What to do in cases where a species is both introduced and endemic?

The San Joaquin Thistle(Salsola ryanii) evolved from a hybridization event between two non-native thistle species in California. The taxa is considered invasive in the state but it is also endemic- as it occurs nowhere else on the planet.

I do not think it is possible to mark something as both Endemic/Native AND Introduced, but in cases like these, what should they be marked as?

It isn’t an isolated case either. Two ragwort species are also known to have arisen in a similar way, both endemic to the UK: Senecio cambrensis and Senecio eboracensis

Further question, is… should these species be protected? Where do they fall in terms of conservation? They wouldn’t have arisen without people bringing one or more of the parent taxa to an area, but at the same time they are species in their own right.


I have also created a project to track these very specific taxa here: https://www.inaturalist.org/projects/introduced-natives

Please let me know of any other organisms that need to be added.


Interesting question. I don’t have a firm view, but it does seem to me that in these cases, the parent plants are introduced, but the new species is not - it is native, as it evolved in that place, even if the events that led to its appearance were not natural.

One of the Senecio species you mentioned has been the object of conservation actions: https://www.theguardian.com/environment/2023/may/27/york-groundsel-bloom-again-britain-first-ever-de-extinction-event-natural-england These cases would make for a great discussion in a conservation ethics class!


iNaturalist doesn’t have an “invasive” label as “invasive” is a judgement call and not a simple fact. It seems to me that “introduced” probably isn’t appropriate, since the species itself arose in CA?

iNat also doesn’t determine which species should be protected, that would be up to varius authorities.


Right, maybe this should have been in Nature Talk in that case. Right now the thistle is labeled as introduced in CA, I couldn’t seem to change that myself. I suppose its invasive and endemic, then? I agree introduced is probably not the correct terminology to use here.

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I’d probably call it “native”. And again, “invasive” is not a term used for Establishment Means on iNaturalist. The options are endemic, native, and introduced.

Anyone can change the establishment means for a taxon in a place, but it’s not something that’s straightforward. I’ve been meaning to write a tutorial for it.


I guess I should’ve clarified- I meant its regarded as invasive outside of iNat. Just strange labels to be placed on a native taxa when its entire existence is due to historical human actions. I did figure out why I couldn’t change it. on the establishment means page for the taxa, the source list is " Chenopodiaceae of California, US" rather than the actual state list for CA. As Salsola is not in the chenopodiaceae, it won’t let me change the statuses. Just a minor thing.


Another example. Tragopogon mirus is considered native in the PNW of North America. It’s a fertile, allopolyploid species that originated from a cross between introduced Tragopogon dubius and introduced T. porrifolius. I’m uncomfortable calling it native here, but it certainly isn’t native anywhere else. Here’s the link to one of the observations from this population: https://www.inaturalist.org/observations/79330212 The other observations I’ve made are linked to this one.


Fascinating. I’ve added the taxon to the project. Thanks!

I wonder if there are any introduced species that have gone extinct in their native range (other than widespread domestic animals like cows and horses…). What made me think of it is Mariana Swiftlet which has a small introduced population in Hawaii, but its native populations are still hanging on.

Does Brugmansia qualify

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Interesting, I remember seeing one of them in a documentary featuring Sword-billed Hummingbirds, didn’t realize they were extinct in the wild! However they seem too widespread to be considered endemic anywhere, unless any of the species only has an established “feral” population in one place in the world?

The whole genus is extinct in the wild, so every RG one on iNat is either a captive individual or escapees from cultivation. When reading your question, my first thought was camels, like in australia, but I suppose that would also count under the domesticated species thing.


Yeah it looks like Dromedaries have feral populations all over the world, so not very endemic anywhere.
(random out of context camel observations I just came across: 1, 2)

I showed this post to my wife, who is not a plant/ecology person. I asked her whether she thought Salsola ryanii should be considered native or introduced. There was a pause, so I interjected, “I think it should be considered native.” She responded, "I think it should be considered ‘controversial.’ "

Hence, I am suggesting a new option for establishment means: controversial.


Actually, there is one example I know of. Scimitar-horned Oryx was completely extinct in its native habitat but doing very well in Texas, of all places, due to the hunting ranches there.


That might even solve the gray areas in terms of certain escapees. “Controversial” describes all sides very well. ha


I know of a few of these in Hawai’i, Pluchea x fosberii comes to mind along with an un-named hybrid between Neltuma juliflora & N. pallida. I have also found two hybrids between grasses which are what I’m calling “autochthonous” . I have submitted a paper formally naming the grasses, but it’s still currently in review.

I don’t honestly think they deserve much conservation protection moreso than any other weed does.


You could consider to do as we do for our “endemic” Oenothera. We consider them introduced since their existence relies solely on the introduction of their parental taxa.

I think there is an invasive Spartina grass in Britain which is a new species, a hybrid between a native and a New World species.

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