scientists use several terms to categorize the residency status of organisms, while the iNaturalist seems simplistic, offering only three options: Native, Introduced and Endemic. However, there are these two, not rare cases that are hard to match with the iNat categories:
- Archaeophytes: These are the plants which were probably introduced by humans to an area, but the introduction happened a very long time ago, and evidence is usually indirect. In Europe, we consider plants introduced before AD 1492 archaeophyte; however, most of them probably arrived already in ancient times. For example, many of such species (e.g. Papaver rhoeas, Cyanus segetum) are native to the Mediterranean Basin and the Middle East, while in Central and Northern Europe, they are typical weeds of arable lands. These species were spread parallelly with the ancient spread of agriculture. Now many archaeophytes are typical, and some of them are rare and specialist species of pioneer habitats, with completely different ecological meanings from introduced invasive species.
- Neo-natives: This is a rather new term denoting species that settle without human assistance in a new region (see Essl et al. 2019). Such an example is the recent establishment of Carex extensa on an inland salt marsh, very far from its native range, probably due to long-distance transport by water birds. Other examples are when more thermophilous species shift or expand their range due to climate warming. They probably don’t use humans as vectors more than native species, they may benefit from indirect effects of humans (e.g. habitat disturbance, heat islands), but we don’t really know whether they appear because of a dispersal effect or a survival effect.
So, what do you think is the best category for them - native or introduced?
You can check the iNat definitions of these terms which are:
evolved in this region or arrived by non-anthropogenic means
native and occurs nowhere else
arrived in the region via anthropogenic means
So neo-natives would be Native (as seems appropriate) and Archaeophytes would be Introduced.
You can see some discussion of terms here:
but there are other threads as well
I’m not set on the first case, it can be tricky to decide how a plant got there a couple thousands years ago, but the second case would fit the native.
Thanks! Yes, archaeophytes pose the main problem because we don’t really know how they arrived. And now many of them behave more like native species because they have had time to adapt to local conditions (and to evolve!). This information would be lost by treating them as introduced, even if they had arrived by means of some human activity.
In the U.S. we usually use a simple-minded but good-enough system. If it was here before 1492, it is native, whether it evolved in the location or humans put it there. If it arrived after 1492, it’s introduced (also called non-native, exotic, in some cases naturalized). Endemic is a subcategory of native, for organisms that are native only to the region being discussed.
I like this solution! Practically, you consider archaeophytes as natives.
Yes. Archaeophytes are natives, in this system.
Like almost all categories in nature, there are exceptions and ambiguities. You already shared some great examples.
How do we really know a species is non-native? It might seem like an obvious category, but if you think about it, the “evidence” of absence before a certain date is just absence of evidence! I know taxonomists who don’t agree that certain species, widely regarded as non-native, are actually non-native. They just think the species was under-collected before a certain date. This is especially true when there is no strong ecological or geophysical reason for the species not to have spread naturally. For example, species that are “native” to Eastern North America, but are considered “Introduced” in Western North America (e.g. American Bullfrog).
Also, what about species that have both native and introduced genotypes? Phragmites australis is a classic example from North America, where you have to ID to subspecies (often very difficult) to distinguish the native from invasive. In iNat, if you only ID to species, it will say it is native. Only the observations that have been ID’d to species have the Introduced tag.
" if you think about it, the “evidence” of absence before a certain date is just absence of evidence" – Not necessarily. As we work out phylogenies, especially with DNA sequences, we often learn where species X’s relatives are and can sometimes even determine approximately how large a founder population probably was.
For example, we now have good DNA evidence that the sedge Carex leporina, long considered native to Europe, was introduced from the Pacific Northwest of North America.
Sometimes we have evidence (such as historical records of introductions, population changes since presumed introductions, and discontinuous habitats) for believing the creature didn’t get here on its own (e.g. American Bullfrog in the Pacific Northwest.
OFF: “For example, we now have good DNA evidence that the sedge Carex leporina, long considered native to Europe, was introduced from the Pacific Northwest of North America.”
Could you show me a publication about this, please?
I think it’s the article referenced in this discussion with Dr. Anton Reznicek: The Ovales article is in International Journal of Plant Sciences 167: 1029-1048. 2006. I thought I had a PDF of this – but I could not locate it. I can send you a reprint by snail mail if you like. Our sample of Carex leporina (which we called C. ovalis, of course) from the west coast consistently fell into a different position from Eurasian plants, suggesting (as we note in the Biogeography discussion, pg. 1042) different origins. It may well turn out that the solution to the Carex ovalis nomenclature problem for the west coast is that K.K. Mackenzie was right, and they should be called C. tracyi! But that’s a bit premature, and needs some morphological work. Andrew and I did have some more sampling to show that plants from eastern N America, and New Zealand (clear-cut introductions) clustered with Eurasian plants, unlike the west coast plants, which were usually sister to C. feta (which is a bit weird). Another explanation, of course, is that the west coast thing we sampled had undergone a past hybridization event with some native species.
If not, let me know and I’ll try again to find the reference.
Thank you, it was enough for me to find it. Really surprising result!
This whole thread but specifically @sedgequeen pointing out that organisms present in North America prior to 1492 are considered native has me wondering once again about a question I used to ponder. Did viking explorers introduce organisms to North America? I recognize that finding out would be very difficult considering that later European explorers weren’t exactly treading softly.
Probably the Vikings introduced little or no vegetation that stuck around, considering how brief their time in North America was. However, it’s possible.
Evidence for that would be confounded by natural transatlantic dispersal. Taxa found in northeastern North America and northwestern Europe would be the ones to look more closely at.
Even if it wasn’t introduced? I can’t cite any examples but it isn’t impossible that birds or marine species could spread from the Old World to the New by their own efforts.
I can’t cite any examples but it isn’t impossible that birds or marine species could spread from the Old World to the New by their own efforts.
Cattle Egret comes to mind.
Other possible candidates include Fulvous Whistling Duck, White-Faced Whistling Duck and Southern Pochard.
And of course, monkeys and hystricognath rodents from way, way back.
I’d be open to the idea that it got here naturally and therefore calling it native, but that’s hard to prove. As I said, using 1492 as the cut-off for native vs. introduced isn’t perfect, but it’s theoretically simple and generall good enough.
The vikings were in Greenland (technically part of NA) for 450 to 500 years. Although most evidence suggests that the occupation of L’Anse aux Meadows in Newfoundland was very short there are suggestions that Greenland Norse made trips to Newfoundland and possibly the mainland to collect building timber. Given how pernicious some weedy species can be I have a sneaking suspicion that some plants species would have remained and spread after the decline of initial Scandinavian colonization.
I agree the Greenlanders could have left a legacy of weedy plants there. In fact, I’d be surprised if they didn’t. However, brief trips to mainland North America, even the brief attempt at settling there, didn’t cause the habitat changes that might have welcomed the Vikings’ weedy plant followers. Not impossible, of course. An interesting idea to pursue.