Habitat loss = extinctions??

[SkepticLance]

In response to your requests for more of Lomborg's thinking, some selected quotes. Obviously this is a tiny part of the whole. If you need more, you will have to go to your public library and get out the book.

 

Page 252.

"Lovejoy constructed a model to back up Myers controversial figure of 40,000 (species lost to extinction each year). Lovejoy's model is in reality attractively simple. A large part of all species are found in the tropical rainforests. If we simply allow the rainforests to remain in place, nothing happens. If we cut down all the rainforest, practically all the species will disappear. Lovejoy then assumes that if half the forest is cut down, a third of the species will disappear.

 

And there you have it. With an estimated 50% to 67% reduction in rainforest in 20 years, we get a localised reduction in the number of species of 33 to 50%. Lovejoy estimates this will lead to an overall reduction in the number of species in the world of approx. 20%."

 

On page 253

"Wilson formulated a rule of thumb. If the area is reduced by 90%, then the number of species will be halved."

 

Page 254

" In the US, the eastern forests were reduced over two centuries to fragments totalling just 1 to 2% of their original area, but nevertheless this resulted in the extinction of only one forest bird."

 

Page 254 about Puerto Rico.

" the primary forest had been reduced by 99% over a period of 400 years. 'Only' 7 out of 60 species of birds had become extinct although the island today is home to 97 species of birds. This indicates a serious problem with Wilsons rule of thumb."

 

"We get to understand the situation when we are told that the overall forest area of Puerto Rico never fell below 10 to 15%."

"In fact, FAO figures show that about half of all tropical forest that is cut down is converted to secondary forest."

 

Lomborg then spends half a page describing the problem of lack of data.

 

"Heywood and Stuart (referring to a book) point out that the recorded extinction figures for mammals and birdsare 'very small'. If the extinctions rates are similar for all other species, and if we assume 30 million species, we get an annual extinction rate of 2300 0r 0.08% per decade. Since the area of rainforest has been reduced by approx. 20% since the 1830's, it must be assumed that during this contraction, very large numbers of species have been lost in some areas. Yet surprisingly, there is no clear cut evidence of this."

 

Page 255 about Brazil's Atlantic rainforest.

"almost entirely cleared in the 19th Century, with only 12% extremely fragmented forest left. According to Wilson's rule of thumb, one ought to expect half of all the species to become extinct........the group could not find a single known animal species which could properly be declared to be extinct..."

 

Lomborg concludes a new extinction rate of 0.7% in 50% years globally.

 

I think you can see from these quotes, that Lomborg claims estimates of extinction rates from habitat loss are substantially exaggerated. Does anyone on this forum have data to the opposite?

[Paralith]

I think that it's actually more likely that Lomborg is understimating extinction rates.

 

From: http://rainforests.mongabay.com/0908.htm

 

Ward (1997) uses the term "extinction debt" to describe such extinction of species and populations long after habitat alteration:

 

Decades or centuries after a habitat perturbation, extinction related to the perturbation may still be taking place. This is perhaps the least understood and most insidious aspect of habitat destruction. We can clear-cut a forest and then point out that the attendant extinctions are low, when in reality a larger number of extinctions will take place in the future. We will have produced an extinction debt that has to be paid. . . We might curtail our hunting practices when some given population falls to very low numbers and think that we have succeeded in "saving" the species in question, when in reality we have produced an extinction debt that ultimately must be paid in full. . . Extinction debts are bad debts, and when they are eventually paid, the world is a poorer place.

 

For example, the disappearance of crucial pollinators will not cause the immediate extinction of tree species with life cycles measured in centuries. Similarly, a study of West African primates found an extinction debt of over 30 percent of the total primate fauna as a result of historic deforestation. This suggests that protection of remaining forests in these areas might not be enough to prevent extinctions caused by past habitat loss. While we may be able to predict the effects of the loss of some species, we know too little about the vast majority of species to make reasonable projections. The unanticipated loss of unknown species will have a magnified effect over time.

 

This is the abstract from an article from Conservation Biology (Volume 16 Issue 3 Page 666 - June 2002), by Ilkka Hanski and Otso Ovaskainen, entitled "Extinction Debt at Extinction Threshold."

 

To allow for long-term metapopulation persistence, a network of habitat fragments must satisfy a certain condition in terms of number, size, and spatial configuration of the fragments. The influence of landscape structure on the threshold condition can be measured by a quantity called metapopulation capacity, which can be calculated for real fragmented landscapes. Habitat loss and fragmentation reduce the metapopulation capacity of a landscape and make it less likely that the threshold condition can be met. If the condition is not met, the metapopulation is expected to go extinct, but it takes some time following habitat loss before the extinction will occur, which generates an extinction debt in a community of species. We show that extinction debt is especially great in a community in which many species are close to their extinction threshold following habitat loss because the metapopulation-dynamic time delay is especially long in such species. A corollary is that landscapes that have recently experienced substantial habitat loss and fragmentation are expected to show a transient excess of rare species, which represents a previously overlooked signature of extinction debt. We consider a putative example of extinction debt on forest-inhabiting beetles in Finland. At present, the few remaining natural-like forests are distributed evenly throughout southern Finland, but the number of regionally extinct old-growth forest beetles is much greater in the southwestern coastal areas, where human impact on forests has been lengthy, than in the northeastern inland areas, where intensive forestry started only after World War II. Ignoring time delays in population and metapopulation dynamics will lead to an underestimate of the number of effectively endangered species.

[Sayonara]

In response to your requests for more of Lomborg's thinking, some selected quotes. Obviously this is a tiny part of the whole. If you need more, you will have to go to your public library and get out the book.

Thanks for that. It is 20 to midnight here so I will have to digest that tomorrow evening (or more likely wed evening, as I have a class after work tomorrow).

[SkepticLance]

To Paralith.

 

I am not pushing Lomborg's barrow. However, his quotes at least carried numerical data. The concept you presented of extinction debt may have validity. However, the degree of such validity cannot be ascertained by your data.

 

We need proper studies and the numerical results of those studies. It should not be too difficult to quantify that extinction debt in a number of situations. After all, there has been numerous cases of habitat loss in various parts of the world throughout human history. A simple study should be able to look at extinctions that occurred at various times following various losses of habitat.

 

Can you quote any such data?

[Paralith]

Can you quote any such data?

 

I know the abstract I quoted is a little dense, but if you read it closely it says this at the end:

 

We consider a putative example of extinction debt on forest-inhabiting beetles in Finland. At present, the few remaining natural-like forests are distributed evenly throughout southern Finland, but the number of regionally extinct old-growth forest beetles is much greater in the southwestern coastal areas, where human impact on forests has been lengthy, than in the northeastern inland areas, where intensive forestry started only after World War II.

 

Unfortunately I can't access the article itself (the part I hate the most about not being a current member of an organization with journal subscriptions >_<), but I think it's safe to assume that the authors have actual numerical data within the paper, and it is summarized here in their abstract. If you have the proper access, I included all the relevant information in my first post so that you should be able to locate the article and read it in its entirety if you would like.

 

Edit:

I've tried to find another concrete example or two. Several of the studies I came across use simulations, which supported the existence of an extinction debt, but it depended on the life history of the species, which makes sense. Then I found this article by Mark Vellund et al, 2005, in Ecology: Vol. 87, No. 3, pp. 542–548, entitled EXTINCTION DEBT OF FOREST PLANTS PERSISTS FOR MORE THAN A CENTURY FOLLOWING HABITAT FRAGMENTATION. Again, the abstract:

 

Following habitat fragmentation individual habitat patches may lose species over time as they pay off their “extinction debt.” Species with relatively low rates of population extinction and colonization (“slow” species) may maintain extinction debts for particularly prolonged periods, but few data are available to test this prediction. We analyzed two unusually detailed data sets on forest plant distributions and land-use history from Lincolnshire, United Kingdom, and Vlaams-Brabant, Belgium, to test for an extinction debt in relation to species-specific extinction and colonization rates. Logistic regression models predicting the presence–absence of 36 plant species were first parameterized using data from Lincolnshire, where forest cover has been relatively low (5–8%) for the past 1000 years. Consistent with extinction debt theory, for relatively slow species (but not fast species) these models systematically underpredicted levels of patch occupancy in Vlaams-Brabant, where forest cover was reduced from 25% to <10% between 1775 and 1900 (it is presently 6.5%). As a consequence, the ability of the Lincolnshire models to predict patch occupancy in Vlaams-Brabant was worse for slow than for fast species. Thus, more than a century after forest fragmentation reached its current level an extinction debt persists for species with low rates of population turnover.

[Genecks]

So, if I take land away from humans, they go extinct? Awesome.

 

I'd have to say that cutting survival needs and food supplies would pretty much kill off any species. If a species can't find a way to protect itself, nor feed itself, then it's going to die. I figure that's more of a physiological look at it. I don't think animals put too much emphasis on their feelings in order to survive: they don't become suicidal.

 

I'm sure animals can become nomadic, but if there are predators and no food, then they become the food. I think the Galapagos Islands are an example of not really having predators. Pandas are a good example of picky eaters, too.

 

I think the Land Before Time movies are prime examples of how an animal could just pick up, move, and go somewhere else in order to survive. Whenever I watch one of those, the dinosaurs are moving, because of environment changes or food shortage. I don't think most animals would be so stubborn to stay in one place because of a social system.

[Paralith]

I'd have to say that cutting survival needs and food supplies would pretty much kill off any species. If a species can't find a way to protect itself, nor feed itself, then it's going to die. I figure that's more of a physiological look at it.

 

Well, the question is if clear cutting a forest and reducing its size will cut "survival needs and food supplies," as you put it, to the extent where the habitat loss itself is a major contributing cause to the extinction of species. (I'm going with what I've taken to be Lomborg's stance on habitat loss, given the quotes provided by SkepticLance.)

 

I think the Land Before Time movies are prime examples of how an animal could just pick up, move, and go somewhere else in order to survive. Whenever I watch one of those, the dinosaurs are moving, because of environment changes or food shortage. I don't think most animals would be so stubborn to stay in one place because of a social system.

 

A big problem with this is fragmentation. Most animals need a corridor of habitat where they can safely move from one spot to another, and they simply don't have it. A professor of mine worked with howler monkeys suffering from this phenomenon - they would get trapped in the fragments, and be far too afraid of dogs and people and other predators to make the trip of who knows what distance over land. Probably if they can't visibly see the next patch of forest, they're not going to leave the one they're in. These are species that spend their lives travelling through the upper canopy. Land travel just isn't how they roll, as it were. They're not smart enough to make the connection, and I think we can all agree that the Land Before Time dinosaurs were highly anthropomorphized as regards their intelligence.

[SkepticLance]

Lomborg appears to be mainly talking about rainforest, and rainforest rarely totally disappears. Even those people in Brazil who assiduously remove the forest to create farm land have a hell of a job trying to stop the forest growing back. It is more difficult than we think to totally destroy that kind of habitat.

 

The howler monkey example is a good one, except for the fact that they are spread over an enormous expanse of tropical rainforest, meaning that there is no real danger of extinction even if a few outlying populations suffer.

[Paralith]

Well, it may or may not take total destruction to drive a given species or two to extinction. Enough combined factors, one among them being reduction of habitat, that drive their populations below a minimum viable number may be all it takes. And with effects like extinction debt, it may be a while until the real ramifications of such situations are realized.

 

Also, I wasn't using the howler monkeys as an example for extinction, just an example of fragmentation preventing migration. The monkeys being studied by my professor are actually hybridizing, and she thinks isolation within fragments may be a cause of it.

[SkepticLance]

Paralith.

You may be correct in saying that a reduction in habitat may be all that it takes to lead to extinction. However, in spite of lots of replies in this thread, we have no clear cut examples. So far, Lomborg is proving correct.

[Paralith]

Paralith.

You may be correct in saying that a reduction in habitat may be all that it takes to lead to extinction. However, in spite of lots of replies in this thread, we have no clear cut examples. So far, Lomborg is proving correct.

 

But have I not provided some evidence that the data Lomborg is using is incorrect, at least to a certain degree? That if he corrected for extinction debt, he would find that deforestation does indeed seem to correlate with high levels of extinction? Lomborg's examples don't seem to be that clear cut themselves. In the quotes you provided he's merely talking about percentages of forest lost to percentages of species lost. Where is the data showing that of the species that did go extinct, or that are severely endangered and are on the brink of extinction, habitat loss played no significant part in their situation? (And I'm talking about species living in areas where habitat loss occurred.) That some other factor was irrefutably the cause?

 

Clearly these are difficult questions to answer, and I'm not saying that the data I provided answers them while Lomborg's does not. I'm merely saying that Lomborg's data is not infallible, and that at this point I don't know if we can firmly say yay or nay to his conclusions.

[SkepticLance]

To Paralith.

The whole point of asking about Lomborg's conclusions is due to the uncertainty. He supplies some statistics that indicate, at the least, that some of the estimates of the importance of habitat loss are exaggerated. However, we need clear cut examples of extinctions caused by habitat loss in order to show its importance.

[Paralith]

Clear cut examples would be great, but as Sayonara and I both said, extinctions are so complicated that finding a clear cut example other than a sweeping knock out of life from a volcano may be next to impossible. And for the same reasons, merely suggesting that some estimates of extinction due to habitat loss might be exaggerated is not enough to say that habitat loss is CLEARLY not significant. Especially considering the fact that the estimates may not be exaggerations at all when extinction debt is taken into consideration.

[SkepticLance]

To Paralith.

I disagree. I think that clear cut examples are not by any means an unreasonable ask.

 

I gave a very clear cut example of a clear cut case of extinction by introduced predator (the Stephens Island Rock wren and the lighthouse keeper's cat). I can give lots more examples. Clear cut examples of extinctions by habitat loss should be readily available. There are heaps of examples of habitats totally destroyed. We should be able to point to these and say : "Here is a habitat destroyed, and this is a list of the species that once lived there that are now extinct."

[CDarwin]

In Bjorn Lomborg's book : "The Skeptical Environmentalist", he makes the statement that loss of natural habitat is a minor cause of extinctions. Two examples are given of places where massive natural habitat loss occurred with very little in the ways of extinction of species.

1. Puerto Rico.

2. Atlantic coast of Brazil.

 

Yet in environmentalist literature, habitat loss is almost invariably described as a major cause of extinctions.

 

Does anyone have any unambiguous examples of cases where habitat loss has caused substantial extinctions? Please try to use examples where other causes are unlikely.

 

You might want to tell your second example to the muriqui. Now it probably wouldn't understand what you were saying since it's a monkey, but if it did it would note that its kind is teetering on the verge of extinction because of the destruction of its Atlantic coastal forests in Brazil. There are about 500 left.

 

Lion-Tailed Macaques provide a yet clearer example. The only pressure they face is habitat destruction. They aren't hunted and they aren't being competed with by introduced species. There are between 400 and 4,000 of them left.

 

You have to realize that in certain environments many adaptable and widespread species will come out just fine, perhaps even most of the species. The problem is that minority that doesn't come out fine.

 

Arboreal primates are particularly vulnerable to habitat destruction, as they depend on delicate forest ecosystems.

[SkepticLance]

To CDarwin

 

The question is not whether loss of habitat can cause harm. Obviously it can. The question is how much?

 

Lomborg suggests that loss of habitat as a cause of extinction is over-rated. A couple of examples of not-quite-extinct does not really answer the question. I am sure lots of us could come up with similar answers. The question is whether the emphasis on habitat loss as a cause of extinction is valid. I am not suggesting it is unimportant. Just asking about how much it contributes to extinctions.

 

Being from New Zealand, I am very aware of extinctions. Since people have been here only 800 years, we are very close to the subject. In other places, the mass extinctions caused by humans may have occurred a long time ago. Australia, for example, had over 100 species of megafauna go extinct at about the same time as humans arrived - 50,000 to 60,000 years ago. Something similar in North America and in Europe. Here, it is recent.

 

When the first humans arrived in NZ, there was a rapid loss of 36 species of native bird. Large birds to hunting. Smaller birds to the polynesian rat. There were undoubtedly many other species lost, such as insects and lizards. One sub-species of fur seal was lost. Most of these extinctions were within 200 years of the first humans.

 

At the same time, about one third of the native rainforest habitat was lost. Insufficient to be a cause of extinctions. We can be pretty sure that all those extinctions were due to humans hunting prey, or the introduction of the polynesian rat.

[Sayonara]

I gave a very clear cut example of a clear cut case of extinction by introduced predator (the Stephens Island Rock wren and the lighthouse keeper's cat). I can give lots more examples. Clear cut examples of extinctions by habitat loss should be readily available. There are heaps of examples of habitats totally destroyed. We should be able to point to these and say : "Here is a habitat destroyed, and this is a list of the species that once lived there that are now extinct."

 

There are two problems with this.

 

The first is that your examples are also examples of extreme ecosystems, with very few trophic connections. These are incredibly sensitive to upsets to begin with, and extinctions require much less pressure.

 

The second problem is one which has already been demonstrated quite adequately. Identifying what is and what is not "extinction due to habitat loss" is not a simple matter, whether or not we say that it should be.

[CDarwin]

Lomborg suggests that loss of habitat as a cause of extinction is over-rated. A couple of examples of not-quite-extinct does not really answer the question. I am sure lots of us could come up with similar answers. The question is whether the emphasis on habitat loss as a cause of extinction is valid. I am not suggesting it is unimportant. Just asking about how much it contributes to extinctions.

 

That's obviously going to depend on the individual case. Are you looking for a general rule here?

 

If you want a clear cut example of changing habitat causing extinction, just look at the end of the Permian. The 95% of species that were killed there didn't die by being hunted into extinction, they died because the changeing climate destroyed their habitats. That obviously wasn't a anthropogenic change, though.

 

It is believed by a large number of climate scientists that we are changing the climate of the planet in similar ways now, which should lead to similar extinctions (if perhaps fewer). That might not be what you're talking about though.

 

There hasn't been much citing in this debate, just people refering to their memory. Most places don't give precise reasons for extinctions, but I did find this stating that 100 extinctions a day are due to deforestation. Many of these are going to be of rarer plant species, which are usually highly specialized so they aren't likely to be out-competed by introduced species and too rare and cryptic to be heavily gathered or prayed upon.

 

Here is a list of recently extinct plants.

 

This site should probably be the final word on the matter. It syncs well with what I think everyone has been saying. In theory, habitat destruction should cause extinctions, but it doesn't seem to in large numbers. It may be the result of a time lag. Habitat destructions weakens the genetic diversity of species so that they aren't able to respond when the next crisis comes and thus go extinct.

[SkepticLance]

To CDarwin

I had a read of your mongabay reference. It reads as a description of the principles that E.O.Wilson used to derive his extinction rates, which Lomborg says does not happen. With all due respect to the people involved, a description of theory is not settling the question. I was hoping for some real world data to show how valid or otherwise, the Lomborg idea is.

 

To tell you the truth, the feed-back I have seen so far on this thread has just led me to think that Lomborg was right. Habitat loss no doubt does cause some extinctions, but no-where near as many as introducing alien predators and diseases, or direct over hunting/fishing by humans.

 

This principle is important. If we are to act to reduce loss of biodiversity, we must know what to act upon. If it is mainly predator/disease introduction, the best place to divert resources is biosecurity. etc.

[SkepticLance]

By sheer coincidence, the latest edition of New Scientist has an article exactly on this topic. It is in the Australian printed edition, 12 May 07, page 43.

 

It begins :

"cutting down the rainforest is a disaster for biodiversity. Or is it?"

 

It quotes work by two rainforest ecologists - Wright and Muller-Landau, published in Biotropica vol. 38, page 287.

They claim that cutting down tropical rainforest is followed nearly always by substantial regrowth of secondary forest, and the secondary forest becomes a repository for biodiversity.

 

The whole New Scientist article gives no clear answers - treating this as a controversy with arguments on both sides.

 

There are clear cut examples to support the hypothesis.

For example :

"Torben Larsen, an internationally recognised authority on tropical butterflies. West Africa, he reports, has less than 3% of its original forest cover but appears not to have lost a single species of forest butterfly."

 

As I said, this article does not, overall, give clear cut answers, and describes counter arguments, but nevertheless provides some extra ammunition to support Lomborg's hypothesis.

[Paralith]

I think the biggest danger of habitat loss is making animals more susceptible to other contributing factors to extinction.

 

I was looking up examples of birds that have gone extinct in the last 50-100 years (I thought more recent examples would probably be better documented) due mostly to habitat loss. And I did find some - but most of the species listed had habitat loss in combination with other factors. I didn't make note of most of them, as your original post asked for something with habitat loss alone mostly to blame. Turning away the majority of the examples I found for this reason seemed, to me at least, to lend support to my statement above.

 

Either way, here are the examples I found so far; some you will find listed as Critically Endangered, Possibly Extinct, usually because there are a few strips of area left to be thoroughly searched, even though a confirmed sighting has not been made for years. Most list other threats to the animals other than habitat loss, but usually indicate that the most devastating blow was the habitat loss.

 

Laysan Rail (http://www.iucnredlist.org/search/details.php/18083/all)

Columbian Grebe (http://en.wikipedia.org/wiki/Colombian_Grebe)

Cuban Kite (http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=30037&m=0)

Imperial Woodpecker (http://en.wikipedia.org/wiki/Imperial_Woodpecker)

Bachman's Warbler (http://www.iucnredlist.org/search/details.php/22927/all)

[SkepticLance]

To Paralith.

Thank you for your research. A very nice list of possible examples. You have done a very good job of searching out and reporting possible examples of species rendered extinct by habitat loss.

 

It appears that most of your examples is an extinction that is a combination of habitat loss with an other cause.

Layson Crake includes alien predators.

Columbian Grebe includes alien predators (rainbow trout) plus over hunting.

Cuban kite includes killings by farmers.

Imperial woodpecker includes over hunting as folk medicine

Bachmann's warbler. Possibly a clear cut case of extinction by habitat loss, but not known for sure to be extinct, since some habitat remains, so far unsearched.

 

Clearly loss of habitat plays a role in these extinctions, but appears not to be the sole cause.

[Paralith]

Well, as I said previously, it's hard to find cases of habitat loss alone. And since you disagreed with me, I tried. But animals don't live in bubbles, and extinction is complicated - I'm all the more convinced of it now.

 

Though the Layson Rail case includes alien predators, those predators did not prey upon the rails themselves, but on the vegetation of their habitat, stripping it completely. Human caused, either way.

 

Both the Colombian Grebe and the Bachmann's Warbler live in wetland areas which have been drastically reduced. Wetlands are particularly biodiverse areas, and have classically been targeted for destruction as in the past most people did not understand their ecological significance; they were considered gross and smelly swamps, and many were filled in. The Colombian Grebe most certainly suffered from predation, but the population was also attempting to survive in a tiny fraction of their previous habitat. I think any species in that case becomes extremely susceptible to any other perturbation. And for the Bachmann's warbler, it like most of the species in this list still lists some hope for finding it again. But I think a sense of pragmatism tells how how small that hope is, especially if there hasn't been a sighting for nearly 20 years.

 

Farmer's may persecute the cuban Kite, but we don't know if that means they went out and looked for them and killed as many as possible. Probably, if one ventured near their farm, they shot it. And once most of the Kite's habitat was replaced with farm - well.

 

I imagine that the Imperial Woodpecker was hunted for folk medicine for as along as humans have been living in that area - at least well prior to deforestation. It was only until habitat loss weakened the population that the folk medicine trade actually may have become significant.

 

However you put it, habitat loss is bad. It's one step closer to extinction, with the next or previous steps involving predation, or pollution, or disease. I don't think one factor should get precedence over the other when it comes to conservation. However, I also understand that resources are limited, but at the rate habitat loss is going, I don't think it's one that can be forced to the backburner.

[SkepticLance]

Paralith said :

 

However you put it, habitat loss is bad. It's one step closer to extinction, with the next or previous steps involving predation, or pollution, or disease. I don't think one factor should get precedence over the other when it comes to conservation. However, I also understand that resources are limited, but at the rate habitat loss is going, I don't think it's one that can be forced to the backburner.

 

I don't think anyone will disgree with you on the importance of conserving habitat. Apart from anything else, climax tropical rainforest is magnificent - a treasure to be protected.

 

However, while habitat loss is clearly a contributor to extinction, it appears to be rare that it is the sole factor. My own reading suggests that the biggest cause of extinction is the introduction of alien predators, diseases etc. Probably followed by over hunting and fishing.

 

If resources are limited (which they always are) then it makes sense to address the major cause rather than a minor one. For example : Tigers in Asia are rapidly heading into extinction in the wild. The primary cause is clearly poaching. To save the tiger, authorities need to direct their efforts against poaching, and avoid side issues.

[CDarwin]

Obviously you can link extinctions more clearly to hunting and non-indigenous competitors, these are things that directly kill organisms. Habitat loss weakens populations, so even if it doesn't directly cause extinction in the short run it can set a species up for much bigger problems in the long run from things like hunting and competition. All you're really saying is that there are two levels to protection: protecting the animals themselves from what kills them and protecting populations from what weakens them.