There’s a lot of these, so here’s an example - Oxford ragwort (Senecio squalidus) arose in cultivation in the Oxford Botanic Garden in England. It’s parents are thought to be two species from Mount Etna in Italy, Senecio aethnensis and S. chrysanthemifolius.
Once in the garden, they quickly speciated and began to escape, where they began to be found around Oxford. During the industrial revolution, railways began to be built, with the track ballast making a perfect habitat to mimic their ‘native’ cliffs in Italy, and the passing trains helping to spread the seeds rapidly. It’s now a very common plant across Britain, particularly in towns and cities on waste ground and old walls.
If that isn’t enough, S. squalidus can hybridise with the native Groundsel (Senecio vulgaris) to make a sterile hybrid, Senecio x baxteri. However, polyploidy has occurred, resulting in two more reproductively isolated species - Senecio cambrensis, Welsh groundsel - a polyploid; and Senecio eboracensis, York groundsel, a tetraploid which went extinct and was recently reintroduced from saved seeds.
Whether these are native or not is debated. The BSBI’s Plant Atlas lists S. squalidus as a neophyte, but S. cambricus and S. eboracensis as native and endemic. POWO lists all 3 as native, and Stace’s New Flora 2019 lists S. squalidus as “neonative”, and the other two as ‘endemic’.
For other examples - Tragopogon mirus (a speciated hybrid of two European species that arose in North America - some sources consider it native to North America), or Sporobolus anglicus, a species that arose in England following hybridisation between a European and an American species.
How should these be treated under iNat’s statuses? POWO is inconsistent (the Tragopogon is not listed as native in North America, the Sporobolus and Senecios are listed as native in Great Britain).
You could argue they are native as that is the area they originated, and that would certainly be true if one parent species was introduced thousands of year ago via a bird and hybridized with a native parent species to produce a new species. That process is not human caused though. From a conservation standpoint, if two nonnative species are introduced by humans, hybridize, and produce a new species, that is a human caused event and I would consider the new species nonnative. If two invasive nonnative species hybridize to produce an even worse invasive species, classifying that invasive species as a native seems very problematic from a vegetation management standpoint. To me, the whole point of calling something native vs. nonnative is to identify whether a species may be a conservation concern in an area with natives possibly needing protection and nonnatives possibly threatening the natives.
Here is an example where one such species is classified as naturalized in the flora of California but POWO says it is native to California. The hybrid originated in California but California considers it nonnative from a management standpoint.
So the consequence of this approach is that the parent species have native ranges somewhere on the globe, but the new species originating from their hybrid products can’t have a native range anywhere on the globe, because the hybrid happened to form beyond the native ranges of its parents?
I suppose that then gives it the same status as a horticultural cultivar formed by artificial hybridization?
I’d think we could still sort out the two issues and manage the new invasive appropriately.
I didn’t really understand the part that a hybridised population became a totally distinct species. Why are they no longer hybrids? I’d love to understand this.
We deal with this in the Pacific Northwest of North America. Diploid Tragopogon species were introduced here. The introduction may have been intentional (the roots are eaten) but the plants escaped and became weeds. They hybridized. Two of the combinations resulted in allotetraploid hybrids that established whole populations; new species. One is Tragopogon mirus that I’ve posted on iNaturalist. After some contentious debated, it was decided that we have to treat these new species as native here, though their parents aren’t. Tragopogon mirus certainly isn’t native anywhere else. This is not satisfying, but it is logical.
Put Senecio vulgaris and Senecio squalidus together and you’ll get Senecio x baxteri, a hybrid that might backcross slightly (this is how Senecio vulgaris f. 'hibernica" appeared), but is mostly sterile.
Senecio cambrensis occurred when that happened, but instead of making Senecio x baxteri, it made something with double the chromosomes that happened to be fully fertile - but was now incompatible with it’s parents, and compatible with other examples of itself. Produces fertile offspring, isolated from it’s parent species? That’s not just a hybrid any more, that’s a fully-fledged species.
Same with S. squalidus itself, or the Tragopogons, or so many others. Hybridisation where something goes wrong and it makes offspring fully fertile, but not compatible with it’s parents.
Briefly, many natural hybridized populations will never form a distinct evolutionary lineage (species), usually because the hybrids are inviable or less fit than their parents, and/or significant gene exchange continues with one or both parents.
But sometimes hybrids are reproductively and ecologically viable, and also become reproductively isolated from their parents for various reasons of genetics, geography, reproductive mechanisms, etc. Once that has happened, they are no less distinct of an evolutionary lineage than any other populations that we usually distinguish as species.
In plants at least, this hybrid speciation scenario is common, and many (possibly most) extant species are the descendants of ancient (or sometimes more recent) hybrid speciation events.
That is how I would treat them. Likewise, it is similar to a hybrid that formed on its own in a greenhouse and then escaped. I don’t think it is accurate saying they are native to an area unless there is a very clear and always present disclaimer about what native means in this particular instance. From a database standpoint, there are so few of these taxa in any particular area that giving them a special “evolved in the area from nonnative species and possibly a threat to native species” status seems unlikely to happen, though that might be the ideal solution.
Given the choice of just native vs. nonnative, nonnative seems the better choice to me. It’s very much a grey area but saying something like that is native without an obvious disclaimer could lead to these being planted in restoration sites. There are already lots of issues with nonnatives getting planted in restoration sites due to misidentifications and/or poor choices in which taxa to plant. It’s best not to make it easier to make even more poor choices. For those that are invasive, it can also mean that their invasion may be overlooked because they are “native”. While I can see many problems associated with calling them native, I don’t see any issues with calling them nonnative except that it hides their true origin, but it hides it no more than just saying “native” does as native in this case is very different from what is generally considered native..
@invertebratist If you want to read further, the jargony term for this is allopolyploidy. It’s part of the reason there’s so many plants in the world as it gives very quick and nearly perfect reproductive isolation, allowing for the formation of new species. It’s very rare in animals however.
I understand your practical conservation management arguments for calling them nonnative. I’m just having difficulty with the logical contradiction of something native to Earth** not being native anywhere on Earth.
Yep, it’s tricky. Are cultivated hybrids native to the area they were first cultivated? Native vs. nonnative is an oversimplification like black vs. white. Both work great when you don’t have any greys or purples.
I’m happy to argue that life native to Earth can be native nowhere on Earth. It is a terribly simple case to make because the word ‘native’ has multiple meanings in common usage.
All life we know is native to Earth in the sense that it originated on Earth. Plant breeders use a similar definition, labelling anything first bred in Britain as native to Britain, even if both parent species are from Australia.
From an ecological perspective, a species is native only in areas where it has extensively co-evolved with other native species. In this sense, many organisms originated through human activity are not native anywhere.
I believe that on iNaturalist, the more useful definition is the ecological one. That said, iNat draws from many different taxonomic sources and which definition is used does vary among (and even within) these sources.
Sure, if you apply one standard for being native to Earth, and a different standard for being native to a portion of Earth, then one can make just about any argument one likes!
The key point is that using the one definition of native that I consider useful, the ecological definition, new artificial hybrids aren’t native anywhere, not even Earth.
Then I suppose that by that definition, any new species of hybrid origin, even a spontaneous allopolyploid within the native ranges of its diploid parents, would start off “non-native,” then would at some indefinite point in the future become “native” after it had coevolved “sufficiently” with other native species?
My head hurts - I think we might need a different word and concept, better suited to these contortions, than “native” or “non-native.”
Native: evolved in this region or arrived by non-anthropogenic means. Introduced: the taxon arrived in the region via anthropogenic means.
The reference is only to the taxon itself, not to where its ancestors may have evolved or how they may have arrived where the hybrid taxon originated.
As I am reading the OP’s examples, the actual hybrid speciation events were spontaneous and unaided, regardless of how the parental taxa happened to come together. Yes, the results may have wide array of different ecological consequences, but I think trying to encapsulate that spectrum in a binary native-nonnative concept inevitably risks oversimplification and misunderstanding, regardless of one’s definitions.
So in answer to the original question, I currently come down on the side of Yes, the new species are native where they originated, and where they subsequently spread unaided.
But even the hybrid wold be considered introduced by iNat definition - it arrived in the region via anthropogenic means. Humans transporting parent and frowing them together in the garden seems pretty anthropogenic to me (not to mention that the first habitats were also anthropogenic).
This means without humans, the species would not even exist. It is similar to horticultural hybrids and cultivars - they are also not native to anywhere.
(the matter is often not so simple, as it is often not clear what influence people had, but for this species, it appears we know exactly what happened, and should be easy to classify it). These matters often raise questeions what exactly is an artificial infulence of humanity? When exactly have stopped being part of nature? Is the current distribution of European tree species native or man-made? It is quite clear many of the were dispersed north and east by early humans, but it is also hard to argue this was an unnatural process
That said,
one nativeness arises from an ecological-evolutionary standpoint (which S. squalidus is not and cannot be), there is also nativeness from a cultural and legal sense (which, if brittish people decide it is, it can be, and gets the legal protections of a native endemic species).
As I read the definition, the hybrid species evolved (e.g., originated spontaneously and became a viable independent lineage) in that location; it was not brought there by humans. Yes, that event might never have happened if its ancestral taxa had not been introduced there by humans, but the definition doesn’t consider the source of its ancestors, nor the level of human disturbance in the habitat of origin. (Who knows how many more-ancient hybrid events might have been facilitated by small human-aided movements of ancestral species beyond their existing ranges?)
Maybe and maybe not - it depends on where else the ancestral species occur without human aid.
Sure, if you apply one standard for being native to Earth, and a different standard for being native to a portion of Earth, then one can make just about any argument one likes!
In my opinion, you’ve already used two different standards by calling something “native to earth” but not native to any area on earth. I think it’s already logically inconsistent. The species is found on earth. Whether it is native on earth is as debatable as whether it is native to the specific region in question, in my opinion. I think any argument about whether it is native to a specific area on the planet would also apply to it being native on the planet earth. And the other user is consistently using the ecological definition for both cases, so I don’t find it inconsistent at all.
I know I’m getting into the weeds a little bit. So I don’t feel the need to go down this rabbit hole of technicalities that is maybe beyond the point of this conversation, but I wanted to bring that up.
In my opinion, this conversation is fascinating but doesn’t really have a clear answer. If I had to say native or non-native, I would say non-native anywhere. But it’s definitely equivocal and no one position is demonstrably right or wrong, the traditional categories just break down.
Just to clarify, I am arguing against that inconsistency, and suggesting that the iNaturalist definition should be applied consistently to the whole Earth and to any area on Earth. Doing anything other than that is what leads to logical spaghetti.