Rewilding

Pleistohorse said:
Here I disagree with you. The Horse (not necessarily the Mustang) is a native animal extirpated by over hunting by humans (climate change? Maybe the last populations in Alaska and the Yukon…but the species seems to being doing fine after a 3,000 to 5,000 year absence).

The Horses present in the Pleistocene and early Holocene were the exact same species.

I’m not really on the invasive species train (at least when it comes to continental environments…islands are a different story). But regarding the Horse (as a species) it’s ecologically (and literally) native to the Americas.

In my opinion. BLM and grazing interests (and 1491 purists) aside.
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It is literally native to the Americas - but not ecologically. North America's ecosystems changed a lot in that period, and the ecosystems evolved without them. Horses no longer provide essential services to North American ecosystems and in fact quite the opposite. Their negative ecological impacts are many and this has been well-documented by many ecologists over the years.

I saw the destruction they cause firsthand on the Gila River Reservation in Arizona. The horses had eaten away all the plants over a huge stretch of desert, except for sagebrush, the one plant they would not eat. This monoculture was nearly devoid of animal life except for a handful of the toughest generalist arid species. That's not acting like a native species should.

Invasive species are an extremely well-documented ecological phenomenon that poses one of our biggest threats to biodiversity today. Frankly I'd consider denial of them of a similar caliber to Flat Earth conspiracies.
 
birdsandbats said:
It is literally native to the Americas - but not ecologically. North America's ecosystems changed a lot in that period, and the ecosystems evolved without them. Horses no longer provide essential services to North American ecosystems and in fact quite the opposite. Their negative ecological impacts are many and this has been well-documented by many ecologists over the years.

I saw the destruction they cause firsthand on the Gila River Reservation in Arizona. The horses had eaten away all the plants over a huge stretch of desert, except for sagebrush, the one plant they would not eat. This monoculture was nearly devoid of animal life except for a handful of the toughest generalist arid species. That's not acting like a native species should.

Invasive species are an extremely well-documented ecological phenomenon that poses one of our biggest threats to biodiversity today. Frankly I'd consider denial of them of a similar caliber to Flat Earth conspiracies.
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I get what you are saying, but you are also describing the effects of Elk in Yellowstone prior to the reintroduction of Wolves. Or environments anywhere that large herbivores are left uncontrolled.

The loss of the Horse (and its predators) was likely a major cause of the California Condor’s retreat to the coast (where sea mammal carcasses sustained the species).

We will likely never see Lions preying on Horses in the American west for sure. Cougars and Wolves (following expansion or reintroduction) may not be effective predators of Horses on a grand scale. Jaguars probably would be. But even if controlled by Humans…where Horse carcasses were left on the range to simulate the effect of predators…scavengers (including Condors) would benefit.

And remember…I’m not advocating Mustangs be left on the range…but that a critically endangered subspecies be (re)introduced into an appropriate habitat.

I don’t think either of us will convince the other…but I can understand your point of argument. I just don’t fully agree.

And using the destructive scale as the definition of “invasive”, I don’t believe all introduced species qualify. Animal populations have migrated and colonized new habitats throughout Earth’s history…the “morality “ of humankind being the agent of dispersal is the real point of debate.
 
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Pleistohorse said:
I get what you are saying, but you are also describing the effects of Elk in Yellowstone prior to the reintroduction of Wolves. Or environments anywhere that large herbivores are left uncontrolled.
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Yes, it is similar, although the impacts of horses in many of these areas are arguably worse than Yellowstone elk. Horses probably would be significantly less of a problem if predators such as wolves were still extant in many of these area (although they likely still would be a problem to some degree, as wolves are not likely to target horses over other prey such as cervids or Javelina).

I'm not against Mustangs because I'm a "1491 purist". I'm against them because of real, measurable, major negative ecological impacts they have on the ecosystem. I'm similarly against the way we manage White-tailed Deer in eastern North America, and they're native. For guidance in these situations, I suggest we turn to Aldo Leopold's famous quote:

"A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise."
 
birdsandbats said:
Yes, it is similar, although the impacts of horses in many of these areas are arguably worse than Yellowstone elk. Horses probably would be significantly less of a problem if predators such as wolves were still extant in many of these area (although they likely still would be a problem to some degree, as wolves are not likely to target horses over other prey such as cervids or Javelina).

I'm not against Mustangs because I'm a "1491 purist". I'm against them because of real, measurable, major negative ecological impacts they have on the ecosystem. I'm similarly against the way we manage White-tailed Deer in eastern North America, and they're native. For guidance in these situations, I suggest we turn to Aldo Leopold's famous quote:

"A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise."
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Very good points.
 
Pleistohorse said:
I would like to see these released into the United States and Canada. I know the feral Mustang has some cultural value…but I’d love to Przewalski’s Horse reintroduced and the Mustang’s removed.
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And believe me when I say that outside of the "pleistocene rewilders" nobody would be in favor of that.

For one, many wouldn't want the mustangs to be removed to begin with and two, ranchers who see mustangs as grazing competition for their cattle would see it as being pointless since you'd be replacing them with an animal they think would do the same thing. And three, many would wonder why a bunch of resources that could be used in preserving native wildlife are instead being used to introduce something from Asia.
 
Chlidonias said:
What do you think it "explains a lot"? Your sentence doesn't really say anything.
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It explains why many ecologists and others in similar fields are quick to place all of the blame the megafauna extinction on humans and why some advocate for Pleistocene rewilding.
 
Pantheraman said:
It explains why many ecologists and others in similar fields are quick to place all of the blame the megafauna extinction on humans and why some advocate for Pleistocene rewilding.
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Not really following your answer. Are you basically just saying that this article is where you found out about the origin of the Overkill Hypothesis?
 
In my unstudied view…I don’t think it can be denied that humans played a role. The rates of extinction across different areas of the world rise when humans appear in those areas. Climate change and the resulting changes to habitat were survived in previous eras…humans were pretty likely the tipping point in the last (kind of like the current) extinction.

Moas were clearly wiped out by pre-industrial people. Steller’s Sea Cows were probably clinging to the last habitat available to them…the Russians finishing what earlier folks started by pushing the animals to a final isolated marginal outpost. The megafauna of the Antilles held-out for thousands of years longer than those on the mainland…until humans arrived. I doubt humans were the only factor in the extinction events occurring in a series of geographically separated environments within just a few thousand years of humankind’s arrival to those areas…but they were the decisive factor beyond much doubt. The timeline alone argues for it (maybe simplistically I guess).

Look at Hawaii’s birds: First the Polynesians show up and the large flightless or nearly flightless go extinct (except for the Nene)…then the Europeans show up (bringing cats and mosquitoes)…then non-native birds who can survive the cats and mosquitoes…pretty clear the deciding factor in the extinction of the easily edible calorie rich birds falls on pre-industrial people (pigs and dogs lending a hand). The early industrial Europeans played a role too…taking out the smaller birds…primarily with invasive species and the diseases they carried.

I know all my examples are of island habitats, or of animals that specialized in very narrow niches…but honestly…without causing offense…I wonder if the arguments against Pleistocene overkill have more to do with modern sensibilities, where we want to let the indigenous peoples off the hook (especially when we can’t blame the later waves of human colonization that followed) and frankly politics, as a means of tying earlier extinctions to the modern boogie man (who is very real) of “climate change.” Just a layman’s theory.

Also factor that the abundance of wildlife and the very landscape of the continents of North and South America as seen in the 17th - 19th centuries were possibly the result of massive population declines brought on by European diseases…think about it.

We find ourselves in the same boat today where the physical changes wrought by humans on the landscape and the changing climate are threatening another mass extinction…but compare the two. Remove humans and most species could adjust to a changing climate (assuming of course a natural occurrence)…stabilize the climate and keep the human factors of population growth and development…the extinction is still on track.

Sometimes it is the simplest answer…

And I’m not a Pleistocene Rewilder…except when I am.

And truthfully the entire concept is more of a thought exercise…kind of like the fantasy zoos we see here. Nothing to get all worked up about.
 
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Conversely to the 2018 article posted above, this partially-available article from earlier this month (linked to a recent paper that I cannot actually find the name of) suggests that, in Europe, humans were entirely responsible for the extinction of megafauna in Europe - the study suggests that, were it not for people, species like the mammoth and cave bear would be more common now than they were 130,000 years ago.

Loss of large animals in Europe is entirely due to people, not climate | New Scientist
 
@DesertRhino150 The thing with studies on the topic is that to this day it's still one of the biggest debates in paleontology and those within the field go back and forth on it and mark my words, another paper will be published blaming climate change. It's pretty much the spinosaurus being aquatic debate version for cenozoic mammals. The point of the article was mostly about the differences between ecologists and archaeologists on how they deal with the overkill hypothesis as well as the origins of the hypothesis itself.

That being said, I've had this simple story concept related to Pleistocene Rewilding. Involving a scientist who firmly believes in the idea and manages to get permission from the USFWS to release African lions into Arizona to replace the extinct American lions, assuming everything will work out.

Only for the big cats to prove him wrong, being a cautionary tale about releasing foreign animals into foreign environments. With the lions wiping out the Mexican wolf population of the release site and decimating naive prey species and unfortunately the lions themselves end up becoming victims of this scheme as well. Because they end up being vilified when in truth, they were just animals in the wrong place at no fault of their own and didn't know they were decimating the native wildlife.
 
DesertRhino150 said:
Conversely to the 2018 article posted above, this partially-available article from earlier this month (linked to a recent paper that I cannot actually find the name of) suggests that, in Europe, humans were entirely responsible for the extinction of megafauna in Europe - the study suggests that, were it not for people, species like the mammoth and cave bear would be more common now than they were 130,000 years ago.

Loss of large animals in Europe is entirely due to people, not climate | New Scientist
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I think I found the original paper - a bit hard to say for sure without being able to read the New Scientist article - but I think it is "Megafauna diversity and functional declines in Europe from the Last Interglacial (LIG) to the present" (published last month, pdf linked below).

It doesn't match entirely with what the snippet from New Scientists says (the paper says, e.g, "would instead have led to a small increase in megafauna richness in the present" rather than the New Scientist's "would be thriving there in even greater numbers today than 120,000 years ago") but that is normal for popular articles.

https://www.biorxiv.org/content/10.1101/2023.06.12.544580v1.full.pdf
 
I can imagine making a large fenced enclosure somewhere in America, maybe tens of square miles, maybe on a large ranch in Texas. There are fenced game reserves of that size in South Africa. Release there bison, pronghorn, horses, camels, wolves and maybe few cheetahs and a pack of lions. Run it as a tourist attraction with a lodge, with science not advertised and releasing animals not an option. This could be the closest to rewilding what can realistically exist in America.

However, there is almost no research how habitats in Pleistocene were actually different from the today America. So nobody can tell whether what would happen on such a ranch is rewilding, or we created something artificial. One of few concrete examples of supposed lost megafauna ecological role would be regeneration and dispersal of some large-fruited trees and shrubs.

There is another rewilding experiment located in an Arctic tundra in Russia. I can imagine a project somewhere in Alaska or Canada, with released wood buffalo, musk oxen and Przewalski horses in addition to caribou. This would make more sense. The land in the tundra is cheap and sparsely populated. The rewilding has a verifiable change: whether grazing and trampling of big herbivores in big density can change today mossy tundra into vegetation dominated by grasses and herbs, more productive and similar to mammoth steppe. Local people might actually be interested in hunting surplus game in the project.
 
Jurek7 said:
I can imagine making a large fenced enclosure somewhere in America, maybe tens of square miles, maybe on a large ranch in Texas. There are fenced game reserves of that size in South Africa. Release there bison, pronghorn, horses, camels, wolves and maybe few cheetahs and a pack of lions. Run it as a tourist attraction with a lodge, with science not advertised and releasing animals not an option. This could be the closest to rewilding what can realistically exist in America.

However, there is almost no research how habitats in Pleistocene were actually different from the today America. So nobody can tell whether what would happen on such a ranch is rewilding, or we created something artificial. One of few concrete examples of supposed lost megafauna ecological role would be regeneration and dispersal of some large-fruited trees and shrubs.

There is another rewilding experiment located in an Arctic tundra in Russia. I can imagine a project somewhere in Alaska or Canada, with released wood buffalo, musk oxen and Przewalski horses in addition to caribou. This would make more sense. The land in the tundra is cheap and sparsely populated. The rewilding has a verifiable change: whether grazing and trampling of big herbivores in big density can change today mossy tundra into vegetation dominated by grasses and herbs, more productive and similar to mammoth steppe. Local people might actually be interested in hunting surplus game in the project.
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Buffalo and Musk Oxen already roam over large areas of Alaska and northern Canada, and Yukon has feral horses already. So not sure what that would accomplish that wasn't already happening.
 
My take on the Pleistocene Extinction in North America.

I honestly have a hard time believing humans were the main cause of the extinction for a couple of reasons.

The first is that we need to remember that they didn't have the firepower we have, nor were they looking to kill for ivory. These were people trying to survive in a new world and happened to find megafauna a reliable food source. And when it comes to giant animals like the mammoth, mastodon, and ground sloth, these animals had a lot of flesh on them, enough to last a tribe for a period of time before they needed to hunt again. And quite frankly, why hunt when you don't need to? So I question whether they would've actually hunted the megafauna rapidly enough to wipe them out.

The second reason is the amount of time humans and megafauna coexisted. Recently human footprints found in New Mexico were dated between 22,000-23,000 years old. Meaning that humans were living on the continent longer than once thought, and lived with the megafauna for thousands of years. Some say this is what they expect when it comes to overkill, I disagree because this is thousands of years of coexistence between humans and megafauna. Plenty of time for the megafauna to learn how to deal with humans, especially when it comes to the proboscideans because modern elephants are very intelligent, and the mammoths and mastodons likely were no different in this regard. And it's likely that the proboscideans would've figured to how to deal with humans and pass this information on to their offspring.
 
Pantheraman said:
My take on the Pleistocene Extinction in North America.

I honestly have a hard time believing humans were the main cause of the extinction for a couple of reasons.

The first is that we need to remember that they didn't have the firepower we have, nor were they looking to kill for ivory. These were people trying to survive in a new world and happened to find megafauna a reliable food source. And when it comes to giant animals like the mammoth, mastodon, and ground sloth, these animals had a lot of flesh on them, enough to last a tribe for a period of time before they needed to hunt again. And quite frankly, why hunt when you don't need to? So I question whether they would've actually hunted the megafauna rapidly enough to wipe them out.

The second reason is the amount of time humans and megafauna coexisted. Recently human footprints found in New Mexico were dated between 22,000-23,000 years old. Meaning that humans were living on the continent longer than once thought, and lived with the megafauna for thousands of years. Some say this is what they expect when it comes to overkill, I disagree because this is thousands of years of coexistence between humans and megafauna. Plenty of time for the megafauna to learn how to deal with humans, especially when it comes to the proboscideans because modern elephants are very intelligent, and the mammoths and mastodons likely were no different in this regard. And it's likely that the proboscideans would've figured to how to deal with humans and pass this information on to their offspring.
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My question is what is the better explanation than the overkill hypothesis? Why is it that in specifically the latest interglacial period that almost ALL megafauna went extinct globally when for the most part they had survived the past ones? If it wasn't humans, whose presence was the major difference during the latest interglacial, what caused this swift and dramatic extinction?
 
Fallax said:
My question is what is the better explanation than the overkill hypothesis? Why is it that in specifically the latest interglacial period that almost ALL megafauna went extinct globally when for the most part they had survived the past ones? If it wasn't humans, whose presence was the major difference during the latest interglacial, what caused this swift and dramatic extinction?
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Environmental changes due to a changing climate. Whenever this has happened throughout Earth's history, there are always species that have gone extinct and it's likely this would've off megafauna species. Another factor to consider is disease. Diseases introduced by dogs accompanying the humans from Eurasia could've passed on diseases onto animals such as Aenocyon dirus and Smilodon fatalis.

I especially think diseases from dogs could've played a part in the demise of these predators due to diseases such as the Canine Distemper Virus being one of the many threats to big cats and social wild canids being in contact with dogs with the diseases.

Did humans play a part? Maybe. But I don't think they were the primary cause of the extinctions and think that putting all the blame on humans is pretty simplistic, to be honest.
 
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