Explaining the carnivoragenic suppression of wild ungulates pointed out by the late Valerius Geist

Valerius Geist (1938-2021), a pioneer in the biology of ungulates (see https://en.wikipedia.org/wiki/Valerius_Geist), died recently (https://www.albernivalleynews.com/obituaries/valerius-geist/).

It seems appropriate to discuss a basic puzzle he pointed out, about the relationship between predators and prey.

See https://en.wikipedia.org/wiki/Valerius_Geist#cite_note-11 concerning the incidence of wild ungulates in the taiga biome of Eurasia and North America.

The following is worth reading carefully, and pondering deeply: https://nanomatic.fi/pdf/PredatorPit.pdf.

Extensive areas of the taiga biome seem 'naturally' empty of ungulates despite having vegetation similar to those areas supporting the moose (Alces alces), the caribou (Rangifer tarandus), and wild sheep (Ovis spp.).

Because the wolf (Canis lupus) and the brown bear (Ursus arctos) are common in these empty areas, Geist suspected that there has been a carnivoragenic (my word, not his) depletion of the populations of the ungulates.

The wolf and the brown bear are such efficient predators that they can reduce moose, caribou and wild sheep to the point of rarity. Geist asserted that a key to restoring the ungulates is human control of the wolf in particular.

Geist hinted at a rationale in which the omnivorous brown bear, sustained mainly by non-ungulate foods, can naturally exert so much pressure on infants that moose, caribou and wild sheep fail to reproduce year after year over extensive areas.

However, the obvious question arises: what sustains the wolf - which is not omnivorous - in empty areas of the taiga biome?

If Geist had an answer to this, I did not see it in https://nanomatic.fi/pdf/PredatorPit.pdf.

I suggest that the answer is the rodents (e.g. Urocitellus, see https://en.wikipedia.org/wiki/Urocitellus#:~:text=From%20Wikipedia%2C%20the%20free%20encyclopedia%20Urocitellus%20is%20a,no%20longer%20be%20retained%20as%20a%20single%20genus, and Marmota, see https://en.wikipedia.org/wiki/Marmot) and lagomorphs (Lepus spp.) which during the Holocene have been the dominant consumers of green foods in the taiga biome.

These rodentiforms are adapted to the extremely seasonal availability of greens by a combination of hibernation and fecundity which allows them to repopulate rapidly after episodic events such as wildfires. The ungulates have a limited advantage in their mobility, but in their overall energetic role in the taiga ecosystem they are subordinate to rodentiforms.

The wolf may prefer ungulates to rodentiforms as prey, but it can sustain its populations on a staple diet of rodentiforms.

With this piece of the puzzle filled in, the whole rationale seems to make sense: the human species has the option, by means of suppressing the populations of wolf and brown bear, of promoting the ungulates.

Would it be simplistic to suggest that, in the taiga biome of the Holocene, we have basically two alternative 'settings' with respect to the ungulates: carnivoragenic suppression or anthropogenic promotion?

הועלה ב-ספטמבר 2, 2021 08:33 אחה"צ על ידי milewski milewski

תגובות

Just don't say this where any faux environmentalists can hear you. This is a primary "burn at the stake" idea for them.

פורסם על-ידי marshall20 לפני יותר מ 2 שנים

@marshall20 In general, the opinions worth respecting are those formed after being so familiar with both sides of an argument that one can present a 'steel man' for either of them with equal persuasiveness. Environmentalists who lack familiarity with both sides have had their opinions assigned to them, not so?

פורסם על-ידי milewski לפני יותר מ 2 שנים

@marshall20 Many environmentalists may also lack awareness that, strictly speaking, Canis lupus is extinct in North America anyway, owing to interbreeding with Canis familiaris. It seems that dark individuals, which are common in e.g. the population reintroduced to Yellowstone, were absent from the wolf in pure form and only arose for the first time as a result of genetic 'contamination' from the domestic dog.

פורסם על-ידי milewski לפני יותר מ 2 שנים

100%. Many environmentalists are passionate, and passions are programmable and easily ignited with a short fuse consisting of few facts.

That is interesting about the wolf. I did not know that. Thank you.

פורסם על-ידי marshall20 לפני יותר מ 2 שנים

Looking at this, a thought strikes me - perhaps what we see is an imbalance in the carnivore guild.

If what you suggest is accurate, the effect is the result of a 'mesopredator release'. Back in the Pleistocene, the carnivore guild in much of these areas would have included big cats (both pantherines and saber-tooths), hyenas, and short-faced bears. The wolf, in such ecosystems, would be a middle-weight carnivore (a mesopredator), whose numbers and impact would have been lessened in competition for prey and direct intraguild predation. This is seen where tigers and wolves overlap, with tigers suppressing wolf numbers.

With the end-Pleistocene extinctions being caused by humans and perhaps in tandem with a changing climate, the effect of humans on the larger carnivores and megaherbivores allowed adaptable wolves to survive and persist in the changing habitat, leading to the status quo we see today.

פורסם על-ידי dinofelis לפני יותר מ 2 שנים

@capeleopard I agree. Perhaps I can summarise the changes in the taiga biome as follows. In the Pleistocene, the regime was one of 'supercarnivores predating megaherbivores'. In the Holocene, both the supercarnivores and the megaherbivores have disappeared, and the regime has become one of human and wolf predating the largest remaining herbivores. Before European arrival, this was more or less equitable in the taiga, because the human species had technical advantage while the wolf had the advantage of being subsidised by rodents in a way hard for aboriginal humans in the taiga to emulate. The result of the balance between human and wolf: the ungulates were fairly common. With the advent of Europeans, for the first time the potential has arisen for wild swings from human-dominated (the wolf is persecuted) to wolf-dominated (by the default of humans sparing the wolf for aesthetic reasons). The problem with the latter regime is that it means suppression of the ungulates to the point of rarity, which is an aesthetic cost. So whether we like it or not it seems we have, in some sense, to choose between the wolf and the ungulates in the taiga biome. Your further thoughts?

פורסם על-ידי milewski לפני יותר מ 2 שנים

Dr. Valerius Geist (Rest in Peace) presented many points, both agreeable and disagreeable, I personally believe his emphasis on wolf-human attacks are slightly exaggerated. Certainly, it's the case that wolves have a cascading effect on ungulate populations within their range i.e. the Holarctic realm, but in restating the perspective of Dr. Geist & the initial iNaturalist journal entry by @milewski, it's a combination of Canis lupus + Ursus arctos that maintain the 'predator pit'/'bio-deserts'/'carnivoragenic supression'. To support this, it was documented in a study of Ursus arctos post-hibernation predatory behavior, in which the males were documented to have killed & consumed anywhere from 7 to 38 Rangifer tarandus calves, alongside a number of Alces alces calves. From careful consideration, the mechanisms of gray wolf pressure and distress added with binge killing by brown bears, are what constitute primary factors preventing Late Pleistocene/Holocene population potentials of taxa such as Ovis sp., Cervus sp., Rangifer tarandus, & even the elusive Cuon alpinus, along with a few others.

However, the objective case remains modern human-lifestyle induced pressure & incurred damages are far more severe/critical in direct & indirect correlation to the pressing matters of ecology & environmental stability. Therefore it's suggested a lessening of anthropogenic disruption coupled with a return to traditional lifestyles, will happen to regulate wolves with respect for an already present niche partitioning (see articles/links below). @milewski rightfully pointed out the Pleistocene Carnivora guild present in the Holarctic was radically different in comparison to now, in particular how it prevented mesopredator release effect. With respect to supporting evidence, in the brilliant talk given by Dr. Geist https://www.youtube.com/watch?v=TBFGlCipnqo, & the website https://peopleofthetiger.com/tag/udege/, it's proven there's a need to regulate wolves in certain zones. In summary of the website, the Udege realized the ability of the Panthera tigris to suppress Canis lupus to rarity, resulting in equilibrium/return of the optimal ungulate density, thereby granting the subsistence hunter gifts of abundance.

"For the Udeghe, killing a tiger remains taboo, a violation of a deep cultural value."

“The tigers keep the forest healthy,” says Yuri Sun, 51, an Udeghe hunter who keeps 150 traps in an area 15 kilometers upriver from Krasny Yar."

“It’s good that the territory has tigers. They bring balance to the forest,” he says. “If there were no tigers, there would be wolves, and they would kill everything.”

Sources :

In Alaska (Nelchina River Basin) : https://www.science.org/content/article/bears-are-bigger-killers-thought-gruesome-video-footage-reveals#:~:text=Overall%2C%20the%20bears%20killed%20an,other%20methods%2C%20including%20aerial%20observation.

In Alaska (Denali National Park) : https://www.youtube.com/watch?v=3_0FUFvuOlU

In Sweden (Northern region) : https://www.livescience.com/highly-predatory-brown-bear-kills-38-reindeer

פורסם על-ידי paradoxornithidae לפני כמעט 2 שנים

The journal here is strikingly accurate, the dependence of Taiga wolves in Yakutia (Sakha) on Arctic Hares Lepus timidus, resulted in intensified livestock predation when the hares became scarce. The ewenki herders in 2013 put a massive effort to bounty the wolves, which by then numbered 3,500!

פורסם על-ידי paradoxornithidae לפני כמעט 2 שנים

"So whether we like it or not it seems we have, in some sense, to choose between the wolf and the ungulates in the taiga biome."
Definitely the case!!

פורסם על-ידי paradoxornithidae לפני כמעט 2 שנים

@tonyrebelo @capracornelius @jeremygilmore @ludwig_muller @oviscanadensis_connerties @tandala @maxallen @douglasriverside @zarek @doug263 @marshall20

Thank you @paradoxornithidae for https://www.youtube.com/watch?v=TBFGlCipnqo, which is one of the most valuable pieces of education available on the Web.

Rest in Peace indeed, Valerius Geist, you will never be replaced.

פורסם על-ידי milewski לפני כמעט 2 שנים

Is this not a case of competition between rodents and ungulates? By sustaining predator populations at levels that dont seriously affect rodent populations, rodents can outcompete ungulates by predation, freeing up resources for local population explosions rather invasion by migratory species.

פורסם על-ידי tonyrebelo לפני כמעט 2 שנים

@tonyrebelo @paradoxornithidae

I do suspect that Valerius Geist may have had a slight 'blind spot' for the rodentiform component of the herbivorous guild.

In African savannas, herbivory is 'oligopolised' by ungulates and proboscideans. Lagomorphs are relegated to an intersitial role, thoroughly subordinate to ungulates. Hyraxes are important on rocky outcrops but do not qualify as rodentiforms because of their slow pace of life; their trophic role is correspondingly limited, even in their habitats. Thryonomys are important only in reedbeds/elephant grass fairly prohibitive to ungulates.

In the Northern Hemisphere, rodentiforms are a far more important component of the herbivorous guild (and the same is true for grouses and, in extreme environments, herbivorous geese). So, it is indeed possible that, in addition to competing directly with ungulates for food, rodentiforms (hares, rabbits, pikas, marmots, ground squirrels, gophers, beavers, muskrat, porcupine), apply indirect pressure on ungulates by means of collateral predation.

The main problem with this rationale is that it remains unclear just how versatile the wolf and the puma are in predating animals the size of ground squirrels and rabbits. It is one thing to claim that these predators can maintain considerable populations on small (suboptimal-size) prey. It is another to assume that such prey could be utilised efficiently enough to maintain populations of the large predators that would be able seriously to suppress populations of ungulates. The actions of humans would, I think, outweigh the rodentiform factor.

What remains, in all of this, is to characterise clearly the niche of the wolf. Most assume that it is just the local version of large predators. However, what seems more likely is that it is 'para-human' in representing what one might call a 'hyperpredatory potential'. What I mean by this is that, just as humans are capable of exterminating ungulates through technical advantage, so the wolf is capable of doing so through extreme efficiency in hunting large prey - including stone-age modern Homo sapiens.

The wolf is the only carnivore (apart from the polar bear, which is marginal to this topic) that is not intimidated instinctively by humans. In this respect, the contrast with the lion is stark. So, in the boreal ecosystem, it comes down to a zero-sum game between wolf and human. Humans coexisted well with a suite of large carnivores in Africa. This, I suspect, is generally impossible with the wolf. In times when people did well, the wolf gave way; and vice versa.

The wolf is not a Pleistocene predator surviving in modernity; instead it is essentially a creature of the Holocene, that shared Northern biomes with us on a basis of 'shifts' in space and time. It only arose in the first place because we exterminated the really formidable carnivores including short-faced bears (and the jaguar and spotted hyena in Eurasia). The wolf arose as our Nemesis, nature's reflection of ourselves in a way. Technically a wild carnivore, but perversely anthropogenic.

This is one of the reasons why I doubt that the wolf is the main ancestor of the domestic dog. Human and wolf are fundamentally incompatible, making even hand-reared individuals poor material for beginning the process of artificial selection.

It seems consistent with this portrayal of the wolf to point out that the Holocene species Canis lupus is technically extinct. All populations now seem to have been hybridised with the domestic dog (which is all the more genetically compromising if the latter is not a domesticated wolf in the first place), and there has been much hybridisation also with the coyote and, perhaps, Canis aureus as well.

So, perhaps the fact that any coexistence is possible, these days, with the 'wolf' in places like Spain, Russia, and Canada is because the inimical nature of the original beast has been somewhat mollified by genetic compromise. The real, wild wolf, despite being even more Recent a species than fully modern Homo sapiens, was never going to be tolerated in a world of guns. We had to wipe it out in its pure form, and we did so more than a century ago (except possibly on the Canadian Arctic islands). The full span of the species was perhaps a mere 30,000 years; we made it by means of our megafaunal exterminations, and then we exterminated it too, in its real form.

Your further thoughts?

פורסם על-ידי milewski לפני כמעט 2 שנים

The Tibetan Wolf Canis lupus filchneri is however very ancient, & is basal in relation to other wolves, both extinct and extant.

פורסם על-ידי paradoxornithidae לפני כמעט 2 שנים

@paradoxornithidae Many thanks for pointing that out. If so, I would prefer to call it Canis filchneri.

פורסם על-ידי milewski לפני כמעט 2 שנים

In regards to @milewski & the statement of "The wolf is the only carnivore (apart from the polar bear, which is marginal to this topic) that is not intimidated instinctively by humans", this video https://www.youtube.com/watch?v=fuffRO2p7EE, originally uploaded on LiveLeak, shows a exemplary display of the innate lack of fear of man. These are also the same gray wolves mentioned that are the most genetically pure Canis lupus (i.e unadmixed genome/minimal introgression) in North America.

פורסם על-ידי paradoxornithidae לפני כמעט 2 שנים

The domestic dog shows its eye-whites to some extent, in convergence (via artificial selection) with its human domesticator:

https://www.dogster.com/dog-training/whale-eyes-in-dogs-what-it-means-when-the-whites-of-your-dogs-eyes-show

https://www.crushpixel.com/stock-photo/white-dog-head-looking-side-1726140.html

https://pxhere.com/en/photo/1380054

https://es.123rf.com/photo_151032531_close-up-of-white-dog-looking-at-camera.html

https://www.shutterstock.com/image-photo/blurry-image-dog-eyes-cropped-shot-1820639393

https://www.shutterstock.com/image-photo/close-eye-large-white-dog-central-1889945464

The eyes of the wolf have a different aspect, and seem more inscrutable than in the domestic dog:

https://www.dreamstime.com/royalty-free-stock-image-eyes-arctic-wolf-canis-lupus-arctos-image14479806

https://www.dreamstime.com/stock-photo-white-arctic-wolf-winter-snowy-forest-image65396503

https://www.dreamstime.com/royalty-free-stock-images-arctic-wolf-snarling-image20772769

https://fineartamerica.com/featured/arctic-wolf-close-up-heather-king.html

http://1.bp.blogspot.com/-xnpfwRkxYJM/VK2mJ1rrwlI/AAAAAAAAvjk/zAwq2mC8in4/s1600/wolf-rain.jpg

https://www.dreamstime.com/arctic-wolf-canis-lupus-arctos-aka-polar-white-close-up-portrait-beautiful-predator-early-spring-image180742529

https://www.dreamstime.com/stock-photo-white-arctic-wolf-winter-forest-snow-covered-image65396291

https://www.dreamstime.com/stock-photo-white-arctic-wolf-winter-forest-snow-covered-image65396344

https://www.dreamstime.com/arctic-wolf-canis-lupus-arctos-standing-winter-snow-canada-arctic-wolf-canis-lupus-arctos-standing-winter-snow-image106096457

Has anyone seen any individual of the domestic dog that has eyes looking like the following?

https://www.dreamstime.com/stock-photo-wolf-rock-watchful-white-arctic-standing-stony-hill-forest-image44758596

https://www.dreamstime.com/stock-photo-white-wolf-dark-background-arctic-image62068126

https://www.dreamstime.com/stock-photos-arctic-wolf-image7269683

To test this idea, I looked for photos showing some eye-white in the wolf:

https://www.dreamstime.com/stock-photo-wolf-image14958360

https://www.dreamstime.com/royalty-free-stock-photo-arctic-wolf-canis-lupus-arctos-image13397965

https://www.dreamstime.com/white-arctic-wolf-canis-lupus-arctosportrait-black-closeup-image104548763

פורסם על-ידי milewski לפני כמעט 2 שנים

"The wolf is the only carnivore (apart from the polar bear, which is marginal to this topic) that is not intimidated instinctively by humans"

I must say that this statement, as well as the statement that the wolf is intrinsically inimical to humans, is something I don't quite agree with.

The lack of fear displayed in Arctic wolves and polar bears comes more from a place of ecological naïveté, I think - humans are relatively thin on the ground in the polar regions, and I don't thinking that any historical hunting by native Inuit was anywhere high enough to seriously change this (I am open to correction though).

Furthermore, the possibility of the wolf's lack of fear of man in the deep past may have what made the domestication of the dog possible in the first place. The meeting between wolves and Homo sapiens may have been a fortuitous event, with curious wolves and people interacting non-aggressively (such friendly relationships between unrelated species are not unheard of, as seen in the case between coyotes and American badgers, or monkeys and medium-sized ungulates, or indeed cases of individual ravens with wolves), such that over time a lupine ecotype may have formed that ecologically associated with man, which would have undergone this slow process of coevolution over thousands of years until we get the dogs of today (with aggressive wolves and proto-dogs being culled by humans or else driven away).

Modern wolves, especially in Eurasia, have developed a fear of humans where they are heavily persecuted and hunted. They are found mostly in remote regions, and it is only now in certain regions where they are not heavily hunted that wolves have began to spread again, even to the point of crossing human-dominated countryside in Europe. Yes, wolf attacks on humans have been well-documented over history, but then so have leopards, tigers, and lions, all of which have had individuals documented as prolific man-eaters despite the species' overall fear and avoidance of humans.

פורסם על-ידי dinofelis לפני כמעט 2 שנים

@milewski There's a discernible difference in their eye color phenotypes, & the artificial selection involved may have been unintentional, since the lightening of pigmentation could be due to genetic bottlenecking. Nevertheless, it's still of interest and actually, I hadn't noticed this coincidental similarity with Homo sapiens until now (I don't really look at domestic dogs and cats).

פורסם על-ידי paradoxornithidae לפני כמעט 2 שנים

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