Ecological damage?

[SkepticLance]

An example of ecological damage appeared in the 17 June 2006 New Scientist. Page 43.

 

Chongming is the world's largest alluvial island, formed by sediment at the mouth of the Yangtse River. Due to deforestation further up the river, lots more sediment has been washed down to this site, and the island has doubled in size since 1950.

 

While this is not a clear cut case of ecological damage, the implication in the article was that it is a bad thing. I started wondering about the reverse. Imagine that the river was dredged to improve access for shipping, and the subsequent higher water flows caused the island to shrink. That would definitely be seen as ecological damage.

 

It seems to me that the idea of such damage is imprecisely defined. Perhaps someone could pass on his / her definition of ecological damage?

[KLB]

No matter how you slice it, there is a giant grey zone where ecological damage is a matter of opinion. Most rational people would agree that the Exxon Valdez oil spill in Alaska caused ecological damage, but in the case you give as an example it isn't so clear cut.

[ecoli]

Most rational people would agree that the Exxon Valdez oil spill in Alaska caused ecological damage...

 

This is sort of random, but my dad taught the daughter of Captain Joseph Hazelwood of the Exxon Valdez tanker. He was her biology teacher at the time of the spill.

 

It was such a big deal at the time, that his daughter was forced to leave the school and the town... I'm not sure where they relocated to.

[KLB]

Apparently after the spill, Joe Hazelwood became a ships safety instructor. I think the response of one of the environmental groups was "well if it's true that you learn from your mistakes then he should be one hell of a good instructor."

[Skye]

It depends on what happens as a result. A larger island isn't necessarily bad, a smaller island isn't necessarily bad. If you start to see things like species diversity and richness dropping though, it's probably a bad thing.

[KLB]

It depends on what happens as a result. A larger island isn't necessarily bad, a smaller island isn't necessarily bad. If you start to see things like species diversity and richness dropping though, it's probably a bad thing.

I think this is a good way to measure it.

[SkepticLance]

What I am hoping for is some decent definition from someone.

I am not sure that a phrase such as 'reduction in species diversity and richness' quite covers it?

 

Let me give another example . I spent most of my adult life in Auckland. This used to have (100 years ago) a harbour with lots of clear water, and pristine reefs covered with seaweeds and reef dwelling fish etc. Due to development (deforestation and removal of ground soil by bulldozers etc) a lot of soil has washed into the sea, and sediment now covers those reefs, while the water has become very silty. Logically, this is a case of ecological damage. Yet a biologist friend of mine assures me that the explosion in sediment dwelling life-forms, and especially nematode worms, means the total number of species has probably increased.

 

From an intuitive viewpoint, the Auckland harbour has suffered ecological damage. Yet, how do we define this damage?

[herpguy]

What I am hoping for is some decent definition from someone.

I am not sure that a phrase such as 'reduction in species diversity and richness' quite covers it?

I don't understand how there could be a real definition of ecoligical damage.

 

However, IMO, Skye was right on for the most part. I think that if the ecosystem is becoming unbalanced (i.e. the population of any organism is falling) and one factor or more is causing it to do so, then there is ecological damage.

 

Edit: My 350th post! Woohoo!

And also, did I use "i.e." correctly? Thanks.

[ecoli]

Edit: My 350th post! Woohoo!

And also' date=' did I use "i.e." correctly? Thanks.[/quote']

 

more or less... and congradulations.

[SkepticLance]

herpguy.

Ecological 'balances' are changing all the time. Sometimes the change is natural and sometimes man-made. I am aware of several forest plants that specialise in colonising bare land after a land-slide. A land-slide seems to be a clear case of ecological damage, since it wipes out a section of forest. Yet without them, these specialised plants would go extinct.

 

I am looking for an idea of ecological damage that goes beyond simply 'any ecological change'.

 

Another example is the Australian bell frog. This species is highly endangered due to a fungus disease. Just before the Sydney 2000 Olympic games, some developers were checking sites for building sports facilities. They found a polluted pond that looked as though it would be a good site. However, an environmental study of the site showed that the pond had the largest population in Australia of the endangered frog. Apparently the chemicals in the polluted pond killed the fungus.

 

The only clear cut example of ecological damage I can think of is extinction. I suspect that a lot of other damages are more aesthetic than real. However, there are some we would all agree on. Polluting the air over a city is damage. Acid rain is damage. Yet how can we define ecological damage in such a way as to make the meaning clear?

[herpguy]

Something can hurt one thing, but help another. This would be damage to the thing that it hurts. If it hurts something to the point that it destroys the food web, then that would be ecological damage.

[SkepticLance]

herpguy.

Thank you for your efforts.

However, I am not sure of the depth of your understanding of ecology. (No offense intended).

 

Ecological change is pretty much ubiquitous. However, such change, even when driven by the worst excesses of human effort does not destroy a food web. Merely changes it. We may get a lake that is pure and pristine, and so damage it that it is overwhelmed by bacteria - both photosynthetic (cyanobacteria) and anaerobic (which cause the nasty smells from bogs). However, a food web is still present and active. In fact, the purest lakes often have the lowest biomass and biological productivity. By contaminating them with nutrients we may make the lake far more biologically productive, but still call the result undesirable.

 

This is why I have a problem with definition. If something cannot be clearly defined, its value as a scientific measure is debatable. Yet ecological or environmental damage is very important. it needs clear definition.

[herpguy]

Offense taken. Why? Not because I think I have a great knowlege of ecology; I know I dont. I take offense because you misunderstood what I said. So, in case it was my fault, not yours, I will restate myself.

 

There is no definition. As of right now, it is all about opinion.

 

I believe it is ecological damage if, well, the ecosystem collapses. I probably didn't make myself clear when I talked about the food web. What I meant is that if the food web collapses, then that is ecological damage because the ecosystem is no longer self-sustained.

 

It is true that everything relies on another. Sure, there are other ways to get food and such, but if every first-level consumer dies off, then the second and third level consumers would also die. This is what I mean.

 

 

If I am not explaining myself clearly, please tell me what I need to say better. Thanks.

[SkepticLance]

herpguy.

Forgive me if I don't understand what you are getting at.

 

My point is that, in ecology, nothing is destroyed (except when extinction occurs). The balance of nature is never destroyed. Ecological change (or damage) simply results in a new balance point. Food webs are not 'collapsed' or destroyed - simply morphed into a new food web.

 

It is tough to try to define 'damage'. I was hoping someone would have a better idea than I have been able to come up with. So far, if species extinction does not occur, the idea of ecological damage appears to be intuitive, rather than scientific. This is not a good situation.

[CharonY]

Actually it is a bit more complicated. The notion that nature is essentially in balance is an illusion. Biotic and abiotic elements in almost any give ecosystem is constantly shifting. Sometimes around some kind of equilibrium, but more often than not there are gradual (if slow) changes. A very intuitive way to see that is considering the fact that species within an ecosystem are evolving and thus open up new niches in a given system.

 

In general I'd say that ecological damage is probably given as a more or less sudden disruption of the given state of a system, resulting in an ecosystem that is distinctly different from the starting point (just pulling some ideas out of nowhere...).

[SkepticLance]

CharonY said :

In general I'd say that ecological damage is probably given as a more or less sudden disruption of the given state of a system, resulting in an ecosystem that is distinctly different from the starting point

 

Thank you for this. An honest attempt at a good definition.

 

Only criticism I have of this definition is that it encompasses a lot of what seems to be necessary natural changes. For example : the land slides I first mentioned, that provide an essential habitat for some species that would otherwise go extinct. Any comments?

[Aardvark]

It is tough to try to define 'damage'. I was hoping someone would have a better idea than I have been able to come up with. So far' date=' if species extinction does not occur, the idea of ecological damage appears to be intuitive, rather than scientific. This is not a good situation.[/quote']

 

A good rule of thumb is that ecological damage has occured where ecological simplification has resulted.

[SkepticLance]

Aardvaark.

How would your definition fit the case of eutrophication of an alpine lake?

 

Alpine lakes are generally very simple, with little life. They are, however, clean, and utterly gorgeous. If someone allows new nutrients to enter, you get a lot more weed growth, organic matter sinking to the bottom, phytoplankton etc. More biomass and more biodiversity. However, the lake become dirty, smelly and ugly.

[herpguy]

Alpine lakes are generally very simple, with little life. They are, however, clean, and utterly gorgeous. If someone allows new nutrients to enter, you get a lot more weed growth, organic matter sinking to the bottom, phytoplankton etc. More biomass and more biodiversity. However, the lake become dirty, smelly and ugly.

Would the dirt, smelly, and ugly lake do anything to cause ecological simplification?

 

(Forgive me if I don't know what I'm talking about)

[SkepticLance]

herpguy,

A typical alpine lake might, despite its beauty, be described as a biological desert. There is usually little life, and only so much diversity. When such a lake is polluted with nutrients, the amount of life increases dramatically. If you count microscopic life, the diversity of life in such a lake also increases. I do not think this could be called simplification.

 

However, it is still a form of pollution, and still results in a drastic ecological change for the lake. I just do not think that the definitions given so far would encompass this change as ecological damage.

[herpguy]

herpguy' date='

A typical alpine lake might, despite its beauty, be described as a biological desert. There is usually little life, and only so much diversity. When such a lake is polluted with nutrients, the amount of life increases dramatically. If you count microscopic life, the diversity of life in such a lake also increases. I do not think this could be called simplification.

 

However, it is still a form of pollution, and still results in a drastic ecological change for the lake. I just do not think that the definitions given so far would encompass this change as ecological damage.[/quote']

Oh, I see. That's kind of like what's happening to the great lakes. An increase in phosphorus causes the algae to bloom in extreme amounts. But the algae kills off a lot of plants and animals.

 

Before I try to suggest something new, can someone please point me out to something that explains ecological simplification clearly? Thanks.

[CharonY]

Ugh you made me trying to remember stuff from my student days.

In general ecological simplification means a reduction of function, complexity and structure of a system.

 

- Reduction of function is the case if certain ecological processes/flows are disrupted. Examples might be carbon or nitrogen cycles. The nitrogen cycle for instance can be disrupted if for instance there is a significant loss of ammonifier/denitrifiers or for instance nitrogen fixers. Or plants using immobilised nitrogen and so forth. This is often coupled with

 

-reduction of the complexity of the system, meaning the loss of elements (usually species) in an eco system. Every species plays a specific role in a given ecosystem and as such a loff of them reduces both, complexity and function of a system. Finally there is

 

-reduction of the structure of a system. A higher structural complexity is characterized by higher diversity and variations of habitats in a given system.

[Chupacabra]

I would suggest using measures of entropy and information content. E. g., microbal species are much simpler than mammals or birds. Then, if the amount of bacteria species increased at the cost of the decline in mammal species, the ecosystem has been degraded. Also it has degraded when the rare or endangered species are replaced by common ones (e. g., rare birds by rats).

[SkepticLance]

Chupacabra.

These are good ideas.

Any idea how to quantify them?

[Chupacabra]

Chupacabra.

These are good ideas.

Any idea how to quantify them?

 

The could be different measures of "value" and "uniqueness". The reverse of the overall count of individuals in a species could be one such measure: we value rare species more than common ones. We can assign every species a "weight" and then quantify an ecosystem composition before and after a change. Again, the length of DNA chain and the amount of unique genetical properties and treats in a species could be measures of its "value".

 

Yet, any such measure would inevitably be more or less subjective. Any ecosystem is rated high if it is beautiful and healthy for humans.