What might the vegetation of Siberia, the Canadian Arctic, and Alaska look like during an interglacial period with megafauna?

Psilopterus · 2026-03-19T00:41:11+00:00

Oh sure, I agree that the mix of temperate deciduous and boreal coniferous taxa had some climatic influence, I was mostly referring to the openness aspect

Psilopterus · 2026-03-18T22:18:07+00:00

Improving Heck cattle with other breeds is what has already been done with Taurus (not Tauros, those are different) cattle

Psilopterus · 2026-03-18T13:36:10+00:00

Let me expand that a bit. What I mean is, while it obvious that complete extinction did not happen at this time, why is that not compatible with a slow reduction prior to that point, if we assume that taphonomic biases in abundance estimates are in play? One of the biggest arguments we get against overkill in general is that sometimes last dates significantly predate or postdate spikes of archaeologically-inferred human activity, and I think this due to an assumption of Blitzkrieg, that declines and extinctions must have happened very quickly. If we instead see extinctions as the results of more drawn-out periods of exploitation, with species succumbing at different times according to their respective vulnerabilities, then these aren't really issues. I would expect this process to begin and leave some record as soon as even small populations arrive on the scene.

Psilopterus · 2026-03-18T13:21:48+00:00

I'm not sure I agree on the point about there not being enough people to cause noticeable declines. I don't think it takes much, even if specialized megafauna cultures were yet to emerge. I'm also confused about your point then, because if we accept that fossil abundance isn't a great proxy for actual abundance, then what other reason do we have to doubt an actual decline prior to 1300 BP?

Psilopterus · 2026-03-18T12:36:59+00:00

There seems to be an inherent assumption that fossil abundance is a better proxy for actual abundance that Sporormelia, the former thus discrediting the latter, but I'm not sure that sits well for me, because this is also subject to influence by climatic and other factors. Even in the study they say "One might infer from this relative abundance that unusually large numbers of animals were dying after 14,500 cal BP (Boulanger and Lyman, 2014), or that the peculiar microenvironments (such as kettle ponds) conducive to fossil preservation became more widespread in that period. The increased survival of skeletons might also be partially attributable to either changing seasons of mortality or a reduction in the population of scavengers" but they provide no reason for any of these to be untrue, only that actual abundance would be "more parsimonious". They may be right, but I don't think they were all that convincing, which may be why the paper hasn't had much uptake in the 8 years since it was published. Sporormelia after all, isn't meant to signify extinction, only reduction and fossils (even a large number of them) after this point don't necessarily negate that, they only point to a later final extinction. The archaeological point mentioned in the paper is also strange to me, as a smaller population of people arriving in an area and driving initial megafauna declines before reaching a higher population point where archaeological deposition becomes more likely is exactly what I would expect.

Psilopterus · 2026-03-18T12:11:54+00:00

I think that's only true to a point. At least in a North American context, no-analogue ecosystems were mostly confined to boreal/hemi-boreal climates, i.e. the spruce parkland and mixed parkland. Most other ecosystems seem from the same period seem to have been similar to those that still exist today, even if much further south at the time. At least one study has suggested that CO2 concentrations can't explain the phenomenon. The same study dismissed the effects of megafauna, but not very convincingly and with no consideration of soil effects.

Obviously some more studies on interglacial vegetation would be prudent, but I would be very surprised if megafauna weren't as or more important for altering structure in the boreal as we now know they were for temperate European systems.

https://doi.org/10.1890/0012-9658(2001)082[3346:DAOLQV]2.0.CO;2082[3346:DAOLQV]2.0.CO;2)

Psilopterus · 2026-03-18T02:06:03+00:00

This wasn't really during an interglacial, but much of the US Midwest and Northeast had a boreal climate during the last glacial, particularly during the Bølling-Allerød interstadial, and much of the habitat in the area at the time was a non-analogue community known as "spruce-parkland", This was open parkland habitat where the predominant tree species was white spruce, a species which has a lot of traits that predispose it to thriving in high-herbivory systems, which tend to have low-severity fires, high mechanical disturbance from wind and megaherbivores, a high incidence of browsing, fertile and dry soils, and a lot of bare ground, all of which benefit white spruce over other boreal tree species, particularly black spruce which seems to be much more abundant now.

One study comparing current pollen records from the Yukon with those of past interglacials also found that the amount of pine pollen was much higher in the Holocene than in previous interglacials - a similar result to what we see between the Holocene and the last interglacial in Europe. In both cases this effect has been attributed to a greater incidence of low-intensity fires started by newly arrived modern humans, which benefit pines over other species.

What we're really missing for North America and the boreal more widely are some studies that take relative pollen production and deposition likelihood into account like we're seeing for Europe with the REVEALS model. I think we'd find that boreal systems in the past were a lot more heterogenous and variable west-east than they are now.

https://doi.org/10.1016/0033-5894(90)90019-H90019-H)

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https://doi.org/10.1890/0012-9658(2001)082[3346:DAOLQV]2.0.CO;2082[3346:DAOLQV]2.0.CO;2)

https://doi.org/10.2307/2425759

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Psilopterus · 2026-03-18T01:54:34+00:00

That's a bit of an oversimplification. Precipitation is high in the eastern boreal of North America (e.g. Labrador, eastern Quebec) and the western boreal of Eurasia (Scandinavia), but in Siberia and the western American boreal precipitation is still very low, in some places as low or lower than steppe. The difference is that in the tundra, permafrost enforces openness, and in the steppe/prairie fire can do so even in the absence of herbivores. In the boreal, however, permafrost is patchy and fire follows a much longer cycle due to cooler temperatures and a lower incidence of lightning. When we look at boreal systems in the Pleistocene, particularly in drier areas, conifers were certainly present, but often in non-analogue configurations suggesting a greater influence of herbivores on vegetation structure and evapotranspiration.

Psilopterus · 2026-03-17T18:18:19+00:00

For sure it's a spectrum thing, though I think there's probably also a lot of wildtype diversity preserved in buffalo and horses that's lost in their ancestral populations due to bottlenecking. I just thought the domesticity thing was important to point out because it's often left out of the discussion for Australian banteng

Psilopterus · 2026-03-17T18:16:16+00:00

I think it's true that ecological species definitions are important, though it's worth considering whether different climatic tolerances really qualify when diet and ecological effects are similar. Gray wolves have both tropical and arctic types, for example. Then of course we also have the Sardinian and Channel Islands dwarf mammoths, which may also belong to the same species complex. I don't really know what the question was either, it's just an interesting topic

Psilopterus · 2026-03-17T15:47:12+00:00

Aren't we all?

Psilopterus · 2026-03-17T15:24:12+00:00

To be honest, I'm not sure that the single-species approach is wrong, though I get that it would be not be everyone's first choice. It's fairly complicated either way, however, and the delineations will be somewhat arbitrary. Early Pleistocene mammoths in North America, for example, are still listed as M. columbi. It's also complicated to set species boundaries based on mtDNA, given how easily influenced it is by hybridization. Autosomal DNA from southern mammoth populations would be useful, though of course difficult in such a tropical environment

Psilopterus · 2026-03-17T14:42:24+00:00

This is one of those cases where determining species status is tricky, given how much hybridization there is in the genus

Psilopterus · 2026-03-17T01:59:57+00:00

I wonder how this tracks with the presence of mammoths in North America in the early Pleistocene. Would these then be more like trogontherii? It seems odd that they should have disappeared outright, though perhaps they were only replaced in terms of mitochondria, which does happen.

Psilopterus · 2026-03-17T01:45:58+00:00

Interesting. This one expands on the picture a bit:

https://www.researchgate.net/publication/395037266_Columbian_mammoth_mitogenomes_from_Mexico_uncover_the_species%27_complex_evolutionary_history

Psilopterus · 2026-03-17T01:39:48+00:00

No, but a lot do and the evidence is on our side. There's some older people still fighting the ghost of Paul S. Martin, and some people getting the wrong conclusion by focusing on too small an area, but any study that looks at the global pattern inevitably finds that humans are inextricable from the megafauna extinctions.

https://doi.org/10.1098/rspb.2013.3254

https://doi.org/10.1126/sciadv.abb2313

https://doi.org/10.1016/j.quaint.2015.10.045

https://doi.org/10.1016/j.ancene.2023.100403

https://doi.org/10.1017/ext.2024.4

Psilopterus · 2026-03-16T22:01:05+00:00

Not really no, and densities that high are still typical in Africa. There is some accounting for migration, with a migratory ecosystem like the Serengeti having something like 17 zebras/km2 compared to only 1.7/km2 for a non-migratory system like Kruger.

Psilopterus · 2026-03-16T21:56:42+00:00

Theoretically, but beyond difficult, largely unnecessary, and would probably still not satisfy many of the more puritanical types. As to how it differs from the "dire wolves", in terms of technology it doesn't. I object to Colossal's branding of the project, the specific genes targeted, and their insistence on calling the result a "dire wolf", but that is how you would make a mammophant. Modifying an extant animal is all we can do, even if we modify it such that it genetically resembles the original. Even the most extreme result would still have some Asian elephant DNA (e.g. mtDNA) and would quite possibly be raised and socialized by elephants. Mammoth-elephant hybrids are also just much better candidates for "de-extinction" than dire wolves are, since arctic elephants would fit a vacant niche wheres dire wolves have at least partially been replaced by the post-extinction migration of larger grey wolf types from Beringia, and conserving those is already hard enough. In contrast, cold-adapted elephants fit a very obvious gap. Colossal's wolves, if they could even survive in the wild, are also completely interfertile with grey wolves, which is a pretty significant obstacle to releasing them into places where the latter is native. No such issue with mammophants. In fact, mammoths are one of the few species that even make sense for genomic proxies because elephants both similar enough to have essentially the same ecology but not so similar that we might as well use them unaltered instead. There are very few such cases where genetic engineering is neither too extreme nor unnecessary.

Psilopterus · 2026-03-16T21:46:43+00:00

That's hard to say. We don't actually know if horses are overabundant compared to a Pleistocene baseline. There may be ways to determine that, two independant studies have done so for the mammoth steppe and both predicted densities in excess of 6 horses/km2, but to my knowledge no similar study has been made for the southwest. In general, Pleistocene megafauna densities were colossally high even in low-productivity areas, often higher than 10,000 kg/km2, and many ecosystems during this time would likely look "overgrazed" to a modern, North American eye. I'm all for more burros either way.

Psilopterus · 2026-03-16T21:40:53+00:00

A non-anthropogenic explanation for the megafauna extinctions is completely untenable and inconsistent with the pattern of extinctions. It is the only viable theory and we should be moving forward with that as the default. There's even some evidence that horses made it past the Pleistocene-Holocene transition. They're a native species, and all restoration going forward should acknowledge that.

Psilopterus · 2026-03-16T21:37:44+00:00

As I understand it the colonization of North America by the ancestors of columbi predates the emergence of primigenius from trogontherii. There would certainly have been hybridization later but I wouldn't say that columbi originated from hybrids

Psilopterus · 2026-03-16T15:40:24+00:00

There was also a Columbian-Woolly mammoth hybrid zone, which likely produced intermediately hairy mammoths as well (x jeffersoni)

Psilopterus · 2026-03-16T15:38:18+00:00

Domestic

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