Many specis could, but introduced populations are not self-repopulated, they’re introduced, we either talk about whole Europe or that grey Mediterranean area, because here they deserve that status and it’d be nice to see more red deer instead of them, if it’s unclear to scientists if those populations are native or not, it’s easier to change status to nothing for those countries.
Going back to your original question, I certainly agree that in many cases it’s unclear whether a species should be considered introduced, reintroduced, or simply native. And where do you draw the line between a long-extirpated population and a restored (reintroduced?) population? There isn’t always a clear answer. I’ve heard some say our Wapiti in the Southwest US are introduced since the native population was extirpated about a century ago. The current population was derived from elsewhere in North America, although they’re the same species but (arguably) not genetically or taxonomically the same as the original. Same for River Otter. It’s an interesting argument although for me the “analogous” forms we’ve (re)introduced are functionally the same.
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I would argue, that “introduced” has a fairly straightforward technical definition - the current focal population referred to was introduced by humans and wouldn’t be present (to the best of our knowledge) without that introduction.
While many people assume that introduced = bad, this isn’t always the case and shouldn’t be assumed. I think if iNat focuses on a technical definition and avoids value judgments, that would be best.
With horses for instance, the current populations are definitely introduced. But that shouldn’t preclude discussions of the value of those populations (positive, negative, etc.). All the questions about whether current populations of horses in NA are beneficial or detrimental and how/if they should be managed can occur alongside our knowledge that the population has been introduced. Calling those populations introduced doesn’t mean that we can’t acknowledge that horses were native to many North American ecosystems in the not-too-distant past. These facts coexist and aren’t exclusive.
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In my opinion, that isn’t nearly as interesting or useful information.
I like to know if a species is a novel addition to an ecosystem, because that usually makes a profound difference in its functioning in that ecosystem. I don’t really care if a species disappeared somewhere for the evolutionary eye-blink of a couple hundred or thousand years or how it was returned there.
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You’re assuming the form that disappeared and the form that has now been restored really are the same species or subspecies. That does make a difference, at least for iNat purposes. The River Otters currently residing in my state are not the native form that is now extinct. If someone used the name Lontra canadensis sonora for a River Otter they saw in the Southwest US yesterday it would be incorrect – that animal no longer exists (to the best of our knowledge) and has been replaced by other forms. And I would argue that the taxonomy of a form that disappeared a couple hundred thousand years ago is far less clear.
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The ecosystem you refer to also continued to evolve for thousands of years without that species present.
I think that if a species ceased to exist and then was “reintroduced”, it is “introduced”, most likely not from the same gene pool.
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Yeah, but it usually evolved for millions of years with that species, its ancestors and/or its functional equivalents present. That makes thousands of years a very short time.
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True, but many believe species evolve most often in spurts. It is impossible to say, but I believe that if something is not there, and man puts it there, that is a definition of introduced.
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I agree that knowing how novel a species is to an ecosystem is more interesting than categorizing the introduction history of a population as introduced or not. But the idea of evolutionary and/or ecological novelty is really a continuous variable with a lot of different contingencies around it that have been discussed by many folks in this thread:
- How long has the species been extirpated?
- How similar is the introduced/reintroduced population to the original?
- What function/s does it serve in its ecosystem?
- How have co-occurring species evolved since the focal species has been extirpated?
- How has the ecosystem as a whole changed since the species has been extirpated?
These (and others) are all interesting and important questions. But there’s no way that detailed, context-dependent information can be communicated by “introduced”/“native” or any categorical term really. There are lots of judgment calls, shades of meaning, and very few “bright lines” in assessing those ideas.
A straightforward definition of “introduced” has a narrow applicability but can be applied in a clear and consistent way across many species. The other, interesting questions are likely only assessable on a case-by-case basis in a way that combines many lines of research and evidence.
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The concept of Pleistocene Rewilding has dealt with many of the same arguments discussed here. Releasing African Cheetahs onto the plains of North America to give our lazy Pronghorns something to run from (since our native cheetah analog is now extinct) is one of the more amusing (to me) proposals.
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Look into land mammal faunal stages. The amount of time the megafauna has been gone hasn’t been long enough in an evolutionary time scale to meaningfully impact how an ecosystem properly functions. Virtually all of the species alive today were also alive in the upper-Pleistocene with the megafauna.
In addition, the ecosystem evolves in a way as well, and for that a thousand years is a lot longer. An ecosystem isn’t necessarily “broken” if it changes (though at times - such as now - some changes are breaking things).
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It is amusing, but I wonder if African Cheetahs in the US would get “bullied” away from their kills by everything (pumas, wolves, coyotes, vultures, etc) they way Cheetahs in the Savannah are, and end up in just as precarious straights, and the Pronghorns not meaningfully inconvenienced.
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Here’s what I envision – because Pronghorns are largely constrained by barbed-wire cattle fences, having to stop and crawl under such fences (where possible) since they can’t jump them, a cheetah would learn to chase one or more pronghorn into a fenceline to make capture much easier. And there are such fences everywhere in Pronghorn range. Sheep fences are even worse and impenetrable to Pronghorn. Just one of the ways the North American environment has changed since the Pleistocene.
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Back to the original questions. If the species occurred in an area in relatively recent history (I don’t know where the cutoff should be – within a few centuries ago? millenia?), and it’s restored, then I wouldn’t call it Introduced on iNat. It’s native and reintroduced.
If there is no consensus or compelling evidence that a species was definitely introduced, it should not be marked as such on iNat.
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On the horse thing: Equus ferus was native to, and evolved in North America yeah, but theres a massive difference between domesticated, feral horses, and proper wild horses. Feral mustangs are so much bigger than the wild horses that once roamed North America (this picture shows a good comparison https://cdn.discordapp.com/attachments/925999133096034347/944350983385940028/4B6BEA85-E43C-44CB-80C3-6C37DC8930F0.jpg)
This size difference is why if you look at those rewiliding projects going on in Europe they often opt for similarly sized, more “basal” breeds, if not straight up Przewalski’s
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On the scale of hundreds of thousands to millions of years, ecosystems naturally “get over” their losses obviously nothing is missing shoveltuskers or boraphagine dogs. When dealing in timescales of tens of thousands of years however, it just isn’t long enough in geologic time to see meaningful changes. Most species naturally exist for hundreds of thousands to millions of years, the ecosystems of the Americas had existed as is for a very long time before humans arrived. Many things that we have to do to manage a “healthy” environment such as controlled loggings/burns, hunting prey species, etc. is due to this ecological imbalance. We even have fruit trees with incredibly reduced ranges that are missing their natural dispersers.
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Definitely agree with you, they are quite different phenotypically from the original population, but at the species level they are still “native”. We also had another horse that is completely extinct as well the “stilt-legged horses” and South America had both of these horses plus an additional endemic horse as well.
Not to derail, but donkeys would be a good example of a species that actually is alien to the Americas current ecology.
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This is almost a philosophic discussion, and I have no firm opinion on it. An example that comes to mind would be the European Beaver. Extirpated in many areas (see: Eurasian beaver - Wikipedia), it is once again present, but has been released by humans from some place else. So it was there, then it was hunted to extinction in these areas, and now it is back because humans put it there. Introduced or not? Or both? In NA the beaver was also extirpated over much of it’s former area, but has re-established itself in many of these areas from existent relic populations. I find it difficult to distinguish between the two. If things changed would the relic European populations have re-establish themselves (except for the British isles, which is physically [and politically?] separated from mainland Europe)? I don’t know the answer.
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There’s definitely a philosophical component to introductions/reintroductions which affects if and how it’s done and how the results are interpreted after it’s implemented. There’s always biological, political, and cultural aspects that come into play on whether to do it or not. I used to think it was rather straightforward until I had to plan and implement some projects myself.
But for iNat purposes, it’s really a yes or no decision (do we classify an existing population as introduced or not?). However even that decision isn’t always simple due to the complicated histories of some organisms and past actions by humans, including wildlife managers.
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