Exotically derived neo-native
Quasi-native
Ambi-native
Confusing
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Contaminated native?
For #1 I guess I’d call it a pseudo-native or quasi-native, for #2 it gets murkier, but for conservation purposes, I’d call it something like a “contaminated native”.
A good example of how murky it can get is with the case of the endangered CA Tiger Salamander (Ambystoma californica) having hybridized with the introduced Barred Tiger Salamander (A. tigrinum mavortium) to create a more “fit” hybrid via hybrid vigor.
CA Fish and Wildlife treats these hybrids as a genetic threat to pure native CTS and eradicates them as far as I know.
Whether that’s the best policy is an open debate, with some sources saying that the helpful genes will proliferate in the native population and boost it, and others saying that differences in life history can be exploited to reduce the hybrid prevalence.
There’s an open flag on this hybrid if anyone’s interested to see what the live hybrid looks like.
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The thing is, allotetraploid hybrids like Tragopogon mirus aren’t artificial. People didn’t make them. Both parental species were introduced and are weeds in North America. The process of hybridization and chromosome doubling has occurred many, many times in earth’s history, usually without input from humans.
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Nope. They are still alien.
The same if an alien secies gives rise to a new species through, for example, autopolyploidization.
@jamie-aa @jdmore ＠kevinfaccenda
Thank you so much for taking your time to explain. I only got into botany recently from specialising in molluscs (thanks to iNat) so it’s very fun to learn all the different concepts.
Going back to the original topic, I tend to consider them introduced (under three classification of Endemic, Native and Introduced). It would be nice to add a different category for these though.
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Let’s just introduce Tragopogon mirus in the Old World and (assuming it does not fail miserably in this new exotic environment it is probably unfit for) voilà! according to some viewpoints it will become native there, since its “parents” were native there.
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Third culture plants?
Given this discussion I’d be inclined to leave them listed as neither native nor introduced and a note as to why.
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You’re right, the hybridization event was in many cases natural. Still, if the hybrid hasn’t yet had time to co-evolve with other native species in the area, it is not, in the ecological sense, native. This gets conceptually trickier when both parent species are native, but we should not expect these things to be conceptually simple. Just like with species boundaries, we are trying to apply simple labels to complicated natural processes that don’t care what we call them.
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I do strongly prefer to limit the question of native vs introduced to one of place of origin, without complicating it with the question of how long it has co-evolved with its neighbors.
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When you consider that an oceanic island’s biota did not all arrive in the same colonization event, I’m not sure either approach fully captures it. If an island has existed for 2 million years, and the first humans arrived there 600 years ago, then any species that arrived there earlier than 600 years ago is considered “native,” whether it arrived 1.8 million years ago, 6,500 years ago, or 750 years ago. Yet the one that arrived 750 years ago clearly had not long coevolved with the earlier arrivals, and may, indeed, have adversely affected them the way an “invasive” would.
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I don’t expect simplicity, but I do expect testability and falsifiability. The current iNat definitions at least meet those criteria.
How much “time to co-evolve with other native species” is the right amount of time to consider something native? Or how many generations? Or based on what biological or ecological indicators?
Many introduced annual species have already been co-evolving with native species for hundreds of generations. Would they also be considered native after some threshold number?
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No, it would not be native
Both parents grow together, or at least in close proximity in Europe, and they have not produced a hybrid species like mirus here, so i obviously needed another factor to arise.
and if you would introduced it to europe artificially, that sentence explains its status in Europe by itself.
nobody is saying the issue is clear cut, there are examples where it really is dubious, but for both Tragopon mirus and Senecio squalidus we know exactly what happend and it should be quite a clear cut.
We brought the parent species somewhere else, and even though both pairs of parents grow in close proximity, their hybrids were non-existent or not succesful in nature, only after human intervention of relocating the parents was the formation of a succesful hybrid possible.
the processess are of course natural, but so is selective breeding. Selective breeding is exactly the same as natural selective, except that the selective forces are influenced or chosen by us. If there was some force outside of humans, that would favour survival of wheat wth bigger grains that stayed on spike, you bet it would evolve very similarly to how modern wheat did from its wild ancestors.
the same here, hybridisation in polyploidisation are perfectly natural processes, but in examples stated hitherto, there is a barrier in nature making that impossible; and only by humans removing that barrier did those species fully and succesfully form away from the natural environment of both of the parents.
Those species are ecologically and evolutionary native to nowhere. This is the exact same process ecologically as the spontaneous formation of hybrids in a glasshouse in a collection of plants that would otherwisenever grow together.
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When new species arise in an area and they are only found there, they are endemic regardless of who the parents are.
If there is no clear answer to the question are they native, it seems the definition of native is left wanting.
Sometimes the only way for a species to survive in any form is to hybridise. There are examples.
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Well, that’s why I wrote “according to some viewpoints”. Yours, mine, others’ - they will likely differ according to the emphasis put on human intent, vs. habitat peculiarity, vs evolutionary process, vs. etc. etc.
(to me with a paleo- background, the situation appears fairly clear-cut: the lineage T. mirus is of course ‘native’ from wherever and whenever its peculiar event of apparition+survival once took place [and has been recorded]; it matters much less if/where/when/how-often the [grand-grand-grand-]parents met and whether this was with the partial or complete help of anemochory or ornithochory or anthropochory)
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