information. There is a species profile on NAS for the catfish but there they are listed as “failed”. I only managed to find an entry on Species Hunter for one that was caught in Florida in 2021, and there are also two entries for them in the Florida Mueseum itchyology database.
This is even more true of the small, understudied invertebrates. In some cases, such as with the glossy pillar snail, we don’t even know where it’s native and where it has been introduced.
-Beech Marten in Wisconsin and Illinois. This species has escaped from fur farms and now occurs in the forests on southeast Wisconsin and northeast Illinois. Due to its secretive and nocturnal nature, it is undocumented on iNat.
-Black-tailed Jackrabbit in southern Florida. There is a small introduced population of Black-tailed Jackrabbit in and around the Miami airport that remains undocumented on the site.
-Red-bellied Squirrel in the Florida Keys. Elliot Key is home to an invasive population of Red-bellied Squirrel. For reasons unknown to me this population is not documented on iNat.
-Silver Pheasant on Vancouver Island. A small population descended from zoo escapees can be found on southern Vancouver Island. Its rural location, small population size and range, and secretive nature means no one has uploaded an observation yet.
Theres a lot of weird fish down in urban south Florida. Haven’t heard about the Rhamdia though not surprising. Can’t remember the name for the life of me but I found an instagram account once of someone finding a canal or ditch or something full of serpae tetras.
The Bypass Canal over in Tampa is reportedly loaded with weird fish too, reportedly theres a fish farm somewhere nearby, I’ve seen people finding threespot gouramis there, probably some other stuff that escapes but barely establishes you can find if you’re real thorough with a dipnet
I believe capybaras have been seen in northern Florida near Gainesville, although I don’t think it’s been determined whether they’ve established a breeding population or not. Capybaras did live in Florida during the Pleistocene, so depending on definition, they could potentially be considered a native species.
There’s no official breeding evidence but they have a large population and are usually assumed to be established. I was going to mention that one but forgot.
Does anyone have examples from other countries? There must be many examples of fish, I know there’re guppies and other small aquarium species that live near plaes of where hot water connects with rivers and no ice is formed. So far, this species wasn’t documented on iNat locally.
I’ve heard about a small pond hidden away somewhere in New Zealand with a population zebra danios, apparently reproducing thanks to it getting warmed during winters? but never spreading out of that pond
Keep in mind there’s the possibility that introduced populations have been observed on iNaturalist but not identified. When I noticed Australian buttongrass in Tucson, AZ there were only two observations of this plant in North America (years old) and it did not show up in any of the computer suggestions for the area. I dug into local herbarium records and found that it had been transported over with cattle fodder… I forget when, 1930ish maybe.
Once I made a successful ID I made a point of observing it when I had the chance, which seems to have helped “seed” the computer suggestions as I’ve seen several more observations by other users since then.
I do not have particularly rich knowledge of plant ID in general, even less for grasses, and much less for grasses. Determining what I was seeing took some effort, and it’s very possible there’s observations for the same species that have never been IDed past “Plants” or “Grasses” - I’ve never actually checked!
e: As soon as I posted this I went and had a look, and yep- there’s one that’s 5 years old and has never gotten past Poaceae. I’ll have to have more of a look.
I think the Colombian hippos are generally on their way out? too small of a gene pool and I think inbreeding is already starting to adversely affect them
I think any drop in population is likely due to terrible poaching (more in the article, the end is tragic) and Colombia’s plan to address the hippo problem.
From the article:
In October 2021, Cornare launched its latest plan to get the wild hippo population under control: treating the animals with GonaCon, a contraceptive for both males and females. Twenty-four hippos have since been dosed using darts, according to Echeverry. They join 11 that have been chemically castrated since 2014.
(Bolding mine) If 35 of 70 are rendered unable to breed, that would adversely affect the rate of population growth, I would think. (I am not a hippo specialist, though. I just knew about Pablo Escobar’s hippo legacy.)
Many of the introduced/invasive arthropods present in Hawaii are present but not yet recorded on other islands throughout the Pacific. I recently posted the first obs of bromeliad mosquito (Wyeomyia mitchellii) and strawberry sap beetle (Stelidota geminata) for Pacific islands outside of Hawaii. There are several yet-unrecorded species that meet these criteria
I like this thread. A nice reminder that there is always more to find.
Apparently there is a population of moose in the remote Fiordland wilderness in the southwest of the South Island, New Zealand that are descended from a herd released in 1910. No iNat records.
I never got the “native in the Pleistocene” argument. Things have changed since then, and a lot of ecosystems have since developed to the point that the reintroduction of Pleistocene species could absolutely knock things out of whack.