Habitat loss = extinctions??

[Sayonara]

No, I am not Lomborg.

Shame

 

Lomborg uses several examples of loss of habitat, and all translate as deforestation.

My point earlier today was that deforestation is not just "loss of habitat", it is the removal of the majority of the ecosystem.

 

I do not want to seem harsh or anything, but to claim this fits Lomborg's definition while rejecting the definitions required for counter-examples given in this thread is disingenuous at best, and outright intellectual dishonesty at worst.

 

Why can't you see that?

[SkepticLance]

To Sayonara

 

I am not sure I like the current direction of this thread. It is rapidly turning into a discussion of semantics.

 

I do not realy see the difficulty. Loss of habitat is something we are all well aware of. We see it in the news every day. It is substantially different to over hunting etc.

 

If we look at alternative causes of extinction, such as the over-hunting and introduction of aliens, then these have effects over a wide range of habitats. When the brown snake was introduced into Guam, it spread to all parts of the island - forest, town, seashore etc. The extinctions it caused were in all areas. Loss of habitat affects only one kind of habitat. If we are talking about, for example, the flooding that comes with the construction of a hydro dam, then that is clearly loss of habitat - not over hunting etc.

 

Here in New Zealand, when the first polynesian people arrived 800 years ago, they destroyed about one third of the rain forest. This is clearly loss of habitat. They also hunted into extinction 11 species of moa bird, to provide them with food. They also introduced the polynesian rat, which caused many other extinctions of small bird species.

 

I do not see why it is so hard for you to distinguish between loss of habitat and other causes.

[Sayonara]

I am not sure I like the current direction of this thread. It is rapidly turning into a discussion of semantics.

Semantics is crucial when you have someone who is presenting a popularist, media-hijacked version of an ecological state as if it were a universally agreed biological term. By which I mean him, not you.

 

I do not realy see the difficulty. Loss of habitat is something we are all well aware of. We see it in the news every day.

No. What you see is network disruption. What you are told is that it is habitat loss. Newsreaders rarely use scientific terminology correctly at the best of times; they have no chance when scientists disagree on the scope of definitions.

 

It is substantially different to over hunting etc.

Re-reading this thread in its entirety should - at the very least - give you some pause for thought over that. Remember: habitat denial is functionally indistinguishable from any literal definition of habitat 'loss'.

 

If we look at alternative causes of extinction, such as the over-hunting and introduction of aliens, then these have effects over a wide range of habitats. When the brown snake was introduced into Guam, it spread to all parts of the island - forest, town, seashore etc. The extinctions it caused were in all areas. Loss of habitat affects only one kind of habitat.

In certain cases, yes. In other cases, no. That doesn't really demonstrate anything.

 

An invasive species can occupy the same niche as the harmed species (which is more likely than not where extinctions are the end result). The red and grey squirrels mentioned earlier are a seminal example.

 

You also cause a new problem here that by tightening the definition of habitat loss still further, to include only one "type" of habitat, without even specifying how we should differentiate between "types" of habitat, you further beg the question by effectively disqualifying the extinctions of all species which occupy an ecologically variable niche, or which have any kind of potential ecological refuges (i.e. the vaaaaaast majority of all life on Earth).

 

If we are talking about, for example, the flooding that comes with the construction of a hydro dam, then that is clearly loss of habitat - not over hunting etc.

It wasn't when I presented it to you as an example.

 

Here in New Zealand, when the first polynesian people arrived 800 years ago, they destroyed about one third of the rain forest. This is clearly loss of habitat.

I would agree. However it is also loss of network. Which one killed off populations? Animals and birds don't just drop down dead because their favourite perch is missing, but they do tend to starve when there is no system to support them.

 

Do you see what a quagmire we step in to here?

 

I do not see why it is so hard for you to distinguish between loss of habitat and other causes.

It's not that ecologists can't distinguish (as in "at all"), it's that Lomborg apparently provides no definition other than one which produces a tautology.

 

 

Look, I realise this isn't what you expected to hear when you created this thread, but we are honestly providing the only ecologically rational response. Sorry.

[SkepticLance]

Sayonara.

 

Perhaps you might like to suggest a way to get past this.

 

Perhaps you could suggest a definition, that permits 'loss of habitat' to include such things as deforestation, drying of lakes and ponds, desertification of previously lush areas, flooding by hydro lakes etc; while excluding over-hunting by people, and introduction of alien species, and pollution.

 

There are, of course, lots of examples of natural loss of habitat, such as caused by volcanoes, landslides etc. I would rather we kept the discussion to human caused events.

[Sayonara]

I have already proposed a solution: we accept that denial is functionally the same as loss, which is what the ecology mainstream appears to be doing anyway.

 

The alternatives are to support a definition of habitat loss in which either special pleading plays a role, or tautology results. Neither of these particularly appeal.

[bombus]

SkepticLance,

 

I could write a book saying how guns have never killed anyone, and are therefore not at all dangerous.

 

I could show that no-one has ever been killed by a gun. They have not even been killed by bullets. Furthermore, people who have been shot and subsequently died did not even die from blood loss, nor the damage sustained by the bullet. No, because in every case they died due to lack of oxygen to the brain.

 

Obviously, this would be a ridiculous thing to argue, but Lomburg is pretty much using the same type of argument.

 

His interpretation of the stats is meaningless, useless rubbish.

[SkepticLance]

I think that Sayonara is trying to win a point by quibbling about definitions, and bombus by skirting around the main point, instead of contronting it.

 

There is no argument against the idea that loss of habitat is a contributing factor to many species extinctions. However, what I see as the major causes (alien species introductions, and over-hunting/fishing by humans) have many, many examples where they are clearly the sole causes of said extinctions. Loss of habitat lacks this distinction.

 

When I started this thread, I was essentially testing a statement by Lomborg, and seeing if anyone could come up with examples to disprove his statement. I think that those who replied have proved that loss of habitat is often an important contributor to extinctions, but rarely a sole cause.

[lucaspa]

Lomborg uses several examples of loss of habitat, and all translate as deforestation.

 

I do not think you can, in all honesty, talk about the other main causes of extinctions, and call them loss of habitat. Not in the context of this discussion. That is, over-hunting, over-fishing by humans. Introductions of alien species. Pollution. etc.

 

So you admit that Lomborg is using a very limited definition of "habitat loss". Thank you.

 

Introduction of alien species also results in habitat loss by replacing the habitat that was there with another one that is dominated by the alien species. In terms of deforestation, the introduction of kudzu in the southern USA is resulting in deforestation as the kudzu chokes out the trees. Birds and insects dependent on those trees for food, shelter, etc. are going extinct thru "habitat loss".

 

Pollution is the same thing, isn't it? If you have an oil spill, then the oil is messing up the water and destroying the habitat that birds and other marine life depend on. Instead of a habitat of clean water, you have a habitat of oil. They have had "habitat loss" and the result is loss of the population in that area.

 

Shoot, now that I think about it, even over-hunting or over-fishing is a habitat loss for the other species in that ecosystem. Those species are a necessary part of their habitat. In doing the research to answer you, I ran into at least a dozen papers documenting the catastrophic results of losing the top predators in an ecosystem: the very species that humans tend to over-hunt and exterminate. For the rest of the species in that ecosystem, they have had "habitat loss" when those species are removed.

 

It appears that Lombock is trying to make the very narrow point that deforestation in some areas did not result in widespread extinction. However, I'm willing to bet that he got extinction of the local population! It's just that there was enough remaining habitat -- forests elsewhere -- that the species didn't go extinct because there were remaining populations.

 

If Lombock would have stuck to the narrow point, he might have been valid. But in extending this to generalities, he has had to ignore data and manipulate the definition of "habitat" to the point that it is no longer recognizable. It appears a classic case of overinterpreting the data and making conclusions much wider than the data can support.

[lucaspa]

Sayonara.

 

Perhaps you might like to suggest a way to get past this.

 

Perhaps you could suggest a definition, that permits 'loss of habitat' to include such things as deforestation, drying of lakes and ponds, desertification of previously lush areas, flooding by hydro lakes etc; while excluding over-hunting by people, and introduction of alien species, and pollution.

 

Why would we want to do that? Flooding by hydro lakes does destroy habitat, for instance!

 

There are, of course, lots of examples of natural loss of habitat, such as caused by volcanoes, landslides etc. I would rather we kept the discussion to human caused events.

 

Why? You were asking for examples of extinctions being caused by habitat loss. If you lose habitat thru a natural loss, the species that went extinct are just as extinct as they are if the habitat loss is caused by humans.

 

We are looking at whether habitat loss causes extinctions. If it happens when natural forces destroy habitats, then it will happen when humans do it. What you are trying to do is exclude data that falsifies Lombock's (and your) position. Can't do that.

[Sayonara]

I think that Sayonara is trying to win a point by quibbling about definitions, and bombus by skirting around the main point, instead of contronting it.

...and I think that you are stonewalling anything that disagrees with what you think, and cherry-picking examples.

 

I cannot possibly be "quibbling" about definitions, since I have been making the valid and REAL point that the ecological definition of habitat loss is a somewhat subjective term.

 

You need to start taking notice of what is being said, or this thread will just be locked as a waste of time.

[bombus]

...and I think that you are stonewalling anything that disagrees with what you think, and cherry-picking examples.

 

I cannot possibly be "quibbling" about definitions, since I have been making the valid and REAL point that the ecological definition of habitat loss is a somewhat subjective term.

 

You need to start taking notice of what is being said, or this thread will just be locked as a waste of time.

 

Indeed! Well said.

[SkepticLance]

OK.

 

Can we agree that the key part of 'loss of habitat' is the word loss.

 

In other words, loss of habitat occurs when one or more vital ecological supports are removed. For example : if a bird species suffers loss of the trees that supply fruit for food, and goes extinct - that is loss of habitat. Of course, it could be other vital factors that are lost - not just food.

 

The alternative drivers of species extinction, by contrast, come from adding an inimical element, such as an extra predator.

[bombus]

OK.

 

Can we agree that the key part of 'loss of habitat' is the word loss.

 

In other words, loss of habitat occurs when one or more vital ecological supports are removed. For example : if a bird species suffers loss of the trees that supply fruit for food, and goes extinct - that is loss of habitat. Of course, it could be other vital factors that are lost - not just food.

 

The alternative drivers of species extinction, by contrast, come from adding an inimical element, such as an extra predator.

 

Some introduced species drive native species extinct by being more successful in exploiting the same food resource, thus leaving the natives with no food. As far as the native species is concerned that is essentially the same as cutting down the trees that produce the food. Thusly, it has the same effect as your narrow definition of habitat loss.

[Sayonara]

You might say, in fact, that denial is functionally the same as loss.

 

If this thread was a Star Trek episode, we would have figured out that it was a temporal anomaly all along about 60 posts ago.

[SkepticLance]

Sayonara

You are correct. We do not seem to be getting very far.

 

We are all aware of the distinction between habitat loss and other extinction causes. If nothing else, it is well covered in popular literature. I thought my offered definition had some possibilities, but it looks as if my debate partners would rather destroy a possible definition than try to construct one. If we cannot try for a more constructive approach, then we probably should end the thread.

[1veedo]

If you mean local extinction, just as a side-note (I'm sure this isn't exactly what you're talking about), the area where I live used to have elk when the first settlers came. They even called one town/settlement Elkview, the river is called the Elk river, and hens the Elk river valley which is where I live (Pinch, right beside of Elkview).

 

Anyway the elk no longer inhabit this area. I'm not sure how much is directly because of habitat loss but humans definitely do effect animals.

[biofreak]

due to loss of forested lands which used to be the habitats of wild elephants in the dalma hills of northern districts of west bengal in india,no. of those elephants are in a decline from 2004.most elephants die because they if mistakenly trespass into the farmlands which actually have been cultivated after destroyin gthe rainforests, they get entangled in the wires of the fences which are electrically charged and die of electrocution. sometimes, locals kill these wild elephants for coming into the civilized quarters.so actually loss of habitat does lead to extinction in a major way.